A little confused with KISS configuration

[mhackney]

I thought I would shout out and see if anyone has a handle on KISSlicer. Basically, when I configure everything and then generate gcode, the speeds and feeds make no sense! I am trying to do a 1:1 comparison to Slic3r and can't get KISS to do what I want. Here's the situation:

(some stuff removed for simplicity)

Code: Select all

; printer_name = Rostock MAX
; every_N_layers = 0
; num_extruders = 1
; firmware_type = 2
; z_speed_mm_per_s = 15
; z_settle_mm = 0
; bed_size_x_mm = 240
; bed_size_y_mm = 240
; bed_size_z_mm = 300
; bed_offset_x_mm = 0
; bed_offset_y_mm = 0
; bed_offset_z_mm = 0
; bed_roughness_mm = 0
; travel_speed_mm_per_s = 500
; first_layer_speed_mm_per_s = 15
[b]; xy_accel_mm_per_s_per_s = 1500[/b]
; lo_speed_perim_mm_per_s = 15
; lo_speed_solid_mm_per_s = 15
; lo_speed_sparse_mm_per_s = 15
; hi_speed_perim_mm_per_s = 15
; hi_speed_solid_mm_per_s = 15
; hi_speed_sparse_mm_per_s = 15
; ext_gain_1 = 1
; ext_material_1 = 0
; ext_axis_1 = 0
; ext_gain_2 = 1
; ext_material_2 = 0
; ext_axis_2 = 0
; ext_gain_3 = 1
; ext_material_3 = 0
; ext_axis_3 = 0
; model_ext = 0
; support_ext = 0
; support_body_ext = 0
; raft_ext = 0
; solid_loop_overlap_fraction = 1

; *** Style Settings ***
;
; style_name = Infill 25%
; layer_thickness_mm = 0.36
; extrusion_width_mm = 0.55
; num_loops = 1
; skin_thickness_mm = 0.8
; infill_extrusion_width = 0.55
; infill_density_denominator = 0
; stacked_layers = 1
; use_destring = 1
; loops_insideout = 1
; infill_st_oct_rnd = 0
; inset_surface_xy_mm = 0

I set the lo and hi feedrates the same to try to pin down why I am not getting what I expect. So, with the above configuration, here is a short gcode snippet of the first print gcode in the file:

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; 'Perimeter', 1.2 [feed mm/s], 15.0 [head mm/s]
G1 F30000
G1 X9.4 Y-14.49 Z1.36 E0
G1 F900
G1 X9.4 Y-14.49 Z0.36 E0
G1 F3300
G1 E7
G1 F900
G1 X9.16 Y-14.58 E7.0217
G1 X8.9 Y-14.5 E7.0437
G1 X2.06 Y-14.5 E7.607

Note the G1 F30000 - where is that coming from? Apparently, KISS moves to the start position at 3000mm/sec even though I have my XY travel set o 1500 mm/sec (see bold line above)? Then it prints at 90.0mm/s even though I have set all feedrates to 15mm/s? I have changed the feed rates from 15 to 45 and the generated code is exactly the same!

90mm/s is causing me problems with the "filament ejection" problem that I am trying to diagnose. Perhaps I am misunderstanding KISSlicer configuration?

[Polygonhell]

It's your travel speed 500mm/s == 30000mm/m which is what the firmware takes

[mhackney]

I was hoping you'd pipe in Polygonhell!

Hmm, in the Printer->Speed configuration it says "All speeds in [mm/s]". I see that KISS does not insert a G21 (set units to mm), which I overlooked. So, the default movement units for the firmware is mm/min?

And, what about the actual print speed? I see that F900 if it is mm/m is indeed 15 mm/s - but why did that not change when I reran after setting to 45 mm/s?

And finally, when the code set for 15 mm/s runs, it is obviously a lot faster than the Slic3r code configured for 15 mm/s and this higher speed results in the filament rejection issue.

[Polygonhell]

I was hoping you'd pipe in Polygonhell!

Hmm, in the Printer->Speed configuration it says "All speeds in [mm/s]". I see that KISS does not insert a G21 (set units to mm), which I overlooked. So, the default movement units for the firmware is mm/min?

And, what about the actual print speed? I see that F900 if it is mm/m is indeed 15 mm/s - but why did that not change when I reran after setting to 45 mm/s?

And finally, when the code set for 15 mm/s runs, it is obviously a lot faster than the Slic3r code configured for 15 mm/s and this higher speed results in the filament rejection issue.

For whatever reason every slicer that I know of uses mm/s for configuration.
GCode uses either mm/min or in/min depending on the last G20/G21, every printer firmware I've looked at defaults to mm/min.
In terms of 15mm/s is faster on X than Y IME that's usually a cooling issue where the slicer is using something other than the selected value F900 is 15mm/s after that it's up to the firmware. The latest Slic3r has some sort of acceleration control in software as well (which seems like a very bad plan given there is already one in the firmware) which will likely slow it down below the requested speed.
Why didn't it change? I don't know I'd have to look at the configurations, in addition to cooling there is a second limiting value in KissSlicer that caps the maximum extruded volume/s which is per material and overrides requested speeds. As it turns out this is really useful for materials where you can't extrude them quickly like Nylon.
In terms of extrusion rates (extruder RPM) that's only dependent on requested extrusion width, layer height and actual speed the head is moving when extruding, Slic3r tends to extrude SLIGHTLY (within 10%) more volume for the same settings ass KiSSlicer IME.

[mhackney]

Thanks Polygonhell. I've been fooling around a little more and I think I have it under control. Firstly, the issue that I thought I had with KISS not changing when I changed mm/s from 15 to 45 was "operator error" or "senility". I was only looking at the 1st layer speed and neglected/forgot to look at the 2nd and higher layers. It is, of course working as expected.

As for me thinking it was printing faster, now that I actually timed a layer printing it is relatively close. So, I think I am good to go. I do like the "wipe" feature in KISS, does a nice job it seems. For some reason though, with the same speeds, the KISS code is causing my extruder to do the filament jam thing. More investigation required.