The JGRO CNC Router - The Past, The Present and The Future ...
I started the JGRO project quite some time ago looking for a way to make better wood patterns for metal casting. In hindsight, it is rather funny, A guy makes a wood CNC machine to do his wood working because he is such a lousy wood worker. Seems like a catch 22 to me! Well, I can only work wood to a certain point and beyond that I just stay away from the big dogs and stay on the porch. When I tried to make patterns like the cross slide piece for the gingery lathe I went through four iterations before I made a pattern that I was happy with and then was not satisfied fully. Sand casting only requires a couple of degrees in taper to pull from the sand and more than that makes the part look funny to me. That was the main reason for the CNC machine. I could cut tapers, fillets, sprues and riser plates all at the same time and I could go on my merry way with the casting and other fun stuff.
I completed the initial build in 2006 if I remember correct and then never really used it. Life got in the way and I had no time to cast and other things. I was busy remodeling and building a shop and a myriad of other stuff. The machine was stuffed into the basement of my out building where it got water damaged. It sat there till last year when I dug it out wanting to make a couple of plaques for two of our pets we buried in the back yard. To my wife the cat and dog were like family. So I thought it would be a nice thing to do.
After replacing the upper and lower bed and the gantry bottom on the machine to get it running again, I started doing some cutting. My problems were rigidity or rather the lack of it. First it was the X-Axis pipes, they were fairly rigid, but lacked and real room for adjustment. I never could get the bearings to ride on them the way that I wanted them too. That led to another change using a design from buildyourcnc.com that utilized box slides rather than pipes. That was a world of improvement, but still I am plagued by lack of rigidity in the Y and Z axis. They flex if I run too fast and as a result I have to take slower cuts and more passes. Now this would not have been a problem if I were only occasionally cutting something for me. However, since folks have learned what the machine can produce, I get more and more requests for things made from it.
That brings me to now. I have decided that I need to build a new machine for two reasons. First, I want a machine that is rigid enough that I can take some light passes on aluminum and have the ability to cut wood at a decent speed. Second, I want a larger cut area. I effectively have about 14" x 24" to cut in. At the time I thought that would be just fine, but I would like to cut some doll houses and route designs into our kitchen cabinet doors and well as a few other larger projects. This time I thought I would look around to see what was out there as far as plans before I pulled the trigger. I knew that I wanted a machine that I could build myself, and I didn't want to have to design one. The two that I had in mind were the mechmate and the Kronos Robotics KRMx01 or KRMx02. I decided that I will build the Kronos Robotics KRMx01 with some modifications. I would like hardened steel rails for the slides and use the KRMx02 Z axis for further router support and rigidity. I have to thank Michael Simpson of Kronos Robotics for helping me to come to that solution. I have to give credit where credit is due. Michaels KRMx02 machine is a ROCK SOLID RIGID machine, but I want the added accuracy of a lead screw over the rack and pinion. Having said all that, one never really knows where a CNC build will take them. Watch the KRMx01 CNC pages for what I actually do and how I get there.
Now, in closing let me say some good things about the JGRO router. Then entire project was a pleasure to build. It made me scratch my head too many times to count trying to figure things out. I learned everything I know about Vector Graphics, Motor control, G-code, tool offsets and tool changing, CAD software, CAM software, EMC2 (now LinuxCNC) and more from this one project. The learning opportunities that are presented in a project like this will fill many hours of time and when comprehended and put together are a very fulfilling exercise. Would I do it again??? YOU BETCHA!!! If you just want to learn the basics of these systems and your willing to take the time and do it. I would say go for it. Joe, the guy who designed the JGRO Router and gave it to the rest of the world is forever in my debt. He has caused me to cuss, bleed, scratch my head, get out of my comfort zone more than anyone ever has and I never met or talked to the guy. Thanks Joe!
That pretty much wraps up what I have to say about this project. I will continue to posts any changes to the machine that I make and any projects that I cut with it if I can remember to take a picture. So you might want to occasionally look and see if there has been an update. When I finally put the machine to bed for the last time, i will be sure to let you all know. Till then, Happy Cutting, Casting, Mold Making and Solder Melting!!!