AnyCubic Photon- Boilers Coming Out Oval-Shaped

[JayWizzleHizzle]

I've done plenty of small prints before while testing out my OO Scale Port of Par Alfred and Judy shells. Their small size meant I never had many problems with distortions, but now that I'm trying to print a significantly larger model, I've found that the boiler is coming out more of an oval shape.

 

I slice my models in ZSuite and print on an Anycubic Photon. I print primarily with clear resin, at a layer thickness of 0.05 mm and a 10 second exposure time. The walls that make up the model are 1mm thick, from the boiler to the cab to the runningboard. I add supports only on the inside of the boiler, not the outside. I've also attached pictures from the slicing software itself so people see how I'm adding supports.

 

If anyone has had similar problems and managed to fix them, any help would be greatly appreciated!

Edited July 21, 2021 by JayWizzleHizzle

[DGO]

This is one of the annoying things that happens when you are basically stretching the resin with each layer, the sides of the boiler are thinner (I assume it is hollow) than the top/bottom of the boiler so it distorts non uniformly, you can try 3 different things, 1. add more supports to the boiler area, both inside and out, 2. Try printing at 45 degrees to the bed of the machine (if you have room) 3. Split the structure into multiple parts which will give you better control of each part, try to keep the wall thicknesses uniform as much as possible for each part, printing any cylindrical structure at 45 degrees to the build plate will give you a series of ovals of fairly uniform size as opposed to a series of rectangles that vary in size as you go up the boiler.

 

Before you do any of this get a micrometre and print a 1cm cube with something different on each face as an identifier and then measure it, check that your 1cm cube is coming out perfectly dimensioned, if not adjust the settings in the software. Do this for each resin you use and check also for shrinkage pre and post final cure.

 

PS the yellowing of the clear resin suggests that you are over exposing it, clear resin generally requires less exposure compared to say grey resins 

 

David

[JimFin]

I would agree with printing at 45 degree to the build plate rather than flat. This would significantly reduce the size of each layer and reduce the suction which will contribute to stretch.

[JayWizzleHizzle]

I certainly wouldn’t mind tilting the model to prevent this. The only problem is 45 degrees would massively increase print time. Do you think 22.5 degrees would suffice? Or would 45 degrees be the only sure fire way?

[DGO]

1 hour ago, JayWizzleHizzle said:

I certainly wouldn’t mind tilting the model to prevent this. The only problem is 45 degrees would massively increase print time. Do you think 22.5 degrees would suffice? Or would 45 degrees be the only sure fire way?

You could give it a try, 45 degrees is typically used as most people can remember it but I've seen a diagram somewhere where different layer thicknesses have different optimal angles for printing, if I see it again I'll drop a link in here.

 

[JimFin]

The optimum angle is the ArcTan calculated using the layer height and pixel width. 45 degrees for a mono X and 46.77 on the photon. 

 

Full explanation here. 

 

22.5 degrees may help with improving the circular outcome, why not slice a couple of small sections of the model or simply create a short section of tube mimicking the boiler and do a couple of test prints at different angles.