Strange shrinking problem with a flatcar

[Chris333]

Go into setting on ChiTuBox, you can change everything.

[Lemosteam]

Chris your suggestion and me removing the deck thickness between the ribs appears to have worked perfectly. now just the deck on top and some weight underneath may just be the ticket.  But I have some other tricks up my sleeve...

[Sokramiketes]

Is there a manual way to program the first layer to expose slightly undersize first, for bonding, then at the proper size (but same Z value) for the correct dimensions?

I feel like the elephant foot can be fixed in the programming.

[Lemosteam]

Is there a manual way to program the first layer to expose slightly underside first, for bonding, then at the proper size (but same Z value) for the correct dimensions?

I feel like the elephant foot can be fixed in the programming.

Not that I can see, BUT, if you over expose a layer you will get Bloom, or hardening past the boundary of the slice.

[Sokramiketes]

Yeah, and maybe with a large footprint anyway, you don’t need to over expose the bottom layers. It’s just so much cleaner to print on the plate.

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Milwaukee Road gondola side.

[SkipGear]

Wait I can change the intensity of the light output?  no wonder I am seeing so much bloom. not knowing this the only thing I have been messing with is the standard layer exposure time of 3.6, and that was based on the RERF recommendations,

How do that from factory settings?

On the printer, click tools, then press the settings icon (gear wheel) in the upper right. UV power comes up in the menu, then click it to adjust.

[Lemosteam]

Yeah, and maybe with a large footprint anyway, you don’t need to over expose the bottom layers. It’s just so much cleaner to print on the plate.

(Attachment Link)
Milwaukee Road gondola side.

Not criticizing but I can see the bloom curve on the very end of the panel.  And I agree. the plate can make for a very nice surface.

I have not yet tried lowering the exposure on the first layers when printing right on the plate.

[Sokramiketes]

Not criticizing but I can see the bloom curve on the very end of the panel.  And I agree. the plate can make for a very nice surface.

I have not yet tried lowering the exposure on the first layers when printing right on the plate.

100% there is bloom here.  That's why I'd love to solve the bloom problem in software.  Maybe I'm not describing the idea fully, so let me try again.

Think about the first layers as a picture frame.  There's the picture in the middle, and the frame.  I feel like there could be two exposures.

1) Expose just the center of the picture, for as long as needed for bonding.  Let the bloom happen, but within the footprint of the picture frame.
2) Expose the full picture frame, for less time, to keep the dimensions.  It would cover the bloom, without making the bloom worse. 

Does that make sense?  Let the bloom happen, but within the overall boundry.  Then a shorter cure around the border, for a perfect part.

[SkipGear]

You can design the part to compensate, if it is a simple enough part, especially with the way the Anycubic Mono ramps down the layer time. You just need to design in a roughly 45 deg undercut that is 10 layers thick. I use 45 deg for my raft edges and there is always a nice square flange at the very bottom of the raft.

[Sokramiketes]

You can design the part to compensate, if it is a simple enough part, especially with the way the Anycubic Mono ramps down the layer time. You just need to design in a roughly 45 deg undercut that is 10 layers thick. I use 45 deg for my raft edges and there is always a nice square flange at the very bottom of the raft.

Does this method add thickness to the part?  I'm picturing a lot of cleanup afterwards, for something like this gondola side I'm OK if the back is flat, but carving off a big raft doesn't sound any easier than supporting it with columns. 

[SkipGear]

The undercut would be on the original part so no thickness added. I can draw you an example but it will have to wait, I'm at work right now.

[Lemosteam]

Hi Tony I tried that but since the flat has profile on the sides (rivets and stake pockets) its not that clean.

[SkipGear]

I was thinking more for Mike's example.

[Sokramiketes]

The undercut would be on the original part so no thickness added. I can draw you an example but it will have to wait, I'm at work right now.

Thanks Tony!

[SkipGear]

Thanks Tony!

At least for my printer, this is how I would do it..... Printing at .025mm layers, the ramp down on the Photon takes 10 layers so make a .25mm bevel on the build plate side of the model. The more complex the model, the more challenging it cousl be to get it right as inside corners could cause an issue.