[Solved] Print failed when scaled up


#1

Hi everyone, I finally got my moai calibrated and printing after a week or so of struggling. Turns out I didn’t have any leveling issues, but rather a thin layer of dust that had gathered on the galvo protector glass. Don’t build your printer in dusty places!

Anyhow, I had a question about how much supports are needed for scaling up a model. I tried two test prints (there were the upper body of a figurine I had previously printed) after I had finished all of my calibration. Both of them were oriented the same, and were the same model. The only difference was that the first was scaled to one inch, while the other was scaled to four. The smaller print came out successfully and looks beautiful (even those tiny fingers printed successfully!). However, the larger print failed completely with only some of the supports ending up on the build plate. Both models were sliced on the latest version of Asura, and with the default support settings. I did hollow out the model and add holes, but it didn’t even get that far so I don’t think that was the issue. The only extra bits I did was add a few extra supports where it seemed like the software missed a few overhangs. Am I correct in assuming that my failure on the larger model is due to a lack of support structures? If so, what kind of support density should I be aiming for on those larger models? (default is 5mm spacing with 2mm thickness i think…)

I am printing on the FEP vat with peoply clear resin. Door is sealed and chamber is heated. I am aware that the FEP vat requires thicker and more numerous supports, but I couldn’t find a number to go off of. I also slowed the PM motor speed down to 10. Thanks in advance!


#2

there are some information i need you to provide:
1.picture of the model in Asura
2.what’s the density of the supports?
3.are there any drain holes generated?
4. are the two models prints on the same files or are they separate prints?


#3

I didn’t save the original file so i made a rough recreation.

  1. The density of the supports are as shown in the image (5.00).

  2. The model was hollowed out, and there were holes placed in the print, but I didn’t even get that far. All I got out of the print was a few loose support structures. The main body failed to print at all.

  3. The models were printed separately one at a time. I was sure to clean the vat, strain the resin, and allow ample time for the resin to warm back up to temperature before beginning the second print.


#4

Do you have a hole in the top of her head? If not, it would create great suction causing the print to fail.


#5

I didn’t put a hole at the top of the head. Perhaps that is the issue then? Of the limited amount of digging I was able to do, I never really got much information on hole placement. If I place one at the top of the head, how would I go about patching it post print? Can I use a hand held UV laser and put a drop of resin on to cure it?


#6

Yes that is how drain holes are filled afterwards.


#7

it is not very clear on the scaling, do you mean you scale after making the support/hollowing?
normally, it is best to scale first, then do hollowing and add support

the holes should be as close to the lower layers as possible so the hollowed object does not create very strong suction force.

and you can also increase the support tip to 1.2mm if it is breaking to easily


#8

I’ll divide it up as to be as clear as possible as to what I did.

  1. Small Model: Import > Orientation > hollow/holes > supports > export gcode

  2. Large Model (failed): Import > Scaled > Orientation > hollow/holes > supports > export gcode

I currently have another print in progress, and it seems to be going well so far. This time I bumped up the support count and added in a suction hole at the top of the model. The print is just visible past the lip of the FEP vat, and it looks like it’s turning out just fine. Here’s hoping it completes!


#9

Yeah, you need at least one hole near the baseplate so air pressure can equalize inside the print and eliminate the suction effect. I tend to put at least two near the baseplate, and at lest two more down the length of the model in places that are easy to patch. I also put holes at the top but they are really only used to drain excess resin.

Also, when lifting a print like this off of the baseplate with supports, consider using larger contact points to help the model stay “zipped” to the supports. Or, orient the print to use a flat region, and put that on the baseplate. Even if the software thinks that this is the optimal orientation to print this model, that doesn’t mean it’s the best way.

You need to consider the physics of the printer and the printing process when making a decision on orientation, supports, and hole location.


#10

Print was successful! There was a small incident whith the very bottom layer where a piece stuck to the vat, but it’s tiny and I know why it happened. I seem to have over cured it as well, but the important part for me here is that I can officially say I have things working :slight_smile: Time to read up on curing tips