[SOLVED] Rings Printing Oblong/Ovoid

[flameswithin]

Hi everyone. After weeks of our Solus not running right, I FINALLY got successful prints again yesterday. It seems the issue was film tension. I had been installing the film flat on the table without any stretch, a method that had been working beautifully for us for 6-8 months. At a loss, I went back to installing the film using the method in the setup videos and voila! The rings finished beautifully without any slag or over-curing and the surface finish is an immaculate satiny gloss.

But the rings are effing warped. The oblong/ovoid shape is actually more pronounced in person. The round shank of the ring is slumped down and to one side. I've read through a ton of threads here but I'm still pretty stumped. What's the cause and solution to this?

If it's diagnostically relevant, I'm using an Optoma HD37, 42xy 25 micron, B9 emerald resin at default exposure settings.

Thanks.

[mongerdesigns]

First of all I would check the grid to make sure the aspect ratio is correct. Are you getting exactly 80mm x 45mm?

Second, I would check the film again. Do you have the 1mm gap between the bottom of the tank and the printer when you rest the tank on top of the quartz? If not then your film might actually be loose.

[flameswithin]

Thanks for your reply. The grid is measuring a very precise 48x27 (I specified 42xy in my original post, I think I had that wrong, sorry, we're using the smaller 48x27 grid size). I'm using the default barrel distortion parameters recommended by you and they have worked fine for us prior to this round of problems.

Like I said, I installed the film as per the original instructional video (not the one with the spacer tool, which we haven't purchased yet). Here is how our vat sits on the quartz without the thumb screws:

What else could I check? The default exposure time for the B9 Emerald resin is 6 seconds. Should I go higher? Is the resin perhaps slumping because it's not being cured hard enough?

[mongerdesigns]

Please remove the Y support inside the ring and try the print again. It's possible that it actually distorts your model.

Another thing to try is to use the Scale Adjustment (File, Setup, Scale Adjustment) to correct this. You will need to print a 10x10x10mm cube and then measure it and put the new values on the bottom row. Or if you know in which direction the ring is off, then you can calculate the number. For example, 9.7 will make models 3% larger in that direction. Keep in mind, this feature is still in beta.

[mongerdesigns]

Default exposure time for Emerald is not 6 seconds per layer. At 42xy25z it's actually 4.5 seconds.

What's confusing is that you said that you are using (42xy 25 micron), however your setup is for the 25 micron XY resolution.

At that setting, the default exposure is much much lower than 6 seconds. Please post a screenshot of your resin settings.

[flameswithin]

Hi Monger,

You are correct that I misspoke in my original post. We are using the 25 micron settings at 48x27 grid size.

I have printed a 10x10x10 cube and made scale adjustments in the past that resulted in a perfect 10x10x10 cube (that was a happy day).

I've just checked my exposure settings again. I thought that I had reset the exposure settings for the emerald resin, but apparently I had not, which is why the exposure was so high.

So, I am going to remove the supports in 2 of the bands and try growing them again now. I will post my results this afternoon.

[flameswithin]

Hey again,

So as per our last messages, I reset the exposure times for the B9 Emerald resin and removed supports from the rings, but the results were the same. The rings are deformed with and without supports in exactly the same place and way. What else could be the cause for these distortions? Thanks.

[mongerdesigns]

It's hard to tell from the picture, but is the distortion on the left side of the ring?

You may need to try and replace the film, because it can either be improperly installed or stretched out on one side, causing that distortion.

Post a screenshot of what the scene looks like in Contour. Would like the see the orientation that you're printing with.

[flameswithin]

I followed the film installation procedure in this video *exactly.* I got these distorted results immediately with this brand new film install. If installing this way doesn't work, what can I do differently to ensure good results?
https://reify3d.wistia.com/medias/rlt30j3k87

Yes, the ring slumps down to the left side. Here is the scene. I decided to grow a supported and unsupported version as a control to see if the supports were the problem.

[flameswithin]

So, I just took another look at the model under the microscope and noticed something. The horizontal grow lines appear nice and straight on one side and slightly slumped and curved on the other (I realize you can't see the left grow lines well in this photo). This would seem to be a smoking gun for the film being unevenly stretched. Is that a fair assumption?