[ny_racer_xxx]

OK, I took the first step and bought the brackets for the gantry off ebay....

I plan on building a gantry that can handle 24x36, ultimately plasma, some testing with a router, maybe a drag cutter, and probably testing the whole rig out with some sort of crude plotter.

Basic Design:
Square Tube Skate Bearing Design, Rack and Pinion Driven XY and Screw Driven Z axis

Pre-made Gantry Bracket Kit
6008 Bearings/Hardware Etc
14-1/2 Degree Pressure Angle Gear Rack, 24 Pitch, 12 Tooth Pinion
Gecko G540/270oz motors, 48v 7.3 Power Supply
Mach3

I almost bought a TB6550 clone kit off ebay, the price makes it sound so attractive, but even if I get it working correctly, with only a 24 volt power supply, the performance wouldn't be that good, and the support of the G540 Mach3 can't be matched...

Attachment 265632Attachment 265634

[ny_racer_xxx]

I have the square tube cut for the gantry, not much to look at, but I'll post some pics of that later.
Received my electronics from Automation Technology Inc. I was going to order from Kelling, but it looks like Automation is the "store" for Kelling.

I bought their G540 Hybrid 270oz 3 axis system that included a 48v PS, I also added an additional 270oz stepper for my Z axis.

Speaking of which, that's about the only thing besides a plasma machine I'm waiting on. I ordered a ebay special out of Canada for the Z axis. Delrin bearings and nut, and using a 3/8-16 threaded rod for drive. I might upgrade that later to a acme thread or ballnut setup.

McMaster is due in today from UPS with the rack gear and hardware...

[ny_racer_xxx]

Well, got the gear rack and pinions from McMaster... I should have realized that the plan called for a 20 pitch, 20*pa rack, that's 1/2" x 1/2". Th issue with the 20*pa rack is that I couldn't find a pinion with a 1/4" bore, so I went with a 14-1/2*pa rack that I could get the correct pinion, but..... The 14-1/2*pa rack is 1/4" x 1/4", and the pinions won't line up!!!! FUDGE!!!!

I did find a plastic pinion from MSC in 12t, 20 pitch, 20pa in 1/4" bore.... Sigh.... MSC PN #03115227, which is actually a Plastock 20-12. 20-12

So the 14-1/2*pa goes back, and I reorder the 20 pitch, 20*pa rack...

I didn't like the 1/4" x 1/4" stock anyway, really flimsy and really crooked....

CR

[Torchhead]

If you want those smaller motors to give you decent acceleration consider the nice gear reduction units from CNCRouterParts for the 23 frame motors. The gear on the 23 model is a 20-20 pitch and you can get it for 1/4 or 3/8 shaft motors

Standard Rack and Pinion Drive, Nema 23 | CNCRouterParts

[ny_racer_xxx]

Thanks for the information, I've looked over their stuff... The problem is my brackets will only accept a direct drive...

This is my starter setup, I plan to upgrade at some point....

On another note, I got it all wired and powered up today, installed Mach3 demo real quick, couldn't get anything to move. I have to go through Mach3 better to make sure it's setup correctly...

CR

[ny_racer_xxx]

Got the motors moving today, the old laptop was the culprit. I tried another IBM Thinkpad I have, fired right off....Attachment 267140Attachment 267142

I ran the motors first with the default config, and the G540 had all the wrong ports, x was y and a was z...

I loaded the Gecko G540 profile, and everything was happy, I even managed to get the x axis slaved....

[ny_racer_xxx]

I received the correct rack and spur gears today. I also received my Z axis.... I had to tap the plastic spur gear for a set screw. Mocked up the gantry, barely moves, and no torque? WTF? Checked the motor, everything looks fine, sounds like the gear is slipping???
Checked the power supply, 48 volts.... Hmmmm, checked my resistors, 500 ohm? Huh? OK, the values I picked would give me 2.8k....IF IN SERIES!!!! In parallel, gives me about 500 ohm, not good.
Changed out the resistor to 2.8k, PERFECT!!!!!

[ny_racer_xxx]

Quick mock up of the gantry with the Z axis drive....

[ny_racer_xxx]

Mostly together, gantry done, frame done, calibrated x and y axis, ran a quick test drawing...

[ny_racer_xxx]

Setup the Z axis, built a better plotter pen... I pretty much have everything sorted, I ordered a Dewalt 611 and mount today... I also order some motor covers and drag chain to neaten everything up a bit...



Finished product:
Attachment 269280

[ny_racer_xxx]

Controller screen shot while plotter running...

[ny_racer_xxx]

I finally got fed up enough with the plastic gears... I called the manufacturer, and they suggest drilling and tapping the plastic for a set screw to secure the gear... The set screw keeps backing out, and slipping down... I couldn't find one and I don't think they make a 20 pitch, 20 pressure angle pinion with a 1/4" shaft. What the stock gear is a 5/16" bore and drilled for a roll pin.
So what I did was source a bushing that's for a 1/4" shaft and 5/16" OD, then drilled the roll pin bore and tapped that for M4 thread. So far it looks a lot better, but I haven't tested it yet.

I also got in the NEMA 23 Covers and jacks for the motors to clean up the wiring, and also a Kelling G540 control box to clean up the PS and controller. I sourced some control cable from McMaster, and I have three 1 meter sections of drag chain coming, that should clean most everything up...

Attachment 269588

[ny_racer_xxx]

Got it all back together jogged it back and forth a couple of times, all looked good...
Tested the inputs for the limit switches, I found input 4 is dead. Called tech support at Gecko for the G540, basically useless. Now it's in solid fault, and has to go back...

I paid more for what I thought was a better product than some of the Chinese stuff, but that G540 is junk!!!! I should have known when I first got it, it so small and flimsy looking. It's easy to hook up and get going, but not very robust, just real crappy and more "Chinese" feeling than the Chinese stuff!!!!

Hopefully I can get my money back and put together a BOB with separate motor drivers, probably end up cheaper...

CR

[ny_racer_xxx]

I ended up getting a replacement G540, best i could do in short notice. Folks at Automation Technology were very understanding...

Put it back together, built a spoilboard frame and trued up the spoil board... Working on drilling the spoilboard for Tee Nuts for hold downs..
I have this idea for hold downs made from 3" aluminum channel...

Attachment 274536

[ny_racer_xxx]

Making some Anti-Roll Bar Bushings

Finished Products
Attachment 275770

[BTA PLASMA]

The G540 is a decent box but in the CNC plasma realm it really needs to be used in a way that doesnt allow the drives to take a grounding. The G540 is prone to noise issues as well. We have a G540 working on a Thermal dynamics hi frequency unit since 2011 and one on a Maxpro 200 since 2013. Properly shielded from the EMI they will last but that is something rarely done in the industry. The G540 is almost what I would call hobby grade but anything in any configuration made to work in production should not always be called hobby grade. The build is looking interesting. One thing you may notice from direct drive is a fast rapid but a massive torque loss at higher acceleration rates and those rates used by folks running a reduction. A 20 pitch gear with a .750 pitch diameter or even a .625 diameter is much smoother than a 14.5 degree pitch gear and rack so your definately on point there

[ny_racer_xxx]

Thanks for the kind words, I was starting to think I was talking to myself!!!!

The G540 is working fine now, must have been a bad unit... The thing that bugs about the G540, is what they charge you for a really flimsy crappy little unit... It works well, it's pretty much dummy proof, but it's not very robust. If it's going to be a hobby unit, then it should be about 1/2 that price, and if it's suppose to be a professional unit, then it should be a bit more sturdy...
You can buy one of those crappy Chinese TB6560 boards for $75, if somebody put 1/2 a thought into designing a good one, I can't see it costing more than $150.

I did some .125" steel plate last night, did a lot better using climb milling versus conventional...

[daniellyall]

I have a G540 been running for 5 years with not a single problem you just need to connected them up the correct way

[ny_racer_xxx]

And that's another thing.... It should have some kind of circuit protection against hooking up wrong, ie, a diode or a fuse...
Like I said, the thing works fine, I just think it's a bit pricey and kind of cheesey for what you pay....

CR

[alan_3301]

You cut this out with a router?
what kind of bit and feed / speeds did you use?

Thanks for the kind words, I was starting to think I was talking to myself!!!!

The G540 is working fine now, must have been a bad unit... The thing that bugs about the G540, is what they charge you for a really flimsy crappy little unit... It works well, it's pretty much dummy proof, but it's not very robust. If it's going to be a hobby unit, then it should be about 1/2 that price, and if it's suppose to be a professional unit, then it should be a bit more sturdy...
You can buy one of those crappy Chinese TB6560 boards for $75, if somebody put 1/2 a thought into designing a good one, I can't see it costing more than $150.

I did some .125" steel plate last night, did a lot better using climb milling versus conventional...