New Phrozen Sonic Mini 8k S

[Chris333]

Just went to lower the base layers exposure time on the 8Ks and used my 8K setting as a base. But noticed that I was running the 8K at 4.5 seconds for a regular layer and the 8Ks was auto set at 1.5 seconds and the print came out great. Maybe the light is stronger on the 8Ks?

[Sokramiketes]

I was dealing with some post-print warpage on N scale passenger car bodies, and was just contemplating your 4.5sec layer time.  When I pull the body right away and cure it, it stays relatively straight.  If I leave it, like I print it overnight and then get to it later, it's a bananna when removed. 

So I was starting to wonder if the short layer times weren't curing enough, and then the surface is curing and causing a curl before the rest of the model is cured properly.  Like the surface gets taught and shrinks up a bit... kind of like laser cut relief on one side of a piece of wood?

Anyway, I was just about to try longer layer times to see if that cured more before the final cure.  Interested to see if you notice warping on the test prints at less layer time, at least than before...

[Chris333]

If I remember correctly I kept turning up the exposure to try and close up the tiny holes I was getting, but I later printed the "Cones of Calibration" with those new settings and it passed.

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I still get some warping. I try to cure the bottom of prints first, but have no idea if it helps. I read the resin curing has something to due with molecules lining up and connecting to each other. After that my head started to hurt...


I lowered the base layer exposure on the 8Ks and the print started to pull from the plate. Strange that these two printers have such different settings.

Oh and all the file thumbnails on the printer are turned 90 degrees to the side. Some one else on Facebook said theirs does it also. Doesn't effect prints though.

[Chris333]

Got my ACF film ($$$$) and well. Save your money. It prints fine, but there ends up being a light texture on all the vertical surfaces. Very faint and maybe covered right up with primer, but overall the nFEP is better. The suction effect on flat prints is exactly the same with nFEP and ACF so no improvement.

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Possibly the one benefit of the ACF would be durability. It may last longer, don't know yet. But the cost increase may equal out because I can buy a whole roll of nFEP for pretty cheap.

[peteski]

Got my ACF film ($$$$) and well. Save your money. It prints fine, but there ends up being a light texture on all the vertical surfaces. Very faint and maybe covered right up with primer, but overall the nFEP is better. The suction effect on flat prints is exactly the same with nFEP and ACF so no improvement.
Possibly the one benefit of the ACF would be durability. It may last longer, don't know yet. But the cost increase may equal out because I can buy a whole roll of nFEP for pretty cheap.

But as I understand wasn't increased printing speed the big selling point of ACF?

[Chris333]

Yes, but speed is not something I care about. I just figured if the release tension was less (for speed or for whatever) that the deformed edges would be less.


Oh and pics. These are both with nFEP. Bottom is the last print on the 8K and top is the first print on the 8Ks. Only change is no more tiny holes.



What I was trying to resolve with the ACF is seen in the side view of the end beams on the car. They are drawn square, but deform from pulling away from the FEP.

[Erock482]

Chris, have you tried the Sled type supports others have posted? I've used those slightly extended past the car ends to significantly improve that warping you're looking at.

Basically, a long narrow triangle shapped support drawn in your slicer. thin enough on top that you can wiggle it side to side to break it off.

[Chris333]

I printed the same car shown above on my Elegoo Mars 4 Ultra with the same results.

Not sure what is meant sled type supports, but I don't think so. Can Chitubox do that? But I don't see how the supports are the problem.

This is how it's supported:

[robert3985]

But as I understand wasn't increased printing speed the big selling point of ACF?

That was the big "marketing point". 

As far as selling, it's pretty obvious that from a sales standpoint, finer details is a much better selling point than printing speed.  If both higher speed AND finer details can be accomplished simultaneously...then that will be the best selling point.

Cheerio!
Bob Gilmore

[Lemosteam]

I printed the same car shown above on my Elegoo Mars 4 Ultra with the same results.

Not sure what is meant sled type supports, but I don't think so. Can Chitubox do that? But I don't see how the supports are the problem.

This is how it's supported:

Chris, this is my biggest bitch with resin printing.  Your upper flanges aren't sagging; they are thickening around the tips of the supports between the vertical ribs. The vertical ribs provide end support for the overhang and it looks like it droops in between, but its not- it's just excess resin that semi solidified.

Measure it against CAD.  I'll be there is at least 0.5mm of added material that pooled around the tips.  I simply have not found a support style that eliminates it and have resorted to shaving the excess material away before curing the part. I compare it to building a plastic model as there is always work to do after it comes out of the vat.

This is also why its hard to make nice fitting kits- the visual side looks great, but anywhere the design is supported, gets totally messed up dimensionally and visually.

[Chris333]

John, I know what you are saying about the upper rim area. But I was more upset about the end beams not being square.

They should be square like the upper left red box. I added the angle shown in yellow to try and "help". What ends up printing is more like the lower right red box.



If I could make the end beam print square then I would move on to that upper ring you mentioned. I could maybe even sand it a little.

[Lemosteam]

@Chris333 , Try larger diameters on the lower part of the supports or x and y axis bracing between the supports to stiffen them as a system. I think straight thin posts sway during the printing process (see below), which would explain why the bottom of the beams are moving in X and are offset for several layers (or the layers above those are being pushed out in X. Have you measured that dimension across the length at the top and bottom of the beam? Which is closer to design intent? Something is moving a site part prints.

One guy mentioned something to me on FB and it seems to have helped me a lot, but it adds time, is the light-off time. He said it gives the print time to rest/reset during all of the hydraulic movement of the resin during the lift and compression of the build plate while the UV array is off. Once settled the layer is exposed. I think it was eight seconds.  I think he also suggested a higher lift after each layer for similar reasons.

[Erock482]

Chris,

The supports would be drawn in whatever drafting software you're using, in my case (And I think yours) Sketchup.

Heres a image of what I use on my Box Car/Stock Car projects currently. Sleds are in Orange. They're about 6mm high, and the tops are as wide as a light support tip would be so they can be easily removed.
[ Guests cannot view attachments ]

[Chris333]

So it is just like a regular support, but it goes the whole length of the car?

[Erock482]

Basically, I found that extending them past the car ends helps eliminate the warp you see on end beams. I print mine in sections with gaps between to make them a little easier to remove, you can also put holes in them to reduce resin use.

It's a whole lot faster to support models too since the bulk of the car and thus supports are already drawn.