Cupping mitigation (enabled through PSE) is great when geometry cannot be changed (customer geometry) or is otherwise undesirable.
I understand how and why it drastically increases print times when cupping is present (massively extending squish and peel times), but why does it greatly increase print times when no cupping is present? For example a large print we just started now, 3hr33mm to 5hr52, with no cups?
I can see a case where some layer are ‘nearly cups’, i.e. parts printed on the build platform, with drain holes - for the first few layers, even though drain holes are present, the cross sectional area through them is tiny until the drain holes build up.
Hi! Thank you for sharing your question!
To look into why this happens, it would be best if our team could have a look at your .form file. Please let us know if you can share an affected file.
Hi Sophie, I can’t share the exact file - but I can reproduce it in a demo part. I will print the part and share the .form when done, thanks!
We have also found that cup mitigation often still results in localised banding, where the relief for cupping is a cross hole.
For example, the below part is heavily cupped at it’s base, until the print reaches the first layer of the cross hole perpendicular to the build platform.
As shown below.
However, for the next few mm of build Z height, after the cupping is theoretically no longer present due to the cross hole (where presumably cupping mitigation does not apply), heavy part banding still appears.
Presumably this is because the cross sectional area through which resin can flow during squish and peel is still very small in the first few layers where the cross hole is present.
As such, I suspect significant part quality improvements could be made if Preform were to keep cupping mitigation enabled, until such a time that a sufficient cross sectional area (for the resin viscosity in use) is exposed, or - allow the user to specify the number of layers which cupping mitigation remain active for, above the Z height of the detected cupping.
We’re running this demo part now and will add photos when done.
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Images below; printed at 100um layer height, Tough 2000 V2, to pronounce the effect visually. Form file attached also.
The inside pictures show nice and clearly that the cupping witness marks start at the exact layer where cupping is theoretically no longer present, but practically speaking very much so, until enough drain area is exposed.
CUPPING MITIGATION DEMO.form (729.2 KB)
Thank you for flagging this further issue with cup mitigation! I’ve forwarded your findings and the suggestion to expand the cup mitigation setting beyond the actual cup to the responsible team.
This seems to be a separate problem from the originally described behaviour where cup mitigation extends the print time of jobs without cups. Let us know if you have an example of this scenario as well!
No problem!
Will do - interestingly I can’t reproduce it (the extended time issue) on several parts, including the test part printed above. I will revisit the parts where we first saw the issue!
