ehanpaul8
Posts: 1
Joined: Thu Oct 08, 2020 10:53 am

Setting Brim print speeds

Thu Oct 08, 2020 11:12 am

I've got a print that doesn't want to stick (that's not the issue by the way) so I'm printing a brim with two layers for a more solid connection both to the side wall and the bed. The first layer's brim prints at the same nice slow speed as I have set for my first layer. The second layer's geometry prints at the regular speed I've set for the print. So far so good. But the Brim on this 2nd layer prints at some insane speed; minor collisions (at normal speed) with plowing-ridges from the first layer wouldn't matter but at this accelerated pace the collision knocks the print off the bed. The stiction to the previous layer can't keep up either (or perhaps its a flow rate issue - see below) - so the nozzle just ends up dragging the extruded plastic along with it.

Apart from editing the code directly, is there a way to set brim speeds?

And for bonus points: In editing the code to solve this I noticed that even though the XY speed is increased the feed to the nozzle is not. Does S3D not compensate for XY speed by increasing or decreasing flow through? (I mean it doesn't, I can see that in the Gcode, but why not? )essay writer

S3D-Jake
Posts: 872
Joined: Wed Jun 20, 2018 12:45 pm

Re: Setting Brim print speeds

Mon Oct 12, 2020 1:28 pm

ehanpaul8 wrote:
Thu Oct 08, 2020 11:12 am
...
Apart from editing the code directly, is there a way to set brim speeds?
...
The brim/skirt should be getting printed at the "default speed". Also known as the speed at which Infill gets printed at. If this speed is too fast to be printed atop the brim/skirt beneath it, you may need to decrease the speed this setting is configured to in the first place.

ehanpaul8 wrote:
Thu Oct 08, 2020 11:12 am
...
And for bonus points: In editing the code to solve this I noticed that even though the XY speed is increased the feed to the nozzle is not. Does S3D not compensate for XY speed by increasing or decreasing flow through? (I mean it doesn't, I can see that in the Gcode, but why not? )
The extruder flow rate is automatically handled by the firmware. In a G1 move that features both X Y Z and E parameters the F value given or specified previously controls the speed of X Y and Z movement with E being scaled accordingly by the firmware. Please let me know if you know of a firmware where this is not the case.

See notes on G0/G1 here: https://www.reprap.org/wiki/G-code#G0_.26_G1:_Move

Also, if you're seeing what looks like under-extrusion when printing at your specified "default speed", I'd look for issues of under-extrusion in your infill segments too.
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