How would you print this? Material and supports
Hello,
I am trying to find the best way to print this part:
The part has the form of a dish and has to be translucent (STL file attached).
I have started with printing thin, flat layers of white PET. If layer thickness is low that would give good results. But to print the dish shape I hink it's necessary to print some form of supports. If I print supports with the same material, I get an uneven surface where the supports are. Because of the gap between supports and part the filament strings are not forming solid surface and are clearly visible when light shines through. I have printed some other parts with BVOH as support material any maybe that would give a better surface above the supports. But I have found that after a material change from BVOH, layers with only small connection areas are getting unstable. This may be due to the change between printing temperatures so that there is no proper bonding between the layers or there may be some support material (BVOH) carried off tho the parts material.
I appreciated any opinions which way to go. Or do you think it's simply not possible to do it with FFF printing?
Rainer
... seems I can't upload or attach an STL file
RE: How would you print this? Material and supports
You have two issues to solve:
1. Translucent and FDM is not a good combination. You will require post processing to reduce the uneven surfaces. Check other threads, it's common question.
2. Best print orientation for higher quality walls is vertical (standing). As you don't have a good base to hold on the plate, I would make one and remove it in the post processing step. Avoid any supports, thick brim and slow print speed might do the job.
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RE: How would you print this? Material and supports
STL and similar files must be zipped then attached.
Like Nikolai said - printing a lens is problematic. Almost everyone resorts to sanding - priming - sanding - priming - sanding to get gloss finishes. A few have been having good luck with MSLA printing - better chance at even and clear translucence, with a touch of transparency.
Cutting the part in half, then using a large brim might be worth considering. Then trim and glue the halves together.
RE: How would you print this? Material and supports
I understand the idea of printing the part vertically. I have printed some kind of poles that way but they had more contact to the heatbed and also to the brim. I think I have tio design a "smart" base that gives enough support for the vertical part and is fairly easy to remove.
Rainer
RE: How would you print this? Material and supports
Probably there are better methods then FDM to do it, but it's the only process I have at hand. I see that it would be much easier to make it with two parts. But when I use opaque material as I did, I can only get I translucent by keeping it very thin. I think it would be really diffcult to glue this parts.
Rainer
RE: How would you print this? Material and supports
Something like this may work ... wings make contact to support upper 50%, and supports everywhere to 90 degrees. Bed adhesion will be critical for the first few layers.
RE: How would you print this? Material and supports
@tim-m30
Thanks for your suggestion. I will try this. I had some problems with the support you used because my part is a bit more complex (concave). That's why I can't use auto generated supports. And a simple block as a support enforcer would still build support material in areas I don't want to have it. Now I have made a custom support enforcer in the design software by subtracting the real part from a narrow block. Looks good after slicing but I think I have to tweak the settings for the support a little. Maybe set the distance for the support interface to the part to zero and have a bigger value for the spacing of the interface pattern. Hope that this makes it easly removable but still gives enough support for a good surface.
Rainer
RE: How would you print this? Material and supports
With a concave part, just place a support blocker over the areas support is not wanted. Adds a simple extra step, and works very well. You could use a replica of your part, just a tad smaller diameter, a tad thicker, and add it as the blocker. That would cover the lower regions very well, and a simple block can cover the top half the lens.