Thunterman's jgro iteration

[thunterman]

This is my first post after reading / learning over the past year or so. I had built a little demo two axis machine to learn the concepts of CNC. After that I was ready to jump in and build a working model. I chose the jgro design. This is a very nice design to begin with as the construction is not very complicated for a novice to intermediate woodworker. Jgro, thanks for providing the plans!

Although this is a good design, aligning this thing is a "bear". I don't think I ever will be able to get it to where I want it to be. There is just too much flex in the long Y axis pipes to get to align properly. I'll live with what I have for now as I only will be cutting wood and I don't need to have “.001” accuracy.

I started work on the machine in April of last year (2005). After many trips to the local hardware stores and purchases on eBay and other sites, I have a working CNC router today!

Here are some specifics of the machine. I use 3/8" 16tpi alltread for the leadscrews because the end bearings I had would accept a 3/8" shaft. I will upgrade to 1/2" acme or maybe ballscrews in the future. The adjustment blocks are made out of 3/4" UHMW plastic as are the AB nuts. I used the trick of freezing the AB nuts before taping them. They turn without almost any effort.

The controller is a 3 axis HobbyCNC kit. Thanks to Dave R. from HobbyCNC! This kit goes together very easily as long as you take your time and have some decent soldering skills. (My background is electronics/software). I'm running three Vexta 118oz-in 2 phase 1.5amp motors; yes they are a little underpowered for this machine, so I just run at a lower ipm rate. I built a 33.5vdc unregulated power supply to power the machine.

For a spindle, I will be mounting a 400W 24000rpm "trim router".

I built a mobile cart/stand for the machine so I can move it around my garage or outside when the weather is cooperating (I live in Minnesota, USA - "You betcha!").

I have wired home and limit switches on all three axes. At the present I am having some noise/crosstalk issues on the long limit switch wires. I will need to wire the shields on wires to ground to resolve this issue. I hope that will correct the problem.

I have been using a "demo" copy of Mach3 and also TurboCNC. I like them both. I'm leaning toward MACH3 as I like the interface that this software provides. The price is reasonable for this software and I will probably end up purchasing this. I also have a demo copy of VCarve. Very nice software, but the price is giving me second thoughts as I may develop my own carving software instead using the Delphi programming language.

What speed do I run at? Well, I've tested various micostepping rates and ipm's
and presently running at 1/4 step rate and about 40ipm with maybe a slight bit of resonance. I will have to do some more testing to determine the best rate.

Don't even ask me what this thing has cost me so far! I'm not sure I want to know, even though I have kept all my receipts. This a hobby, don't ya know!

OK, this is a long winded post. I know you guys/gals like pictures, so I have a web site setup that has quite a few pictures and a video of the "First movement" You can read/view it here: http://cnc.hobby-site.com/cnc.htm

JUST DO IT!
Thunterman

[Weldtutor]

Thunterman
That is a great record of your project shown on the web site you created.
Thanks for sharing the info & the link to it.
This is part of why CNC Zone is such a wonderful place!
WT

[randyf1965]

I tried to view the video twice... gets to 96-97% then stops

[thunterman]

weldtutor, thanks for the comment! I'll keep adding pics and videos until I run out of disk space (4.3G)!

randy, I tryed downloading the video from my work PC and allthough it's slow I was successful. Try saving the file first before attempting to open it. My web server is running on a old 200mhz PC that is loaded with Win98 and sits in my furance room! If still unsuccessful, I'll try to resize the video or use a different format(quicktime)

[spalm]

Thunterman, such drama on your video. Very professional.

Good job. You have been very quiet and very busy. Mark of a true Minnesotan.

Flex and alignment problems in the JGRO is part of the learning experience. Your prototype long pipe side rail support looks promising. Maybe there is a way to make the pipe holder thingies individually adjustable.

Have you tried a .1uf cap across the limit switches to reduce noise?

3/8” 12 Acme would give you a cheap speed upgrade without changing your bearings. (If you care).

Steve

[dighsx]

Thunterman
Your machine is looking good. I finished my about 6 months ago and have been down some of the same roads you have. I used ½ 10 acme screws on mine and have been happy with the speed. But I’m running 276oz steppers, which I think might be a good upgrade for you in the future. As for the software end of things I tried just about every demo under the sun. After many hours I had settled on Mach2/3 for heart of things and then Sheetcam and Meshcam. That way I could cover the 2.5D and any 3D work. Then I stumbled on a demo copy of Vcarve. When I saw the price I had my doubts. But I after beating up the demo and about 50 emails to their support guys (who are great by the way) I took a chance and bought a copy and I couldn’t be more then happy. I’m not sure what you plan on using your machine for but if it’s signs, carvings and 2.5D work, etc you can’t beat Vcarve.

Two threads you should check out if you haven’t already are:
Vcarve Gallery
New - VCarve Wizard Software

Also being a fellow programmer I had ideas of writing something of my own. But then the thought accrued to me that I can spend all that time writing something and working out all the bugs or I can start using my machine now.

Well good luck with your build, and no I don’t work for Vertric. I just think bang for the buck it’s pretty good stuff. There’s my two cents, use them as you see fit.

[thunterman]

steve, creating videos, just another one of my too many hobbies! The wife says I have some compulsive tendencies! I had fun creating that video. The prototype side rail support that I had created also had flex in it since I used MDF to construct it, so I decided not to use it as it didn't provide much support anyways. I'll live with the rail flex for now as I'm planning to build another machine. I'll try the .1uf cap trick and see if that will correct the noise issue on the limit switch wires. Thanks for the tip. Using 3/8 acme is also a good choice for me. I'll give that a try this spring.

Jay the current motors I'm using were fairly cheap to purchase. This is one area that I will upgrade in the near term. I'll be mounting a trim router for a spindle this weekend and we'll see if these motors can handle the added weight and speed.
On the software side, MACH3 will be my choice for the controlling software. Sheetcam and Meshcam will provide all my needs for cutting 2.5 and 3d. Vcarve is a great piece of software, very nice user interface, well layed out and intuitive, however the price may be a little high for my "hobby work". Yes, I had viewed those threads on vcarve, very nice work. If I can generate some revenue from this hobby, then maybe I'll purchase the software.

[randyf1965]

must just be me! even downloading it it gets to 96% then just stops downloading with 6 seconds to go.

[buscht]

thunterman, Good job. I downloaded the video and it started playing at about 50% download and didn't have a problem.

Somewhere on the web, I remember a site with a CNC controlled long arm quilter. That might be a good project for you. It seemed to complicated to me because you had to worry about skew in the material and other fabric related problems.

Anyways, good job. I'm in Rochester, about an hour and 1/2 from the twin cities.

[thunterman]

randy ,I don't think my little web server is handling all the added traffic well, in fact it crashed today. I may have to upgrade to a faster machine. This weekend I'll add a second video that will be a smaller download, so hopefully that'll work for you. I probably will also have some more pics.

buscht, well at least some are able to download the video. I think building a CNC quilter would be a little out of my league. I didn't even know what CNC was a year ago! I need to work with the jrgo for awhile to learn all the software (g & m codes, cad/cam etc....). I think this will take quite awhile. Good to see there are others in MN that are on this forum...

[randyf1965]

I have a sister in law that has a manual quilter, uses aluminum tubes and uhmw slides to move the sewing machine back and forth and roll the material manually from 1 spool to another... alway thought of cnc'ing it.

I will get some more info on it if anyone is interested... I know she bought in from a quilting shop in Iowa a couple of years ago

[ger21]

Originally Posted by thunterman I have wired home and limit switches on all three axes. At the present I am having some noise/crosstalk issues on the long limit switch wires. I will need to wire the shields on wires to ground to resolve this issue. I hope that will correct the problem.

If your using Mach3, try increasing the "Input Debounce" in the Logic settings screen, to maybe 2000, or even 5000 and see if that helps.