All steel, no welding, 2000x1300x250mm

[eurikain]

It's certainly impressive I can see a lot of work has gone into this.

Hi Clive !
Thanks ! Yes, you are right, probably more than 30 hours of modeling so far, because I went through several designs, and had never used SW before, so I had to learn everything from zero ! But now I've got most of it figured out :D Great program to work with, though sometimes a bit frustrating.

I do worry about the straightness of the steel to get an accurate machine.

I understand, I am not sure myself as it is an experiment. In the project I linked in my original post, they got a .1 play on joints, 0 play on holes (that's what I've got), and they cut the plates on a .001 accuracy machine, so plays were correct when cut. The machine that will cut my parts has more than .001mm so I'm not really worried about cut straightness. if all edges, joints, teeth and pockets are cut straight I wouldn't see how there could be any straightness error :/ Where would they come from ? Are you talking about the steel straightness itself ? May be I can ask them to surface the sheets from which they cut the parts on both sides ? Would that be a fix ?

May I ask why you have not gone with square profile rails?

Price :) ! The goal was to make things cheapER. 12 SBR20UU blocks cost me $60. Stainless steel shifts will be less than $50 for all axis. Shaft supports are integrated to parts and don't add any cost to the machine but a few seconds of cutting.

I look forward to watching this develop. ..Clive

Thanks ! I am very excited to get the model ready and working so I can send the parts to the cutter :) !

[Wal]

Price :) ! The gold was to make things cheapER. 12 SBR20UU blocks cost me $60. Stainless steel shifts will be less than $50 for all axis. Shaft supports are integrated to parts and don't add any cost to the machine but a few seconds of cutting.

Hi Eurikain.

I've used TBR20's on my build and they work well etc. BUT, if I was building it again I'd use profile rail. Why? Rigidity (my rails aren't really long enough for this to be an issue for me) and ease of maintenance. Have a look at the attached pic:



The bearing housing in the block will work it's way loose from time to time despite the top and side grub screws that are meant to hold it in place (you can only nip 'em up so far before the unit binds). Once the bearing housing has loosened it will, over time, rotate and eventually the sharp corners of the cylinder will scrape along the rail supports. This isn't a catastrophe, nor should it lead to a catastrophic failure, but it's an annoyance that'll cost you time and an extra thing to watch out for. No biggie for a hobbyist like myself, but if downtime's something you want to avoid then do yourself a favour and buy profile rails...!

Wal.

[eurikain]

Hi Wal, and thanks for the input :)

I appreciate the advice ! Though I think I won't worry much about this as this is my first build and as I don't intend to machine things that often (I'm still a student and the machine will only be accessible on weekends). I went with SBR rails because in my humble opinion replacing a $5 SBR block every so often is not such a problem :) The machine design is done so that you can take it easily apart whenever you want and put it back together without loosing starigthness, rigidity or anything, as steel won't move when mounting / unmounting.

May be in a later version of this machine I will switch to profile rails and HWIN blocks though :)

[Wal]

That's fair enough. Just thought I'd give you a heads up. Best of luck with the build!

Wal.

[eurikain]

That's fair enough. Just thought I'd give you a heads up. Best of luck with the build!

Wal.

Very nice of you, that's what this forum is for and I'm looking forward to reading all you guys' caution advices and design improvement comments !

[eurikain]

Hey mates ! (hahahahaha for those of you who will get it)

I spent yesterday modeling the Y axis. Today I will make the gantry sides to fix the Y axis, fix its motor, and connect Y and Z if I have the time.

Here is a render of the Y axis with a section view (calculated weight is 28kg):

[Wal]

Looking at your renders - in reality, your rails will be supported along their entire length, won't they? Not at intervals, like you've got them in the images..?

Wal.