Preload not working?

[Abom]

I'm experimenting with the seam settings, and no matter what, the seam is bulged before and after the layer start. Looking at the gcode, it preload is set to zero for every layer, even though the settings at the top of the file confirm that it is set to the value determined by the testing. This implies to me that preload isn't actually working, but I thought I'd ask here for confirmation. I'm using the Alpha build from May 20, 2019.

[pjr]

Hi

Can you please zip up and upload the G-code from a small object where this is happening.

Thanks

Peter

[Abom]

I've since learned that the preload is executed in the destring operations, but none the less I can't see any evidence of it working.
Another oddity (to me at least) is that although I'm using a 1mm destring, the 'suck' command is

Code: Select all

G1 E98.69919 F3000

While the prime command is

Code: Select all

G1 E1 F3000

Thanks for answering. I was seriously worried that this forum wasn't actually active.

Edit: Bear in mind that I've been trying different things to test their effect, so you may see settings that look strange. Feel free to comment.

[pjr]

Not a lot wrong; preload is working, but it's set to zero as your drive length - the distance between filament drive gear and nozzle (Settings/Printer/Extruder Hardware/DrvLen1) is set to zero, which means that preload is not required.

Code: Select all

; Prepare for Destring
G1 X103.446 Y109.75 E16.4506
G1 X103.577 Y108.666 E16.56034
G1 X103.883 Y107.632 E16.66877
G1 X104.332 Y106.696 E16.77308
G1 X104.962 Y105.795 E16.88362
G1 X105.725 Y105.023 E16.99276
G1 X106.588 Y104.396 E17.09999
G1 X107.403 Y103.978 E17.19199
G1 X108.363 Y103.649 E17.29401
G1 X109.385 Y103.467 E17.39839
G1 X110.407 Y103.451 E17.5012
G1 X111.278 Y103.437 E17.58871
G1 X112.185 Y103.437 E17.67991
G1 X112.833 Y103.438 E17.74505
G1 X113.222 Y103.438 E17.78414
G1 X113.351 Y103.438 E17.79717
;
; 'Destring/Wipe/Jump Path', 0.0 [feed mm/s], 70.0 [head mm/s]
; 'Destring Suck'
G1 E16.79717 F3000

You have Absolute E values, so there's a suck of 1mm.

And then the destring prime:

Code: Select all

; Reset extruder pos
G92 E0
; BEGIN_LAYER_OBJECT z=8.065 z_thickness=0.404
; Perimeter Length = 89.289757
;
; 'Perimeter Path', 6.0 [feed mm/s], 60.0 [head mm/s]
G1 X113.378 Y103.438 Z8.065 E0 F13800
; 'Destring Prime'
G1 E1 F3000

The G92 E0 resets the extrusion count, so the prime of E1 is correct.

Hope this helps


Peter

[Abom]

Well Damn! I swear I remember setting that too! Thanks, who knows how long it would have taken to figure that out on my own.

edit: discovered what happened. I copied the profile, and when that happened it changed to a printer profile that I had started with, but later discarded. I should have deleted it.

[pjr]

Pleased to have assisted

Peter