Datacop's JGRO Build

[guerd87]

Im currently playing with a version of RhinoCAM I have, but Ive used the trial for vcarve and cut2d and seems so much easier. I might buy it one day.

I would paint them all in complete sections unless you really need to unbolt some part of it

I would do:

Gantry
X axis
Z axis
Cutting Bed
Bottom torsion box and end supports

With mine I screwed and glued the bottom torsion box to the ends as I dont need to move mine around, if yours are bolted you might want to separate them. When I painted my gantry first I used some builders putty around the edges to seal it up and then sanded it off, talk about time consuming! For the bed I just used some really thick paint on sealer and it worked just as good.

[datacop]

In preparation for the final build stages for my JGRO, I turned my attention back to the electronics..

If you've read my HobbyCNC build thread, you saw that I had hard-wired my steppers directly to the controller. This worked fine for testing, but "real world" means that I would need a way to separate the steppers from the controller from time to time.

I went down to our local Fry's (http://www.frys.com/) electronics store and purchased 16x 9 pin D-Sub shells and a pack of 10x 9 pin male and 9 pin female connectors. I cut the steppers free from their umbilical cord and wired up the connectors. I put male ends on the controller and female on the steppers. I also took a step further and wired up the splices for the 8 wire steppers to 6 wire controllers in the male 9 pin D-Subs in the controller. This allows me to use a standard 9 pin "Extension" cable between the steppers and the controller (although, I'm going to make my own).

With the steppers free, I can turn my attention back to mounting them on the machine and finalizing the assembly. I hope to be cutting chips by the end of the month if all goes well!

[datacop]

I'm to the point where I need to install the motors and threaded rod.. but the plans JGRO drew up is absent of the motor couplers.

I was wandering through Lowe's today to come up with some inspiration on how to couple them, remembering that a lot of people used rubber hose. Based on the hoses that I found and played around with I didn't like the amount of torsion that I could put on the tube... Now I realize that it was just twisting a hollow tube without any center core, but still.. it made me feel hinky.

I then found some white plastic pipe... 1/4" ID, 3/8" OD. It's the ridged kind but can be rolled up into a spool. From my initial "show room floor" tests, I could bend the pipe up and down.. side to side, but couldn't twist it.. looked promising. I picked up a few feet for a buck and some 1/4" to 5/8" hose clamps...

First thing I did was to cut about a 2" length of the plastic pipe. Once that was done, I put one end in the bench vice and tapped the other 1/4"x20. So I've got an untapped end and a tapped end. The untapped will go onto the smooth output shaft of my stepper, and the tapped for the lead screw. Now keep in mind that this pipe is fairly ridged, and I wanted to use hose clamps to compression fit the couplers.

I took the tapped pipe to the band saw, and cut a slit down the threaded end to the middle of the pipe (about an inch). Then I turned the pipe to the smooth end and rotated it 90 degrees from the first slit and cut the other end halfway down again. (Hopefully the pictures will give you a better idea than my trying to explain it)..

I slipped the smooth end over the output shaft on the stepper and clamped it down with the hose clamp. Once that was secured, I threaded the lead screw into the other end until it made contact with the output shaft of the stepper and clamped it down as well.

Which leads me to where I am today. I've got the X axis and Z axis up and running with motors and lead screws.

[datacop]

The cold and flu has been passed around the datacop household like a bad penny for the last two weeks.. so not a lot of work has been done in that time period..

Since we're all starting to feel better, the man child and I made our way out to the garage today and put together a "quick and dirty pipe polishing rig". Basically taking some 4" lengths of 3/4" scrap MDF and some left over skate bearings.. we made a set of rollers for the pipe. The rig that we came up with works for both our 1" pipe and our 1/2" pipe.

Using a standard gas pipe cap on an end with the center drilled and a 1 1/2" bolt threw it acted as the "bit" for the drill. My son spun the pipe while I used the scotch bright to "polish" it up.

After the pipes were done, The machine was put back together and the electronics were brought out to the garage. I'll get a monitor arm and mount the monitor on the back side of the machine upwards and a keyboard drawer to slide out from the bottom of the table where the machine rests on. The only things that will be on the shelf below the machine is the controller, computer and shop vac for dust collection.

I'm looking to be cutting chips by Monday.

[datacop]

In an effort to keep the promise to myself to be cutting chips by Monday, I created the patch cables for each axis from the controller to the steppers and put them on the machine.

Once everything was connected as it should be, I fired up Mach 3 and set each axis into motion.

Let me rephrase that, I fired up Mach 3 and turned each axis stepper.. parts didn't actually move

This leads me to the problem of "setup and tuning".. what's the best way to do that? Should I take the lead screws out and tune each axis "free", then put the lead screws back in? About the screws.. how "snug" should they be against the HDPE anti-backlash nuts? Mine are incredibly snug.. even after the freeze then tap method.

Should I abandon the all-thread and invest in ACME threaded rod and anti-backlash nuts?

I feel like I'm close.. but oh so far away at this point

[datacop]

I've spent the day taking the machine apart and tuning it. I removed all of the lead screws and set up each axis to roll straight and true in relation to each other, then reinstalled the screws.

I have motion on the machine!

Setting up Mach3 was a bit interesting.. The "Steps Per" setting when using 1/4" 20 all thread and the hobby CNC pro kit with the 305oz motors should be set to 8000.

I find I can't go above 30 IPM on the motors or I get a harmonic in them and they stop turning.

[datacop]

So I've got the machine dialed in and apparently working well..

As I was jogging back and forth, the Y Axis and X Axis performed very well. The Z axis however, when going down... the lead screw unscrewed itself from the pvc pipe coupler that I had made. Evidently I just can't get enough compression to hold the screw down with the pipe clamps.

I've ordered a set of clamp on couplers from http://www.dumpstercnc.com/. Hopefully they will be here quickly. I'll make a new Z axis coupler in the mean while to see if I can get at least something cut.

[datacop]

So I went to bed last night feeling beat down and defeated. I received an email from Tim @ DumpsterCNC saying that he was out of town and wouldn't get my order shipped to me until the end of the week. I had set a personal goal for myself to be cutting chips by the end of the day to day and it looked like I wasn't going to make it.

About 3am, I woke up with a fit of inspiration with a thought of how I could solve my motor coupler problem in the short term. I reset my alarm for 7am (I was going to sleep in.. labor day and all) and headed out to Lowe's first thing in the morning.

Digging through their "specialty" fastener section I found some 1/4" ID 1" zinc plated steel spacers.. digging around in another box, I found some 10 24 set screws. Grabbing a handful of each, I paid my hardware store exit fee and took off for Harbor Freight. While in the glorious land of cheap Chinese tools, I picked up a spring loaded center punch and a new 2 1/2" vice clamp for my drill press.

Back home, I marked the 1" spacers with the center punch, loaded them up in my shiny new vice and drilled out the set screw holes. Once done, I tapped them to 10 24, inserted the set screws and mounted them on the motor shaft and all thread. FINALLY! Solid movement on all of my axis. Time to make the spindle mount.

As I mentioned previously, I'm using a Bosch Colt 1hp palm router for my spindle. I like it because it's fairly light weight, has an excellent shaft to mount a clamp to, variable speed and a nice *long* power cord. I cut the mount from a piece of HDPE 3/4" stock that I had laying around on the band saw.

Once I had the router mounted to the Z axis, I put the cutting surface back into the machine, stacked up a "waste board" and a piece of work material just to admire the progress... My son and I went stopped by Staples after our Sunday lunch and picked up an LCD Monitor Arm and Keyboard drawer. After everything was buttoned backup the boy said he wanted to see the machine move...

One thing led do another, and chips were flying! Granted, they were flying as we jogged the machine back and forth instead of from a GCode program.. but baby steps right? :-D

I'm fairly happy with where we're at with the machine.. waiting on the motor couplers from Dumpster... Need to pickup the universal T tracks from Rockler (They were closed for Labor Day when I went by this morning) and get her painted.. but the feeling of being defeated is gone.

Now, who wants to teach me how to use Mach 3 and VCarvePro? :-D

[dustin1706]

Haha nice work man!

For mach3 you are going to want to watch these rather dry, but very informative videos on their website.
http://www.machsupport.com/videos/

Also, to get square corners, you will need to read this document.
http://www.machsupport.com/docs/Mach3_CVSettings_v2.pdf

As far as hold downs, T tracks are great. Another excellent hold down is actually "carpet tape" it is a thin double sided VERY strong adhesive tape that you can get at walmart, home depot etc. The first time I tried it, I covered the entire backside of a 12"x12" piece of MDF with it and had to use a chisel to pry it off afterward! It doesn't take too much tape to hold.

[datacop]

Triumph is MINE!

Thanks for the tip on the carpet tape! I downloaded the trial of Cut2d, fed the machine the gcode snack.. and watched in wonder as the last few months of work came to fruition...

After several years of wishing and wanting...

[nomedia="http://www.youtube.com/watch?v=THAv_bDlpoE"]YouTube- JGRO First Cut[/nomedia]

[sonex128]

Nice! I have to get busy on my router.

Brian
Claremore, Ok

[datacop]

I love opening presents!

My order from Rockler came in today..

I'm a little disappointed that the 3' tracks didn't come with any sort of mounting bolts to attach the track to your work surface. But it is what it is..