Possible Slic3r problem

[tb750]

I don't know if it's a problem with the GCode, but I'm having issues with the first layer that I haven't see posted before.

I have a Rostock Max v. 1.99999 (One of the last ones shipped that has most v1 parts and some v2 parts.
Repetier Host v 0.95F
Slic3r v 1.00RC3

I used it several times with no problems, then after long prints I noticed it would suddenly have trouble printing the first layer. Here is what is happening:

The bed and nozzle heat up to temp
The print job starts
It starts the perimeters and will do one of the following
1) Nothing. No ABS is extruded at all
2) It will gob out blobs of ABS at the same point at the job
3) It will print a faded "ghost" layer of ABS
While it's not printing, the extruder motor is basically chewing the ABS filament to pieces. It's either skipping, or reversing at random intervals and breaking the filament. I've pulled at least 10 sections of broken filament out of the tube so far.
-a) There is no reason that the filament should be retracting. Imagine printing the base layer of a large rectangular box. When the hot end is in the middle of a line in the middle of the box the extruder motor will reverse. This happens several times in places it should not.

What is even more baffling is that when it gets to the second layer it'll be fine. It finished the job perfectly. That's if it can get to that part without breaking the filament.

I don't know if it will help, but here's about 200 lines of GCode from a job I've been trying to print:


; generated by Slic3r 1.0.0RC3 on 2014-04-10 at 19:51:58

; layer_height = 0.4
; perimeters = 2
; top_solid_layers = 3
; bottom_solid_layers = 3
; fill_density = 0.39
; perimeter_speed = 30
; infill_speed = 30
; travel_speed = 200
; nozzle_diameter = 0.53
; filament_diameter = 1.80
; extrusion_multiplier = .9
; perimeters extrusion width = 0.50mm
; infill extrusion width = 0.75mm
; solid infill extrusion width = 0.75mm
; top infill extrusion width = 0.75mm
; first layer extrusion width = 0.70mm

G21 ; set units to millimeters
M107
M190 S90 ; wait for bed temperature to be reached
M104 S235 ; set temperature
G28 ; home all axes
G1 Z300 F7500 ; lift nozzle
M109 S235 ; wait for temperature to be reached
G90 ; use absolute coordinates
G92 E0
M82 ; use absolute distances for extrusion
G1 F3300.000 E-1.00000
G1 Z1.350 F12000.000
G92 E0
G1 X48.280 Y-37.400 F12000.000
G1 Z0.350 F12000.000
G1 E1.00000 F3300.000
G1 X51.510 Y-37.390 E1.26530 F540.000
G1 X52.160 Y-37.360 E1.31874
G1 X52.810 Y-37.290 E1.37244
G1 X53.210 Y-37.220 E1.40579
G1 X53.770 Y-37.090 E1.45301
G1 X54.150 Y-36.980 E1.48550
G1 X55.040 Y-36.650 E1.56347
G1 X55.930 Y-36.200 E1.64538
G1 X56.500 Y-35.850 E1.70032
G1 X56.820 Y-35.620 E1.73269
G1 X57.570 Y-34.980 E1.81367
G1 X58.240 Y-34.280 E1.89325
G1 X58.610 Y-33.830 E1.94110
G1 X58.840 Y-33.510 E1.97347
G1 X59.190 Y-32.940 E2.02841
G1 X59.380 Y-32.590 E2.06112
G1 X59.640 Y-32.050 E2.11035
G1 X59.790 Y-31.680 E2.14314
G1 X60.080 Y-30.780 E2.22080
G1 X60.210 Y-30.220 E2.26802
G1 X60.280 Y-29.820 E2.30137
G1 X60.350 Y-29.170 E2.35507
G1 X60.380 Y-28.520 E2.40851
G1 X60.390 Y-25.410 E2.66396
G1 X60.380 Y28.490 E7.09103
G1 X60.350 Y29.160 E7.14612
G1 X60.280 Y29.810 E7.19981
G1 X60.210 Y30.210 E7.23317
G1 X60.080 Y30.770 E7.28039
G1 X59.970 Y31.150 E7.31288
G1 X59.640 Y32.040 E7.39084
G1 X59.190 Y32.930 E7.47275
G1 X58.840 Y33.500 E7.52769
G1 X58.610 Y33.820 E7.56006
G1 X57.970 Y34.570 E7.64104
G1 X57.270 Y35.240 E7.72063
G1 X56.820 Y35.610 E7.76848
G1 X56.500 Y35.840 E7.80085
G1 X55.930 Y36.190 E7.85578
G1 X55.040 Y36.640 E7.93770
G1 X54.150 Y36.970 E8.01566
G1 X53.770 Y37.080 E8.04815
G1 X53.210 Y37.210 E8.09537
G1 X52.810 Y37.280 E8.12873
G1 X52.160 Y37.350 E8.18242
G1 X51.490 Y37.380 E8.23751
G1 X-51.510 Y37.380 E16.69741
G1 X-52.170 Y37.350 E16.75168
G1 X-52.820 Y37.280 E16.80537
G1 X-53.590 Y37.130 E16.86981
G1 X-54.080 Y37.000 E16.91144
G1 X-54.680 Y36.790 E16.96366
G1 X-55.050 Y36.640 E16.99645
G1 X-55.590 Y36.380 E17.04567
G1 X-55.940 Y36.190 E17.07838
G1 X-56.510 Y35.840 E17.13332
G1 X-56.830 Y35.610 E17.16569
G1 X-57.280 Y35.240 E17.21354
G1 X-57.980 Y34.570 E17.29313
G1 X-58.620 Y33.820 E17.37411
G1 X-58.850 Y33.500 E17.40648
G1 X-59.200 Y32.930 E17.46141
G1 X-59.650 Y32.040 E17.54333
G1 X-59.800 Y31.670 E17.57612
G1 X-60.050 Y30.910 E17.64183
G1 X-60.220 Y30.210 E17.70100
G1 X-60.290 Y29.810 E17.73435
G1 X-60.360 Y29.160 E17.78805
G1 X-60.390 Y28.500 E17.84231
G1 X-60.390 Y-28.510 E22.52483
G1 X-60.360 Y-29.170 E22.57909
G1 X-60.290 Y-29.820 E22.63279
G1 X-60.220 Y-30.220 E22.66614
G1 X-60.090 Y-30.780 E22.71336
G1 X-59.800 Y-31.680 E22.79103
G1 X-59.650 Y-32.050 E22.82382
G1 X-59.300 Y-32.770 E22.88957
G1 X-58.850 Y-33.510 E22.96071
G1 X-58.620 Y-33.830 E22.99308
G1 X-57.980 Y-34.580 E23.07406
G1 X-57.280 Y-35.250 E23.15364
G1 X-56.830 Y-35.620 E23.20149
G1 X-56.510 Y-35.850 E23.23386
G1 X-55.940 Y-36.200 E23.28880
G1 X-55.050 Y-36.650 E23.37071
G1 X-54.160 Y-36.980 E23.44868
G1 X-53.780 Y-37.090 E23.48117
G1 X-53.220 Y-37.220 E23.52839
G1 X-52.820 Y-37.290 E23.56174
G1 X-52.170 Y-37.360 E23.61544
G1 X-51.510 Y-37.390 E23.66970
G1 X48.180 Y-37.400 E31.85778
G1 X48.280 Y-36.730 F12000.000
G1 X51.720 Y-36.720 E32.14032 F540.000
G1 X52.120 Y-36.700 E32.17322
G1 X53.090 Y-36.560 E32.25371
G1 X53.590 Y-36.450 E32.29576
G1 X53.970 Y-36.340 E32.32826
G1 X54.790 Y-36.030 E32.40026
G1 X55.260 Y-35.810 E32.44288
G1 X55.610 Y-35.620 E32.47559
G1 X56.110 Y-35.310 E32.52391
G1 X56.830 Y-34.760 E32.59833
G1 X57.480 Y-34.140 E32.67211
G1 X57.750 Y-33.840 E32.70526
G1 X58.070 Y-33.440 E32.74733
G1 X58.300 Y-33.120 E32.77970
G1 X58.610 Y-32.620 E32.82802
G1 X58.800 Y-32.270 E32.86073
G1 X59.020 Y-31.800 E32.90336
G1 X59.330 Y-30.980 E32.97536
G1 X59.440 Y-30.600 E33.00785
G1 X59.550 Y-30.100 E33.04990
G1 X59.690 Y-29.130 E33.13040
G1 X59.710 Y-28.730 E33.16329
G1 X59.720 Y-25.400 E33.43680
G1 X59.710 Y28.720 E37.88195
G1 X59.690 Y29.120 E37.91484
G1 X59.550 Y30.090 E37.99534
G1 X59.440 Y30.590 E38.03739
G1 X59.330 Y30.970 E38.06988
G1 X59.020 Y31.790 E38.14189
G1 X58.800 Y32.260 E38.18451
G1 X58.610 Y32.610 E38.21722
G1 X58.300 Y33.110 E38.26554
G1 X58.070 Y33.430 E38.29791
G1 X57.750 Y33.830 E38.33998
G1 X57.480 Y34.130 E38.37313
G1 X56.830 Y34.750 E38.44691
G1 X56.110 Y35.300 E38.52133
G1 X55.610 Y35.610 E38.56965
G1 X55.260 Y35.800 E38.60236
G1 X54.790 Y36.020 E38.64498
G1 X53.970 Y36.330 E38.71698
G1 X53.590 Y36.440 E38.74948
G1 X52.690 Y36.620 E38.82486
G1 X52.120 Y36.690 E38.87203
G1 X51.720 Y36.710 E38.90493
G1 X-51.750 Y36.710 E47.40343
G1 X-52.140 Y36.690 E47.43551
G1 X-52.700 Y36.620 E47.48186
G1 X-53.590 Y36.440 E47.55644
G1 X-54.090 Y36.290 E47.59932
G1 X-54.800 Y36.020 E47.66171
G1 X-55.270 Y35.800 E47.70433
G1 X-55.620 Y35.610 E47.73704
G1 X-56.120 Y35.300 E47.78536
G1 X-56.440 Y35.070 E47.81773
G1 X-56.840 Y34.750 E47.85980
G1 X-57.140 Y34.480 E47.89295
G1 X-57.760 Y33.830 E47.96673
G1 X-58.310 Y33.110 E48.04115
G1 X-58.620 Y32.610 E48.08947
G1 X-58.810 Y32.260 E48.12218
G1 X-59.030 Y31.790 E48.16480
G1 X-59.310 Y31.060 E48.22902
G1 X-59.470 Y30.520 E48.27528
G1 X-59.560 Y30.090 E48.31136
G1 X-59.700 Y29.130 E48.39105
G1 X-59.720 Y28.740 E48.42312
G1 X-59.720 Y-28.750 E53.14506
G1 X-59.700 Y-29.140 E53.17714
G1 X-59.630 Y-29.700 E53.22349
G1 X-59.450 Y-30.600 E53.29887
G1 X-59.340 Y-30.980 E53.33137
G1 X-59.180 Y-31.430 E53.37059
G1 X-59.030 Y-31.800 E53.40339
G1 X-58.720 Y-32.450 E53.46254
G1 X-58.310 Y-33.120 E53.52705
G1 X-58.080 Y-33.440 E53.55942
G1 X-57.760 Y-33.840 E53.60149
G1 X-57.490 Y-34.140 E53.63464
G1 X-56.840 Y-34.760 E53.70842
G1 X-56.120 Y-35.310 E53.78284
G1 X-55.620 Y-35.620 E53.83116
G1 X-55.270 Y-35.810 E53.86387
G1 X-54.800 Y-36.030 E53.90649
G1 X-53.980 Y-36.340 E53.97850
G1 X-53.600 Y-36.450 E54.01099
G1 X-52.700 Y-36.630 E54.08638
G1 X-52.140 Y-36.700 E54.13273
G1 X-51.750 Y-36.720 E54.16480
G1 X48.180 Y-36.730 E62.37259
G1 F3300.000 E61.37259
G1 Z1.350 F12000.000
G92 E0
G1 X48.279 Y-33.723 F12000.000
G1 Z0.350 F12000.000
G1 E1.00000 F3300.000
G1 X51.526 Y-33.717 E1.26669 F540.000

[Tinyhead]

To me it almost sounds like your nozzle height is too low to the bed. Are you sure the extruder is reversing and not skipping because it's not able to get the filament out? It would explain why it suddenly works on the second layer.

I looked at the code quickly and I don't see anything that would suggest a retraction for the 2 perimeters.

[mhackney]

Not a gcode problem. You are most likely experiencing either a Z=0 calibration problem (this does change and needs to be teamed occasionally, your "ghost layer" is a giveaway that the nozzle is too close to the bed at Z=0) OR you have a plugging problem in the hot end. ABS is not prone to plugging though.

Bottom line, something is preventing the filament from extruding. The comment about once the 1st layer is done, the print goes fine really indicates a Z offset problem.

[tb750]

Okay, the Z calibration was off a bit (about .5). Let's see if that fixes it. Thanks for the quick replies!

[mhackney]

.5mm is an eternity...

[tb750]

Apparently so. May I be the first to say that you guys (or gals) are geniuses. It is printing perfectly now. Thank you so much! If I weren't already doing the bald thing I would have pulled my hair out a while ago.