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View Full Version : Round #2, Rack Driven second model.. (or Mil's working jigsaw puzzle)



milhead
04-02-2007, 02:49 PM
Well the first machine gave me such joy.. Since I've been cutting with it I was bouncing ideas off myself for the shape of a second...
With too many hours playing around eBay I found myself the proud owner of a longish 44" Thompson linear slide table and 4 48" gear racks.. Both I did not expect to win but that's eBay for ya.
So, the design is a rack driven X and Y gantry but unlike my first machine, the gantry will move forward and back instead of left to right. I have a tiny garage and want the parked gantry to expose the spoil board as a work surface.
Much of the gantry mechanism design is inspired by the Aussie router guys that have built an excellent looking machine out of aluminum.. I'm trying to mimic much of that stuff in baltic birch and a few aluminum parts.

While I don't have the design all worked out yet, Here is what I've got in the ready box...

1 44" Thompson slide Table (My Y-axis, another eBay score)
4 48" Martin Gear Racks, with pinion gears (eBay is a great place, 1 extra)
2 48" 1-1/4 stainless steel rods to be used for the gantry bearing (donated by a buddy)
4 Thompson open linear bearings to fit the stainless rods (a $50 eBay Score!)
2 sheets 1/2 baltic birch
20 3/8-7/8 ball bearings.
1 new (second) 4-axis HobbyCNC kit (2 X axis motors, 1 Z-axis motor...
1 NEMA34 450oz motor (for the Y axis)
1 PorterCable 7518 router (cheeper refurbished from a vendor than from eBay)
Couple belts and pullys (These things are harder to figure out than I thought)
loads of wire and cable
loads of leftover screws and bolts

Obvously, I'm branching off my cheep at all costs guideline that I followed for my
first machine ("What am I going to make is the Popular Question..") But I'm
still trying to keep costs down..

I'm hoping to have as much fun building the second as I did the first one..

Anyway.. Attached are some drawings and the first cuts on the machine (Having a CNC to cut out parts is so nice!)

Miller

milhead
04-10-2007, 04:16 PM
Over the weekend I got to spend some time working on the unit.. I put the y-z slide big parts together... and started on the Y-axis pully supports..

I need to make some sort of stand for the y-axis until I get it put together. As long as I keep it smallish I can stay in the living room

milhead
05-04-2007, 04:28 PM
Well, It's been a busy couple weeks doing everything 'but' my CNC machine but I knew summer would be that way...

I've got most of the Z-Axis complete and need only mount the limit switches and motor before it's done.. Now I'm starting to figure how to build the gantry and Y-Drive that will all ride on the carriage (rack design)...

My next step is to put the gantry crossbar together, I'm planning a built up box structure made from the same 1/2 ply that I've made everything else.. Then I can mount the Y-Drive rack to the top of it

If you're good with visulation you can imagagine from the photos that the box gantry is about 3" deep...

I apoligize for the headlight strap holding this all together.. I've not mounted much yet... Pardon the wires as well...

Mil

rustamd
05-07-2007, 09:02 PM
Machine is starting to look good.

What kind of gear reduction are you going to be getting from those timing pulleys/belts?

Greolt
05-07-2007, 11:17 PM
Looking good Miller. :)

I like how you have kept the Z axis nice and compact. How are you going to drive it?

That slide for Y axis will need to be supported well. To make it torsionally stiff.

Keep the pics coming.

Greg

milhead
05-08-2007, 04:22 PM
For the Gantry motion I have 6:1 reduciton and am planning on using my 300Oz HobbyCNC motors (one on each side).. I'm pretty confident that that should work ok. The rack gears travel about 2 inches for a single rotation.

My main concern is the Y-Axis setup with a single motor (even though I upsized to a 450oz motor) that I'm starting with a 3:1 reduction... The combination of the big PorterCable motor and Z-Azis (along with the Y-Drive parts) is going to be a larger appratus than my old machines gantry... I may have to up the motor if I can't get a nice combination of ramp and cutting torque in the Y direction.

Down in the bowels of the Z-Axis is a older but nice ballscrew I picked up on eBay with no balls... After a bit of expirimenting I found a nice fit and it's possibly the highlight of the system so far. I have the Z-axis motor monted now and it's looking pretty complete, I'll get some more photos this weekend.

I am concerned about the possibility of torsional deflection I could see on such a long gantry (48") The aluminum rail between the two bearings is very rigid but the two rails are closer than I would like together. If it turns out to be a problem I will add a bar above the gantry and mount a third rail on it.

So far everything seems to fit very tightly and there is minimal play.. There is certanly none of the systamatic flex under load that my whole last router had....

We'll see what the weekend holds, I need to get the gantry (Or at least the first cut at it) put together before I know how things are going to run.

Mil

milhead
05-09-2007, 02:09 AM
Had to cut another peice of HDPE but got the Z-Axis motor mounted...

milhead
05-10-2007, 03:33 PM
I got the box for the gantry put together.. I'm hoping that this structure combined with the aluminum channel holding the rails will give me enough rigidity.. Mostly I'm woried about rotational bending deformation, I really cant see the the thing flexing a whole lot on the Z or X axis, It's pretty stout.

Greolt
05-10-2007, 05:27 PM
That certainly looks stout! :)

Can you show a pic of the cross section of the rail that bolts to this?

I am interested in the mounting surface between the rail amd the ply.

If I am seeing your earlier pics right, I'm thinking you might want a strip of metal between the two.

Greg

milhead
05-11-2007, 12:35 PM
Hi Greg...

The photo below shows the cross section.. The main reason I included the two internal ribs in the gantry was to support the pressure of the aluminum channel that supports the rails.. The bolts all fit down the 3/8" gap in the middle of the beam. On the back I considered (am still am considering) a strip of steel or aluminum to support the nuts but for now it's just washers... Since I have 11 bolts holding the rail in place, I'm hoping that I don't need to torque too tightly on any single bolt.

My task this weekend is to find a good way to mount the Y-axis transmission thing to the carriage.. It's big and odd shaped but not shown in the photos below, you'll have to scroll up a bit to see it. These photos
show the rack I'll be using for the y-axis drive....

I've also not started yet on the X axis slides and base because I'll get relegated to the garage for sure as the thing starts to occupy it's final footprint.... Since two axis are controlled solely by the motors on the carriage I'm going to get the carriage working fully begore I start the base and real gantry supports..

(What you see in the photos are just some 2x4 feet I put on it so that it quits tipping over.. Complete with furnature protecting felt pads so I can stop scratching our project table). The hight of the gantry off the table is a little higher than I expect it to be off the machining surface in the final I'm not planning on cutting anything more than 3-4 inches high...

Making one of the solid body projects that I have seen looks like a great way to burn more time and bits after I complete this machine..

Mil

Greolt
05-13-2007, 03:47 AM
What!!!!!!! you're allowed to do this on the kitchen table!!!!! :eek: You must have one very tolerant partner.:)

I see in the pics in the previous post that the mating surface on the back of the rail to the ply is wider than I had thought. Should be fine.

Looking good. Keep it up.

Greg

milhead
05-16-2007, 02:56 AM
Well, I have to admit that I have a very cute!, Very tolerant gal that allows me to build part of this on the project table.. But it's a 6x10 foot table and I still only consume half of it... (most of the time)

I got the gear rack mounted and the transmission mounted as well.. I used 3/8 bar stock to clamp the wood to the aluminum rails, We'll see how it works.. Al,l I have left to do is get a spring that will lightly hold the pinion gear into the rack. I intentionally put the hinging axis in line with the gear so there should be as little pressure on the spring as possible.

I had some dialog with the company that made the gears and they were concerned about pressing the gears together to acheive the 0 backlash.. As a result I'm trying to keep all of the forces on the gear in the same axis as the rack. I think a little graphite or perhaps some grease but I'm concerned that it would attract cuttings and dust... It's still a long way from the cutter and faced the other way (a geometry credit goes to the Ausse rack guys).

Below shows the assembly (Without the router mount plate) from all 4 sides to try to convey the jigsaw puzzle nature of the assembly but It is all very tight and has no noticible play. The spring will replace the bungee that I have in place at the momemt.

I think I will take some time to build the electronics for this router, perhaps I can get a moving Y and Z in a video or somthing...

Mil

Greolt
05-16-2007, 03:18 AM
Well, I have to admit that I have a very cute!, Very tolerant gal ........................

Well you tell her that I said that you should treat her well and be nice to her.

The really good ones don't come along all that often and you should hang on to her.

Now go give her a hug and tell her how special she is.

End of sermon from Grandpa Greg. :)

milhead
05-16-2007, 04:02 PM
I'll be sure to pass your message along.

milhead
05-21-2007, 02:47 PM
Spent Saturday night building my controller kit from HobbyCNC, The new kit generates far less noise in the motors.

I bought 3 non-working 38V 15A ASTEC supplies on eBay and was able to swap AC and DC components until I was able to get a working supply.. Now I have a microwave transformer to get rid of and all the other parts for a unregulated supply like I used in my first project.

http://www.youtube.com/watch?v=zqVuDStjzlk

Here is a short video of the motors turning.. Not very exciting but kinda cool, When I get the Z and Y axis wired up I'll see if I can video some rapids.

In the video, The two left motors are going to run on either side of the gantry. The other 23 motor will run the Z axis, The larger 34 motor will be used to drive the Y azis...

I'm still a bit nervous about the weight of the thing but have seen lots of other folks trade mass for rigidity and am unfortunatly making that trade as well.

Miller

milhead
05-22-2007, 01:29 AM
Well, I got the motors mounted and can now rapid in the Y-axis at 900ipm.. (Yow!).... Quite a ways above what I was shooting for.... It actually went quite a bit faster and started to stall at 1200.. I got scared and set it back to 900 in Mach...

Take a look at the Video...
http://www.youtube.com/watch?v=LQ0WbGnQsO8

The z-axis ball screw is really noisy but has no detectable play.. Comes with low-balling on ebay I guess...

My biggest concern is the torque that I can generate from the Y axis at low speeds. Since the motor that I bought has a 1/2" shaft I was only able to get a gear raito of about 3:1 for the Y drive... Each pinion rotation is a little over 2" so my resolution is about 0.002 per step. When I started this router I was shooting for a 5:1 or 6:1 ratio....

For the gantry motion, I will have a 5.5:1 and two 300oz motors pushing so I'm not too concerned.

To test the cutting force torque I tried to stop the carriage on a 15ipm move and the whole gantry (which I weighed at 70lbs with the router installed) started sliding across the table.. It almost headed for the floor so I decided I'd wait until I can cut somthing to see how it does.. For now I seem to have acceptable resolution and more torque than I need....

Next steps are limit switches and some sort of acryclic plenum for the vacuum system... Again, once I start moving the gantry, I'll probably need to move the whole kaboodle to the garage...

Miller

Greolt
05-22-2007, 03:42 AM
Yeah that's pretty quick Miller.

Gets to the other end in a hurry Hey. :)

What kernal speed are you running Mach at?

Greg

milhead
05-22-2007, 01:52 PM
Mach is running in the slow speed on my 1.6Ghz laptop... Be WARNED! I do not use this setup to cut.. My laptop caused me several unfortunate dives of a spinning bit into my nearly complete workpeices before I converted and dedicated an old PC to running Mach solo in the garage. The laptop is so polluted with software that sometimes notepad has a hard time running..

In fact the high speed is not do to any great speed of Mach but due to thelack of reduction reduction that I'm using on the Y axis.. Currently 72:25, since the pitch diameter of the pinion gear is .750.. Add pi and some other calculations my Y axis is way overgeared at 433 Mach Pulses per inch... That gives me a theoritical (sp) best resolution of a little under 0.002...

For reference with single stepping my last machine was using direct drive 10TPI acme threaded rod.. In Mach that translated to 2000 pulses per inch or a best resolution of 0.0005"... (Mind you this is lost in the backlash and flex of my machine #1)..

I wanted a possible resolution of 0.001 or better so I'm seeking a drive pulley in the 10-15 tooth range that will fit on my Y-azis motor 0.5" shaft...

I'll loose my 900ipm rapid (sad face) but 450 or so will still appease my impatience enough if I can actually get the accuracy of the machine within a few (hopefully less than 10) thousandths...

Miller

milhead
06-01-2007, 12:58 PM
Well I'm short on photos but am currently cutting the mounts for the main X linear bearings..
I've completed my final design of the gantry drive and again have about a bizillion parts that I have to cut out and fit together.. Jigsaw Indeed.

Below are the side and front drawings of the gantry drive, I'm not 3D software savy so you have to visulize quite a bit....

Mil

Greolt
06-01-2007, 09:19 PM
Looks good Mill.

Don't forget to tie the two plates solidly together.

Show us some pics when you have them cut.

Greg

milhead
06-03-2007, 12:41 AM
I finnished cutting the mounts for my linear bearings.. attached are the photos of the fresh cut mess and a shot showing how the plastic will retain the linear bearings.
You have to look at the drawings above but I'm planning on running some bolts through the blastic to add some rigidity, hopefully it will not flex enough so the bearings will spin..

Mil

milhead
06-13-2007, 02:25 AM
Well, A few softball tournaments (for my kid) have stolen time from this recient obsession but this week I was able to cut the parts to suspend and slide the gantry.

You have to use some imagination to fit the peices below together but so far things are going together nicely.

I'm concerned about flex from the plastic bearing mounts but can trade them out for some delrin mounts or perhaps aluminum if I really get into a pinch.

The biggest downside with this design compared to my last is the sheer number of parts, and with each one I need to find a way to attach them together.. Often I wonder if it's going to shake like a dog cage once I assemble it.

My next task is to drill and tap the rods that the bearings will ride on.. That should be interesting.

Mil

zoltan
06-13-2007, 05:46 AM
Hi MIl,

Do you have a full set of drawings of the new machine? I would be interested as your solutions look great.

Thank you,

Zoltan

milhead
06-13-2007, 11:54 AM
Hi Zoltan;

I'm slightly embarrased to say that I have most of the work in a TurboCad but I'd put forth that it's not a 'full set of drawings'... More like a workspace..

All of the parts except the large gantry beam are in it, I made the gantry on the table saw and router table. I will update the drawings..

The bearing mount drawing is correct but I modified the toolpath to duplicate the parts and added the path for the keyhole cutter that cuts the actual bearing seat. If your interested I can post the g-code for that as well.

In retrospect the X-slide design could be far more simple if I'd used some commercial slides but a friend gave me the two 1.25 stainless rods so I'm going out of my way to use them.

The attached zip has a my giant .dxf file in it.. The image is just a screen shot of the single page of the drawing. It's not very organized but has all the correct dimensions.

Mil

milhead
01-02-2008, 08:23 PM
Hi Folks, I'm now in a new house, new garage, Soccer season is nearly past, Another soccer-softball gap is coming up soon and I'm going to dust off this second router and get it complete.. I'd like to join the ranks of the folks who can cut out a guitar and neck and the first machine just ain't big enough.

I'll post some photos soon but have switched to a set of commercial rails that will make moving the gantry require fewer moving parts, I just could not get the UHDPE mounts to properly secure the open bearings. Since the thing is nearly 4' square rigidity is my #1 design concern. I have to make all kinds of allounces on my first machine to battle the flex in the gantry.

Somehow I'm left with less room in the new 2-car garage than I had in the old apt garage (I've not figured that one out yet)..

Mil

biotech1
01-03-2008, 01:07 AM
:cheers: Looking good so far I am also kinda interested in plans for this machine...



Pat...:rainfro:

milhead
01-07-2008, 01:43 PM
:cheers: Looking good so far I am also kinda interested in plans for this machine...

Pat...:rainfro:

Hi Pat;

Like I said a few months ago.. I have a big Turbocad drawing that I use more as a workspace than as formal drawings.. I'm attaching a largish
DXF file which is my whole workspace.. The 18x26 squares that contain
all the cutout parts are the size of my #1 machine bed so I toss parts
into those squares before I generate toolpaths with vcarve

I've clipped out the old rail stuff and now have the new x-rails in the
drawing.. I have some photos of the transmission and mountings that I'm making but don't have them posted yet.

I'm also guilty of building the machine with the Z-Axis first then designing Y and X respectively. It seems that this way I can get bigger as I go on and the problems are easier solved. (Just my experience, I'm not suggesting that this is any proper sort of method)

The other lesson (learned from Joe, Thanks Joe!) is that this router uses much more baltic birch than MDF. I like working with it much more and I think it will remain a bit more solid in the ling run. It allows a lot lighter design as well.. I think my Gantry is now in the 50-60 pound arena when I add the big router.

The second image is a breakdown of the new trans (Red) and gantry mount (blue) that I'm working on now...

Mil

biotech1
01-07-2008, 08:44 PM
I would like to use the rack & pinion setup. To make a 4'x4' or a 4'x8' table..

milhead
01-08-2008, 10:38 AM
I would like to use the rack & pinion setup. To make a 4'x4' or a 4'x8' table..

I'm pretty happy with my Y axis which is my first R&P endevor.. I did have some email discussions with an engineer from the company that makes the gears and he was concerned with my application. I wanted to find the force that I should use to press the pinion into the rack with in order to minimize backlash and maximize gear life. He replied that the gears are not intended to provide zero backlash, and If I needed it I should use two pinion gears slightly offset in order to reduce it.

Needless to say I'm not going to listen to him and have a spring assembly that holds the pinion gear pressed into the rack. My design tries to keep a hinge on the same plane as the rack so that drive forces are as close to 90 degrees to the pinion-to-rack force.. I'll probably use a graphite lubricant to keep things happy but it's not a full time machine.. I seriously doubt that I'll wear my gears out. The biggest concern that he voiced was that the pinion may bind in the rack.

After I get a working X axis put together I'll get to play with it more. I also would be interested to hear if anyone else using a R&P setup as really followed the application papers for their gears.

Mil

milhead
01-08-2008, 12:00 PM
Started putting one of my transmission boxes together this weekend while the Portland winter drained outside.. The belt setup below gives me a 6:1 reduction off the stepper motor.

Since the pitch diameter of the Pinion gear is 0.75, I get close to 2.36 inches per rotation...

180steps/rotation * 1 rotation/2.36 inch * 6

Gives 450 steps / inch or 1 Step / 0.002 inches...

Running the motor at 500RPM will get me a rapid of 200 IPM...

It's where I'm starting at....


Like my lathe below? And the new cramped workspace?

Mil

milhead
08-04-2008, 04:11 PM
Well, I've had very little time to work on the second machine but am creeping forward at a snail's pace... I figure if I really had a schedule it would just be another job right?
Anyway I got the two x-axis slides put together with a little mini y-axis, I'm going to use this configuration until I get the drive complete to save space. The drive mechanism will be quite complex (More than I originally thought) but I think I've gotten past all the issues.
Anyway, below is the mini-y version.. (I call it my x-axis testbed.).. Hopefully with winter coming my free weekend time will pick up.

milhead
01-05-2009, 05:04 PM
My fiance has been loading the gift-sign for Christmas queue so much that no #2 CNC machine work has been happening... We'll see how 2009 goes... My signmaking skills have increased significantly..

milhead
01-12-2009, 02:35 PM
I have some rather severe space issues while building the second machine.. Boy I'd love the big spaces that I see in some of the photos!
Anyway, I'm using a mini-gantry to build my y-axis so that I can fit in my garage while building... I do have a reserved space for the full machine but it's covered by all the parts and lots of junk!..

The drawing below is how I'm going to rest the gantry-drive assembly on the base. I tried making the wood interior supports for the channel aluminum last night but die to drawing error (love these) was 0.04 off and the whole thing would have been out of kilter... I get to do it again tonight.

I'm hoping that by tucking the rack up under the channel I'm going to be less effected by chip-fodder causing me issues.

Mil

Added the photos of the rail; supports showing how the Y-axis (front-back) direction Drive fits together... It's kinda just setting there now, I need to bolt it all together..

harryn
01-14-2009, 11:14 AM
I have major space constraint problems as well. That is what is driving me toward making the Y axis vertical. Now, I just hope it will work out in the end.

http://cnczone.com/forums/showthread.php?t=38940

milhead
01-14-2009, 11:55 AM
In this design I have several belts that will run between shafts on bearings.. The bearings I'm using have an inner diameter of 0.373 or 0.374 as best as I can measure with my inexpensive caliper.

My 3/8 drill rod that I want to use for shafting is too big to easily get the
bearings on without some kind of press or a lot of pounding. I'm really worried about too much banging as I don't want to bend any of the shafts.

My current solution is to sit with the shaft in a drill and run emery cloth over it until the bearings can be knocked on with light tapping.

Question: For a bearing/shaft around 3/8in does anybody know off the top of their head what are the dimensions that would give me a loose/tight fit of the bearing on the rod?..

I sanded two down for the z-axis drive but need 4 (or six if I need to install a reduction stage) for the y-axis.

I don't have ready access to a machine shop.

Miller

harryn
01-14-2009, 01:04 PM
Hi Milhead. The bearing / shaft interface is an interesting area that I am also trying to really understand. You can see my attempts at figuring it out by looking at all of the bearings and shafts I am finding and posting in my thread.

You would think that in an engineering program, they would have offered the very useful class on "how to pick a bearing", but didn't, or at least I skipped it.

In my particular case, I am mostly looking at 1/2 in, but the concept is still similar. As far as I can tell, drill rod can be +/- a fraction over the spec size. Shafting rod tends to be +0 / - a little. Then of course, there is the whole metric vs inch shaft and bearing aspect, some of which are quite close in size.

McMaster, Applied.com (former Bearings, Inc), timken's web site, and sdk have been my sources of info so far.

It looks like slightly heating the bearings or freezing the shaft prior to mounting is a "common method". Freezing the shaft makes it just small enough to slide in, then when warmed back up, it is like a press fit. This of course makes it interesting if you need to remove them of make minor "adjustments".

BTW - I used one of the on-line deflection calculators to get a feel for deflection on various shaft diameters. If you are working with 3/8 in, keep it real short and low loads. Even for 1/2 inch, I plan to keep the length of unsupported shaft under 12 inches with a beaing on each end.

milhead
01-14-2009, 02:44 PM
Thanks Harry..

The bearings are pressed into a HDPE casing, then pressed into an opening in the wood. after I get several of these pushed together (max 4 bearings on a shaft) It get's tough to push the internal bearings... On the other hand I don't want any play as it will directly turn into play in the x and y axis..

Fortunatly, Most of my shafts are below 4in.. But will take some pretty
healthy bending loads.

harryn
01-14-2009, 04:25 PM
That's always the trick, isn't it. The shaft is never just a shaft and bearings, and the bearings placement is almost always important. The pinion pretty much dictates your shaft size so you just have to work around that.

I have toyed with the idea of using plain bearings.

Perhaps if you post the bearing part number, we can get some more info on the specs of the inner race and insight on shaft specs from someone that actually knows what they are talking about vs my wild guessing.

milhead
03-03-2009, 11:16 PM
So leveraging from what several folks have done here, The following is what I came up with... I haven't installed it yet but I'm feeling pretty good about it.

Mind you this is for my first machine... Not the rack driven model.

Mil

milhead
03-08-2009, 03:27 PM
Cut out and cleaned up all the parts for the gantry drives.. No wonder that I've been putting it off... Hopefully next photo will be the completed drive units..

milhead
03-10-2009, 12:22 PM
Completed the glue parts for the gantry drive systems... The center
part will hinge so that a spring can keep the rack and pinion gears
meshed all the time...

harryn
03-10-2009, 02:16 PM
Wow - lots of parts and building going on.

milhead
03-11-2009, 02:50 AM
It's taken almost a full audio book of assembly but the gantry drive mechanical is nearly complete... The once pile of parts is now largely two moving parts in a larger frame...

Below I'm holding the drive units on the mini-gantry assembly and am hopefully a few hours away from trying to move the thing via motors!!

The mini-gantry assy is also getting pretty heavy...

milhead
03-31-2009, 04:42 PM
Bought a working computer off Ebay to drive the whole thing... Then spent a couple days putting the controller together...
These photos show the computer and big supply for the drive electronics... I need to build a shelf for the CNC electronics and install the front panel controls.

nlancaster
04-01-2009, 07:37 PM
Good looking work.

You have a PM.

milhead
08-12-2009, 12:28 PM
It's amazing how many weekends I have spent on Soccer and Softball fields where I would have been much happier with a drink in hand tinkering in the garage... Well.. Son quit playing soccer at U17 after winning a lesser state championship (coincidently I retired as head soccer coach).. We just returned from a week in Oklahoma where my daughters softball team played their last games at the 18 Gold National Championship and lost every game but had a blast!.... (seems that it's time to quit coaching kids softball as well!)

But the machine is patient knowing that I will come back eventually...

I don't have any photos but traveled down a rather large rat-hole when I discovered that in my original drawings I calculated clearances using a Baltic birch thickness of 0.5in... Oops I don't know offhand how much but it's substantially thinner than that. In my design I have a couple spots where I stack and glue several pieces of the birch together...

Well it turns that I'm almost 0.1 short for clearance for my x-axis drive pulleys and my little HDPE bearing holders intentionally invade a shade into the same space to keep the pulleys from rubbing the walls.

To combat the problem I need about a 0.08 wood spacer that I can glue into the stacks so that I have room....

After layering enough veneer by hand on one side I thought.. "Woulden't it just be easier to fly-cut a peice of wood to the right thickness so that I could save 7-8 layers of veneer that took alot of labor to get right..."

Hmmm, how would I hold such a thing...

After several attempts to flycut masonite to the right thickness I decided that using clamps to hold it was impractical because as soon as the material got thin It would flex and give me a very wavy non regular thickness...

With all the time I spent, I should have just started layering veneer again (sigh) but this was more fun. I have probably one of the rare machines with a 0.8in rosewood spacer sandwiched in the woodwork.

I went down a second rat-hole/rat-hole when I decided that I would use a vacuum hold down for the piece that would keep the thing more consistent.. Needless to say that I encountered a new rash of failures...

My next attempt will be just to tack my piece of wood to be cut thin to a larger piece of wood to hold it and fly cut the whole thing.

Fingers Crossed!

Anyway, Now that coaching is a thing of the past, (at least until grand-kids).. I should make some more progress.

Happy Cutting!

Mil

milhead
08-17-2009, 10:57 AM
Will with a couple hours Sunday I got the gearboxes (beltboxes) put together and bolted onto the faux-gantry. In the photos remember the I'm replacing the little 11 inch gantry with the full fifty-odd inch one before I can put it to work.. So I'm still working on the low real estate x axis testbed. Also missing int he photos are the two main bolts that will go all the way through both gearboxes and the length of the gantry. I think these will be 5/16 threaded rod.

There will also be an adjustable tension spring mechanism replacing the two clamps. The tab on the front of the gearboxes is where I want to mount the springs.

Being my first belt driven project I'm still unsure how tight the belts need to be.. (are there any guidelines?). I worry that If I tighten the belts too much it will 1) reduce motor life and 2) cause additional load on the motor. Too loose and it turns directly into axis play.

I also have to come up with a spacer or some sort of wedge or jack-screw to adjust the motors if I want to tighten them off the stops. I don't trust the bolts-in-wood to keep the motor from slipping. The room for adjustment was an afterthought when I first put together a fixed version of the gearbox and think that there is a little play in the belt. I calculated the distance using a manufacturers specification but it seems loose.

I am still a bit concerned that the reduction of the x-axis is not enough for fine-grain resolution. I have it will be but my primary goal with this gantry is to remove the flex that my first design has. If needed I have room in the gearbox for some sort of reduction gear in the middle. Proper belt lengths for that are another reason that I made the motor mounts adjustable. Currently I'm calculating 0.002" per step on the motor which sounds high to me.. (Any opinions here would be greatly appreciated).. Can micro stepping be counted on for position or is it mostly a ramping and smoothness knob???? I could rebuild the gearboxes to put a belt reduction of 2:1 or 3:1 inside them.

Anyway the photos below show the assembly of the gearboxes (again) but hopefully this time they will not come apart until I'm doing my final assembly.

Mil

milhead
08-19-2009, 11:19 AM
I added the springs to the gear boxes last night and ran the two long 3/8 thread-all through the gantry.. The gearboxes are now complete... The thing seems rock solid compared to my #1 design.

I have a computer and am setting up linux(heron) and EMC2 just because I prefer linux to windows.. I have a windows license for the box but am actively trying to move all but my main PC to linux. I'm hoping that I can get as comfortable with EMC2 as I am with Mach. If not I can always pay the second license fee and move back.

If I can get the controller setup, I'll try some moves of the faux-gantry.. I'm really curious what kind of movement I can get out of it. It's small by the standards of many of the machines in the logs here but it seems colossal to me. When I get it moving I'll post some video links.

I really don't want to have to increase the size of the gantry motors as I'll have to overdrive or replace my HobbyCNC controller.

My contengency plan here is to find some NEMA-23 replacements in the 400+ oz-in... I'll also change to Gecko-Vampire drivers as well since I have toasted controllers with an open circuit. Otherwise I'll have to redesign-recut-rebuild the gearboxes (ick)..

The Y-Axis was happily moving rapids at up to 900ipm (see my old videos on page 2).. My cutting goal remains around 100-150 ipm.

Old Video Link, don't expect anything new here.
YouTube - CNC #2, Gantry Motion

Mil

ger21
08-19-2009, 11:24 AM
For hobby use, you can run two machines with 1 Mach3 license.

milhead
08-19-2009, 11:34 AM
Cool, I did not know that...

(Again convicted of not reading manuals)...

Mil

harryn
08-19-2009, 02:46 PM
Hi Mil - nice work.

You mentioned a lot of work to deal with a small thickenss offset - something like 0.1 inch IIRC. I would probably just use brass shim stock. Most hardware stores sell precision brass stock and it can be bonded pretty well to the wood. Very handy stuff.

Movement of 0.002 in / step - that is actually pretty good if you ask me. I assume you mean that 200 steps per rotation = 200 x 0.002 inch - right? Depending on your view, you could go down to perhaps 10 microsteps to get smaller steps, but you will loose some torque doing that.

Keep in mind - you are routing wood, not milling steel. This is often a tough one for me for my build. My goal is for the machine to be 5 - 10 x more consistent than I am by hand. As it turns out, that isn't too hard, and my goal can easily be met with +/- 0.025 inch. (not exactly world class work, is it?)

One of the challenges that come from R+P and belt drives vs screw drives is that the motor is holding more of the torque vs the screw thread holding the torque. In many stepper drivers, they tend to turn down the current when the motor is at idle to reduce heating. This is fine for screw drives, but I think it is not so ideal for us belt / R+P users, so consider to turn this off, and watch for motor heating in the process. The wood stepper mounts are fine, but the stepper motor designers assume that the heat will come out through that mount - some Al might be needed - or a fan.

I cannot remember which belt you are using to recommend a tension, but brecoflex has a catalog that discusses tension settings. It will show up in backlash, so you sort of adjust tension to reach a desired backlash point.

milhead
08-19-2009, 03:08 PM
Hi Mil - nice work.

You mentioned a lot of work to deal with a small thickenss offset - something like 0.1 inch IIRC. I would probably just use brass shim stock. Most hardware stores sell precision brass stock and it can be bonded pretty well to the wood. Very handy stuff.



In a storm of simplification I just tacked a piece of masonite to a big flat board with my trusty 77 adheasive, thinned and cut out my shapes then popped them off with a scraper. Somewhere in the photos you can see the one I made out of the rosewood veneer buildup, I don't know why I got so complicated.. (sigh)...

Hopefully the holding torque won't be too bad. One of the downsides with the massive rails I have (but I got a good deal) is that they are fairly difficult to move compared to my X axis and even my gas-pipe/skateboard-bearing setup in Machine #1. I've not played with the issue yet and am waiting to see if my 300oz motors can even get the thing moving... I would have preferred a further reduction in motor:pinion ratio if only to give me a warm fuzzy here.

Thanks for the other information! Hopefully I'll be able to put it to the test soon.

Mil

milhead
08-22-2009, 02:16 AM
When I had the Y and Z axis moving on the gantry. I pretty much had a breadboard controller built up on the counter.

Before I get the X axis coing I'm going to have my controller put together.

Right now It's a dual boot Linux Windows machine. I'm going to try to get Mach and EMC running. Mach because I'm already very familiar with it and EMC because I'm a Linux fan!..

The computer I'm using (a bludgeoned HP dc5000) did nto report so favorably with the EMC latency test. The jury is still out but I'm not planning on replacing the computer.. We'll have to see on that one.

Anyway, I'm writing this post on the controller, all seems to be workign well so far.

This weekend I get to add wires, fans and some eStop circuitry.

Below are the photos of the very cramped controller box while being built.

I have also added the adjustable springs and large gantry bolts.

We'll see if I can get X axis motion by the end of the weekend.

Mil

milhead
08-24-2009, 02:05 AM
Well, I spent the time today to make cables for the controller. Making the short parallel cable and long USB, Power, Audio, and LED's pretty much consumed my day.

At the end I tossed a spare stepper on the X-Axis and after configuring the ports in Mach was able to turn servos fine.

I'm going to try my motion tests before I get all the eStop, Vacuum and Spindle electronics installed. I have a little circuit board ready for that stuff but have a couple other projects that need to get done first.

Hopefully tomorrow night I'll move the whole thing to the garage and try moving the gantry.. Fingers crossed.

In fact, the only time that I have had to back up is when I installed a 5 volt supply in the cabinet that I did not need, the HobbyCNC controller supplies enough 5-volts to run the relays and E-Stop circuits.

I do need to pull everything back out in order to cut-out and install the fans.. I'm planning on at least two blowing in (with a filter) and another blowing out. Hopefully keeping the box under positive pressure will keep the fans from sucking in dust from the garage.

Mil

harryn
08-24-2009, 08:16 PM
I have had mixed success with fans and filters. Perhaps consider instead to use a small "blower". You can get them from Newark and others in various sizes.

Blowers provide not only velocity, but also a little bit of pressure to overcome pressure drop through filters and distance. That is why the "fan" in your furnace is not really a fan, but actually a centrifugal blower.

milhead
08-25-2009, 11:25 AM
I have had mixed success with fans and filters. Perhaps consider instead to use a small "blower". You can get them from Newark and others in various sizes.

Blowers provide not only velocity, but also a little bit of pressure to overcome pressure drop through filters and distance. That is why the "fan" in your furnace is not really a fan, but actually a centrifugal blower.

That's probably a good idea but since I've been building these CNC machines I acquire scrap fans whenever I see them.. I've got lots. If the temp goes up in the box I will have room under it to switch from a fan to a small cage blower if I mount it external to the box. It would probably be more quiet too but any will be lost in the noise of the vacuum and router when the thing is turned on.

The inside is getting pretty crowded and I need to leave room for two gecko drives if the HobbyCNC/300oz pair cannot drive the gantry to my satisfaction.

Current plan is to have a pretty powerful 120mm AC fan and two 24V Fans that are going to be connected to the Controller power switch. Also, the PC case fan will connect to the Computer power. I can crank up the speed on the PC fan via the BIOS if I need a little extra push. The PC Case Fan and the AC fan will blow in the bottom of the case through the filters with the two smaller 24 volt fans venting at the top. The goal is that all the heat will travel up and out.

It will be pretty easy to replace the AC fan with a blower if the fan does not work. I figured I would just increase the filtered airflow until the interior of the case stays moderately warm.

Does anyone know what steady-state internal case temperature is recommended/desired? I believe computers run pretty comfortably in the 120 degree range. Since I have a lot of power hungry electronics of packed into this little case it is definite concern.

My other thermal concern is getting heat out of the motors. As somebody pointed out, since all my motors are mounted to a nice wood insulator there is not a lot of heat flow leaving the motors. I do have a stack of large-ish heat sinks that I was going to bond to two sides of each motor to try to get some heat out. Do any Motor-savvy readers have opinions about doing this? Should I sand the paint off the motor before slathering with conductive goo and applying the heat sinks? The heat sinks I have are almost 2 inches square with about 1 inch slotted fins, I have no idea how to calculate the heat flow stuff so I'm looking for 'rules of thumb'

Does anybody actively cool steppers like they do spindles? Water or what-not

Mil

ger21
08-25-2009, 11:31 AM
I've seen people mount fans to blow air over their steppers. I think I may have seen a heatsink too, but can't remember where.

milhead
08-26-2009, 05:52 AM
Well... Watch the Video!

I got the thing moving at last... Notice two full years after my last video which showed the X and Z axis.

YouTube - CNC2 GantryDrive2

The rapids are at 700ipm then you get to see the Y portion of cutting some curves..

I'm calling this the Y axis because I'll have the thing rotated 90 degrees to the left when I really set it up.

Now I just need to put all the parts together.. Add paint, limits, and so on, and so on... Maybe it will not take another two years... But I still have a lot of work to do.

milhead
08-26-2009, 11:06 AM
Hi Folks!

In a couple other logs that are currently going on there is talk about resonance as an issue. In my video there is one slow move near the end where the thing makes all kinds of grumbling noise. Is this an example of the resonance? If you can tell from the video.....

Might dampers make a difference?

Mil

ger21
08-26-2009, 11:16 AM
In my video there is one slow move near the end where the thing makes all kinds of grumbling noise. Is this an example of the resonance? If you can tell from the video.....

Might dampers make a difference?

Mil

That's what mine sounds like. The damper made a world of difference on my Y axis. I'll finish my two X axis dampers tonight and let you know how they work out. I'll try to post some video showing the difference.

harryn
08-26-2009, 02:53 PM
Always nice to see motion. It seems pretty stout.

I think most of the motor heat is generated by the magnets, which are attached to the outer case. I would think a fan blowing over it would be enough, but if you want to add more surface - sure go ahead. A large part of the resistance to heat transfer is remakably in the interfaces, so the most important thing is to actually make the thermal transfer "goop" as thin as possible, but still cover / fill everything - as in a few thousandths thick.

ger21
08-26-2009, 09:49 PM
Damper video here.
http://www.cnczone.com/forums/showpost.php?p=657501&postcount=180

milhead
08-27-2009, 01:17 AM
Well tonight I ran my code again and after paying attention to your video paid attention to the sounds as the machine would ramp through the 180ipm area where the noise was so bad.

Just for a test I mounted two 4 inch wood wheels to the back side of my steppers.

With no weights in the wood (just 4" disks) It made much less noise, I may cut another set with weights in them.

I suppose it will just cost a bit of acceleration to have the weights attached but it does seem to smooth things out. Is there another reason not to have them besides the weight and acceleration?

Mil

milhead
09-04-2009, 03:47 AM
WooHoo!

Made what I think is a pretty good deal off Craigslist today... I still need to test the steppers.. What's a good way to load them for testing?

11 Steppers (9 Nema 34 and 2 Nema 42)
3 4ft axis worth of V bearings and rails
16 feet more of rack.. with 4 pinions
and a 34V 32A Supply
3ft ballscrew with nut..

All for $350...

Since all the motors are bipolar I ordered a G203 so that I can play with them and make a video of any that I want to eBay..

Some I want to use but the rest will be up for sale... All used in a failed prototype (Not the equipments fault).

harryn
09-04-2009, 12:24 PM
Well tonight I ran my code again and after paying attention to your video paid attention to the sounds as the machine would ramp through the 180ipm area where the noise was so bad.

Just for a test I mounted two 4 inch wood wheels to the back side of my steppe

With no weights in the wood (just 4" disks) It made much less noise, I may cut another set with weights in them.

I suppose it will just cost a bit of acceleration to have the weights attached but it does seem to smooth things out. Is there another reason not to have them besides the weight and acceleration?

Mil

Every system has a "resonant frequency". An example might be 100 hz (pulled this number from the air) Each time you hit this 100 hz, or a multiple of it, then things will resonate.

If you just add rotating mass, it changes this resonance frequency, I think it raises it, but cannot remember for sure. If you are fortunate, it will raise it high enough to be above where you operate. Ger21 commented that his dampers are rattling (working) over quite a range of speeds, indicating that the resonant frequency for his system is quite low. This sort of surprised me considering the materials he used should be more dampening than say Al construction.

The wood actually is doing 2 things, since it is not completely "solid", like a piece of Al, there is also some dampening going on as well - not nearly as much as a more sophisticated damper, but definitely some. It is sort of like an engine flywheel effect. If you are still getting some resonance, you can glue on some rubber and see if that solves it.

milhead
09-04-2009, 01:03 PM
If you just add rotating mass, it changes this resonance frequency, I think it raises it, but cannot remember for sure. If you are fortunate, it will raise it high enough to be above where you operate. Ger21 commented that his dampers are rattling (working) over quite a range of speeds, indicating that the resonant frequency for his system is quite low. This sort of surprised me considering the materials he used should be more dampening than say Al construction.

I'm half way through a calculation at home to see what at what gantry speed the rotating dampers energy will approach the energy of the moving gantry itself. Wikipedia is a great source for density and moment of inertia stuff..

Hopefully it's negligible.. But if not, the gantry will appear to have a much larger mass at high speeds than at small.. I want the small speed acceleration to be as high as possible for V-Carve sort of work but want the high speed rapid too... Someone mentioned that I can get an updated version of Mach that allows asymmetric motor ramps if it really turns out to be a problem.

Stay Tuned... I may actually get time to work on it this weekend.. (lots of rain in the forecast).

Mil

milhead
09-08-2009, 02:09 AM
Since I've knocked off some other projects I was able to remove everything from the controller box and install the cooling... All I have left on the controller is the e-stop, limit, spindle and vacuum control circuits.. Oh, and more cleanup and routing.

In the controller has two fans used when just the computer is turned on that are basically PC case fans.

When the Power is on for the Motors and stepper controller, the two larger AC fans come on... Currently there is a lot of airflow in the box even with the filters on the goes-in.

Should be a day or two before I get back to work on the mechanism again and can put the controller behind me.

milhead
09-13-2009, 11:22 PM
I spent the weekend setting up to build the real work surface and mate the real gantry with the gantry drive.

I ripped all the birch ply on my table saw then was going to machine the holes and slots on my CNC#1 machine. Well I'm such a noob with my table saw, possibly due to the 5' x 5' peice of birch, that the lines went everywhere...

I was about to start cutting everything before I got the idea to bolt the whole set together and send them through the planer! Worked like a champ except that I get pretty sweaty hefting a 40 lb board through my planer.

Using a jig that was a bunch of pegs for alignment I was able to cut all the holes and slots today in a rash of smaller machinings.. In the end it looks pretty good and I'm pleased. I'll be assembling the base sometime later this week.

The other allowance that I chose, I wanted to leave space to put my NEMA 34 motors in to drive the gantry.. You can see on the right side of the gantry drawing where I have both motors shown. Currently I'm using the Nema23 motors but will have the option of redesigning the belt housings to hold the size 34 motors in a later update or if the smaller motors just don't cut it... (pardon the pun)...

Mil

milhead
12-17-2009, 02:37 AM
Luck runs some funny routes.

I built the stepper motor controller over two years ago for this router and have used it off and on several times to test the mech...

Well finally I get the mech all put together and when I hook up the motors and get ready to experience the joy of a full system...

I get sparks and smoke.... Grrrrrrrr

Happened a few days ago and now I've got it mostly fixed but other projects are looming... My Christmas goal may be past if I can't get the controller working....

Anyway, He're is the completed table and mechanism.. Also a photo of my partally reconstructed board, I'm still missing 5V but Dave and HobbyCNC is helping me get it back together...

Happy Cutting, Fortunately I still have Machine #1 to entertain me..

Mil

CarveOne
12-17-2009, 06:43 AM
Ouch!! That looks like what I expected to get when I first turned on my CNC machine's 72Vdc 20 amp power supply recently. At least I haven't fried anything yet. I've had more trouble getting a new computer and Mach3 configured so far. I too was hoping to be able to meet a Christmas deadline for first runs.

CarveOne

milhead
01-20-2010, 02:48 AM
Missed my Christmas goal by a few weeks but the thing is up and moving as a unit!

Almost three years in the making..

Hasn't cut yet, but will by the weekend..

Take a look!

Mil

YouTube- CNC #2 Lives

CarveOne
01-20-2010, 07:03 AM
Very nice milhead! You're gonna have fun with that one.

CarveOne

tajord
01-20-2010, 07:20 AM
I've been waiting a long to for this day, this baby looks like it'll be a winner, congrats mill, very well done.:cheers:

ZipSnipe
01-20-2010, 10:00 AM
Very nice Millhead, I don't usually comment on the wooden cnc machines but this one you have done a nice job, keep it up!!!!

ger21
01-20-2010, 07:07 PM
You better take it apart and paint it right now, or it'll never get painted. ;)

Looks really good, though. Nice job. And 3 years is nothing. :)

milhead
01-20-2010, 08:40 PM
You better take it apart and paint it right now, or it'll never get painted. ;)


Yeah, I've already thought about that... My #1 machine is still only partially painted from 3 years ago....

But I do have paint!....

Fortunately the Baltic birch is pretty tough stuff...

milhead
01-22-2010, 11:40 AM
Made some more progress, but have a large billiards tournament this weekend... Not to sure how much time I'll get in the garage...

I actually cut some parts last night (mounts for my limit switches) after sitting down to get the vacuum head designed (Where I only made conceptual progress)..

I cut pockets at 100 and 200 IPM with good success except for the fact that I lost some registration on the 200IPM cuts. I am not sure at this time if it's lost steps, slipping shafts, or possibly a hopped timing belt. It was sooooo much fun to watch it cut at 200IPM that I think I'm going to shoot for that as my goal. (mind you my first machine standard cutting speed is 20 IPM)

My first order of business is to tension the timing belts for the two-motor gantry drive. I've never really tightened them since I put the thing together (grin) I do have a method in mind and an adjustment to tension them. This would also be a good chance to get some paint on them.. We'll see if I'm that patient...

Need some help and opinions on this one: <-- PLEASE HELP!!!!
I have 6 timing pulleys that cannot be allowed to slip.. and since the shafts are all so small they are not keyed and only have set-screws. Should I file some flat spots on my shafts to tighten the keys on? The shafts that I made don't concern me much but all of the motor manufactures say not to modify the shafts... Or is there another way to lock them up that I'm not aware of.

Also at 200IPM it produced gobs of chips... (gasp).. I need to get the vacuum system up and running pronto or I'm gonna be knee-deep in chaff before I can spit (But what a blast it was!!!! I made my wife come watch but I don't think she'll be taking up the hobby soon)

I enjoy watching the machines cut too much to build a vacuum head with the hose coming out of the front of the router (where it makes most sense but occludes the view.) So I'm going to run a plexi duct up one or both sides of the router and attach the hose on top. Thus keeping my little plexi-enclosed, LED lit, cutting stage clear of obstructions...(Some folks require a big stage, mine might fit 2 decks of cards).. It's funny and embarrassing the hours that I've hung around just to watch the machines cut but I'd be bummed if I was not able to watch...

I'll get some photos or a video up soon!

Mil

milhead
01-26-2010, 06:15 PM
My vacuum attachment is looking way too elaborate... I have a bunch of acrylic so I may try to make it anyway but now I understand why folks just mount the vacuum hose right in front of the router...

Here is the basic drawing.. We'll see if I have the craft skills to form this thing out of plexi....

ger21
01-26-2010, 06:39 PM
It's funny and embarrassing the hours that I've hung around just to watch the machines cut but I'd be bummed if I was not able to watch...

While I'd really like to watch, dust and chip free operation is more enjoyable. :)

Try locktight, or epoxy to hold the pulleys in place. But you may not be able to remove them.

milhead
01-26-2010, 08:02 PM
Try locktight, or epoxy to hold the pulleys in place. But you may not be able to remove them.
That's a tough call, assembling and disassembling is kinda required... Did you have an opinion about filed flat spots? (Ok... Dremeled flat spots.).. Is it a bad thing to do... I can also put some locktite on the setscrews..

whiteriver
01-29-2010, 03:58 PM
I think that's the best wooden router I have ever seen. Very well done!!.
Get it painted.

Donny

Jason Marsha
01-30-2010, 02:40 PM
Good job milhead

milhead
01-31-2010, 01:37 AM
When I took it apart to tighten up I've started putting a coat of paint on it... Opinions please...

Just a thought, it's supposed to be Allis Chalmers red but it looks kinda blood red... (gulp).

Mil

MyCattMaxx
01-31-2010, 08:48 AM
Them fighting colors....Around here it's John Deere green and yellow...LOL
Even my bird feeders are yellow on green posts. (Now where did I put my JD underwear)

Looking good.

milhead
02-01-2010, 02:47 AM
It's still weird to see it cutting after all this time... Here's a video of surfacing my table.. It will still cut a bit bigger but I'm still cagey about the 200IPM cuts..

It's also clear that I need to do more work on the vacuum apron.. My first attempt just allowed a rash of wood to fly out from underneath.. I've seen a video that uses a clear vinyl skirt that is attached with Velcro to the router. All I have is a shop-vac that pulls air through a separator, not a proper dust control system.

YouTube- CNC #2 Cutting a level surface

Mil

CarveOne
02-01-2010, 03:42 AM
It's looking good milhead. Very nice job.

CarveOne

milhead
02-06-2010, 11:57 PM
I've spent time to get the Router and Vacuum tied into the Mach spindle control..

I used the machine to cut out a crate and forms to hold a couple NEMA 34 steppers and did not take a picture but was nervous about one consistent artifact the the machine left i what was supposed to be a rectangle...

These photos are from the first sign that I have tirned out. Now it really takes longer to design then cut... All in all the thing cut out pretty well from a scrap of red oak.

Next I'll try something a tad larger....

Mil

CarveOne
02-07-2010, 07:21 AM
I've spent time to get the Router and Vacuum tied into the Mach spindle control..

I used the machine to cut out a crate and forms to hold a couple NEMA 34 steppers and did not take a picture but was nervous about one consistent artifact the the machine left i what was supposed to be a rectangle...

These photos are from the first sign that I have tirned out. Now it really takes longer to design then cut... All in all the thing cut out pretty well from a scrap of red oak.

Next I'll try something a tad larger....

Mil

Looks good Mil. I like red oak for all sorts of projects. And then, sometimes I fall back on the less expensive stuff like cardboard just for the weirdness and humor of it. :)

CarveOne

mlabruyere
02-07-2010, 02:15 PM
It's also clear that I need to do more work on the vacuum apron.. My first attempt just allowed a rash of wood to fly out from underneath.. I've seen a video that uses a clear vinyl skirt that is attached with Velcro to the router. All I have is a shop-vac that pulls air through a separator, not a proper dust control system.
Mil

Hey Mil,

I was having the same issue no matter what I was using as an apron. Plastic, rubber, brushes......I still got dust blowing everywhere. I've got a 6HP shopvac.....it'll suck start my truck....it's a small truck....:)

The problem is the "spindle" which in our case is an air-cooled router. I built my new dusty skirt such that I divert all the air from the router to the sides. This allows the vacuum to remove almost all of the dust and debris from the work surface. It woks pretty darn good. I'll post some picks....it's not the prettiest dust skirt but it works. ;)

ger21
02-07-2010, 03:41 PM
You need a thick brush, and it needs to be at least 1/2" longer than the router bit, so you get a good seal on your work. If there's an opening, dust and chips will get out. Your dust collector or vacuum should be sucking more air than your router is blowing, so if the brush seals to the table, you shouldn't have a problem.

milhead
04-21-2011, 05:46 PM
Just thought it looked impressive but I was leveling a hunk of wood I bought. The thing was too thick to fit under my gantry so I had to write a program to resurface from rear to front (which would allow clearance as it cut)..

I over shorthanded and used the wrong G command... Wound up with 700ipm

Turns out it worked ok.. cut a bit rough and I'll have to do a finish
cut.. But it was fun to watch.. Normally on this machine I cut around
80-150 ipm..

YouTube - resurfaceat700ipm

milhead
07-29-2011, 08:42 PM
I don't claim to know at all what I'm doing cutting something other than wood but volunteered to cut a piece of aluminum for a buddy this weekend and figured I'd better test to see how it works before I ruin his stock and my reputation...

Suprisingly it came out pretty well using a 1/4 up-cutter... Hopefully I have enough blade left to cut his piece this weekend...

35ips, 0.035in pass depth.. I kept compressed air on the bit in an attempt to keep things cool...
oh, and the speed on the big porter cable router was set to 10,000rpm

What do ya think?

Mil

Senna
07-29-2011, 08:48 PM
That looks really darn good!!! Gives me hope that I'll also find success when I attempt the same...!!!

So just air... NO lubricant like kerosene or some use WD-40...??? Hmm...

BOOMER52

milhead
07-30-2011, 12:26 AM
Killing two birds with one stone, I now exhaust the router above the dust boot.. This has the added benefit of lowering the boot nearly an inch and it seals much better...

An easy fix, two years too late, I cut a big wood path the other day with the new boot and could hardly tell that the machine had been used afterward..

Here's the basics...

p.s. it makes a great hole in which to stick the locking wrench when I change bits...

acondit
07-30-2011, 10:04 AM
Killing two birds with one stone, I now exhaust the router above the dust boot.. This has the added benefit of lowering the boot nearly an inch and it seals much better...

<snip>
p.s. it makes a great hole in which to stick the locking wrench when I change bits...

Sweet!

CNC Lurker
08-01-2011, 01:43 PM
I've spent time to get the Router and Vacuum tied into the Mach spindle control..

I used the machine to cut out a crate and forms to hold a couple NEMA 34 steppers and did not take a picture but was nervous about one consistent artifact the the machine left i what was supposed to be a rectangle...

These photos are from the first sign that I have tirned out. Now it really takes longer to design then cut... All in all the thing cut out pretty well from a scrap of red oak.

Next I'll try something a tad larger....

Mil

I need to make a key-slot also, did you hand-code the key-slot or does the program you are using have a key-slot plugin or something?

http://www.cnczone.com/forums/attachment.php?attachmentid=99428&stc=1&thumb=1&d=1265518604

milhead
08-09-2011, 09:30 PM
I start from a small on-line generated toolpath and modify it for the keyway cutter
something like. This one creates a keyway 2 inches long centered at 0.
I x/y/z-zero the unit in above where I want the slot and go!

I have dual vertical 10 inch and 16inch keyway programs that I run often as well for bigger stuff.

( 2 Inch Horizontal keyway )
( Mach2/3 Postprocessor )
N20G00G20G17G90G40G49G80
N30G70
N40T0M06
N50G00G43Z0.7874H0
N60S12000M03
N70G94
N80X0.0000Y0.0000F60.0
N90G00X-1.0000Y-0.0000Z0.2362
N100G1X-1.0000Y-0.0000Z-0.3F20.0
N110G1X1.0000Y-0.0000F60.0
N115G1X-1.0000Y-0.0000F60.0
N280G0Z0.2362
N290G00Z0.7874
N300G00X0.0000Y0.0000
N310M09
N320M30
%

milhead
02-06-2012, 12:27 AM
As part of my big upgrade I'm moving to motors that are too big to run with my HobbyCNC controller.... In come some Geckos to replace my gantry and X drive.

It's still fun to make machine parts (In this case the controller mount) on my my machine before I perform the upgrade...

I cut this out of wood first to test fir all the holes then cut the aluminum plate, The back is covered with heat sinks and has a breeze across it.

CNC Lurker
02-06-2012, 01:38 PM
I start from a small on-line generated toolpath and modify it for the keyway cutter
something like. This one creates a keyway 2 inches long centered at 0.
I x/y/z-zero the unit in above where I want the slot and go!

I have dual vertical 10 inch and 16inch keyway programs that I run often as well for bigger stuff.

( 2 Inch Horizontal keyway )
( Mach2/3 Postprocessor )
N20G00G20G17G90G40G49G80
N30G70
N40T0M06
N50G00G43Z0.7874H0
N60S12000M03
N70G94
N80X0.0000Y0.0000F60.0
N90G00X-1.0000Y-0.0000Z0.2362
N100G1X-1.0000Y-0.0000Z-0.3F20.0
N110G1X1.0000Y-0.0000F60.0
N115G1X-1.0000Y-0.0000F60.0
N280G0Z0.2362
N290G00Z0.7874
N300G00X0.0000Y0.0000
N310M09
N320M30
%

Sorry, forgot to say thanks for that code!

milhead
06-28-2012, 03:23 AM
Yeah I realize that I can buy them off ebay for almost what the AL cost me but there is something about I figured it out here at home... Where no schedule exists it's a lot more fun...

Replacing my HDPE router mounts with AL ones should help me stiffen up the whole thing some. My mounts flex small but visible amount if I press on the router.

While I was cutting these out I also had one of my Z-axis slides loose a retainer and dribble it's little roller bearings all over the table mixed in with the AL chips.. Since I bought the things off ebay 5 years or so ago I've not been able to locate any spares..

Using a magnet I was able to retrieve 24 of the 28 roller bearings... After a few hours of tinkering I was able to get the slide reassembled (sans 4 rollers).. Manufactured a replacement retainer.. Liberally applied lock-tite to all the screws and was back cutting with a tragic-redesign avoided!

Feeling a bit lucky about that one...

milhead
07-07-2012, 02:26 AM
I got tired of having to correct my BIOS settings every time I cycled power because my battery was dead..

While I had the whole think taken apart.. I replaced the Drive with a 60 GB SSD drive.. A new battery, a new XP install and none of the old gack that was on the controller before (including an old dual-boot Ubuntu).

I also replaced my old partally toasted Hobby CNC controller (That really has done good service) with 3 more Gecko Vampire controllers. Just the controller update has given me a pretty healthy jog speed update.

And cleaned up a lot of wiring that has bugged me for years!

Anyway.. It looks alot like the old one but will hopefully work for a few more years...

Mil

CarveOne
07-07-2012, 06:53 AM
More Geckos always sounds like a good plan. :) All that work and expense will be well worth it.

milhead
07-09-2012, 05:45 PM
All that work and expense will be well worth it.
While I'm nowhere close to covering my hobby-ish hours the parts are all paid for from oddball jobs and ebay auctions of industrial junk.....

My painting and 'sharpie' has even gotten better.

CarveOne
07-10-2012, 10:03 AM
That looks really good!

I haven't done any color signs yet, just stained oak V carved simple stuff.

milhead
07-10-2012, 01:10 PM
That looks really good!

I haven't done any color signs yet, just stained oak V carved simple stuff.
Super easy to do....

1) Cut the design slightly deep (say 0.03) into the wood...
2) After cut slather it with sealer to close up wood end grains
3) Slather paint in the recessed areas you want colored...It's ok to get paint on top... Let it dry... (Acrylics are fast and don't run too bad up the grain)
4) fly cut 0.03 off the top to clean up.. (Actually I normally just sand the paint off with a sander unless it's real detailed).. These were small enough to go face down on the belt sander...

5) For the battling horses in this one I wanted dark so I used a sharpie to color them black.
6) Seal it up!

I made 4 for the local restaurant, total time cutting and painting was about 1 or 1.5 hours.... Workin' for Margaritas that day...!

I've done lots of these... Quick and easy $$ once you figure it out... https://picasaweb.google.com/milhead/DropBox?authuser=0&authkey=Gv1sRgCK7UlaG12sTBgwE&feat=directlink

CarveOne
07-10-2012, 02:58 PM
So, you troll for work at the local den of margaritas and senoritas too, huh? :)

Now you know why I made all the Aztec and Mayan calendars, and fajita trays. I get to sample new flavors (and get free lunches on occasion) when I deliver something new.

Your sign work is far ahead of mine. I haven't done any texturing work yet either. The elliptical sign that you changed the date on - a shallow V carve line on the edges of the inlay would mostly hide the difference in the look of the wood grain and would look purposeful as part of the design.

milhead
06-04-2013, 09:55 AM
Spent some time working on more mount replacement parts.. After cutting a bunch of signs the machine is at least paying for itself and bits...

186942

Cutting the baseplate was a mess but except for an occational squirt of WD 40 pretty easy.. 1200RPM, 30ips, 0.05 depth..

https://www.youtube.com/watch?v=RFNY4D2tge4

Some of the signs are looking better too!

186944