Warping High Temps prints before curing


#1

hello everybody,
I am printing with HT resin, and I am experiencing issues with warping, almost all my parts are warping before curing them. here is an image of an example of a part that is giving me issues:


the supports are the standard density at 1 and contact point at 0.8mm with layer high of 100microns

I wanted some feedback from other users, this warping can be eliminated by lowering the layer high? or augmenting the density of the supports? I could find how is affected the warping of a print by these parameters.


#2

I find that with my engineering components that are of a cylindrical or conical form and concentricity is important, I will print the part as close to the vertical as possible and rely on the mechanical properties of the form. Eg a card board tube is difficult to crush along its longitudinal axis when compared to crushing it along its axial axis.

The supports algorithm is very good but it is a starting point and does not always do the job perfectly. We often design in sacrificial supports of our own, run the supports algorithm and then edit contact points away from sensitive areas on our component

Increasing density of supports is one solution and so is reducing layer height, The thing to look out for is the self supporting over hang of each printed layer. You will probably find that the warping is incremental starting at the very early printed layers especially with solid and relatively heavy parts.

When we have something tricky to print and there are conflicts of requirements for the F2 we print using several support methodologies and orientations in one run and pick the best to refine further before we go into production.

Another setting up trick we use is to intentionally reduce the number of supports and run the preform program and check for the “unsupported minima areas” highlighted in red we then go into edit mode and then “over support” this area (often useful to go into support in preform - edit supports to remove supports that may be hiding highlighted under supported areas, Sounds more complicated in words than in practice!

Hope that helps and let us know how you get on.

ATB


#3

Hi, I just logged in to ask about the same issue.
I print with Standard Grey, Standard White and High Temp and there’s warping in every model I print that has thin walls (actually HT shows the least amount of warping for me…)

I read all the topics on the matter on the forum and here is what I tried based on the suggestions given:

  • Orient the model so it’s not parallel to the build plate -> Done that, doesn’t seem to help…
  • Make the model thicker -> It helps a lot but sometimes it’s really not a solution
  • I moved the printer to another office with a more stable temperature and (hopefully) less humidity because they said those could be a factor too. I have to make other tests but it doesn’t seem to have that much of an impact (or maybe there just isn’t enough difference between the two rooms).

What I plan on doing:

  • Print directly on the platform.
  • Try not to print overnight to avoid temperature changes in the print even though it won’t be ideal for my work routine
  • Try other resins, any suggestion?

#4

Do you have any images to show context and extent of warping?


#5

here is another photo (where the part is a small cube of 1x1x1cm…)


and in the original part that i post it you can see the warp of the part. it is possible to see that the cylinder in the upper part its axe is not parallel with the axe of the lower part (cone part)
thanks for all the information


#6

well from what greymatter was saying the first thing I will try is going up with the support density. it is sad as the surface is not the same but i need accuracy in the geometries. if you could try the same model with different layer highs and could give a feed back i would appreciated, as i am paying for the printing time a lot…

thanks


#7

maybe printing it in the build plate directly? something like this: (I find it quiet reasonably but i have never printed directly in the build plate… any recommendations?)


#8

Would not expect that result on a 1cm cube. I have just added a 1cm cube as per Preform set up and a 1cm cube as we would do it. It is being run in clear as that is what is running on the F2s at the moment. Will let you know result.

Noticed you mentioned printing straight onto the platform. It will give you a good print except for the first mm near the build platform will be distorted.

If you are ok with it, send the stl so I can see inside shell.


#9

here you have the file of the cubes, from what i can observe in the printing layers they are “cruved” it doesnt show in the photos… but they are like C where the curved part of the C is pointing to the build plate. 19.09.09 13.91ml 1hr 30min HT.form (182.5 KB)


#10

Morning otaolafr
I have run some controlled experiments and I do get a distortion on one corner of your test cube.

I have set up the cube:

  1. your way
    2.point supports along the edge
  2. linear support along the edge (my preferred)
    see attached .form fileBILL TEST 01 FLF otaolafr.form (397.1 KB)

Now the way the print works, the cube starts to print as a pyramid balancing on a single support, and this single support has to take all the loads until the next support is met.

Now for most people this does not really matter as geometrical tolerances are not that important for their needs.

My first solution worked better and this was not disernable distortion across the 6 faces when tested on a engineering square. What I dont like is the chip out on the edges. This is a higher density where it matters.

My second solution supports all three edges nearest to the print platform all the way (I just picked 0.4mm thickness as first guess - you can go smaller) my support structure is given further support by the Preform program. I use this technique a lot and there was no distortion. I clean up edges by scraping with a scalpel under a microscope and finish off with 2000 grit wet and dry resting on thick piece of float glass.

Now I did run this with clear at 25 micron layers and not with the HT, but it shows the same distortion, so it is a processing issue and not a material issue. The F2 is great but sometimes you have to work with its limitations when you are pushing the limits.

Now coming back to your original component. If it is essentially solid and not shelled out it will be relatively massive and with a 0.1mm layer thickness this distortion will be exacabated as there will be a little distortion on every layer.

Now printing flat on the build platform is an obvious solution but you have to allow for some layer distortion in the first few layers. What I tend to do is to add an extra say .75mm to the base then machine or sand off afterwards by 0.75mm.

I hope this helps. Let me know how you get on.

ATB


#11

I’m currently printing the test cube in HT resin V1 (I don’t have v2)
I’ll let you know about the result.


In preform 3.0.2 there’s an option to print on the build platform if you want to try that.


#12

I printed the cubes and they all look good.
First one on the left was printed with one corner on the bottom.
The second was printed with the auto-orient function.
The third was printed directly on the platform.

I can see no deformation except on the first one where the corner that supports all the cube is slightly deformed.
BTW I don’t think your problem here is with warping. To me warping happens only after I print and cure the resin and only when there are flat and thin (1-3 mm) surfaces (and I’m still trying to solve that with no success…)

I’m no expert but I think there’s a problem with the calibration of your printer. I suggest you to contact Formlabs support directly since it looks like they’re no longer replying on the Form 2 subforum…


#13

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