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Questions on my first print not adhering to build plate


#1

I’m trying to print a medallion with text and a logo in reverse to be used to imprint clay. My model is oriented with the edge attached to the build plate. The first layer that I measured off of a failed print is 3cm x 1cm and I don’t have any base layer.

The first time, layer 1 had exposure time of 60 seconds. The remaining layers until it dropped at layer 30 had an exposure time of 30 seconds.

The second time, layers 1-10 had an exposure time of 90 seconds. The remaining layers until it dropped at had exposure time of 25 seconds. It dropped around 80 layers.

I read that the attachment layers should be 10x that of the other layers, so I was woefully short on both prints.

My current questions are:

Should I add a separate attachment layer before my model starts? Any suggestions on size for x & y, in comparison to the 3cm x 1cm layer 1 that did not stick? I’m printing at .2 mm, so how thick of separate attachment layer would you suggest?

Or, should I just try the print again, but make layers 1-10 have a 5 minute exposure time?


#2

Hey!
What resin?
What resolution(size of the build area)?
Any images of the model or failed print?


#3

Spot-HD, 75 microns. Here’s two shots of the first failure.

Here’s some shots of the 2nd failure.

Here’s a picture of the model:


#4

Here’s fail #3. I exposed the first two layers for 5 minutes and the succeeding layers for 30 seconds.
There was a thin set of wings at the attachment, that were not there on the previous prints. It looks like the the fail was near the same spot based on the letter “M” on the model.

Any ideas? Should I add that a base? How big, how thick?

One more shot. Print #2 in the back, Print #3 in the front.


#5

Generally speaking, I like using an attachment layer that is 1 layer thick with a total surface area about 2-4X the area of the layer of the part with the greatest surface area.

The easiest way i’ve found to do this is to modify the first layer PNG directly using MS Paint and draw one or more rounded rectangles.


#6

Thanks. That’s a much easier solution than actually adding it to the model.

About adjusting other settings, I was lifting by 7mm, would lowering the amount of lift (say 5mm or 3mm) and the speed of the uplift place less stress on the attachment layer and the base?

Thanks.


#7

If the model is big, you might need to tilt the model as the letters are hanging without supports.


#8

Thanks, for that suggestion. We’ll see how this print goes. I expanded the area of the 1st layer like jkao suggested, so far it’s still attached.


#9

The larger attachment area helped and as tech support said, the letters we a bit slanted, so I tilted the model, bumped up the build area to 100 microns and added supports. Now I wait. Thanks for your help.

Update:
The print came out great, no more slanted letters. It took 5 hours vs. the last vertical print that took 8 hours. I reworked the model to have it fit flat to the build plate and it printed in 48 minutes.


#10

Lying flat is a lot more difficult. If the model is too thick, the shrinkage could pull it away from the platform. How did you manage to make it work?


#11

Yes, I ran into that problem twice where the base was too thick, my vat surface rippled and the base did pull away from the platform. What I did was cut the base thickness in half and I ended up having to use a new vat, the other was just too rippled.

So, I’m curious. Is the rippling in the vat, rippling of the silicone, the teflon sheet, or both? Is the rippling permanent? I looked at jkao’s video about relaying the teflon sheet and since the vat is pretty useless, thought I’d give it a shot. Is this a waste of time, since jkao wasn’t relaying the teflon due to rippling in the vat, but cured resin underneath the teflon.


#12

I’ve only had rippling occur on the soft vat. It occurs when the film shifts laterally, locking in deformation due to lift forces.

The easiest way to remedy rippling is the carefully remove the film, starting from the corner closest to the ripple, until the film over the rippled part is lifted off the soft silicone. Then, carefully push the film back down onto the vat.

Reseating the film this way does weaken the adhesion between the silicone and the film, so gradually, it will be easier and easier for the film to shift.


#13

Thank you for the great advice.


#14

Soft vat is only good for tiny models that do not require precision. It is also easier to print on the soft vat. When the film is severely warped, the resin may enter between the film and the silicone. It is very rare that the resin could get below the silicone. The Teflon is only a protective film for the silicone as resins tends to react with silicone. The separation is done by the elasticity of the silicone and the flexibility of the acrylic. Hard silicone has less elasticity so the stretching of the Teflon film is less and the lifetime of the film is longer.