Thank you gregg, I get all that I have printing for a few years but why is doing it at the end of the print when none of those variables have changed. There must be setting somewhere that tells it to slow down there.
Ta
Thank you gregg, I get all that I have printing for a few years but why is doing it at the end of the print when none of those variables have changed. There must be setting somewhere that tells it to slow down there.
Ta
But they did change. The rest of the parts finished and left the tall printing alone. The "Minimum Layer Time" came in to play and slowed the print down.
Open the gcode and search for "LAYER:???" and for the "???" pick a layer that is above the rest of the models. Look at the print speed "F" parameters and you will see they are no longer what the setting was, but rather what Cura calculated would be required to maintain the Minimum Layer Time.
I'm printing a model that tapers to a smaller size at the top. Print speed is 50mm/sec in Cura and for the base that's what is in the Gcode.
G1 F3000 X148.244 Y81.42 E4127.05171
but at the top
G1 F996.9 X151.702 Y88.151 E1730.83803
In the case of that print it dropped from 50mm/sec to 16.6mm/sec. That is certainly enough of a Delta V to change the exterior finish.
You can adjust the "Minimum Layer Time" down, or you can adjust the Minimum Speed upward. Cooling can become an issue when layers go down quickly one-on-top-of-the-next.
Edited by GregValiant
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GregValiant 1,454
Different materials react differently. The "Glossiness" is a function of the: printing temperature, the fan speed, the printing speed, the layer height, and the tendency of the material itself and even the material color bcause the additives have an effect.
If I print silky silver PLA at an outer wall speed of 35mm/sec and with no fan on the outer walls, at 0.1 layer height, it comes out shiny and more "chromelike". It does take a lot longer to finish a print though.
At a print speed of 60 and using the fan, it dulls up by quite a bit.
I've noticed the same thing with PETG (but to a lessor extent). Regular black PETG can come out very shiny (you can still see the layer lines). CF filled PETG comes out dull no matter what as it's just sort of lumpy and so doesn't leave a flat surface to reflect the light evenly.
Depending on the material, there are a couple of post-process options that involve things like aquariums and acetone.
With PLA parts in the glass enclosure of the aquarium, and a lid on it, the acetone fumes can make the surface flow a little and eliminate (at least partially) the layer lines.
A member here (CloakFiend but he hasn't been around in a while) did a lot of this sort of thing including electro-plating models.
"If you want a finish like 12 coats of hand-rubbed lacquer you will have to put 12 coats of lacquer on it and hand-rub it out." - GregValiant.
Edited by GregValiantLink to post
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