I put my previous build on hold, mostly due to space constraints in my shop but decided to upgrade my present MillRight MegaV router. I made a kit to hopefully perform the upgrades in a day. Increased Z travel to 6" Increased height under gantry 6.25" Conversion from V-wheels to linear bearings on X & Y axis Conversion from Acme to ball screw on Z-Axis Improve rigidity and overall accuracy of base/platen This makes the machine very similar what MillRight calls their MegaVee Pro except that has a Masso controller. They want $8k+ for that. I have <$2k into the original purchase, $270 for the ball screw and all linear rails and bearings, and $200 for the aluminum tooling plate. -I like that price much better! I will retain the rack & pinion drive on the X & Y axis, Nema 23 steppers, limit switches, controller, and beams. I debated replacing the beams too but at that point I may as well just sell the MegaVee and start a from scratch build of the other machine. Instead, I think I will make that other machine a smaller envelope dedicated metal/hard material machine. Anyway, due to the previous effort, I had already done a lot of CAD modeling of the components which was very helpful for the design work. Here's the kit: Structural steel tube weldment skinned with .500" aluminum tooling plate: The rest: -More to come. Best, Kelly
I got it swapped over. Took the better part of a day then another half day to make all the little brackets for the drag chains, limit switches, and little details. The motion felt really nice after assembly. Need to do some leveling, tramming, and general tuning. Been busy but should have some time this weekend to get back down to business. Best, Kelly
That's epic!, the hours in that job with the designing, casting and machining. The result is outstanding compared to the original machine.
Thanks Mark. The CAD work occurred over a long period an hour or so at time in my easy-chair so no idea what I have into that......it was more of entertainment. I've been using it and continue to tune and tweak. The biggest chore will be leveling the bed plate. Though the aluminum tooling plate is very uniform thickness and flat, the steel weldment it mounts to is not as precise. Right now it varies about .010" across the entire surface, mostly low in the center, which isn't too bad considering it's just a structural steel weldment, but not good enough for me. For now, I can just mount a particle board platten and plane it with the router to correct it. In the long run, I may shim the underside of the tooling plate at the low spots. It's good enough for foam pattern work now and definitely an improvement over the original machine. -I'll keep plugging at it and make refinements over time. I also don't know for sure how straight the aluminum beams are. I have steel beams that are precision ground but didn't use them. I may make a more rigid, precise, dedicated machine for aluminum work with a smaller work small envelope. Best, Kelly
There was a gentleman on YouiTube who was using a laser line and a webcam CCD with no lens, using software to plot the peak intensity of the beam, sort of a sine wave profile. He was able to measure straightness fairly accurately. Come to think of it, his work was probably already mentioned in this forum.
Yes, but only for the initial rough adjustments. It really depends upon what metrology equipment you have to work with. For me that's pretty basic and not much. I actually started with a precision level and adjusting leveling feet on the table legs, but again that is just a gross adjustment. It quickly becomes a tail chasing exercise if the table isn't flat. So I move onto getting the variation in distance from quill to table height as good as possible with a dial in the collet. This is a good next step, but again, it doesn't mean the table is flat, just that it will cut at consistent depth of cut. It can still have warp in any given direction. I have a precision straight edge that I borrow from a friend to check this, but there isn't much sense in doing it until you get things pretty close. But if you do all that, then precision level the table again, then check with trammimg head/dials in the collet to get the carriage and gantry plumb, you can usually get pretty close. It's a lot of doinking around, but I only need to do the whole dance once, and that is usually in multiple sessions of improvement as jobs require. On my previous particle board bed plate, I had a set screw next to each mounting screw, so I just jogged the head/dial to each mounting screw, set the height with the set screw, tightened the mounting screw, and depth of cut was set. I didn't want to drill all those extra holes in this tooling plate. I'll need to shim the plate, which will be tedious. I had seen the method in Mark's post before, but I don't have the laser and getting one and set up is as big of a task as just getting on with the iterative process which though crude, is probably good enough bearing in mind these are just extruded aluminum beams and although they are very good for what they are, they won't have the straightness of a precision ground and scraped beam. If I make a dedicated metal machine someday, I'll have to get more serious about the degree of precision, but for now, for the work I do, doing what I describe, then planing the surface of a sacrificial bed plate, or mounting, dialing and tramming a secondary platen will be close enough. For doing foam patterns, if I'm within .005" variation depth of cut across the entire workspace envelop, it usually means a small fraction of that depending upon the size of my part. If I mount a piece of MDF and plane it, it can reduce variation to about what I can measure which obviously is well beyond that needed for foam patterns. The rack and pinion drive seem to repeat to <.003 in 24" of travel in X&Y. The Z ball screw seems to be repeating to within what I can read on a .001" graduation dial. It's still just a hobby grade cnc router........need to be realistic about what it can do, whether the effort is worth it, and what's good enough. Best, Kelly
Watching videos of the extrusion process shows these curved extrusions fresh out of the die which then get stretched to straighten them. That's got to be quite straight and an ingenious method to ensure straightness. The people handling the product probably introduce more bending afterwards.
That tension stretching method has actually been quite common (and effective) in precision extrusion for many years now. I use to specify them and it was actually quite remarkable the profile tolerances they could hold. You're right, because if they are not handled carefully, it's all for not. Best, Kelly
Did some test and tune cuts and then took it on its maiden voyage.........machined the valley pan plenum shelf on one of my intake manifold castings. Then I machined the cover for the plenum from .25" MIC6 tooling plate. It has a number of O-ring glands for sealing the plenum. Came out Nice. The surface finishes were better than expected. I made that MDF platform from my old platen bed board. It gets the stock up close to the gantry so I can use short stiff bits on thin stock. The aluminum bed plate still isn't level across the entire surface so I just shimmed this MDF platform until its surface was within a couple thousandths and went to it. I'll have a video of the build in the not-too-distant future. Best, Kelly
Great to see those upgrades, machining those manifold parts must be very satisfying! Thanks for the video, very informative
Even though it's the same controller and motors, makes me pucker a bit since I have so little time on the machine since the upgrades. Lose a few steps and.......disaster. Scrapping a hunk of foam is one thing, but a large, finish machined, casting quite another. I wouldn't have chosen the castings for the maiden voyage, but I had to get a couple of them done, and thankfully things went smoothly. Large foam patterns are better candidates because cost of stock is cheap and it exercises the range of motion at high speeds. I'm looking forward to getting some more hours on it. Best, Kelly
