Ray, truth be told, I fully expect you to win. I just want the competition to be at the highest level, and I know you are capable of that. I have a selfish motivation, of course, but it also hopefully benefits the many readers of this thread to observe the process.
I think we agree that the mechanics, complicated as they may be, are not the lion's share of an ATC, but rather the control and sensors. I would speculate that those who can build the mechanism are many, those who can create an autonomous and safe control system are few. That's where I see the real competition. The finish line includes all sensors and 'release candidate' level fully functional control code. I also want to follow what Hood and other 'non-contestants' are doing with regard to sensors and control code.
Actually, the sensors and code on mine turned out to be quite trivial. The code is barely two pages of dead-simple C that took only maybe two hours to write and debug.
To consolidate your questions from the last couple posts, let me say that yes, I am familiar with 'C'. There are several thousand lines of it in my InTurn™ motor control system. And less volume but far greated intensity code in my balancer. Although I am a lightweight with electronics, I get by with the 90% learn and 10% do methodology.
I am going to acquire a Kflop board based on your endorsement. Initially, I just want to replace the smoothstepper, but I have similar needs to yours down the road, so the sizeable learning curve is an investment that will pay off, methinks. You mentioned loaning a board, but the way it is worded, I cannot tell if you mean loading an ethernet Smoothstepper or a Kflop board. 
Must've been a SmoothStepper I was referring to. I only have the oneKFlop of my own, and a backup that actually belongs to a friend.
As to machine complexity, I have 4 axis of Mitsubishi J3 series industrial drives (and motors) and the spindle is a Copley Controls Xenus drive pushing a big DC brush motor. I am starting to talk to these devices in real time to get at some of the pertinent staus info they provide and create a 'reactive' system that can act on the data from the drives to adjust the paramaters on a CNC machine in real time. Another machining center feature to bring down to we mere mortals. Hence my interest in your amazing work with the Kflop. Yeah, I did some homework on that.
Anyway, I threw this machine together quick and dirty to get enough Y travel to do a specific project. I have since boxed and welded up the column and now it has decent performance. My 'permanent' mill will be similar, but larger, much heavier and of course will have the spindle and tool changer from this thread. Since the spindle is completed (except for the die spring) and the ATC is almost done, I am revisiting the pile of parts and the frame design. Today I purchased a 9" x 42" Bridgeport mill table to add to the pile.
There has been no progress on my ATC because I had some unanticipated work to accomplish, however, I expect to start making progress again on the ATC today. I am simultaneously making a new spindle from A6 tool steel, (which will be fully hardened and ground) and ditching the bellevilles. I expect there will be a lot of interest in my big fat die spring because it *probably* can be implemented on an existing spindle which has no way to get the typical disc spring arrangement installed. Next couple days I will post some photos of the ATC assembled on the side of the new head.
I see from the photos you posted that the swing arm has been eating its Wheaties. Very nice piece! 
I also note the pivot has an upper and lower mounting. Double nice. Significant improvements from the prototype, as one would expect. Q: curiosity, how did you form the smooth curve in the skirt?
The pivot arm bracket is actually the prototype. The top support for the pivot was always planned, it just took a while to get it built, and made it much easier to remove the whole assembly from the machine during initial tinkering and debugging. The "skirt" was just rough hand-formed over a piece of 4" diameter aluminum round, then fastened in place with 6-32 screws. I'm very pleased with how nicely it came out. I now have the door operating as well. I used a simple tension spring to pull the door open, and a cable from the door to the mounting arm on the ram to close. The geometry is such that with just a short (18") piece of bicycle brake cable inner wire fastened between those two points, it pulls tight when the arm parks, and goes slack when the arm pivots to the quill, allowing the spring to pull the door open. Could'nt be any simpler or cheaper.
Now that my annoying spindle problems appear to be resolved, I can finally get back to work! Looking forward to seeing what you come up with. Your work always leaves me feeling totally inadequate! :-)
Regards,
Ray L.
Guest
Show Posts