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Welp, its happening. In the pursuit of rigidity, I’m building out my own X and Z axis. Will there be too much weight for the Y-Axis? Probably. I’ll be using my heavily modified X-Carve to make all the plates and mounts that will be needed for this project.
I will be editing this top portion as the project continues, updating the status and adding pictures/video as they’re made. I want to keep the OP as a “current status” page with the CAD, and will post progress as replies.
Floating ballnut bearing mount (also an X-axis brace, .125")
Components:
(2) SBR16 Rails 700mm
(4) SBR16UU linear bearings
(1) 1605 x 700mm ballscrew w/ bearing blocks and ballnut
(1) Rexroth PSK60 x300 linear actuator
~350 sq. inches of .25" 6061 aluminum plate
Wide view. Believe it or not but the big X-Z mounting plate has the holes drilled/tapped to mount to the x-carriage if I wanted to (but the weight is too much, I think).
X-Z plate cut and quickly test fitted, looking good so far, waiting for more material to come in before the side plates.
All plates are made of .25" 6061 aluminum plate, unless otherwise specified. I used Fusion 360 to design the parts and create the assemblies to ensure everything will fit.
And the first video in the series, cutting the stepper mount for the Z:
Do you have objectives for the build? Is there a certain amount of work you’ll have the machine doing or certain levels of rigidity that you are looking to achieve?
Is there a specific reason you went with a full depth pocket for the circle cutout? My guess is for the finish, but maybe not…
The objective is to be able to push a 1/8" end mill to it’s limits in aluminum. Basically, using GWizard you get feeds and speeds but generally speaking I have to dial them back quite a bit so the frame can take it and not chatter. Currently Im doing a .01" depth of cut when profiling, I’m hoping to be able to hit .04" at the same feed rate/RPM.
I did a full pocket because of the thick material. Chip evacuation in aluminum is critical espeically in materials atleast .25" thick. Recutting chips can cause chatter/vibration which will cause your endmill to chip and soon snap in half. Im playing it safe by doing a pocket instead of a outline with tabs (at the cost of tool life).
Indeed! I had a LED ring on the spindle, but I somehow managed to break it a few weeks ago already have another on the way from amazon, but it will probably take a while to get here. I already recorded some more footage that needs to be edited, with no LED. Ill see if I can figure out a solution for the last few pieces.
I need that EXACT stepper mount for the EXACT same purpose! My Z was set for a NEMA 17. It looks like you are ramping the plunge on your profile cut, because I see your feedrate slow down periodically. It looks like the ramp is .01" over a .5" run. I had my last experiment set to “ramp” but it continually ramped down throughout the cut. So every inch or so it went down about .001" Do you think that would be a problem?
Also, would it be better for my less powerful 600 watt spindle and manual chip evacuation to “Pocket” the profile cut? Like a .2" pocket profile using the .125" bit?
Hey, I welcome the questions, I get to flex a little bit
Continuous ramp is essentially a boring operation, and so long as you aren’t cutting more than the maximum step down you set (in my case .01") you should be okay. There might be some strain on the z-stepper, I’m not familiar with NEMA17s or their power, but I don’t think it will be too big of a problem. I have mine set to a 6 degree ramp that slows down to 15"/min or so. The CAM operation can take distance, but I find manufacturers list their ramp in degrees so I always use that.
I think pocketing is a really safe operation in terms of chip evacuation. Granted if the pocket is way too small you can still have problems. The good news is that a .2" pocket is small enough to bore out. I usually do this for holes that are less than 2x the cutting diameter (.25" wide for 1/8" endmill). It’ll go a lot faster and you shouldn’t have too big of an issue with chips.
I did, and there are a ton on ebay very similar. The thing I don’t like about the one you linked is that its very expensive, and uses a leadscrew rather than a ballscrew. I managed to snag the above Rexroth used on ebay for $100 (no shipping) which is a steal if you ask me.
A lot of the similar ones on ebay are $150-$200, but don’t come with a stepper motor.
Oh, also the Rexroth style “encased” linear bearing is significantly more rigid than using the rod-style rails. The Rexroth is rock solid.
I see where you are going and I do understand it. But the belt drive system is still going to be a huge weakness on the mill if you are not going full ball screws all the way around… My large mill is very close to this style but with 3/4 plates and 60 x 60 extrusions with a work area of 21" x 37" x 8". I have looked at more upgrades to the XC but there comes a point when you are just better off building everything new for ball screws ( much like you are) and leaving the belt system and thin extrusions of the XC off your new mill if you are looking for a good upgrade. Though at that point I think it is no longer an XC and is more of a new mill… I looked at going this path, but I think once I do a few upgrades on the larger mill, I will be building something out with full ball screws in the 15 X 15 size range and giving the XC to the Maker Space or something after that. You might find issues when you cut circles and such with having belt drive on part of your mill and ball screws on the rest. Ball screws never give or skip like the belts can/do. But I am looking forward to seeing how things works out for you.
Yeah, I was thinking the same thing. My fall-back is to get a moving table style Y and making a couple adapter plates (or all new side plates) to attach it to the base. If I can get a steal on another linear actuator like my Z but with more than 12" of travel I’d be set. I have a few other ideas in the noggin worst comes to worst
Tried to cut setting 600watt spindle to 20,000 rpms, .05 DOC, 30 ipm, 6 degree ramp, destiny viper. It was better but still awful, the cheap spindle dogs when cutting significantly reducing the rpms. I will try again with the Makita installed in place of the spindle, as soon as the Elaire collet arrives (all my aluminum bits are 1/8th ").
Updates! I managed to cut the sideplates last night and do a test fitting. All is looking good, but there are two things i overlooked in the design.
First being the Z axis’ bottom height, which may only be an inch or 2 from the bed. The Z axis’ mounting holes are spaced 100mm, so worse case I can gain a free 100mm of bottom clearance by shifting the axis up 1 set of holes. Alternatively, I already have the holes drilled in the X-Y plate to flip the Z-axis around, have the truck mount to the X, and the back mount to the spindle. This would increase the amount of weight the Z-Axis stepper needs to move, so I’m not sure if this is a viable route. Ballscrews are tough though, so who knows, maybe it’ll work.
Second is the Y-Axis stepper mounts. The rails interfere with the top-back hole in the stepper mounting pattern. Easy to fix, i just mount the Y-axis steppers before attaching the sideplate to the 3060 extrusion.
Other than that, it slides smoothly and there isn’t any binding! I still need to check for squareness, but I can’t really do that until it gets mounted properly since the side plates may not have been perfectly square when they were screwed down to the bed when being cut.
I ran into a problem that I wasn’t anticipating. When moving along the Y-axis and stopping the x-axis will wobble a little bit, I think because of the weight and/or height. I’m going to try an correct this with acceleration/deceleration adjustments, adding extrusion parallel to the Y rails to stiffen things up, and probably get some threaded rod cut to length to go between each set of Y-axis plates (you can see i have 3 unused holes on each plate).
Also need to get some proper connectors for the X and Z wiring since I can’t use a terminal block anymore. Also need to figure out a drag chain mount.
Can you put angle braces between your super tall plates and the cross beams? That should stop the wobble and if they are mounted in the back, they shouldn’t interfere with movement.
Also - your settings worked PERFECTLY on my original x-carve. I cut Christmas trees out of 1/8" aluminum and the sides were very, very smooth! So excited to try it on my dedicated aluminum machine when my collete comes in. Thanks again. I cut a pocket into my wasteboard exactlyl the size of the stock so it “Snaps in”. Then I screw it down.
I’ve actually solved the wobble. I took the old 500mm long 20x20 extrusion, drilled and tapped the ends M5 and braced them between each Y-axis rail. I also lowered the acceleration to 250mm/s. Heres a pic (still finalizing the setup, ignore the random wires!):
– 1/8" 2 Flute uncoated – (2) boring operations and the “engrave”
.03" DOC (I’ve hit .05" DOC, but I wanted a cleaner edge for the engrave)
Slotting
60IPM
20K RPM
