Scars at layer start

[MartinNYHC]

Hi All,

I'm pulling my hairs out for days now to solve a print quality issue. Any help is very appreciated.

I always have some ugly scars at exactly the same place where the layer starts (please see attached picture). Any ideas what can cause this?

Thanks, Martin

Print settings:

Code: Select all

; G-Code generated by Simplify3D(R) Version 4.1.2
; Oct 3, 2020 at 9:20:49 AM
; Settings Summary
;   processName,Process1
;   applyToModels,xyzCalibration_cube
;   profileName,Cube - PLA
;   profileVersion,2020-10-02 19:07:37
;   baseProfile,Creality Ender 3
;   printMaterial,PLA
;   printQuality,Medium
;   printExtruders,
;   extruderName,Primary Extruder
;   extruderToolheadNumber,0
;   extruderDiameter,0.4
;   extruderAutoWidth,0
;   extruderWidth,0.4
;   extrusionMultiplier,1
;   extruderUseRetract,1
;   extruderRetractionDistance,1
;   extruderExtraRestartDistance,0.05
;   extruderRetractionZLift,0.2
;   extruderRetractionSpeed,3600
;   extruderUseCoasting,0
;   extruderCoastingDistance,0.1
;   extruderUseWipe,0
;   extruderWipeDistance,1
;   primaryExtruder,0
;   layerHeight,0.2
;   topSolidLayers,3
;   bottomSolidLayers,3
;   perimeterOutlines,3
;   printPerimetersInsideOut,1
;   startPointOption,3
;   startPointOriginX,0
;   startPointOriginY,500
;   sequentialIslands,0
;   spiralVaseMode,0
;   firstLayerHeightPercentage,130
;   firstLayerWidthPercentage,130
;   firstLayerUnderspeed,0.5
;   useRaft,0
;   raftExtruder,0
;   raftTopLayers,2
;   raftBaseLayers,2
;   raftOffset,4
;   raftSeparationDistance,0.14
;   raftTopInfill,100
;   aboveRaftSpeedMultiplier,0.5
;   useSkirt,1
;   skirtExtruder,0
;   skirtLayers,1
;   skirtOutlines,2
;   skirtOffset,4
;   usePrimePillar,0
;   primePillarExtruder,999
;   primePillarWidth,12
;   primePillarLocation,7
;   primePillarSpeedMultiplier,1
;   useOozeShield,0
;   oozeShieldExtruder,999
;   oozeShieldOffset,2
;   oozeShieldOutlines,1
;   oozeShieldSidewallShape,1
;   oozeShieldSidewallAngle,30
;   oozeShieldSpeedMultiplier,1
;   infillExtruder,0
;   internalInfillPattern,Rectilinear
;   externalInfillPattern,Rectilinear
;   infillPercentage,20
;   outlineOverlapPercentage,40
;   infillExtrusionWidthPercentage,100
;   minInfillLength,5
;   infillLayerInterval,1
;   internalInfillAngles,45,-45
;   overlapInternalInfillAngles,0
;   externalInfillAngles,45,-45
;   generateSupport,0
;   supportExtruder,0
;   supportInfillPercentage,25
;   supportExtraInflation,1
;   supportBaseLayers,0
;   denseSupportExtruder,0
;   denseSupportLayers,0
;   denseSupportInfillPercentage,15
;   supportLayerInterval,1
;   supportHorizontalPartOffset,1
;   supportUpperSeparationLayers,1
;   supportLowerSeparationLayers,1
;   supportType,0
;   supportGridSpacing,4
;   maxOverhangAngle,50
;   supportAngles,45,-45
;   temperatureName,Primary Extruder,Heated Bed
;   temperatureNumber,0,0
;   temperatureSetpointCount,1,1
;   temperatureSetpointLayers,1,1
;   temperatureSetpointTemperatures,190,60
;   temperatureStabilizeAtStartup,1,1
;   temperatureHeatedBed,0,1
;   fanLayers,1,2
;   fanSpeeds,0,100
;   blipFanToFullPower,0
;   adjustSpeedForCooling,0
;   minSpeedLayerTime,15
;   minCoolingSpeedSlowdown,40
;   increaseFanForCooling,0
;   minFanLayerTime,45
;   maxCoolingFanSpeed,100
;   increaseFanForBridging,1
;   bridgingFanSpeed,100
;   use5D,1
;   relativeEdistances,0
;   allowEaxisZeroing,1
;   independentExtruderAxes,0
;   includeM10123,0
;   stickySupport,1
;   applyToolheadOffsets,0
;   gcodeXoffset,0
;   gcodeYoffset,0
;   gcodeZoffset,0
;   overrideMachineDefinition,1
;   machineTypeOverride,0
;   strokeXoverride,330
;   strokeYoverride,330
;   strokeZoverride,400
;   originOffsetXoverride,0
;   originOffsetYoverride,0
;   originOffsetZoverride,0
;   homeXdirOverride,-1
;   homeYdirOverride,-1
;   homeZdirOverride,-1
;   flipXoverride,1
;   flipYoverride,-1
;   flipZoverride,1
;   toolheadOffsets,0,0|0,0|0,0|0,0|0,0|0,0
;   overrideFirmwareConfiguration,1
;   firmwareTypeOverride,RepRap (Marlin/Repetier/Sprinter)
;   GPXconfigOverride,r2
;   baudRateOverride,115200
;   overridePrinterModels,1
;   printerModelsOverride
;   startingGcode,G21                                         ; metric values,G90                                         ; set absolute positioning,G28                                         ; home all,M561                        ; Disable any current bed compensation,G1 X150 Y150 F6000,G90 G1 Z3 F400,M400,G92 Z4                    ; Reset z to 8 to allow jogging up to touch bed to nozzle,M291 P"Jog the Z Axis until the bed and nozzle are touching and click OK" R"Setting Z=0" Z1 S3,M400,G92 Z0
                ; Set z = 0,G90 G1 Z3 F400,M400,G1 Z5,M400,G30 S-1,M400,G1 Z5,M400,G30 S-1,M400,G1 Z5,M400,G30 S-1,M400,G1 Z5,M400,G30 S-1,M400,G1 Z5,M400,G30 S-3 ; measure probe height and set it.,M400,M500 P31 ; save trigger height to config-override.g,G1 Z5,M400,M280 P0 S160 ; reset Bltouch in case of errors,M557 X29:316 Y14:310 S20:20  ; mesh grid dummy,G29                ; mesh bed leveling,G29 S1              ; load bed mesh,M221 S100                                    ; set extrusion factor,G92 E0 F100                                 ; reset extruder,G1 X12 Y166 Z5 F6000              ; move to wipe,G1 E10 F300                                 ; extract 10mm filament to fill nozzle,G92 E0                                      ; reset extrusion distance,G1 X-8 Y166 Z3 F6000,G1 X-8 Y196 F6000,G1 X-8 Y166 F6000,G1 X-8 Y196 F6000,G1 X-8 Y166 F6000,G1 X-8 Y196 F6000,G1 X-8 Y166 F6000,G1 X-8 Y196 F6000,G1 X-8 Y166 F6000,
;   layerChangeGcode,
;   retractionGcode,
;   toolChangeGcode,
;   endingGcode,G91             ; relative positioning,G1 Z10 F3000     ; move Z up 10mm,G90            ; absolute positioning,G1 X0 Y0 F3000           ; move home,M106 S0             ; turn off cooling fan,M104 S0          ; turn off extruder,M140 S0             ; turn off bed,M84              ; disable motors,
;   exportFileFormat,gcode
;   celebration,0
;   celebrationSong,Funky Town
;   postProcessing,/Library/Frameworks/Python.framework/Versions/3.7/bin/python3 /Users/martin.ziegler/tools/bin/meshgrid.py "[output_filepath]"
;   defaultSpeed,3600
;   outlineUnderspeed,0.5
;   solidInfillUnderspeed,0.75
;   supportUnderspeed,0.8
;   rapidXYspeed,9000
;   rapidZspeed,1002
;   minBridgingArea,50
;   bridgingExtraInflation,5
;   bridgingExtrusionMultiplier,1.05
;   bridgingSpeedMultiplier,0.8
;   useFixedBridgingAngle,0
;   fixedBridgingAngle,0
;   applyBridgingToPerimeters,1
;   filamentDiameters,1.75|1.75|1.75|1.75|1.75|1.75
;   filamentPricesPerKg,30|46|46|46|46|46
;   filamentDensities,1.25|1.25|1.25|1.25|1.25|1.25
;   useMinPrintHeight,0
;   minPrintHeight,0
;   useMaxPrintHeight,0
;   maxPrintHeight,0
;   useDiaphragm,0
;   diaphragmLayerInterval,20
;   robustSlicing,1
;   mergeAllIntoSolid,0
;   onlyRetractWhenCrossingOutline,0
;   retractBetweenLayers,0
;   useRetractionMinTravel,1
;   retractionMinTravel,2
;   retractWhileWiping,1
;   onlyWipeOutlines,1
;   avoidCrossingOutline,1
;   maxMovementDetourFactor,3
;   toolChangeRetractionDistance,0
;   toolChangeExtraRestartDistance,0
;   toolChangeRetractionSpeed,600
;   externalThinWallType,0
;   internalThinWallType,2
;   thinWallAllowedOverlapPercentage,10
;   singleExtrusionMinLength,0.5
;   singleExtrusionMinPrintingWidthPercentage,50
;   singleExtrusionMaxPrintingWidthPercentage,200
;   singleExtrusionEndpointExtension,0.2
;   horizontalSizeCompensation,0

[MartinNYHC]

Another picture...

[dkightley]

The infamous blobs and zits!

Unfortunately, there's no "magic" setting to resolve it! You'll need to read the following and sort the problem out by detective work and small adjustments:

https://www.simplify3d.com/support/prin ... -and-zits/

[MartinNYHC]

Thanks. I already played with coasting which had no effect. Will also enable wiping to see if there is any difference.

[dkightley]

If you start to notice small defects on the surface of your print, the best way to diagnose what is causing them is to watch closely as each perimeter of your part is printed. Does the defect appear the moment the extruder starts printing the perimeter? Or does it only appear later when the perimeter is completed and the extruder is coming to a stop? If the defect appears right away at the beginning of the loop, then it’s possible your retraction settings need to be adjusted slightly. Click on “Edit Process Settings” and go to the Extruders tab. Right below the retraction distance, there is a setting labeled “Extra Restart Distance.” This option determines the difference between the retraction distance when the extruder is stopping and the priming distance that is used when the extruder is restarting. If you notice a surface defect right at the beginning of the perimeter, then your extruder is likely priming too much plastic. You can reduce the priming distance by entering a negative value for the extra restart distance. For example, if your retraction distance is 1.0mm, and the extra restart distance is -0.2mm (note the negative sign), then each time your extruder stops, it will retract 1.0mm of plastic. However, each time the extruder has to start extruding again, it will only push 0.8mm of plastic back into the nozzle. Adjust this setting until the defect no longer appears when the extruder initially begins printing the perimeter.

If the defect does not occur until the end of the perimeter when the extruder is coming to a stop, then there is a different setting to adjust. This setting is called coasting. You can find it right below the retraction settings on the Extruder tab. Coasting will turn off your extruder a short distance before the end of the perimeter to relieve the pressure that is built up within the nozzle. Enable this option and increase the value until you no longer notice a defect appearing at the end of each perimeter when the extruder is coming to a stop. Typically, a coasting distance between 0.2-0.5mm is enough to have a noticeable impact.

Nothing there about wiping!!! Look at the bit I've highlighted....

[S3D-Jake]

The infamous blobs and zits indeed! Thanks for jumping in to help this new user out, Doug.