[RLC]

Hey Guys,
New here, so I hope this is the right place to post.
I currently have a RF31 (round column) Mill/Drill with an off the shelve CNC kit. I went this route 1st (a) bolt it on and go (b) technical support (c) wasn’t sure if I would keep the mill or buy a bigger one. After 2yrs I have found that the round column is not a problem for me, how ever, 2amps and small steppers (260 oz/in) is. I have decided to “Roll my Own”. After countless hours of reading on the web here is my plan.

(3) Gecko G202 Drivers > Geckodrive
(3) 640 oz/in Steppers (sealed) > Campbell Designs
(1) Breakout – Combo Board > Campbell Designs
(1) Mach 3 software > Artsoft Software
(1) 48vdc ~ 15amp power supply > Transformer Technology Inc.
(extra amperage is for 4th axis down the road)
(1) I-Pac keyboard emulator > Ultimarc
(A) 0.875” Ball screws on the “X” & “Y” > undecided on a vendor

I’m in the process of building a stand from 2” sq tubing to support the machine then adding an 11ga pan and sides for flood coolant (similar to the Tormach stand) then off to have it powder coated. I constructed an aluminum enclosure that houses the PC, 15”LCD monitor, USB mini keyboard and Joy Stick. There is still plenty of room in there for the other items listed above, I’m hoping with shielded wire and good placement of components that this wont be a problem (electrical noise). To the left of the monitor is panel 6.25” wide by 17” tall to add buttons and switches and possibly an MPG down the road. There are still things that need to be worked out and/or purchased, but I believe these will be minor hurdles. Sorry for such a long post but I wanted to paint the best picture I could so that anyone wanting respond would have a better idea of what I was doing. I’m sure there are other products out there that would cost less, but these guys seem to go the extra mile to help out.

Robert

[Karl_T]

Seems like you've got a good plan. But, I think you'll get this all done just to find that your machine is no longer rigid enough.

I'd consider starting with a CNC machine with a dead control. Then you already have the large steppers (or servos) and ball screws. Sell yours to buy the parts you need. This one just went on ebay last week:

http://cgi.ebay.com/Bridgeport-Serie...QQcmdZViewItem

Karl

[Ron111]

RCL,
It does sound like you have a plan. If you like your present mill go for it. I have 1 question. How could you learn so much with out having to ask a single question? Noticing that this is your first post. I am impressed.

As you know, post a few PICs (for those of us that are easily entertained). I sure you have found the documents and articles for building your power supply and for connecting steppers and other stuff. We have not had a good thread about CNCing a RF-31 in a while and I as well as others certainly will enjoy following your progress.

After reading you post again, it sounds like you had already cnc your machine once and are upgrading to a stronger drive system.

Well welcome to the forum!!! and do share your conversion with us. Look forward to seeing it go together!!

Ron

[ViperTX]

Welcome RLC, depending on which part of the country you're in....I would look at getting a VMC or other CNC machine with a dead controller as Karl_T stated.

[RLC]

Finding a good used machine isn't an option for me..Texas is a big state I live as far south as you can get, there are some machines coming out of Mexico that I have looked at but most of them are in really bad shape (I have seen as much as 75 thou or more backlash). I read alot of posts about the round column, but I like the fact I can swing the head out of my way for set-up. I have never had to make any changes to the head once I have started a project nor have I had it Slip. There are several Mini-Style VMC out there in the $30k range that are nice, but in the past 2 yrs I only have about 70hrs total on my mill/drill...I will try and document my progress and I sure there will alot of questions to come

Robert

[RLC]

I've up loaded a few photos of the coolant tub. here is the link (maybe)
http://www.cnczone.com/gallery/showg...ser/16333/sl/r
They are in members galleries

[RLC]

Got my motors and break out board in today, Geckos and power supply should be here with in a few days. With the plug and play assembly of PC's my control panel so far was really easy..now the "Plug and Pray" starts. seems there is alot of wiring that needs to done...hopefuly no "Magic" smoke will come out. I'm also posting a bearing support design in the photo gallery to see what you all think.

[Ron111]

Saw the bearing block with the angular bearings and thats the way to go. Have you worked out your preloaded ballnuts yet? Lots of details, but your clipping right along.

Ron

[RLC]

Ron,
haven't even checked on that yet, I knew the bearing / supports it has from the factory are junk as far as trying to remove any play in the screw. And 3 bearings on 2 screws wasnt going to work either. Like I mentioned earlier the mill has a cnc kit on it now (way too slow, 10ipm). I'm working on the coolant and the new controller. will get the coolant up and going with the old sytem to make the new parts needed

[RLC]

I was wondering on the coolant pump if your could use a Cartridge type Bilge for the boating industry? They generally live in some pretty rank conditions and and can pump 800gph? The cartridge is cleanable as far a debri getting into it.
Thanks in advance

[kochevnik]

Keep in mind, the Gecko 201 and 202 series are 10 microstep drives. For example on my machine, I use 200 steps/rev steppers (standard) and a 20 TPI screw. The parallel port gives me about 16000 Hz under turbocnc. So 16000/(200 * 20) means 4 inchs per second (240 IPM) MAX for full step drivers. If I would be using a Gecko 202 like you, the max speed I could get would have to be divided by 10 (microsteps) giving me just 24 IPM MAX speed.

201 & 202 - very accurate/smooth but not very fast
210 & 212 - more choices between speed and smoothness

YMMV

[project5k]

:cheers: way south texas huh?!?! im in seguin, not all the way to the bottom, but close enough...:cheers: just thought i'd give you a howdy and a wave!

[RLC]

kochevnik,
using your formula and my numbers I come up with about 96ipm, which is plenty fast for a mill/drill. I uploaded a few photos of the controls. Hopefully will be able to get back on the stand / coolant in the morning (work keeps getting in the way). Nice size shop your building JP.

[philbur]

I think there's a typo in the formula. Should it be 16000/(200*20). 4"/sec though seems to be the correct answer. However 20 TPI seems rather fine for a lead screw.

Regards
Phil

Keep in mind, the Gecko 201 and 202 series are 10 microstep drives. For example on my machine, I use 200 steps/rev steppers (standard) and a 20 TPI screw. The parallel port gives me about 16000 Hz under turbocnc. So 16000/(200 * 2) means 4 inchs per second (240 IPM) MAX for full step drivers. If I would be using a Gecko 202 like you, the max speed I could get would have to be divided by 10 (microsteps) giving me just 24 IPM MAX speed.

201 & 202 - very accurate/smooth but not very fast
210 & 212 - more choices between speed and smoothness

YMMV

[kochevnik]

philbur - yeah, thanks, I fixed that. I'm running a TAIG and I just bought a Gecko and got this question answered by Mariss, so that's why I contributed to this thread.

One thing I notice no matter how fast your mill is, you always want something faster.

[RLC]

I haven’t really had any time to work on the conversion or the coolant tank. I did run across 14-lighted switches from 2 old video games, I was able to salvage them before the games were trashed. Have been playing with mach3 to see which buttons I want as a physical button on the control panel. I have seen some really good panels here and there for use with mach3 but no good articles on actually setting them up. I have some photos of my control panel (less some of the buttons) I will try and get uploaded here in a few days. I have kind of decided to wait on the ball screws till a later date seeing how I have 2 jobs coming up that will require a lot of machining.

[RLC]

Finally got back on the coolant tub today, taking a break from welding so it doesn’t warp the 14ga steel. I found the disk with a few photos of the console, they have been uploaded into my photo gallery. Camera was left at home will get some photos of it completed (less powder coating) soon. I have added two ¼” NPT couplers through the back right corner 1 will supply coolant, the other is for regulated air for blowing off parts before removing them. I plan on getting the mill mounted to the stand/tub in the morning, and might even rig some plumbing and make a few cuts with coolant.

[RLC]

Once again I was side tracked from the project (work....lol). A few design changes also slowed me down. After cutting the opening for the doors the front was a little flimsy so I've added 1" angle around the top edge for support. Originally I had planned on powder coating the stand/tub but now I'm considering having the inside sprayed with rubberized truck bed liner. Hopefully this will do several things: seal if any pin holes (leaks) in the welds, cut down on any resonance (seeing how this a open box) and give cutters and parts a soft place to land should they be dropped. Anyone ever use bed liner for this? 3 new photos have been added to my gallery, time to get back to the project.

[saris]

Why are you going with the gecko g202's? Save some money get the g201's. I think there exactly the same, except the 201's have an idiot proof circuit, preventing miswiring.

Just follow the schematic and save 80 bones!

Buy a few cases of brewskis:rainfro:

[RLC]

I have a question about power supplies, after reading several articles its seems standard that the power supply should be 20 times but no more 25 times the rated voltage of the stepper motor but in reading the documentation on my gecko 202’s it states that a minimum of 4 times the voltage is needed. My motors (3 total) are rated at 5.5amps and 2.3volts, which equates (using the 20~25x) to 48vdc/11amp power supply. What would the disadvantage be of using a powering supply rated at 35vdc/15amp. I had originally planned on purchasing a power supply but do to the cost I started looking at building my own. The problem I have ran into is that the transformers rated for my needs start to get pricey as well, but if I drop the voltage requirements down they come back down to around the $100.00 range for the complete power supply. Not being an Electrical engineer nor knowing enough about electronics thought I would get some input from the people that do know.