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InventIt
12-02-2003, 05:58 PM
Hey Guys.
Been checking out your router tables for a few weeks now and decided to finally start building mine. I will mostly be using it for Plasma Cutting steel plate. I'll be making various tool plates for the Z axis if I want to mount a router or other tools to it.


The basic frame layout. 1.5" x 3" x .125 steel tubing.
Working area about 30" x 54" x 5"

Here's a few pics.

InventIt
12-02-2003, 06:02 PM
On the side of the tube are the linear rails. THK RSR12 linear bearings bolted to a 3/4 x 1/2" cold rolled flat which will be welded to the side of the tube.

InventIt
12-02-2003, 06:06 PM
A lot of holes to drill and tap...19 on each rail x 4 rails.

InventIt
12-02-2003, 06:16 PM
Here is one side nearly completed. I am going to use two motors for this axis. One on each side of the gantry.

Some specs:
Vextra 440 in oz steppers
Gecko drives G201
Radio Shack 30V 1000ma power supply
Nook 1/2" x 10 5 start (2 pitch) leadscrew
Delrin "home made" nuts



So far I got 374 IPM running a 800mhz PIII with MachII
I think I'll need to upgrade my computer to go faster...

InventIt
12-02-2003, 06:43 PM
Home-made Acme Tap

InventIt
12-02-2003, 06:50 PM
Close up of left side of gantry plate showing linear bearings and lead screw nut.

Keep in mind that I usually build without plans :rolleyes: So, if it looks alittle crude... :)

pack rat
12-02-2003, 06:58 PM
Nice bearings and great speed. I was wondering how did you mount the support for the motors? It looks aluminum but I saw the tackweld on the side. What size is it? I enjoyed your pictures and looking forward to more. Nice work, keep it up. chris

balsaman
12-02-2003, 07:53 PM
Cool router so far! You radio shack PS might be a little light. That's only 1 amp. What are your motors rated at?

Eric

InventIt
12-02-2003, 08:18 PM
pach rat:
The mounts for the motors are alum. and are bolted to 1/2" steel drilled and tapped plates that are welded to the corners of the frame.

balsaman:
--BTW, I enjoyed reading your buildups, nice job on your router(s)---
Yeh, so far the 1 amp has been doing the trick. But your right, I probably will have to upgrade. I may wire two 30v tranformers together in series to get 60volts and 1 amp. I need speed more than torque since I am only dragging a torch and not a pushing a router for now.

avsfan733
12-02-2003, 08:38 PM
looking at your pictures reminds me of a question i have been meaning to post.

Has anyone had any success/problems with mounting the lead screw on one side of the machine? I have been planning on putting mine underneath in the middle (x axis). I would like to mount it on one side like your picture but am worried about that possibly cocking the gantry as it moves. Doing it this way would save me the trouble of having to raise the table but it seems like pulling on one side would through off the movement. Am I nuts?

balsaman
12-02-2003, 08:47 PM
I believe he is using two lead screws for the axis.

InventIt,

If you want to use transformers, you will need to rectify it and filter it. The DC that comes out is around 1.4 times the ac voltage. Two 24 volt transformers gives you 48 volts, rectified you will get ~70 volts DC. Perhaps you mean two 30 v RS powersupplies..

What's the motor voltage and amps? I would think you need one RS powersupply for each motor...at least.

Eric

InventIt
12-02-2003, 09:41 PM
avsfan733:
I am using 2 leadscrews for the reason you mentioned. I did run the gantry with just one motor/leadscrew hooked up. It tracks straight without any load but the unsupported end of the gantry is very weak. It could not support a router without flexing.

balsaman:
Sorry to confuse you. I did mean two RS power adapters 30V each tied in series to give 60v.

Motors Specs:
PK296-4.5
440 Oz In
2.8 Volt
3.18Amp/Phase

Motor Performance Chart (http://www.orientalmotor.co.jp/WebObjects/UPOMStep.woa/WebServerResources/PIC/graph/t_pk296-f4.5b_bipolaru.gif)

More Specs (http://www.orientalmotor.co.jp/cgi-bin/WebObjects/UPOMStep.woa/wa/F3?typeNameId=1&modelName=PK296%2DF4.5A&seriesId=2PK&frameSize=85)


Rob

balsaman
12-02-2003, 10:11 PM
You will need a 10 amp supply at least I would think.

Eric

ezland00
12-02-2003, 11:07 PM
Nice home made Acme tap. Can you show me how? i don't really want to pay $50 for a tap.

It looks like you just used the leadscew and cut it right?

InventIt
12-10-2003, 09:14 PM
Update...
Got the right side lead screw completed. Now I have one step motor/lead screw combination on each side (to prevent the gantry from skew). Did some testing and it's not looking good :mad: Problem is, during rapid moves one stepper may miss steps or completely stop altogether. Well the other side just keeps on going and next thing you know the whole gantry is twisting and flexing. I did notice there was some binding in the lead screws and after loosing that up it did work better. It's just not working like I want it to. Actually worked better with just one lead screw/motor.

Looks like I'm going to have to re-design. I need to just use one stepper/lead screw. Somehow I’ll have to tie the two sides together. I'm thinking some kind of cable arraignment like on a drafting board or maybe I'll just go with timing belt drive ;)

Any ideas???

Rob

steveald
12-10-2003, 11:19 PM
Hi Rob,
If you use 2 leadscrews, and one motor mounted between them with two timing belts, one going to each leadscrew, then you would have identical motion on both sides of the gantry. Before re-designing mechanically, I would try using the rated current to the motors first. For 2 motors at 3.18A per phase the maximum current draw on your power supply would be 4.24A (plus the requirements of the other axis motors) using bi-polar step drivers.

Steve.

Jan
12-11-2003, 10:19 AM
A question regarding your homemade thread tap and lead screws.
Have you run the machine long enough to have any heat build-up problems between the screws and nuts. I'm also making a homemade tap and noticed that there is a very close tolerance between the two,good for anti-back lash, but maybe not for the amount of friction.

InventIt
12-11-2003, 12:23 PM
ezland00: Yes I just used as piece of acme rod and ground a taper on the end with flutes for the chips.

Jan: Can't really say as of right now. I have not really ran the table except for some testing. I did notice some warmth on the screws after a few rapid moves. I think the friction on my machine is a misalignment problem rather than a close tolerance in the nut.

InventIt
12-11-2003, 12:35 PM
If you guys are having a problem with friction on the leadscrews use this product. Slip Plate dry graphite lube. I thin it with enamel reducer and paint it onto the leadscrew. Let it dry and run it in. The more you run it, the smoother it gets.

georgebarr
12-13-2003, 03:37 AM
I am in the process of building my metal frame CNC. I am also using THK linear bearings. I have one question. How did you precisely drill all the holes for your linear bearings so that each hole is exactly evenly spaced? What sort of method did you use.

Thanks,

Stevenpats
12-13-2003, 06:57 AM
Clamp the rails to the table with C-clamps and use a transfer punch to mark the holes. Remove rails and drill out the marked holes with 1/8" bit, then the proper drill size for the tap you are using, using a drill press if you have one. Using a drill press helps keep everything square. Verify everything is straight and square before you commit to marking the holes.
Steven

balsaman
12-13-2003, 11:01 AM
I too noticed the leadscrew and delrin nut will heat up when high speeds are involved. It's another reason I went to the amco nuts.

Backlash is very small with the delrin. Be aware tho that it's also very hard to measure with the delrin nuts, because the delrin is springy, so backlash changes with load. You can't compensate for that in the software. It's usually not an issue, unless you are cutting very heavy material.

Eric

ger21
12-13-2003, 11:07 AM
Are you still using that 1a power supply? If so, I wouold think that that's the reason you're 2 leadscrews aren't working out (the lost steps on 1). Are you setting 1 as a slave in Mach2? I wouldn't think you should be losing steps on the 1 axis with 400+ oz-in steppers. But if you're not supplying the rated current, you're not getting the full rated torque. I would guess it's either that, or you're just trying to go too fast. And more voltage would get you more speed. Before redoing you're entire setup, I would get or build a 60V, 15a power supply and see the difference it makes.

Gerry

InventIt
12-13-2003, 06:23 PM
Originally posted by georgebarr
I am in the process of building my metal frame CNC. I am also using THK linear bearings. I have one question. How did you precisely drill all the holes for your linear bearings so that each hole is exactly evenly spaced? What sort of method did you use.

Thanks,

I used 3/4 cold rolled steel to attach them to. I just used a scribe to mark the center by dragging the point down the lenth of the steel while the other point hangs over the edge. The important thing in my setup was getting the two rails perfectly lined up with each other so they join correctly. Then just transfer the holes over from the THK rails and drill on center to THE SCRIBED LINE and the transfered line.

InventIt
12-13-2003, 06:36 PM
Originally posted by ger21
Are you still using that 1a power supply?...
Gerry

(Please understand that I can be hard headed about some things)

To answer your Q. Yes. Only 1amp, I do think that 1AMP should be all i need to get the unloaded gantry to make rapid moves. It seems I have an alignment problem within my lead screw/motor/nut and the drag is causing the actual problem.

However... I think the two lead screw idea is a bad one. Unless they are tied together mechanically and ONE motor controls them. So most likely I will head in another direction with this. I like the pulley/timing belt setup the best.

balsaman
12-14-2003, 06:30 PM
To answer your Q. Yes. Only 1amp, I do think that 1AMP should be all i need to get the unloaded gantry to make rapid moves

I doubt it. I troubleshoot for a living. If I have learned one thing it's, when in doubt, always try the easiest thing first.

Eric

InventIt
02-12-2004, 08:16 PM
UPDATE...

Well, this project has taken many different changes. That’s what happens when you build without a plan ;) I found out quickly that I have a lot to learn designing CNC tables. Anyway this is what happened.

Originally I was using one stepper motor on each side of the gantry to prevent racking. That did not work out so well since one motor can miss a step and the other motor has no idea its brother is not in the same place. I was testing rapid moves when one motor completely stopped as the other continued. It nearly twisted the whole frame and gantry out of square :(

The other problem I found was in the accuracy of my building of the lead screw and motor mounts/bearing mounts. All three pieces were not in alignment. This created a lot of drag on the motor as it tried to overcome the friction of the binding lead screw.

This picture shows the two lead screw assemblies after I removed them from the frame and squared/aligned the screws.

InventIt
02-12-2004, 08:30 PM
After becoming very frustrated with the light duty rectangular tubing I was using, I decided to scrap the first frame and make a new stronger frame. The new frame is made from 2” square steel tube 1/4” wall. This tubing is much straighter and the sides are flat and square. Also the small linear bearings I was using were looking like they would be too small to hold up to the forces of the router and the weight of the gantry. So I got some wide THK RSR15 linear bearings to replace the smaller ones. These larger bearings fit perfectly on the 2” tubing.

This is the pic of the second frame.

InventIt
02-12-2004, 08:35 PM
Here u can see a mockup of the new wider THK bearing sitting on top of the 2" sq tubing frame. Fits perfectly.

InventIt
02-12-2004, 08:38 PM
In the last pic the bearing was mounted directly on top of the tubing. I thought it would be better to make the design more modular. So I mounted the bearings on a piece of flat cold roll steel and then I'll bolt the steel assembly to the tubing frame. This gives me adjustment of the linear rails.

InventIt
02-12-2004, 08:41 PM
Bearing mount for the leadscrew. (That's not where it goes, it's just sitting there for the pic.) U can see the other on mounted under the rail.

InventIt
02-12-2004, 08:47 PM
This is the other end of the lead screw mount. The timing belt pulley will mount between the blocks. Both blocks are loaded with a plain ball bearing to support the lead screw on both sides of the pulley. This will eliminate flexing of the lead screw when the belt acts on the pulley.

InventIt
02-12-2004, 08:54 PM
WELL...

This is where things go in another direction again :) I found this beast at the metal supplier. 6” tall 4” wide and ¼” thick. This is going to be my gantry. I’ll attach my THK linear bearings to the 6” side of the tubing to make my X and Z axis.

Can u say ridged....

InventIt
02-12-2004, 08:59 PM
Here the gantry is just sitting on the linear bearings to get an idea of what I’ve got.

High Seas
02-12-2004, 09:04 PM
MASSIVE! WOW-OOO-WOW. THAT IS BIG! Don't let the gantry slip off the ways! You'll dent the floor.
:cheers: Jim

InventIt
02-12-2004, 09:20 PM
As u can see, I have seriously strayed from my original design. I wanted to make a plasma cutting table that could double as a router table. There just are not enough similarities in the two types of uses. The plasma needs fast movement, only two axes, and can be made from a light frame. The router table needs a sturdier frame, three axes, more clearance under the gantry, and slower speed. So, this table will most likely have to be dedicated to CNC routing and hopefully some light duty alum milling. I guess I'll just have to make a plasma cutting table too :)

Here is that beast of a gantry wearing its new linear bearings. I salvaged the smaller bearings and mounted them parallel to the larger ones to help prevent flexing of the Z axis. BTW, I have 40” of movement on the X and 38.5” on the Y axis. Plan on at least 10" on the Z axis.

ballendo
02-12-2004, 09:24 PM
Hello,

I won't argue that you're hard headed...

Why do you "think" that only 1 amp is enough?

I'm willing to bet it's not! And others have said so too...

What is the motor rating?

(Hint: If the motor rating is more than .25 amps, you're not being hard headed, you're ignoring reality...)

While a stepper won't use the full current ONCE it is at top speed, it DOES require current to get there...

The RESULT of your self-imposed limitation is good, IMO. Using one motor is nearly always a better idea. Having said that, there are a LOT of commercial machines --and homebuilts-- that work well with two motors. But they don't try to starve the motors for current becaust they "think" it's okay:D

Why not use a chain or timing belt across the machine to drive the 2nd screw. There is no need for the motor to be in the middle, so just change one motor mount plate to a bearing and make screw extensions to mount the pulleys...

Hope this helps, I sure don't understand why you won't try more amps... Oh well, to each his own.

Ballendo



Originally posted by InventIt
(Please understand that I can be hard headed about some things)

To answer your Q. Yes. Only 1amp, I do think that 1AMP should be all i need to get the unloaded gantry to make rapid moves. It seems I have an alignment problem within my lead screw/motor/nut and the drag is causing the actual problem.

However... I think the two lead screw idea is a bad one. Unless they are tied together mechanically and ONE motor controls them. So most likely I will head in another direction with this. I like the pulley/timing belt setup the best.

InventIt
02-12-2004, 09:29 PM
Here is a good way to convert your drill press to a thread tapping machine. Just took the motor belt off the pulley and use my cordless drill with the clutch set to prevent the tap from breaking. Takes a little coordination to hold the drill and guide the spindle into the hole, but it taps straight.

InventIt
02-12-2004, 09:32 PM
BTW, I am using spiral flute taps. These taps are awsome. One pass right through and the swarf comes OUT of the hole as a single twisted curl. Just like a drill bit.

ballendo
02-12-2004, 09:39 PM
Hello,

Since you appear willing to start over to improve things, you may want to put those expensive bearings on the SIDES of the frame, where they won't be as likely to attract dust and swarf. Don't forget to plug the mounting holes; it's easy for stuff to get in there and then from there into the bearing tracks themselves.

Moving the linear bearings will also make the machine stiffer. Take a look at the load directions and values for the bearings you're using...

Hope this helps,

Ballendo

P.S. Modern linear bearings often fail the TLAR test. Because we just don't believe that the small bearings can give the load ratings claimed. But they DO! The bearings you have now are FAR, FAR in excess of what's required...

TLAR= That Looks About Right

Case in point: Thomson improved their line of ball bushings so that you can basically use the next smaller size. But they report that the "old" sizes still sell as before. because when people go to purchase the item built using the "new" bearings, they fail the TLAR test, and the sale is lost. MFRS. realise this and use the bigger sizes even though the engineering doesn't need it! Ah, Human nature<G>


Originally posted by InventIt
Here the gantry is just sitting on the linear bearings to get an idea of what I’ve got.

InventIt
02-12-2004, 09:58 PM
Originally posted by ballendo
Hello,

I won't argue that you're hard headed...

Why do you "think" that only 1 amp is enough?

I'm willing to bet it's not! And others have said so too...

**Snip**
Hope this helps, I sure don't understand why you won't try more amps... Oh well, to each his own.

Ballendo

Relax ballendo. You’re telling me if beating on it with a small hammer doesn’t fix the problem… get out the sledge hammer :)

I understand the need for more amps. However, the problem was a misaligned lead screw that was binding. The motor has plenty of power, on 1 amp, to test my slide assembly if the screw was free to turn. Remember, I’m just testing my design before I move forward. The last thing I want to do is build a big mistake into the design. I want to know my design is going to work without problems. Now is the time to change things. Not after it’s built and running. The problem I had before with two motors was an eye opener. If I had 10 amps and the one motor stalled the other motor would have torn the whole table apart. What would that solve?

That problem justified my reasoning for tying the two sides together mechanically rather then solving the problem with more amps. I think I made the right decision even if others don’t.

InventIt
02-12-2004, 10:09 PM
Originally posted by ballendo
Hello,

Since you appear willing to start over to improve things, you may want to put those expensive bearings on the SIDES of the frame, where they won't be as likely to attract dust and swarf. **snip***
Ballendo

Yeh, was thinking about that. I didn't think about the dirt in the holes though. :( I was kind of leaning toward an enclosure on both sides of the bearings with a wiper where the upright to the gantry slides back and forth. Like a long bristle brush. That idea won’t work on the X axis though. I'll have to think about that.

foamcutter
02-12-2004, 10:27 PM
InventIT,
Your machine is looking great. Your a man after my own heart, I figure if you got it up stairs you don't always need to put it on paper. And when you do need to put it on paper, a napkin at the burger joint or an old business card works fine. I also agree with you let's get it right before we really put the coals to it and tear everything up. Anyway I just wanted to tell you, Ya do'in fine young man! Ron

InventIt
02-12-2004, 10:51 PM
This is a mock-up of the uprights. Just to give you an idea of how it is layed out.

I can't decide on a good way to mount my gantry to the uprights. I want to have it bolted in a way that it can be adjusted in both up/down and fore/aft. I was thinking of a large alum plate maybe 1" thick and sized to slip fit into the end of the gantry tube. then bolting the plate to both the gantry and the side plate in the picture. What do you think?

Whatever I do it must be strong and grab all sides of the gantry tube to tie it all together.

Any ideas?????

pack rat
02-13-2004, 12:35 AM
Nice work.I guess wherever you go you have CNC on your mind, even the metal supplier. Nice thing about carrying plans in your head is you can change them on the spot as soon as you see something that improves the idea.

InventIt
02-25-2004, 09:46 PM
WOW I'm excited...

I made my first cuts today. Actually, I was just testing the machines abilities and trying to get an idea of how good (or bad) things are going to work. Made a temporary mount for the Porter Cable 2.25 hp router. Just using the X axis I first tried a piece of wood. No problem. nice clean, smooth cut. About 40 IPM

U can see the temporary mount for the router just clamped to the gantry uprights...

InventIt
02-25-2004, 10:05 PM
I setup a 3/4” block of aluminum and made a few passes with a ½” ball end mill. Just a little vibration. Next I ran a ½” straight end mill at 32 IPM/15,000RPM through the aluminum. That worked great. One pass and a very smooth finish. I think the coolest part of this was watching the chips "spray" about 4 feet from the cutter as it went through the aluminum.

So now I’m feeling pretty confident. Decided “what the heck” I’ll try milling a piece of steel. It worked great. One pass 12 IPM/10,000RPM nice smooth finish.

So far so good. Now I just have to complete the Y and Z axis and tidy-up my mess of wiring. Can't wait to have three axis all working together.

This is a pic of the aluminum plate on the right, the steel plate on the left and the high helix end mill I used.

Mr.Chips
02-26-2004, 12:17 AM
Thats neat.
Some people run before they put on limit switches. But run before a Y AND Z axis? You win the first prize showing what can be done.
Good job InventIt, I'm just envious.

Hager

InventIt
02-26-2004, 09:31 AM
Mr. Chips
Yeh, I guess I just couldn’t wait to see what it can do. It gets difficult putting so much time and effort into something when you don’t even know if it’s going to work. I really needed some reassurance after all the time I’ve invested into the project.

I do need to mill slots into the back of my Z axis. Now I know I could use the machine, to do the milling I need, to finish assembly of the Z.

High Seas
02-26-2004, 11:37 AM
InventIt -
LOVE the adjustment for the belt tension and what a great 2-d machine (just "pushin' yer leg)! Its Real Cool!

Yo've been real busy and I ws just wondering, would you mind summarizing your system? I'd be interested in:
Computer Subsystem: Software, CPU speed, OS
Drive Subsystem: Motors (data too please), type rails, acme/ball screws (lead, starts, etc),
Controller Subsystem: Controller (driver), Power Supply
Results: Travel/Feed rates and (oh no!) Accuracy, Precision, Repeatability
Cost: (if you'd dare)

As much as you can stand to provide would be great.
Maybe we could capture your success and start a little database as to what works and how! You can pm me if you like - I'll collect and try and cook it down and post in Tech Articles if that fits.

Once I get a few inputs - I'll start a separte thread just for this - but first I'd like to see some input to make sense of the organization and display. Don't everyone write at once - I may need a new mailbox!

:cheers: Jim

HomeCNC
02-26-2004, 12:30 PM
Results: Travel/Feed rates and (oh no!) Accuracy, Precision, Repeatability

NO! Please not that again! :rainfro: :p

Mr.Chips
02-26-2004, 12:36 PM
Thanks for asking that Jim.
I'd like to see that in a standard format for every machine built.

It's a big help to beginners and saves the person building it a lot of time down the road answering the same question repeadily.
Hager

InventIt
02-26-2004, 01:28 PM
Originally posted by High Seas
InventIt -
LOVE the adjustment for the belt tension and what a great 2-d machine (just "pushin' yer leg)! Its Real Cool!

Yo've been real busy and I ws just wondering, would you mind summarizing your system? I'd be interested in:
Computer Subsystem: Software, CPU speed, OS
Drive Subsystem: Motors (data too please), type rails, acme/ball screws (lead, starts, etc),
Controller Subsystem: Controller (driver), Power Supply
Results: Travel/Feed rates and (oh no!) Accuracy, Precision, Repeatability
Cost: (if you'd dare)
*snip*

:cheers: Jim

Hey, the belt tensioner is just temporary until I can get more bubble gum from the super market. Then I'll fix it together. :) JK

************
Briefly these are the specs:
Acme 10 TPI 5 Start screws (1:1 belt drive)
440 oz in Vexta Steppers PK296-4.5A
Gecko drivers
THK RSR15W linear rails
2x2x1/4" steel tube frame
Porter Cable 890 Router 2.25hp
Mach1 on a P2 800mhz running under Win2000
motors turn about 700-800 rpm max = 350+ IPM
power supply will be 70V 8-10Amp w/10000uF cap

Have to get back to ya on the Travel,Feed rates, Accuracy, Precision, Repeatability etc.

High Seas
02-26-2004, 02:33 PM
InventIt - Thanks for That! The remainder as you get it. Gum - yeah....
Hager - We'll get this "sussed" - eh?
Home CNC - I hear ya! (But I JUST GOTTA know!)

PS - any other data/info that members feel is relevant - lets add it too.
:cheers: Jim

arvidb
02-26-2004, 05:17 PM
Originally posted by InventIt
I setup a 3/4” block of aluminum and made a few passes with a ½” ball end mill. Just a little vibration. Next I ran a ½” straight end mill at 32 IPM/15,000RPM through the aluminum. That worked great. One pass and a very smooth finish. I think the coolest part of this was watching the chips "spray" about 4 feet from the cutter as it went through the aluminum. *snip*

Oh, now I'm reeealy envious! :D That spraying of aluminum you talk about has been my mental picture and the driving force for my machine so far :)

Thanks for posting data on feed rate, RPM etc. Do you have a part number/manufacturer for that bit/end mill so I can look up what type, mtrl etc it is?

Thanks,

Arvid

InventIt
02-26-2004, 07:20 PM
arvidb
End mill is from American Carbide banner on this site.

# 7005000 and (ball nose) #4005000

InventIt
03-02-2004, 07:30 PM
Got the Z axis completed today. Just have to mount it to the X axis.

Two axis down one to go...

InventIt
03-02-2004, 07:41 PM
another view of the Z axis.
In pic the top plate mounts to the X axis and the tool/router mounts to the bottom, longer, plate.

I used a finer acme tread on this axis becuase it has less travel and I figured I could take advantage of the increased resolution.

Z - 10TPI - 2 Starts or 5 Turns per inch.
X and Y - 10TPI - 5 Starts or 2 Turns Per Inch

Testing showed about 150 IPM, so it's still pretty quick.

pack rat
03-02-2004, 11:00 PM
Superb job. You do nice work.

pack rat
03-02-2004, 11:57 PM
I reread the tread again cause I really like the design. I was wondering if you made the tap for ACME 10, 5 Start screw? That would make the 0.5" lead pitch, or two turns per inch. Are you getting that lead with the derlin nut? I was under the impression that I could only make homemade taps with 1 start lead. Thanks

InventIt
03-03-2004, 12:14 AM
Pack Rat,
Yes, I made a Acme tap for both the 10-5start and the 10-2start. Delrin taps easily. The hard part is getting the correct configuration on the home made tap. I cut small slots into the tap and they plugged up quickly. Larger slots would be better. Pushing the tap hard into the hole helps it to get started.

ynneb
03-05-2004, 02:18 AM
He he, The thing I like is the way you chop and change ideas along the way.
Trial and error as you go.
Better that way, than finish it and find it doesnt work.
I love the big photos. Pictures speak a 1000 words.
Keep posting them.

InventIt
03-10-2004, 11:22 PM
Made some progress...

It's actually stating to look like something. Finally got three axis working. Mounted a pen in the router and ran some gcode. It's really cool to watch it do it's thing :)

Next I'll work on the wiring and make a stand for it.

InventIt
03-10-2004, 11:29 PM
Cut these pieces the other day. They have a car theme, can anyone guess which? Think "Ram Air" and "Super Duty"....

Hobbiest
03-11-2004, 12:39 AM
lets see...Pontiac and Buick both made a 455 I think. Pontiac would be the one with the ram air though. GTO maybe? Are you impressed with the 8020 slides? doing some nice work there guy! How about some closer and different angles on the Z axis?

High Seas
03-11-2004, 08:15 AM
Solid looking machine. Like the 80/20 slides -- when can we see a close up of the slides?

They "look" sturdy and maybe DIY? Material? Delrin?

If you've beaten the worries over 80/20 slide systems not being tight - there'll be a big cost saving by using the frame as slide rails!
:cheers: Jim

ger21
03-11-2004, 10:46 AM
The slides are THK type. look at his previously posted pictures earlier in the thread.

Gerry

applewood
03-11-2004, 02:01 PM
It's a nice looking machine.......... I was born the son of a poncho buyen MAN............400 RAM AIR IV...........67 GTO is my fav. car period... 389 3 duces.Keep going Ill keep watchen.Ray

InventIt
03-11-2004, 08:39 PM
67 GTO...Very nice car. 69 GTO was my first car. Oh yeh, nothin like a 17 year old behind the wheel of a 350HP car. Spent more on gas and tires than anything else. Ah, the good ol days.

Hobbiest
03-11-2004, 10:09 PM
So did I get it right? OK...maybe it was the Judge?

InventIt
06-30-2004, 11:42 PM
Hobbiest got it right. Pontiac theme on the alum pieces.

Well, it's been a few months since I updated my build on here. So, here's where I am so far. I have most of the basic machine together and working. I guess I got caught-up in the software side of things. Anyway, still need to complete wiring, make a control box, build a stand etc.

So, here's a few more pics of what I have done recently and a few pics for those who asked to see certain parts.

Z axis. Simply a sandwich of two 3/4 " alum with THK slides mounted between them. Acme screw runs between with a large delrin nut inside conected to the front mounting plate. Stepper is mounted to the top of the back plate.

InventIt
06-30-2004, 11:53 PM
Another pic of the Z axis. Not a great pic but it shows how thin it is. Only 2" thick and very sturdy. Decided to use a finer pitch acme screw on the Z axis so the stepper would be able to easily raise the weight of the Z and any attachments mounted to it.

InventIt
07-01-2004, 12:04 AM
Ok, here's the fun part.

This pic shows the machine cutting a letter "T" from a 12gauge steel sheet.

I rigged my plasma torch handle with a wire coming out to connect to a micro switch that is mounted on the side of the torch holder. When the machine plunges down the torch holder hits the metal work piece and "floats" driving the Z axis down a small bit more activates the micro switch therefore stating the arc and piercing the workpiece. It works really well. Just pick the Z up and the arc stops via the switch.

InventIt
07-01-2004, 12:11 AM
This is the reason I built the machine to have a open area without mechanical parts under the working area of the gantry. Later I will build a sheet metal pan to catch the dross.

InventIt
07-01-2004, 12:18 AM
This shows the metal grate I built to hold sheet metal for plasma cutting. The grate just rests on the horizontal beams of the machine. It simply slides out to change to a different operation.

Soon I will build a table top for wood routing.

svenakela
07-01-2004, 06:15 AM
I've been thinking for a while, and this will for sure be my second project! :)
You've made a really nice machine.

-Sven

InventIt
07-28-2004, 07:29 PM
THK Rails and Paint :drowning:

Well, it's getting to the point where I may actually start to consider painting this beast. That thought brought up a question about the THK linear rails I have mounted on my router.

I'm not sure if it would be a good idea to remove them and paint the whole gantry or to leave bare metal exposed (on the gantry) where the THK rails are mounted? I was thinking that the paint may be soft and allow the rails to slip/move if I painted underneath them. If I mask out a area where the rails mount and paint the rest of the gantry (so the rails are securely mounted to the metal) it may be better.

What do you pro's think???

signIT
08-07-2004, 01:20 PM
Hi,

I have exact the same toughts about how to, I talked to a guy who makes skate grinding devices he sad that it really doesn't matter if you make a diy machine, it will be as good as you ever can expect.
But... if you are going to grind the surface before mounting the rails you have a tough job, I consider to order a special shim made of some fancy plastic and cut it out so it will fit the THK rails of course without painting just a slight spray with some good grounding like Loctite.

It is very hard to get high precision without a mechanic high tech workshop so I will enjoy what I can do with common sense.

Regards

SignIT

InventIt
08-13-2004, 07:52 PM
More progress.
Built a table for the router. Had a chip pan made for the table top, 18ga stainless with the edges turned up and tig welded to be water tight. Did this so I can add flood coolant later. Of course, it has wheels and leveling feet too. And a large drawer for tool storage. Later i'll add metal sides and maybe a dorr to the left of the drawer. :cool:

The second pic shows the aluminum disks i turned to rest the base of the machine onto the ss table top. I turned a groove in the face of the disk to insert a rubber O-ring for a seal against the table top so no coolant drips through the bolt hole.

InventIt
08-13-2004, 08:11 PM
Now I just have to re-assemble the top of the router. Then it's the dreaded wiring and control box that needs alot of attention. Ordered some limit switches from www.automationdirect.com (thanks to BigDaddyG for the link).

I'm thinking of buying a Komo Spindle off ebay. I think the heavy bearing and machine type collet setup would be much better for cutting aluminum. It's 3hp with a ER style collet. 5/8" capacity collets. I have a VFD for my lathe, I think it will run the spindle. Guy wants $675 for it. What do you guys think? Is a spindle like this much better than a Porter Cable 2.25 hp router? Any advice would be appreciated. Thanks, I have no idea what i'm getting into with this spindle.

InventIt
08-13-2004, 08:30 PM
Just wanted to say THANK YOU to CNC Zone and the great people on here. I know this project would never have happened without the awesome resources here.

ger21
08-13-2004, 09:50 PM
I think those are about $3-5000 new. Expect to pay about half if you have to have it rebuilt at some point. At work we have 9HP spindles, so I can't really say how much power the 3HP will have, but probably quite a bit more than the PC you're using. And it should last a LOT longer. They're very quiet, too. Sorry I can't be more help.

signIT
09-19-2004, 11:17 AM
Hi InventIt,

Just a question about your end bearing for the z-axis how do you manage the bearing for minimum play and what type of screw and nut are used?

I will start a cnc project with THK rails X and Y 640mm x 640mm the best reference I ever seen is your project very well done.

Greetings

Leffe

InventIt
09-20-2004, 10:45 AM
Thanks SignIT,
The Z axis screw is supported at the bottom by a bearing block that bolts to the z axis plate. I turned the acme screw down to 3/8 and threaded it with 3/8" fine thread then used a friction nut to get slight preload on the bearings. The bearing block is just a 3/4" thick alum plate with a pocket on eack side for a 3/8" roller bearing. The top of the acme screw is not supported, it just connects to the stepper via. a helical spring coupler.

Txfatboy
09-25-2004, 09:18 PM
Great Machine. I would like to see a final picture. Also what software are you using? :banana:

calaber40
01-04-2009, 07:21 PM
hi guys im new to this cnc stuff and a quik learner when it comes to building things. im well into my build and am at the point of installing my 2 screws under the table for my gantry. what worries me now is what i have read in regards to 2 stepper motors running each screw and having them go out of sink ,so to speak, and all hell brake loose. i was first going to go the one stepper motor in the middle with 2 screws and a timing belt .motion tech . the supplier of my rails and electronics advised that i would get to much backlash, this way.is this true ,or does he want to make more money off of me.lol.my machine is about 48''x60'' so the belt will be spanning about 20 to 24'' across. i am looking to cut foam , mdf . and useing a trim router . if anyone have any imput on this area of a biuld , it would be very appreciated.you can see my cnc in the photo gallery.[ these are the pros and cons i ponder]

CarveOne
01-04-2009, 09:04 PM
hi guys im new to this cnc stuff and a quik learner when it comes to building things. im well into my build and am at the point of installing my 2 screws under the table for my gantry. what worries me now is what i have read in regards to 2 stepper motors running each screw and having them go out of sink ,so to speak, and all hell brake loose. i was first going to go the one stepper motor in the middle with 2 screws and a timing belt .motion tech . the supplier of my rails and electronics advised that i would get to much backlash, this way.is this true ,or does he want to make more money off of me.lol.my machine is about 48''x60'' so the belt will be spanning about 20 to 24'' across. i am looking to cut foam , mdf . and useing a trim router . if anyone have any imput on this area of a biuld , it would be very appreciated.you can see my cnc in the photo gallery.[ these are the pros and cons i ponder]

I have similar concerns for my second build which will use dual steppers on the x axis. The Solsylva belt drive on my first build can slip if one lead screw binds and the gantry gets out of square. The dual stepper direct drive that I will use on my next build can have more serious problems if one side binds up while jogging at much faster speeds than I have available now. Just have to make sure everything stays in alignment and running freely.

CarveOne

calaber40
01-05-2009, 12:09 AM
hi inventit. i like the way you set up your pully system . is there a reason you went with three belts instead of one with a tensioner .and does the size of the pullies make for more or less backlash. eg. bigger pully more contact on the belt ,so more teeth can bite,that sort of thing.if thats the case ,does it effect the tork on the stepper motor if there bigger.and providing there all the same size.is it possible to get a more illistrated pic of the centre pully setup .really torn up at this point of my build . i dont want to spend 350.00 bones for another stepper , driver , and power supply ,only to find out it will work just as well with a belt system.plus i dont want to ever exsperience my cnc machine rip itself apart if one motor goes Awall lol.ps great build must have read it a dosen times thx .gino.

calaber40
01-05-2009, 12:20 AM
do you think adding a extra motor driver and power supply is cheaper than a pully set .if its less than 350.00 i think all go with the pully set not just for cost but also if something goes wrong it wont tear my cnc all to hell.and exercisums are not cheap either.as a new be at this they say sh??t happins,and it will.any good place to pick up some pullies and belts at a good price?.