Suction Cup Effect - preFORM software is responsabile for that!

Hi there,

We have acquired a new form 2 printer and we are printing big size models fulling as much space of the building volume.
And we are always getting a motor jammed error around layer 20-25

I have been in contact with the support team and here are my conclusion.

The preFORM software is responsable of this error, which generates the supports and the base of printing, in such a way that it is impossible for the printer’s motor to get away from the tank, creating what they call the “Suction cup effect”

Attached the picture.

As you can see the first base is not straight, but it has a contour which is higher and therefore creates an empty space in the middle were air and the uncured resin creates the suction cup effect.

I think you really need to consider to change how the “generate support” functions.
Otherwise the form 2 printer will continue to have the same problems.


Yes, the hollow in the center of the model support base is the issue. The outer edges are flat thus causing the vacuum pulling up on the soft tray surface thus delaminating it.

There needs to be some grooves from the hollow out to the edges to relieve the vacuum that builds up when the Build Plate is lifted. I’ve written about this in the past to no effect.

Stay tuned for future updates :slight_smile: We haven’t found the cupping of the base layers to be especially impactful, but for large cross-sections parts can require a fair amount of force to detach. We’re working on features to address this.

@EmilArtuso If you’re getting a motors jammed error from the base layers, it might be the case that your Z offset is a bit low and your early layers are being over-compressed. You might try iterating upwards slightly with Z fine tuning to see if that corrects this. I wouldn’t iterate beyond positive 0.5mm or so because it could lead to the opposite problem whereas parts detach a bit too easily.


Disagree on the cupping causing vacuum issues. I’ve purposely listened to my machine when doing jobs with large bases. You can hear the motor struggle. Once it’s past the base build it levels out to a normal sound. I’ve had to stop a few prints because the sound was giving me concern that something was going to over heat and break or that the resin tray would be ruined.

I have always wondered about this decision by FL to put that geometry in there considering there are multiple warnings to not put in features like this on your part. I can’t conclusively say it has been a problem, but I have had parts come off around those layers. I look forward to future updates.

@Walter_Gillespie @EmilArtuso Check out the release notes for 2.14.0. The new rafts include vent holes in the sides to prevent any cupping effects.


Really appreciate these changes. Glad to see part names on there!

Why does it not work for Form1 +? :disappointed_relieved:
and supports also? :disappointed_relieved:

Just installed the new version of Preform 2.14.0 and I am not seeing any big improvements, at least not with the piece I used. No vents for the print base and I don’t see any place to make any alterations.

Because they discontinued any and seemingly all work related to the Form 1+. It is a retired product that will not be kept current with new resins or Preform features.

You would see this with the new “color” resin and the new version of black are not able to be used by us. I gather they could be if FL wrote the resin profiles but alas, the product line has been discontinued.

On the other side, IMO, the Form 1+ would not greatly benefit from such a feature due to the completely different peeling process.

It sounds very professional, but …
In the case of supports, not necessarily.
When I generate supports in a graphics program, very similar to those generated in preforms 2.14.0, I have no problems with printing.
My Form 1+ printer is still functional despite being 3 years old, so I hope program support for it will continue as long as the technical capabilities of this printer will allow it (these were the Formlabs’ assurances).
And in this case, I think it is.
So it is not a technical problem but a different one.
Good night.

I have a +0.5 mm on fine tuning and, well, still getting the motor jammed error on layer 20-25, the printer works fine for smaller objects.
But what is the matter to say it has a 14,5x14,5 x 17,5 building volume if the printer stucks on the preform generated base?

One word: ridiculous.

Hi Frew,
i have dowloaded the new version, and finally i see that preForm is generating holes on the base.
I will start the printer today and will tell you the result.


Just to be clear, you do need to regenerate supports to get the new base. It won’t automatically go back and modify a base you created with an earlier version of PreForm.

Again, I have the Preform 2.14.0 installed and do not see any of this. No holes, no label (turned on), etc. Seems strange but this is both large and small pieces.

I take that back. Just did a brand new Preform setup and yes both are there. This should work. Just wonder if the holes are better that slots at the top edge for draining/

You should still be looking into fixing this issue. We’ve been printing regularly 400ml+ parts that are hollowed-out so and they t take probably 50 to 75% of the built plate surface area, and we never got any issues with the Z motor or the tank jamming. These parts have a big raft, drain holes but still several big suction-prone area, they are 173mm tall, the works… everything should go wrong but we never had a failed print.
I’ve seen on this forum images from Formlabs where they print a solid piece of 145x145x170 (or something similar) to test peeling, unfortunately I can’t get my hands on the posts.

I have preForm 2.14 and it created the base with holes.

I already passed the 25th layer and the printer is working on supports without any problems.
Pretty sure the new version of preForm will reduce printing errors.


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