Hi all,

Long time member, first machine build posting. I figured I have taken enough information form the CNCzone community, it is only right to give back with a build log of my newest creation. I hope that others may find some answers in my build methods, and actually encourage feedback + or -. That's what we are all here for right:)

Well, first some rough design specs. The dimensions for this machine are primarily dictated by the size of the parts I was able to obtain. If you want to go cheap, you sometimes have to use what you can get right?!

machine dimensions - 75.5" x 42.5"
cutting area (est) - 36" x 60

stepper drives - Gecko Vampires
stepper motors - 425 oz.in Nema 23

x and y axis - Belt drive
z axis - screw drive

build materials - steel frame, aluminum gantry

more to come................


Let's get started....



Here is the steel frame tacked up with a few welds to finish. It's 11 ga. 1" x 1 1/2" rectangular tubing and 3 inch casters.

Here is the frame now fully welded, painted and rail supports being mounted.

The Gantry is made completely out of 80/20. Most parts are 2"x4" so it is extremely rigid. Bearing adapter plates were made to mate the bolt pattern of the bearing pillow blocks to the 80/20 tslot spacing. The rails are now set, the gantry is mostly together. Very square, no binding, slop or any problems so far. It takes about 2-3 lbs of force to move the gantry right now. I can push/pull from any spot, middle or corner and it glides like butter. Very happy:banana::banana:

looks like its coming along nicely. :cheers:

I mocked up the short axis bearing rails to make sure everything was going to fit right (ok, I just couldn't wait to see what they would look like:)) I don't have any fasteners right now or they would be on there.

more pictures please.

Thought it would be a good idea to chime in and at least let everyone know what direction I'm heading with this. So I grabbed a shot straight from the virtual mechanical design of the machine. I don't have the z-axis designed yet for it, but it should be fairly straight foward when I get there. Disclaimer (all things are subject to change without notice). Fasteners, belts, pulleys, steppers and power supply all ordered today. Should be a busy weekend and all with fishing the opener....

Here is a shot of the long axis bearings and the adapter plate (to mate them to the 80/20. The other is a shot of an old Dahlgren control box that I gutted to use as my control box. It's already fused, has an awesome fan and a lit power switch. All of the panels on the box are replaceable so I can customize it later.

Well I finally got my fasteners that i needed to get the short gantry axis bearings installed. So I installed them and wow are they one there.

Well, alot of the goodies and trinkets that I've been ordering showed up today. This included:

- Power supply
- stepper motors
- some timing pulleys and belt material
- idler rollers
- and a heat sink for the geckos that a friend so graciously donated to the project:)

The drives and power supply will go into the controller box. Now I can start on the long axis drive train. There will be some details on that coming shortly.

The container of M.A.L. didn't come with the order. (Michelob Assembly Lube):cheers:

LOOKING GOOD:rainfro:

OK....well been busy the last few days but I managed to get my long axis motor plate machined (with my older small CNC machine). It turned out pretty good and everything fit perfect (doesn't happen often:() I bolted it to the machine temporarily so I could see if everything was on track.

As you will tell by the pictures, I decided to go back to the fixed belt drive system and a single belt at that. I'm 99% confident that it will work. I don't know how well but everything seems logical about it. It's one of those things that I just have to prove to my stubborn self(chair), I won't learn anything if I don't try and if it doesn't work for some reason I can always recycle the parts for a recirculating belt drive.

Stepinator,

I have been following your build because I have the same idea of building a belt drive CNC router. Printers have been using a belt drives for a long time. What was your reason to go to a fixed belt system?

I have been following your build because I have the same idea of building a belt drive CNC router. Printers have been using a belt drives for a long time. What was your reason to go to a fixed belt system?

Well, I guess I just looked at it as going with a single fixed belt, helps keep the cost of everything down and things to adjust while still being able to have the benefits of a belt drive (speed and accuracy). The more I thought about it, I just wanted to see if I could get it to work with the minimum amount of components. Now I don't need 4 bearings, two jackshafts, 2 to 4 times the pulleys, twice the belt length, etc. Plus it's always fun to do something different:rainfro:

Hope that helps some.

Stepinator,

Where Did You Purchase Your Power Supply Components From?

Thank You

Jeff Alessi

Where Did You Purchase Your Power Supply Components From?

Keling Inc. I got my motors there too. I didn't shop around much for pricing but as far as customer service goes, they are very difficult to beat. If I ever have a problem, they will be there for me.

Hi. Nice build so far.

What is the spacing on your bearing blocks on the long axis? I'm working on the design for machine #2 (2' * 4') so I'm interested in how your single drive works with respect to racking on the long axis...

Ward

What is the spacing on your bearing blocks on the long axis? I'm working on the design for machine #2 (2' * 4') so I'm interested in how your single drive works with respect to racking on the long axis...


Distance between bearing rails is 32", spacing between bearings on the rail is 13" overall from end to end, make sense?

I haven't experienced any racking yet just moving it by hand and such. I have tried to twist or rack the gantry and the table starts turning on it's casters. I can pretty much move the gantry from any point on it with the same amount of force, anywhere from the far outer corners to the very top. The gantry is at about 60 pounds right now and if I give it a small push with only my finger tip it will coast about 3 feet (my 4 yr old daughter almost pushed the gantry off the rails:eek::eek:) All of the round rail bearings are ball bearing and very smooth. There shouldn't be any issues moving it. Through a complex spreadsheet of formulas that I developed, I came up with nearly 260 lbs. of linear force that will be available for moving the gantry and the belt is rated up to like 600 lbs. operating limit with like 800 lbs. failure rating, so I should be good there too.

Makes perfect sense, thanks for the info. My gut has been telling me it should work but it is always nice to back it up with some real world experience. Good luck with the rest of the build!

Ward

here are a couple of snapshots of the drive concept. I'm just using a large bolt for the axle right now because I have one. I will probably use actual rod later.

( You mechanical gurus out there should be able to find my little easter egg mistake in the first picture that did make it to the final piece:tired:. Hint- it has to do with calculating radius and travel from a common reference point. I'm an electrical engineer, not a mechanical engineer:o)

I like the drive set-up, looks good. Like you hinted, it might be easier to tighten your belt by moving your motor in a straight line.....

Great build so far, keep up the great work!

Do you have it running yet? what kind of backlash do you expect, do the belts stretch at all?

Looks good so far. bummer about the motor adjustment slots.. Sh*t happens..

I am going with a single fixed belt on our larger routers for the reasons you mentioned, and for stiffness. The shorter your length of belt, the less stretch. also, the motors are tucked away, so the machines fit in a smaller box.

Do you have it running yet? what kind of backlash do you expect, do the belts stretch at all?

Looks good so far. bummer about the motor adjustment slots.. Sh*t happens..

I should have one axis moving here shortly:):) Once I've done some preliminary tests on it I can determine if I need to go to the recirculating or if I can proceed with the other axis'. As far as stretch, the main drive belt is a 3/4" "L" pitch Polyurethane/Kevlar belt. I need to fabricate a tensioning system to be able to fine adjust the belt tension. I got both of by belt clamps machined out and installed. I didn't think stretching a 6 1/2 feet of belt an 1/8th of an inch would be difficult, boy was I wrong. I needed to stretch the belt the length of one tooth, .128" and it was damn near impossible!!!!:boxing: I Definately need to install a tensioner. I was told that the standard neoprene/fiberglass rubber belts are guaranteed not to stretch more than 3% of their length over the belts lifetime. On my machine that would be about .010" per tooth which isn't really that bad, but with the kevlar belts those puppies don't stretch at all!!!

Should have some pics up soon on the current progress. Still wiring the control box right now for the big test.

I got the drive belt mounted with some aluminum clamps that I machined on my old machine. They work well but I still need a tensioner. (More assembly lube involved:rainfro:

Got the controller box completely gutted of useless items and ready for assembly. Everything is is installed now, just some wires needed to complete the other two drives. I had to disconnect the cooling fan so I could hear if there were any "uh-oh" noises once I fired the box and table for the first time. Once everything is running smoothly in the end, it will be hooked back up for maximum cooling.

Amazingly everything worked perfectly from the word go. No fireballs, mushroom clouds or homemade defibrillators here:banana::banana:. I thought for sure I'd be missing something in all of the excitement but I lucked out.

The motors attach to the back of the controller with banana jacks and plugs, it works pretty slick. I lengthened one of the existing serial port holes to fit the parallel port connector (yea, that sucked:mad:) As I stated before, I'll probably re-cut the front panel so I can get rid of all the BS that's on there now.

Finally, a test of the machine running. Everything is very quiet and smooth. I was honestly very suprised at the results. The gantry is very smooth and very strong even when trying to stop it. Trying to stop it from different points didn't work, that's a good thing. No racking, binding, slop or anything. So far I've run it anywhere from 5 IPM to 300 IPM. I'm confident it can go alot faster but I really don't need it.



Here is a sample video of some basic tests running Mach3 demo. There are some close ups of the drive mechanism working towards the end.

CNC machine belt drive axis test (http://www.youtube.com/watch?v=9QgnD-bgd_4)

:cheers:Enjoy!!!:cheers:

Stepinator,

Where did you purchase the large belt, Please post a link if possible.

Thank You

Jeff Alessi

come on, give us 1000ipm...

Looks like it is working well, I can hardly wait to see how it cuts.

Stepinator,

Where did you purchase the large belt, Please post a link if possible.

Thank You

Jeff Alessi

That particular belt came from McMaster Carr. "L" series, 3/4" wide, white urethane/kevlar.

come on, give us 1000ipm...


Yeah, it was just starting to get interesting. ;)

Yeah, it was just starting to get interesting. ;)

Well later that evening I couldn't resist and was able to mess around with it a bit. I successfully hit 500 IPM with no problems. I'm not sure how fast it will go, but I'm sure I'll find out:devious: It should really scream. At 200 IPM the stepper motor is only turning about 305 RPM.

The calculated resolution is .000312752 per step. As far as actual and repeatability that will have to come later when there something more substantial to measure.

Hi Stepinator


As I am going to use a similar belt drive in my setup I am curious on the gearing you used. I planned on using similar sized pulleys from what I can see in your pics but I don't get that sort of resolution when I do the calcs unless you are counting micro steps.

Cheers

Mark

Hi Stepinator


As I am going to use a similar belt drive in my setup I am curious on the gearing you used. I planned on using similar sized pulleys from what I can see in your pics but I don't get that sort of resolution when I do the calcs unless you are counting micro steps.

Cheers

Mark


Definately including micro-stepping. The most important part is the pulley riding the belt. If that pulley gets too large resolution starts to go down the tubes and speed gets out of hand in a hurry. Transferring rotational movement to linear movement gets tricky. Basically it's like using your cars rearend and transmission but to keep things under control and precise you want to put 6 inch tires on it. If you leave the normal size tires on it you would have to gear it down an extreme amount to keep the precision but at the cost of blowing your engine trying to get any speed out of it. (first example that came to mind, not sure if it makes sense).

Have been pretty busy for the last week, but now I'm back to finishing the machine. I was designing a couple of different z axis' and checking out parts on ebay and really getting frustrated this weekend. I couldn't find all the right parts that I wanted to put together, nothing seemed to do it for me. So I went out to the garage to have a beer (what a surprise) and just sit and think for awhile. I was looking at a pile of surplus stuff from some engravers and old machines when I saw it. All the parts I needed for my Z were right there with a minuimum amount of machining required. It's going to be a inboard v-bearing z axis. The parts are all there and heavy duty too. I really don't need it to be that tall but hey, at least it's free. I just saved myself a couple hundred dollars$$, now my cutting table and surface will be mostly paid for:) The rails are 19 inches, which isn't bad because I can space out my trucks for rigidity without losing too much travel. It has a 14" x 1/2" ball screw that runs 2 TPI (4 TPI, 2 starts). I'm not sure if I will mount the stepper underneath the top plate or on the top as pictured. I'll start with a 2:1 ratio for the belt for now, probably adjust that later.

I just put a couple of bolts in it on the gantry to see how it looked. the 16
8mm bolts should be plenty. I even polished it up a little for some :cool:Bling factor:cool:.

Got the leadscrew assembly mounted. Still need the motor mounting plate on the top and the bearing truck. I also realized I need to clean this landfill before I go any further!!!!!

Looking good Stepinator rainfro:

Your garage has got nothing on mine. At least you can still walk through yours(wedge)

I can't wait to see the final results. I have really been looking forward to see how well a belt drive setup does.

Stepinator,

I may have a solution to your belt tensioning problem......

I had some THK GL15B's that were belt driven....

They tensioned the belt by tuning a bolt that pulled the pulley on one end forwards/backwards...then locked it down with two other bolts, similar to the tensioning mechanism on a motorcycle chain.

In your case, if the ends of your belt are clamped, maybe your could add a tensioning bolt that would pull one clamp further away from the other as it was turned inward.

I could whip up a graphic of the setup..worked for THK...my .02 cents....

I love belts! :) Typically .003 to .005 thou accuracy, and very little wear, and FAST!

Justin in AZ

Stepinator,

I may have a solution to your belt tensioning problem......

I had some THK GL15B's that were belt driven....

They tensioned the belt by tuning a bolt that pulled the pulley on one end forwards/backwards...then locked it down with two other bolts, similar to the tensioning mechanism on a motorcycle chain.

In your case, if the ends of your belt are clamped, maybe your could add a tensioning bolt that would pull one clamp further away from the other as it was turned inward.

I could whip up a graphic of the setup..worked for THK...my .02 cents....

I love belts! :) Typically .003 to .005 thou accuracy, and very little wear, and FAST!

Justin in AZ

That does make the most sense vs. a slotted idler. If a guy really wanted to get picky he could use fine thread bolts too. Making something from the beginning is kind of tough, but making what you already have better is what I find to be fun. I can't wait until I'm at the tweaking part.
Thanks for the input Justin:)

Looking good Stepinator rainfro:

Your garage has got nothing on mine. At least you can still walk through yours(wedge)

I can't wait to see the final results. I have really been looking forward to see how well a belt drive setup does.

Yea, it drives me nuts when I'm in the heat of battle with a project and all I seem to do is knock over more with my rearend than I can set up with my hands:rolleyes:

lol.....me too....

I love it when I grab a tool off my magnetic strip on the wall, and 5 other tools clang on the the concrete floor :rainfro:

Got the Z axis mechanics completed this weekend. Need to wire up the motor, get a couple of pulleys, a belt and mount the tool, but the hard part is done:rainfro:. It turned out pretty darn rugged and smooth. I'm glad that part is over. The Y axis is next and should be the easiest part of the project. Slowly but surely it's coming along.

Hi Steinator,

WHere didyou get therubber bellows for your Z screw, I am assuming there are 2 of em there. Right?

RGDS
Irfan

Hi Steinator,

WHere didyou get therubber bellows for your Z screw, I am assuming there are 2 of em there. Right?

RGDS
Irfan

I had a few smaller engraving machines made by Dahlgren. All of the axis' had them on. Any of the Black Anodized aluminum parts that you see are parts from those machines. I'm not sure where a guy can get them by themselves. I can study the ones that I have and try to post some pictures of how they attach. With a little searching around and a little work alternate styles could be made I think.

I found one on this site http://www.bellowsindia.com/products.htm

Well, it's been awhile since I have posted any progress, simply because I've been to busy to post any entries. That doesn't mean I haven't made any progress though:) I actually have all three axis' running now and running well. I'm starting to build the adjustable cutting surface table now and have some wire cable carrier on order to tidy up the cables. The cutting tool mounting plate is drilled and tapped for a variety of stuff to bolt to it. For starters I will be mounting my Taig mini-mill head to it, so I can make the other tool brackets and misc goodies. :banana::banana:THEN I GET TO START CUTTING STUFF:banana::banana:

I finally got around to deconstructing part of my garage and making room for the new CNC machine. The two older smaller machines are boxed up and stored for parts. Still some cleaning to do, but it's mostly just putting away the 3,000 or so tools that were laying around.

Enough about cleaning, let's get to the new test video of all 3 axis' doing their thing:banana::banana:


TEST VIDEO #2 (http://www.youtube.com/watch?v=dGwZiFQFnvo)

I was just goofing around for the second half of the video, making it more techno-logical:cool:

Sorry if I have offended anyone with the music genre selection.

Everything is looking good, how fast where you running the x axis in that movie? I've been closely following this thread as I'm working on a very similar design for my first machine and everytime you post an update I got more anxious to get my design finished and my build started.

Everything is looking good, how fast where you running the x axis in that movie? I've been closely following this thread as I'm working on a very similar design for my first machine and everytime you post an update I got more anxious to get my design finished and my build started.

Max speed in the first half of this movie is 300 IPM. The second half of the movie is sped up to better match the music:)

Well, everything is pretty much done with the machine now. I got the top cutting surface and t-slot rails for clamp downs mounted to the upper table frame. The upper frame is made out of steel tubing and the top surface is a white melamine(sp?) coated 3/4" mdf with 1/2" aluminum dual t-slots in between. All that is left is squaring and leveling the table. Right now it's off by about .025" to .030" in a couple corners so some shimming is in order but not a big deal. Then it can be fastened to the lower frame in a somewhat permanent manner, then the cutting can begin!!!!!!

Here's a new video of it actually making something on the 4th of July

http://www.youtube.com/watch?v=Wn-9DeWCQW4&feature=user

Hopefully I can have some updates very soon on how the belt-drive system works as far as actual cutting force, deflection, rebound and all that nitty gritty stuff that I'm most interested in. So stay tuned:cheers:

Hi Stepinator,

There seems to be some sort of jerks which I am also facing on my machine, maybe due to other processes running in background on windows?, Even Iam having that problems, see my machine video for just the x-axis -

http://www.cnczone.com/forums/showthread.php?t=46998&page=10

BTW what is the configuration of the computer running Mach.

RGDS
Irfan

Hi Stepinator,

There seems to be some sort of jerks which I am also facing on my machine, maybe due to other processes running in background on windows?, Even Iam having that problems, see my machine video for just the x-axis -

http://www.cnczone.com/forums/showthread.php?t=46998&page=10

BTW what is the configuration of the computer running Mach.

RGDS
Irfan


The jerking is mostly because of changing feed speeds on seperate lines of code (and the acceleration rate). Running the machine in a straight line at a continuous feed rate should not be jerking.

My PC is an old one, AMD 900MHz Duron, 512M ram, no additional software installed other than XP Home.

Mine does jerk in a straight line :) the PC I am using is a celeron 500MHz vintage!

Remember to put on the head phones when watching his video.... It sounds really nice!

Remember to put on the head phones when watching his video.... It sounds really nice!

At office struggling to hands on one :)

Hi Stepinator, nice music composition sir! enjoyed it fully!

Stepinator,

Could you elaborate on your drive system, mainly tooth count on the steppers (small and large cogs)... 3:1 perhaps? (20 tooth to 60 tooth XL and 20 tooth on the L Cog) And what is the source for the red urethane idlers?

Regards...Rick

Stepinator,

Could you elaborate on your drive system, mainly tooth count on the steppers (small and large cogs)... 3:1 perhaps? (20 tooth to 60 tooth XL and 20 tooth on the L Cog) And what is the source for the red urethane idlers?

Regards...Rick


I use 6:1 gear ratios. Urethane rollers from McMaster Carr.

Hows the build going? I check here all the time hoping to see some more progress!

Hows the build going? I check here all the time hoping to see some more progress!

I apologize for the lack of updates lately, I've just been too busy using the machine to actually get some pictures of it.

It really is working nicely. I'm very impressed so far with the performance both speed and accuracy. The table still needs a little leveling but that won't be a problem. At this point I don't think I'll change anything on the machine, I'm just really satisfied with how it turned out. That doesn't mean I won't add other goodies:) to it over time, in fact I'm already designing a touch-probe and a 4th axis for it.