Tray1

Tray1

The STL file and a link to instructions on how to make the waffle bottom are here: Thingiverse and here: Pinshape

May 19, 2017

Birk Binnard Birk Binnard
Revered
563 posts

4 replies


Nice waffle bottom :-)
I find that my belts are grateful if I avoid sharp corners in the XY-plane so I would give each one a fillet. Reduces noise and ringing too :-)
I use at least 1mm fillet radius if possible, but sometimes go down to anything that is bigger than the radius of the nozzle if things are too cramped.
With my weapon of choice (CATIA V5) I would probably make one single pyramid stump, give it fillets, then repeat it along X and Y. I would define the size of the individual "primitives" so that there is always a whole number of them in each direction. Would that also be feasible in Rhino/Grasshopper (which I don't know, but like the name of)?

May 19, 2017

Kerrberos Kerrberos
Beginner
15 posts

The 2 links I gave include a link to a blog page where I describe how I made the waffle bottom - I used a totally different approach from the one you suggested. If you are interested you can see the blog page here: waffle bottom

Your discussion about filleted corners is interesting. My printer, an Atom2 delta, has never had any problems related to drive belts - so square corners were an obvious choice for me.

CATIA, of course, is a far more robust program than Grasshopper + Rhino, so it is probably easier (and more reliable) to make filleted corners with it. However, my sense is the filleted corners would take much longer to print due to the tiny straight line segments the final toolpath would require. The method you describe could be done with my software - I'll give it a try and see how it compares to my current method. But I'll omit the fillets because Rhino has problems exporting a filleted surface as an STL file.

One of the things I did with my printer to smooth out it's operation was to tweak the Acceleration setting in the printer's firmware. Doing this on your printer might help the drive belt problems you mentioned. There is a setting for Acceleration on my printer's display screen. I reduced it from something like 10,000 (or maybe it was 1,000) down to 600. This greatly improved the printer's motion control and made for much quieter printing. It does slow down the printing of complex shapes (ones with lots of short movements), but most of my parts are large so this usually isn't a problem. It does slow down printing the waffle bottoms however.

*Update*

Well I tried your method of making an array of single bumps. It didn't work because of the bug in Rhino having to do with Boolean Difference. Basically this Rhino function is known to "not work in all cases", and I have verified in the past that this is a correct statement. It should probably work in Catia though. Unfortunately that one is a bit out of my price range (even in the capitalistic US (<== for Bart.)

May 20, 2017

Birk Binnard Birk Binnard
Revered
563 posts

I read your blog page (I regularly do!) before I answered and it triggered my how-would-I-do-this neurons!
I have a medium-old CB+ with bartified hotend and so the famous M1203-option, which will usually find itself set to something between 1200 and 1500mm/s2.
After making such a suggestion I have just done a test design to see how it would turn out - the fillets would of course not meet completely but the tiny bridging that would cause should be no problem. CATIA is also known to have some strange behaviours with booleans, particularly when attempting to subtract identical areas/volumes from each other, so that the result would be excatly 0, but in this case (creating a simple 2-dimensional array) it works fine...

May 21, 2017

Kerrberos Kerrberos
Beginner
15 posts

Well I'm happy to hear my blog is of some use to you. What's interesting to me about it is that every time I think I've run out of things to post about (like right now), something new or different crops up and I end up making a page about it. It will be interesting to see what comes next.

Your info about Catia is worth noting - if Catia has problems with 3D Boolean operations then I expect there is not going to be a fix for that anytime soon. From what I can tell, Catia is the top of the heap in the 3D design world, and what you said about it mimics the posting the author of Grasshopper said sometime ago.

Back then I started a discussion about these kinds of problems and what he said was that the solution to a Boolean subtraction boils down to a potentially very complex mathematical problem, and for some of them (depending in the geometry involved) there is no way to solve the problem. He went on to say this is not an end-user issue, but a deficiency with the code in the 3D software. His contention was that software should work the way the end user needs it to.

If only that were always the case.

May 22, 2017

Birk Binnard Birk Binnard
Revered
563 posts
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