New Machine Build- Thomson Superslide @ 270ipm!

[Riceburner98]

Exactly, basically instead of attaching the spindle / motor / etc to the moving plate and having the stage fixed, I would bolt the stage's moving plate to the gantry / top X axis stage, and attach the spindle / etc to the back of the stage. Stage and all would move up and down, so I wouldn't be limited by the distance from the cutter to the stage, or "Z column" as it were.. Down-side is that I'm lifting and lowering probably 15 pounds of stage, plus the motor / spindle setup, all cantilevered out a few inches. The stages are rated at 650lbs, so hopefully they're solid enough? Plus I'll have gas struts to counteract the weight... I dunno. Probably not even worth doing, but I wanna see if I can.

I just checked out your build, impressive!!! Those stages look great. And you're right, it's all about the rapids even if you can't actually cut at 600ipm. I just want to see the thing whiz back and forth between cuts. Should go a long way to speeding jobs up. I've since scaled back my drawings to using 2020 and 1030 parts instead of the 3060, but if I stick the Z up there like that I may need the 3060 after all. Unfortunately everything I have (the stages, the Taig headstock...) is pre-drilled with 1" apart mounting holes, so it doesn't go too well with the 1.5" 80/20 stuff.. More stuff to think about.

I should probably just go with something like you have it, with the spindle hanging down on a plate from the stage.. There's a good 1.5" from the edge of my moving plate to the edge of the stage though, so it'd be hanging down 3-4" to be useful. I had drawn it up like that in one revision actually. Would probably be fine. Just over-analyzing everything as usual! Oh - (if you don't mind..?) How much / where did you get the mic6 plate? Was considering it for some of the parts but hadn't actually seen it anywhere.. For a table, I was thinking .25" thick steel plate bolted to the X stage plate, with a bunch of 1030 extrusions on top of that to form a T-slot table, just deck it flat with a flycutter or something..

[KTP]

Yes, I was wishing the t-slots would align up with some of the NSK robot slide mounting holes too, but they were spaced in metric, and not even spacing that would work with the metric 8020 line. I ended up just making metal plates out of 1/2" aluminum plate to attach the slides to the extrusion.

That is why I didn't do the Z as you discussed. I didn't want the smaller Z motor to have to move the weight of the whole slide + spindle + motor. Besides, if it can fit under the fixed gantry it can fit under my z axis assembly, so I don't see an issue...

I bought the Mic6 on ebay. I started to search cnczone to figure out where people were getting their plate, then decided to check ebay. There are several metal suppliers who seem to list precision ground cast aluminum plate in various sizes, and I emailed one of them asking about a 20" x 20" x 1/2" piece. He got back to me and said he could provide it for $120, and if I wanted it, he would create the auction (which I did and he did). Shipped out the next day, very prompt. The ebay ID is ssshapiro

[Riceburner98]

Well, several months later, back with an update! I (naturally) haven't finished the machine, actually haven't quite started it yet. All sorts of stuff came up as it always does... Every time I design it, I find something else (on eBay!) that will work better. Now I'm up to 18"X by 15"Y by 9"Z axis, with a moving Y plate and an X-Z gantry made of 80-20 3060 extrusions. The 3060 is like $140 a stick (used!), but it should be rock solid.
Anyway... Just wanted to say that the Thomson 2DB12JUBQL24 slide I got for the Y axis is working incredibly well! (15" travel after you subtract the 3" for the ballscrew bearing mounts and 6" for the moving plate, 2 turns per inch ballscrew with preloaded ball nut) I've got Mach2 maxed out for velocity, 4 microsteps / step (1600steps/unit), and I'm getting 1311 inches per minute! I had to crank the acceleration down a bit to get the 1311, but it's doing it! That's 21.85 inches per second! (555mm/sec or 33,000mm/min if my calcs. are correct..) Unfortunately you run out of the 15" of real estate very quickly.. Wish I had a 60" table that could do that! Realistically I'll probably set it at 200 or 300 inches / minute for rapids, but damn this thing is fast! What's a typical industrial CNC machine run for max rapids? Considering the servo motors each weigh as much as my entire mill...
I noticed some play in the ballnut so I took the slide apart and figured out how to adjust the spring washers, but I may have put a bit too much preload on them. Need to check that, it may actually move a bit faster if I get that dialed in just right. According to Thomson, .001" of movement between the 2 ballnuts = 500-1000 pounds of preload..

Ah crap, I also just found the "Max" rating in the Thomson document -- 11.7 inches/sec.. Whoops! Better slow it down before I break something. Maybe it has to do with slinging the lubrication off the ballscrew if you're whipping it that fast. Then again, the same ratings apply to the 10turns/inch and 2turns/inch slides, which doesn't make sense.. Maybe it's the rating of the linear bearings and not the ballnut they're concerned with..


Ok, last experiments of the night... Set the driver (IM483) to 25microsteps / step, so 1 microstep = .0001". I didn't think the motor or the driver could do it... But they do! I can step .0001" at a time, indicated on a tenths dial. 5 steps move exactly .0005". Backlash is currently .0001"-.0003" depending on conditions. With Mach2 maxed out (Kernel speed 35,000HZ on my laptop) I get 209 inch/min rapids. The strange thing is, since the motor is physically turning 10 times slower than on my Taig (20turns/inch) and the slide is so much longer (15" vs 5") 200" per minute doesn't look fast at all! It looks like I'm doing 10" per minute... Crazy. I'm going to crank the Kernel speed to 45,000 Hz, but I think the last time I did that it freaked out the 1.8Ghz laptop. Need to get the 3Ghz machine set up.. Here goes.....

(dramatic pause while I change some parameters and hope I don't crush my tenths dial by accident!)

SWEET!!!! The computer doesn't like it (slow responding on the MDI screen), but it's doing 269 inches per minute on the slide, and I can't stop it with my hands! I'm manually entering "G0 Y10", "G0 Y0", "G0 Y10", etc.. and it's getting there almost before I can finish typing it! Great, now I'm not going to be able to sleep tonight!!!

[Riceburner98]

No really, I'm going to bed soon!! LOL Realizing that .0001" resolution is probably WAY overkill for the machine (my Taig ER16 spindle probably has more runout than that anyway!), I've set it to 5 microsteps / step, so .0005" / step which is more than good enough. That gets me a solid 400 inches / minute, and I have to struggle to stop it with my hands. I think that's going to be good enough! Not bad for a 269oz stepper motor... Hopefully the X and Z axis will behave the same, and I'll be cutting pockets at 400 inches per minute! Albiet with a .005" depth of cut, but damn if it works I'll figure out how to take and post a video of it! The X and Z are 5 turns per inch ballscrews I believe so I'll need to adjust the steps/inch to match, but those are the slides I was moving at 600"/min before so I don't think I'll have too much of a problem. I'll be using 2 of the 9" slides to lift the gantry, and probably some gas struts to help out... This thing's going to be a beast!