I’m trying to decide if it would be better to mount the linear rails on the sides of the 3030 beams or on top. Let me know what your opinions /input and reasonings are.
Depends on the type of linear rail. Some are 4 way type and can be mounted in any direction (THK HSR series). Others only on top (THK SR series). Best to check the rail manufacturer datasheet first.
My preference is on the side since the extrusion helps block out some of the contamination.
I mounted on the tops of the 8020 for the Y axis- longest run with widest span between linear rails (using fully supported 20mm shafts) and top/bottom configuration for the X axis (gantry) to reduce the cantilever of the spindle…
On the Y axis, that placed my ballscrews slightly outside and below the rails. On the gantry (X axis), the ballscrew is on the backside, essentially inside of the gantry (keeping front empty so the spindle is as close to the gantry as possible.)
@Jay_Polo you read my mind, Jay. I wasn’t sure how to orient my ballscrew. Do you have a diagram? Did you mount the blocks to the extrusion, or to a custom designed plate?
The ballscrew rod is shorter than the rails that were sent as a set.
Yeah, I noticed that “sets” of rails and ballscrews don’t seem to consider two big factors: 1.) the spacing between two bearings on a linear rail effectively reduces its useful length by the same amount and 2.) the machining on the ballscrew reduces it’s useful amount. Makes perfect sense, but you need to factor in both reductions as well as how you stagger them relative to each other, to determine total work space…
After lots of sketching this out etc, I determined they were long enough and close enough that I no longer cared to think about it any more!
I ended up putting the Y axis rails on top. Simply attached to the top of the 8020. Made it pretty straight forward to tighten one down and then inch the gantry along the rails while tightening down the opposite side. Which made them parallel and not bind.
Attached the Y axis ball screw to the sides of the 8020 using a bracket to space it out as needed. And essentially made my gantry longer than needed so it would extend over and on top of that ball screw. Seems to work well.
Ok, thanks. I’ll likely do the same
Good luck, and continue to share pics along the way!
I will!
Best piece of advice I was told was to have it all designed before you start ordering parts.
@Paul_Shaw I think that makes perfect sense, if you have confidence in what you are building. But if you are new to this, working on the computer alone is hard to get a sense whether the design is a good one. I needed to hold things up against the frame and get a sense for how best to make things work well together. Not perfect, but I do think it is better than had I done a 100% design before ordering my first part. That said, I do believe I would be able to design a LOT more of my next machine before buying parts. I’m happy with the approach I’ve taken.
send me cyj@imagerywindows.com
@Jay_Polo Thank you. I had a design in mind, but, after beginning the build, others’ input, my own mistakes (calculating measurements, inability to get the exact measurement, inaccessible tool or customizable part(within reasonable cost)) my build kind of evolved. Granted, in a perfect world, I would have done just that; but, I also, wouldn’t have decided to bother building one, I’d have just purchased a Haas.