Job Sliding

Hi,

While using Flexible resin we observed job sliding
Elephant trunk, wall thickness 3mm.
Any guess, why job would slide after few mm of print

Did the printer raise the platform and mid-print reset or ask for more resin …?

To me this appears to show that the part is not supported enough and possibly not orientated to optimize it for flexible resin

I have been printing with Flexible resin recently and found similar results. A couple of things I found helped.
-rotate the part on the bed so that during the peel that supports are perpendicular to the peel hinge. ( this results in less deflection of the part during the peel)
-place the part nearest the hinge as possible ( for me this helped with the amount of stretching that the part and supports went thru during the peel)
-don’t lower the point contact diameter or the support ratio (can break away from the supports to easy)
-try to minimize the amount of resin being cured by the laser by orientating the part to minimize the area of cure. ( i found that the flexible sticks to the PDMS layer with much more stick than the other resins and causes the peel to create larger forces on the part to separate and can cause the part to shift in-between layers)

Take a look at the pics of a part I printed, as you can see I was able to successfully print it after 3 tries and following the steps above.
Also, first pic was with a Form 1+ and the 2nd pic is with the Form 2.

Good luck,
Mike A
Scout Design & MFG

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In my experience it’s best to position the “heavy” end of the object closer to the base. In this case, the base of the trunk should be nearer the base and the tip should be higher up.

It really isn’t “weight”. You need to look at the layers to see how much resin is being cured. The larger (heavier) regions of a print usually have more resin area per layer than the smaller regions. As the supports get taller they’re less able to resist the peel forces without deforming. So you want the areas that will generate the greatest peel forces to be closest to the base where the supports are shortest.

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The job slicing was done by pre-form auto settings!! we did not orient the job, there was no stopping of machine in between process…
Thanks for the responses, we will consider the same for our next job…
We did finishing to the job, color dye and presented to client… They were impressed :slight_smile:

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If you are still printing with both F1+ and F2, are you finding more errors / fails with the F1+ since somewhat recent Preform changes? I used to get very consistent prints with my F1+ until a few months ago. Now I bought a second F2, and am trying to figure out the future of my looks-almost-new (due to careful use) F1+. Heartbreaking, to say the least.

One other possibility is that the heavier peel forces pulled the table slightly, then it stayed in the new shifted position.

This artifact is due to the rigidity of the overall structure, relative to the tank sweep direction.

The orientation of a part is particularly important for flexible material. Not only do you need to first, orient the part for a proper build (say a 45-degree angle off the build plate), just as you would for any build our material… but, because the material is so flexible (and thus the support structure is flexible), you then also need to orient the part so it, and its support structure is as rigid as possible with REGARD TO THE TRAY PEEL DIRECTION!

So for example. If you were printing a pencil…

You would first set up your part and supports for a successful print.

But then, it is imperative, when using the flexible material, that you orient the part and structure such that the motion of the tray will not deflect the part when the tray shears to peel each layer.

So with the pencil example. It should be oriented such that the length of the pencil is parallel to the tray peel direction. If it is perpendicular, the lack of support in the sweep direction will deflect the part, and it will not return to its neutral position before the next layer… and thus you get this.

This is hard to explain without a graphic example. Let me know if it makes sense. I’ve printed over 5-liters of flexible… and it’s a bit special, but, if done well, puts a shame to a $200k Objet. Granted we can’t pick a durometer… but the aesthetic of the part is 100-times better. None of that glossy, sticky Haribo shit.

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Just to be clear.

This problem is not a lack of support problem (as if it were another material).

It is a lack of STRUCTURE problem relative to the peel motion of the tray.

Simply spin the part, about Z (using the same support structure) such that the part (and support scaffold) resists the motion of the tray peeling motion with the least deflection.

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The taller the part, the more important this ‘rule’ is, because the further you get from the build plate, the more deflection the part displays.

I’ve printed a handful of builds that were over 165mm in Z and had none of these artifacts… but that was only after developing this flexible-philosophy… and these parts had features that were less than 0.2mm and not a sign of build layers, much less what ya’lls talking about.

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