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Re: Retraction Issue
Posted: Wed Apr 12, 2017 9:08 am
by Jeff_Birt
The brim does not print at first layer speed, take a look at the snippet of gcode below that I just generated with s3d
Code: Select all
; layer 1, Z = 0.18
M135 T0
; tool H0.200 W0.400
; skirt
G1 X17.300 Y-14.476 F9000
G1 E1.0000 F360
G1 X17.300 Y14.476 E0.8667 F2400
G1 X17.209 Y14.697 E0.0071
G1 X14.697 Y17.209 E0.1063
G1 X14.476 Y17.300 E0.0071
G1 X-14.476 Y17.300 E0.8667
G1 X-14.697 Y17.209 E0.0071
G1 X-17.209 Y14.697 E0.1063
G1 X-17.300 Y14.476 E0.0071
G1 X-17.300 Y-14.476 E0.8667
G1 X-17.209 Y-14.697 E0.0071
G1 X-14.697 Y-17.209 E0.1063
G1 X-14.476 Y-17.300 E0.0071
G1 X14.476 Y-17.300 E0.8667
G1 X14.697 Y-17.209 E0.0071
G1 X17.209 Y-14.697 E0.1063
G1 X17.300 Y-14.476 E0.0071
G1 X16.900 Y-14.397 F9000
G1 X16.900 Y14.397 E0.8619 F2400
G1 X16.870 Y14.470 E0.0024
G1 X14.470 Y16.870 E0.1016
G1 X14.397 Y16.900 E0.0024
G1 X-14.397 Y16.900 E0.8619
G1 X-14.470 Y16.870 E0.0024
G1 X-16.870 Y14.470 E0.1016
G1 X-16.900 Y14.397 E0.0024
G1 X-16.900 Y-14.397 E0.8619
G1 X-16.870 Y-14.470 E0.0024
G1 X-14.470 Y-16.870 E0.1016
G1 X-14.397 Y-16.900 E0.0024
G1 X14.397 Y-16.900 E0.8619
G1 X14.470 Y-16.870 E0.0024
G1 X16.870 Y-14.470 E0.1016
G1 X16.900 Y-14.397 E0.0024
G1 E-1.0000 F1200
; inner perimeter
G1 X12.100 Y-12.100 F9000
G1 E1.0000 F1200
G1 X12.100 Y12.100 E0.7244 F1800
G1 X-12.100 Y12.100 E0.7244
G1 X-12.100 Y-12.100 E0.7244
G1 X12.100 Y-12.100 E0.7244
; outer perimeter
G1 X12.500 Y-12.500 F9000
G1 X12.500 Y12.500 E0.7484 F1200
G1 X-12.500 Y12.500 E0.7484
G1 X-12.500 Y-12.500 E0.7484
G1 X12.500 Y-12.500 E0.7484
Re: Retraction Issue
Posted: Wed Apr 12, 2017 9:26 am
by dkightley
The brim does use the first layer speed.
The brim does not print at first layer speed,
Gents. We have two statements here........both are true! And both can be misunderstood and thought to be wrong.
Yes....the printing speed of the brim/skirt is affected by the first layer speed setting. But that doesn't mean that the actual brim printing speed will be the same as the actual speed of the first layer of the object! The effect of the setting is to reduce the speed by a percentage.
Re: Retraction Issue
Posted: Wed Apr 12, 2017 9:47 am
by brian442
Jeff_Birt wrote:The brim does not print at first layer speed, take a look at the snippet of gcode below that I just generated with s3d
Try to generate that exact same file with a different first layer speed and you will see the F-values for the skirt change appropriately. Your part will obviously use several different speeds, since you have outlines, supports, solid fill, etc - all of which have their own speed modifiers. But the first layer speed DOES change the brim/skirt speed. 100% first layer speed will produce a brim that prints twice as fast as what you would get with 50% first layer speed.
Re: Retraction Issue
Posted: Wed Apr 12, 2017 11:14 am
by dkightley
Re: Retraction Issue
Posted: Wed Apr 12, 2017 3:06 pm
by Jeff_Birt
I know this is getting of the subject but...if I have determined that a speed of 'X' works great for the first layer why would I want to print the brim at '1.5X'? That makes no sense. The speed the brim prints might be scaled with the print speed / first layer speed but the user has no access to that scalar value so at least 50% of the time the brim won't stick to the build plate but the rest of the first layer will.
Re: Retraction Issue
Posted: Thu Apr 13, 2017 7:49 am
by brian442
It's pretty common to print things like infill, perimeters, or supports at different speeds, but if you want to print an entire layer at a fixed speed, then just add a second process for that layer. You can set the outline underspeed and all other speed modifiers to 100%, then just change the default printing speed to whatever you want. That will give you a fixed speed for the entire first layer.
