OzarkCNC - Arkansas CNC ROUTER Project

[OzarkCNC]

Greetings from the heart of the Ozarks!

This is my first attempt at building a CNC router. I have been reading and reading this and other sites to learn as much as I can and I think I am ready to begin.

Most of us 'guys' have to slip these projects under the WAF screen. (Wife Acceptance Factor) but after showing some of the finished work many of you have shared here, my S.O. has decided that I should build this. That leaves the first hurdle scaled with not even a scratch.

And, she even wants to HELP!

So let us begin:

Design: Adopting a partial JOES2006 and phooddaniel (www.buildyourcnc.com) concept.

(I dont have drawing software, so if anyone can point me to a free alternative, I can sketch up my plans)

Motors: 4 - Keling 425 or 495oz/in NEMA 23's. (If I don't use dual X then I can use the 4th for the A axis.)

Lead Screws X & Y -ACME 1/2-10 2 start and Dumpster nuts or maybe Rack & Pinion for X & Y with 1/4-20 ACME for Z.

Driver: G-rex 101 (It future proofs me to 6 axis later on.) The G-rex 100 looks snazzy, but is twice the price for the same functions. If anyone can tell me a good reason to go with the 100 rather than the 101, I'll consider it instead. I also looked at other geckos for their max 80VDC, but who really needs that much voltage anyway? Grex and HobbyCNC drivers operate at 50V or less.

Controller: I wanted to use EMC2 in the worst way with LINUX. But, if I go with a G-REX 10* driver, there is no way to interface the two. Waaa!!

So it looks like Winderz and Mach3 for now. Unless I go with other gecko drivers and use the printer port. Then I can use Linux and EMC2.

A DIY power supply made with a toroidal transformer and dual 10,000 to 16,000 uf caps. I'm looking at a few Antek transformers, but not sure what I can use with the 50V limit of the GRex. I don't want to fry anything with backcurrents.

Decisions.. decisions...

Skeleton:

Length:50-60"
Width: 30"
Height: 8" Z travel with total gantry height ~18"-24"

X torsion box: MDF with 2 - 1" black pipes or CRS angle iron each side and skate bearings for the linear slides.

Y torsion box: MDF with a single 1" pipe/angle top and bottom. (like Joes)

X axis: MDF or masonite(hardboard) with 3/4" drill rod. I'd like about 8" travel.

At some future point, I'd like the Y gantry to tilt 90' (or at least 45') so that my n'th axis can be for turning spindles or table legs with intricate designs. Sort of like a faux B axis.

And finally the heart of the build, the router.

A Dewalt 625 3HP variable speed. I realy like this unit. I've used it and wouldn't trade it for anything!

Maybe someday I can go to a flexdrive cable type spindle. That would make the 90' Y gantry movement easier as well as lighter. I wouldn't have to push 16# of router around.

Thats it for the preliminary in my head design.

Any thoughts so far on something I may have missed?

OzarkCNC

[rustamd]

Looks like it'll be nice machine!

As for software, you can use sketch up by Google, here is link:

http://www.sketchup.com/

[OzarkCNC]

That sketchup program is good for a freebie. I must have a learning curve though, since all I was able to do in the last hour is make a plywood box, then I hit a wrong button and skewed it up. (Or was that screwed) Oh well...

Back to the ole drawing board.... again.

I played with Alibre a little bit last night. Man that is nice, but again, took me an hour just to make a box. I might have to forego the drawn plans and just build it as I go.

Thanks for the link...

Back to my build...

I am ordering most of my costlier parts this weekend. Then heading to the lumberyard early next week.

OzarkCNC

[turmite]

QUOTE=OzarkCNC;347863]Greetings from the heart of the Ozarks!

This is my first attempt at building a CNC router. I have been reading and reading this and other sites to learn as much as I can and I think I am ready to begin.

Most of us 'guys' have to slip these projects under the WAF screen. (Wife Acceptance Factor) but after showing some of the finished work many of you have shared here, my S.O. has decided that I should build this. That leaves the first hurdle scaled with not even a scratch.

And, she even wants to HELP! Now that is great![

So let us begin:

Design: Adopting a partial JOES2006 and phooddaniel (www.buildyourcnc.com) concept.

(I dont have drawing software, so if anyone can point me to a free alternative, I can sketch up my plans) There are tons of free cad systems out there. Following are some links.

http://www.freewarefiles.com/cat_3_3...eling-CAD.html
http://www.freebyte.com/cad/cad.htm#2D3DCADSystems
http://www.eland.org.uk/pages/Misc/cadnotes.html
http://www.cadlogic.com/products/draftit/ That ought to keep you busy a few days trying all those out!!!!!


Motors: 4 - Keling 425 or 495oz/in NEMA 23's. (If I don't use dual X then I can use the 4th for the A axis.)

Lead Screws X & Y -ACME 1/2-10 2 start and Dumpster nuts or maybe Rack & Pinion for X & Y with 1/4-20 ACME for Z.

Driver: G-rex 101 (It future proofs me to 6 axis later on.) Mach3 give you 6 axis of control as well.The G-rex 100 looks snazzy, but is twice the price for the same functions. If anyone can tell me a good reason to go with the 100 rather than the 101, I'll consider it instead. I also looked at other geckos for their max 80VDC, but who really needs that much voltage anyway? Grex and HobbyCNC drivers operate at 50V or less.Well let me start by gently correcting a slight misunderstanding you have. The Grex whatever # you apply to it is not your drive system. the Grex is a high speed pulse engine that basically takes the place of the pc in that it supplies step and directions signals. Mach is the user interface used to be able to control the step and direction the Grex outputs. Your drives will be something you build or you could buy them from Gecko, ie 201 up through 20? for step motors and the servo drivers are numbered in the 300 series. Even if you choose to use a Grex, you still have to have these drive components.

Controller: I wanted to use EMC2 in the worst way with LINUX. But, if I go with a G-REX 10* driver, there is no way to interface the two. Waaa!!

So it looks like Winderz and Mach3 for now. Unless I go with other gecko drivers and use the printer port. Then I can use Linux and EMC2. I will not try to disuade you from EMC2, but if you will look at the number of people having success with Mach and compare that to the number of people having success with E, I think you will come to the conclusion that Mach is a much easier way to go, even if it does requires winderz!

A DIY power supply made with a toroidal transformer and dual 10,000 to 16,000 uf caps. I'm looking at a few Antek transformers, but not sure what I can use with the 50V limit of the GRex. I don't want to fry anything with backcurrents.

Decisions.. decisions...

Skeleton:

Length:50-60"
Width: 30"
Height: 8" Z travel with total gantry height ~18"-24"

X torsion box: MDF with 2 - 1" black pipes or CRS angle iron each side and skate bearings for the linear slides.

Y torsion box: MDF with a single 1" pipe/angle top and bottom. (like Joes)

X axis: MDF or masonite(hardboard) with 3/4" drill rod. I'd like about 8" travel.

At some future point, I'd like the Y gantry to tilt 90' (or at least 45') so that my n'th axis can be for turning spindles or table legs with intricate designs. Sort of like a faux B axis.

And finally the heart of the build, the router.

A Dewalt 625 3HP variable speed. I realy like this unit. I've used it and wouldn't trade it for anything!

Maybe someday I can go to a flexdrive cable type spindle. That would make the 90' Y gantry movement easier as well as lighter. I wouldn't have to push 16# of router around.

Thats it for the preliminary in my head design.

Any thoughts so far on something I may have missed?

OzarkCNC[/QUOTE]

Hopefully the links and info I gave you will help

Mike

[OzarkCNC]

Originally Posted by turmite Well let me start by gently correcting a slight misunderstanding you have. The Grex whatever # you apply to it is not your drive system. the Grex is a high speed pulse engine that basically takes the place of the pc in that it supplies step and directions signals. Mach is the user interface used to be able to control the step and direction the Grex outputs. Your drives will be something you build or you could buy them from Gecko, ie 201 up through 20? for step motors and the servo drivers are numbered in the 300 series. Even if you choose to use a Grex, you still have to have these drive components. Mike

Well that never even entered my mind that the GREX was just an INTERFACE rather than an all-in-one driver. Shhhhhhiiiippp!

That changes everything. I dont want to pay $200-400 just for the luxury of using ethernet instead of the printer port. I still need to hook a computer to everything anyways. Maybe somewhere down the road yes, but I am just a po' boy.

So then the next question that this poses is that I would still need to buy 3 or 4 gecko 201, 202, 203V's to drive the steppers.

Sooooo-

Would I not be better off choosing the HobbyCNC HCNCPRO board that does the same as all of the gecko's combined?

Is this right? I am a little cornfuzed at the moment.

Therefore, by going with the HCNCPRO board, I can only use the Keling KL23H286-20-8B 425 oz/in steppers and not the 495oz/in steppers.

(The 495oz/in steppers are 4 wire and the hobby board doesnt support 4 wire motors)

I could however use other than Keling as long as they were moer than 4 wire steppers.

GROAN

I wanted to have everything here in the next week or two. I guess I didn't have this thought through as I had planned.

I'm going to bed, maybe I can get a clearer grasp in the daylight. Zzzzz

OzarkCNC

[BobF]

[QUOTE=OzarkCNC;348271]

Sooooo-

Would I not be better off choosing the HobbyCNC HCNCPRO board that does the same as all of the gecko's combined?

Is this right? I am a little cornfuzed at the moment.

Therefore, by going with the HCNCPRO board, I can only use the Keling KL23H286-20-8B 425 oz/in steppers and not the 495oz/in steppers.

(The 495oz/in steppers are 4 wire and the hobby board doesnt support 4 wire motors)

I could however use other than Keling as long as they were moer than 4 wire steppers.

GROAN

Get the HobbyCNC kit with 305oz motors. The motors match the board. Not all steppers are rated the same. Apparently the amount of torque you can get depends on whether the driver board is bipolar or unipolar.
I got this in another post.
"I would go with the 305oz in, they can be used later on with a bi-polar board at 425oz in. providing they have 8 wires.

Joe
"
It would appear to me that the motors are the same at least rating wise. They do have 8 wires by the way.
The HCNC kit has everything you need minus a transformer and enclosure. I have my kit built and the motors hooked up and they appear to work well. Of course they are moving nothing but air at the moment.

[turmite]

I just went to their site........wow what a deal. I am not one to normally recommend someone build their first machine with kits, but they have a 4 axis, 4-305in 23 frame motor combo for $192. I'm thinking that is a great deal, assuming you can solder the pcb and compontents correctly. With 6 thumbs on two hands, I find it kinda hard!
Mike

[OzarkCNC]

Originally Posted by turmite I just went to their site........wow what a deal. I am not one to normally recommend someone build their first machine with kits, but they have a 4 axis, 4-305in 23 frame motor combo for $192. I'm thinking that is a great deal, assuming you can solder the pcb and components correctly. With 6 thumbs on two hands, I find it kinda hard! Mike

I went to look again. So I had to order it.

Is anyone here using the 4AUPC driver kit? Any comments? Good-Bad-Ugly?

The deal looked mighty fine for a beginner like me. I can always upgrade later.

I am basically buying the motors and the chopper board is free.

Now the only bad thing is they are gone for 2 weeks. So even though I ordered today, my stuff won't be shipped til after the 10th.

I should be just about ready for the electrics by then.

OzarkCNC

[OzarkCNC]

1018 or 4140

Mcmaster has 1018 1/2 10 2 start 6' threaded rod for $52.11 each

the 4140 is 79.42 each.

Is the harder 4140 worth the extra $27?

[turmite]

Have you considered timing belts as your drive mechanism? I've read it is much smoother and faster than threaded rods.

Mike

[OzarkCNC]

I've considered belts and rack and pinion.

Honestly, I dont know enough about belt pulleys and gears to know how to reduce the speed down to a level that the 305oz/in motors can easily pull.

What about the belts stretching/backlash? Is that a problem? My gantry is probably going to weigh in at close to 30# when complete.

If you can help me pick out the components, I would gladly try to do it that way. Belts are faster and wouldnt cost me $100+. PM me or point me to PICTURES. I am a quick study if I can see a picture of it.

*EDIT* I've looked on the ECONOBELT website before. Just looked at it again and the SDP-SI website too. They both probably have what I need. I just am not sure what I would need. I would still need some sort of screw for the Z axis, or a combination belt and screw. *END EDIT*

OzarkCNC

[OzarkCNC]

OK here goes my thoughts on belts after much reading.

I could probably do it, but still have trouble with the concept of how far to gear down the motor (or at all).

T will be considered gantry travel at 1 revolution of the stepper. Since the stepper can rotate at up to an arbitrary value of 1000 RPM, I would think that the pulley should be quite small.

So to figure out T I needed to put the smallest pulley available on the motor which would be 10 tooth.

THe 10 Tooth pulley has a diameter of .617".

So T= .617 * 3.14159 = 1.938" per revolution

A stepper has 200 steps per revolution.

1.938/200 = .00969 at 1:1 (.010 rounded) Pretty coarse, isn't it?

My 4AUPC driver has 1/2, 1/4, 1/8, and 1/16 micro stepping. This means that I can get down to .010/16=0.0006" per step theoretically at 1:1.

This only leaves one question unanswered. Is the 305oz/in stepper going to be able to haul the 16# router plus the weight of the gantry at 1:1?

Also at 1/16 micro stepping, I can ideally get rapids of *up to* 121 IPM,. But only in a perfect world that doesn't take into consideration mass and acceleration.

Am I on track so far?