I’m getting ready to build a Lowrider, but with some different features to suit my needs. I want to build it on a steel rectangular tube frame such that the entire unit can be hung on wall hooks when not in use. I have an overhead crane and high ceiling in my shop, so I will put a shackle eye on one side and pick it up with the crane. I’ll be adding some gussets to the corners of the frame outside of the working range of the tool which are not shown in the model.
This will be primarily used for plasma cutting steel, although I’ll probably also build a toolholder for a router to play around with wood projects.
I won’t bother making any hose/wire guides, as I can just hang them above the gantry with one of the overhead cranes while in use.
I want the unit to be one-piece and ready for use without any setup when I take it down from the wall, so I’m planning to use 1600mm of MGN12 rail in place of both the Y rail and wheels to keep it unitized. I’m planning to make the XZ assembly as a steel fabrication as shown in the attached screenshots. I’ll weld it then machine the bearing mounts surfaces square and flat. I’ll use the standard Y drive and Z stop. I’m planning to weld some solid round bar into the ends of the X rails and machine a pilot diameter and drill and tap the ends of the rails such that they bolt and spigot into machined bosses in the steel XZ plates for better strength and rigidity.
This will be my first CNC machine build, so does anyone see anything I’m missing or any problems with my plan?
I kind of think maybe linear rails would be nicer for Y, both haven’t been done yet though (or at least not to my knowledge).
I’m wondering is seeing as you are going to make this out of steel perhaps a better method of moving the carriage might be a proper rack and pinion -
because the belt might turn out to be a little fragile in your environment.
That might be a good idea. It would probably increase the accuracy of the cuts because there would be no belt stretch. I like the cheap and simple approach of the LR3’s belt, but a rack could also be done pretty simply as shown in the model view. I found some 1.5m long 15x15 rack on Aliexpress for $75 each free shipping.
That was one thing that I noted building the LR3 is that you could convert to rack & pinion without even changing the Y motor mount. It could also work with Doug Joseph’s hidden belt mod.
Because of the ease of conversion, it would be easy enough to built it with the belt as designed, and if it solves a problem, you could switch it.
On the other hand, if you build with the rack and pinion, you wouldn’t need the Y rail at all. Both sides could use the wheels, since the rack and pinion would serve to constrain the machine in the X dimension… Looks like you want to go with rails on both sides.
would be ALMOST as fast as a belt, but with higher presicion. Threaded rod being the most accurate but probably too slow for you because you plan on running a plasma which needs to move at a considerably faster rate than lead screws will allow
Having built a MPCNC primo. I"m super interested in this version for plasma. I believe having te MGN rail with a rack mounted either to the outside or ideally below being ideal. Does any one have any prototype files they would be willing to share? @ebaikie My plan for table structure is to have the center section recessed so that i can insert a wood waste board and remove if i want to run the plasma.
I’ve been so busy on other things that I got sidetracked from this project. Of course if I had finished building this CNC it would have immensely sped up the other projects that I’ve been busy with…
I can share my model files with you if you want to start where I left off. I modelled this in Inventor, what format works best for you? (Inventor or stp?)
Inventor should be fine. I think we’ll have a similar end goal so I’ll try to keep you in the loop. I like your crane/shackle storage idea. I’m considering something similar.
I was playing around with this design a bit more tonight. I’m working on a version with a stitch welded gantry with a vertical front face. I want to mount an additional W-axis next to the torch holder so that I can lower a pencil die grinder below plasma torch height to spot drill hole centers and engrave parts.
I changed the Y axis to MGN rails and rack and pinion as well.
I’ll update again soon as I do more work on this.
I’m glad to hear your re engaged. I"m considering aluminum as i’m planning to build a tub for coolant. I want to ensure that any possibility for corrosion is kept to a minimum. I think your latest design is much closer to what i envision. my plan is to recess the slats below the top of the table about a 1/2". I want to be able to drop in a wood waste board when i want to run it for alternate purposes then metal.
I’m glad to hear your re engaged. I"m considering alumninum as i’m planning to build a tub for coolant. I want to ensure that any possibility for corrosion is kept to a minimum as well as shedding weight where possible. I think your latest design is much closer to what i envision. thoughts on stitch welding the X gantry to the Y axis plates. And then on your tool plate having a Z axis that moves only the tool instead of the whole x gantry in the z direction?