PETG hair

[dorgeman]

Is there anyone out there who prints a lot of PETG who has found a setting in S3D that reduces angel hair? I am talking about the super fine hairs that you get with PETG - not stringing related to travel moves/retraction. I know that I can remove it from prints by applying a bit of heat after the print is finished. The problem is, the fine hairs sometimes accumulate on the nozzle, get burned and then get dropped as a brown blob into the in-progress print - often ruining it.

I have tried a lot of different settings without any making a noticeable impact. Some things I have tried without success include:

• much greater retraction
• multiple amounts of wipe
• multiple amounts of coast
• z-lift from none up to 4 times the layer height
• no-fan at all, some fan, ridiculous amounts of fan
• lower extrusion multiplier and various amounts of outline overlap
• lower and also higher extrusion temperature
• lower and also higher travel speed
• lower retraction speed (can't go higher without stripping the filament)

That is only a partial list, but it is what I can recall off the top of my head. A lot of that has revolved around travel moves and retraction. I should have listened to those who told me it was not related to those parameters. I have, however tried other things like the extrusion temperature or cooling. Nothing seems to result in either more or less of the fine hairs. I am, in general, quite happy with the quality of prints that I am getting - but I would still like to improve this one thing. Anyone seen this specific problem and come up with a way to reduce it rather than just post-processing it away?

Thanks,

-David

[jimc]

Petg is sticky and you will always get fine hairs to point. The problem is when they are excessive. If you feel they are excessive then there are really 2 things that cause them, not enough retraction and too high extrusion temp. Retraction is easy, 1-2mm on a direct drive extruder is usually enough. Temp is a tricky one. You need to find that fine line where the temp is low enough that you kill the hairs but dont lose layer adhesion. Its usually only a 5 deg window.

[dorgeman]

Hmmm.... I might be out of luck then. It isn't the retract. I can use anywhere from my standard retract (2.8mm) to three times that without any change. I take that to mean that the standard value is already accomplishing what can be done with retract. Changing the temperature doesn't help either. I would guess that the amount of hair that I am getting is just what is in that range that is accepted as normal. I can't help think that there must be some way to eliminate it entirely - but maybe not. I would have thought some of the things I tried would have made a difference. For example, I would have thought that wipe would have helped, but surprisingly it does not.

[jimc]

the higher the temp the more stringy it will be. esun petg for example will get hairy if printed up around 255 but drop that down to 240 and they go away. what brand of petg is it and can you post a picture showing the hairs you are getting?

[dorgeman]

[img]

front of 3DBenchy - with fine hairs

[/img]
[img]

cabin of 3DBenchy - with fine hairs

[/img]

The filament is Inland 1.75mm PETG from Micro Center. The pictures are translucent magenta - but same thing on other colors - at least translucent ones. My understanding is that this is rebranded eSun. I am currently printing at 250C. That is about the lowest I can go before I get much worse print problems. For example, at 245C the cabin of 3DBenchy is a mess - lots of cracks between the layers, areas where the filament is almost opaque, and a very rough surface finish. I can print simple shapes at 245C without problems, but anything that involves a lot of small moves and a lot of retract/reload is an issue. I could try to reduce maybe another degree or two - five degrees is as fine of a difference as I have tried.

I suspect this amount of hair might just be something that people who print PETG accept. It is certainly not hard to remove it after printing. My only concern is that maybe as often as every other print the hairs accumulate on the nozzle, get burned, and then get dropped somewhere onto the print. If it is possible to avoid that, I would like to.

I had thought maybe faster retraction would help. I can't currently do anything with that, but am looking at getting a better extruder to see if maybe that works. I also thought maybe one of the print nozzles with the hardened, non-stick coating might help. Then again, I thought faster travel, more cooling, z-lift, and wipe would help - and none of them seem to make any difference at all.

-David

[jimc]

oh yeah, thats nothin. if you were printing hot you would really know it. i have seen prints come out like almost a solid spider web. what you have there is perfectly normal. before each print i use a small wire brush and give the nozzle a quick scrub while its hot to remove any buildup. if you have excess buildup where it accumulates into a big glob on the nozzle then that is not from the hairs. that is from over-extrusion. petg wont handle any at all. you need that multiplier really dialed in with that material. inland IS private labeled esun.

[KC_703]

Could try some coast (.2-.5) and possibly 5-10% more fan. Coast will stop the extruding (decreasing back pressure) before the tool move. Fan will help to lock that extrusion in place. Jimc is probably right, that might be the best you'll get...

[lafaspot]

I am using PETG from hatchbox, printing on a robo 3d plus, with the following settings:

- changed temp to 243 first layer 238 after
- cooling on after first layer at 100%, minimun type is 15 seconds, reduction to 30%
- bed temp is disable
- bridge [settins to 10sq mm, extrusion multipler 80%, speed multiplier 50%, retraction 4.5 mm]
- retraction [distance 4.5 mm, extra restart distance 0, vertical lift 0, retraction speed 2400]
- print speed 5400mm/min, outline 50%, solid infill 80, support 80%, X/Y axis movement 8400 mm/min, Z axis 1000 mm/min
- everything else is pretty much same as defaults for robo3d printer, fff file below.



below is my PETG_FAT.fff
<?xml version="1.0"?>
<profile name="PETG_FAST" version="2016-05-01 00:04:56" app="S3D-Software 3.0.2">
<baseProfile>Robo3D R1 (with auto-leveler)</baseProfile>
<printMaterial>PETG</printMaterial>
<printQuality>Medium</printQuality>
<printExtruders></printExtruders>
<extruder name="Primary Extruder">
<toolheadNumber>0</toolheadNumber>
<diameter>0.4</diameter>
<autoWidth>0</autoWidth>
<width>0.4</width>
<extrusionMultiplier>0.9</extrusionMultiplier>
<useRetract>1</useRetract>
<retractionDistance>4.5</retractionDistance>
<extraRestartDistance>0</extraRestartDistance>
<retractionZLift>0</retractionZLift>
<retractionSpeed>2400</retractionSpeed>
<useCoasting>0</useCoasting>
<coastingDistance>0.2</coastingDistance>
<useWipe>0</useWipe>
<wipeDistance>5</wipeDistance>
</extruder>
<primaryExtruder>0</primaryExtruder>
<layerHeight>0.2</layerHeight>
<topSolidLayers>3</topSolidLayers>
<bottomSolidLayers>3</bottomSolidLayers>
<perimeterOutlines>2</perimeterOutlines>
<printPerimetersInsideOut>1</printPerimetersInsideOut>
<startPointOption>2</startPointOption>
<startPointOriginX>0</startPointOriginX>
<startPointOriginY>0</startPointOriginY>
<startPointOriginZ>300</startPointOriginZ>
<sequentialIslands>0</sequentialIslands>
<spiralVaseMode>0</spiralVaseMode>
<firstLayerHeightPercentage>90</firstLayerHeightPercentage>
<firstLayerWidthPercentage>100</firstLayerWidthPercentage>
<firstLayerUnderspeed>0.4</firstLayerUnderspeed>
<useRaft>0</useRaft>
<raftExtruder>0</raftExtruder>
<raftLayers>3</raftLayers>
<raftOffset>3</raftOffset>
<raftSeparationDistance>0.14</raftSeparationDistance>
<raftInfill>85</raftInfill>
<disableRaftBaseLayers>0</disableRaftBaseLayers>
<useSkirt>1</useSkirt>
<skirtExtruder>0</skirtExtruder>
<skirtLayers>1</skirtLayers>
<skirtOutlines>2</skirtOutlines>
<skirtOffset>4</skirtOffset>
<usePrimePillar>0</usePrimePillar>
<primePillarExtruder>999</primePillarExtruder>
<primePillarWidth>12</primePillarWidth>
<primePillarLocation>7</primePillarLocation>
<primePillarSpeedMultiplier>1</primePillarSpeedMultiplier>
<useOozeShield>0</useOozeShield>
<oozeShieldExtruder>999</oozeShieldExtruder>
<oozeShieldOffset>2</oozeShieldOffset>
<oozeShieldOutlines>1</oozeShieldOutlines>
<oozeShieldSidewallShape>1</oozeShieldSidewallShape>
<oozeShieldSidewallAngle>30</oozeShieldSidewallAngle>
<oozeShieldSpeedMultiplier>1</oozeShieldSpeedMultiplier>
<infillExtruder>0</infillExtruder>
<internalInfillPattern>Rectilinear</internalInfillPattern>
<externalInfillPattern>Rectilinear</externalInfillPattern>
<infillPercentage>30</infillPercentage>
<outlineOverlapPercentage>15</outlineOverlapPercentage>
<infillExtrusionWidthPercentage>100</infillExtrusionWidthPercentage>
<minInfillLength>5</minInfillLength>
<infillLayerInterval>1</infillLayerInterval>
<infillAngles>45,-45</infillAngles>
<overlapInfillAngles>0</overlapInfillAngles>
<generateSupport>0</generateSupport>
<supportExtruder>0</supportExtruder>
<supportInfillPercentage>30</supportInfillPercentage>
<supportExtraInflation>0</supportExtraInflation>
<denseSupportLayers>0</denseSupportLayers>
<denseSupportInfillPercentage>70</denseSupportInfillPercentage>
<supportLayerInterval>1</supportLayerInterval>
<supportHorizontalPartOffset>0.3</supportHorizontalPartOffset>
<supportUpperSeparationLayers>1</supportUpperSeparationLayers>
<supportLowerSeparationLayers>1</supportLowerSeparationLayers>
<supportType>1</supportType>
<supportGridSpacing>4</supportGridSpacing>
<maxOverhangAngle>45</maxOverhangAngle>
<supportAngles>0</supportAngles>
<temperatureController name="Primary Extruder">
<temperatureNumber>0</temperatureNumber>
<isHeatedBed>0</isHeatedBed>
<relayBetweenLayers>0</relayBetweenLayers>
<relayBetweenLoops>0</relayBetweenLoops>
<stabilizeAtStartup>1</stabilizeAtStartup>
<setpoint layer="1" temperature="243"/>
<setpoint layer="2" temperature="238"/>
</temperatureController>
<temperatureController name="Heated Bed">
<temperatureNumber>0</temperatureNumber>
<isHeatedBed>1</isHeatedBed>
<relayBetweenLayers>0</relayBetweenLayers>
<relayBetweenLoops>0</relayBetweenLoops>
<stabilizeAtStartup>1</stabilizeAtStartup>
<setpoint layer="1" temperature="1"/>
</temperatureController>
<fanSpeed>
<setpoint layer="1" speed="0"/>
<setpoint layer="2" speed="100"/>
</fanSpeed>
<blipFanToFullPower>1</blipFanToFullPower>
<adjustSpeedForCooling>1</adjustSpeedForCooling>
<minSpeedLayerTime>15</minSpeedLayerTime>
<minCoolingSpeedSlowdown>30</minCoolingSpeedSlowdown>
<increaseFanForCooling>0</increaseFanForCooling>
<minFanLayerTime>45</minFanLayerTime>
<maxCoolingFanSpeed>100</maxCoolingFanSpeed>
<increaseFanForBridging>0</increaseFanForBridging>
<bridgingFanSpeed>100</bridgingFanSpeed>
<use5D>1</use5D>
<relativeEdistances>0</relativeEdistances>
<allowEaxisZeroing>1</allowEaxisZeroing>
<independentExtruderAxes>0</independentExtruderAxes>
<includeM10123>0</includeM10123>
<stickySupport>1</stickySupport>
<applyToolheadOffsets>0</applyToolheadOffsets>
<gcodeXoffset>0</gcodeXoffset>
<gcodeYoffset>0</gcodeYoffset>
<gcodeZoffset>0</gcodeZoffset>
<overrideMachineDefinition>1</overrideMachineDefinition>
<machineTypeOverride>0</machineTypeOverride>
<strokeXoverride>228</strokeXoverride>
<strokeYoverride>254</strokeYoverride>
<strokeZoverride>203</strokeZoverride>
<originOffsetXoverride>0</originOffsetXoverride>
<originOffsetYoverride>0</originOffsetYoverride>
<originOffsetZoverride>0</originOffsetZoverride>
<homeXdirOverride>-1</homeXdirOverride>
<homeYdirOverride>-1</homeYdirOverride>
<homeZdirOverride>-1</homeZdirOverride>
<flipXoverride>1</flipXoverride>
<flipYoverride>-1</flipYoverride>
<flipZoverride>1</flipZoverride>
<toolheadOffsets>0,0|0,0|0,0|0,0|0,0|0,0</toolheadOffsets>
<overrideFirmwareConfiguration>1</overrideFirmwareConfiguration>
<firmwareTypeOverride>RepRap (Marlin/Repetier/Sprinter)</firmwareTypeOverride>
<GPXconfigOverride>r2</GPXconfigOverride>
<baudRateOverride>250000</baudRateOverride>
<overridePrinterModels>1</overridePrinterModels>
<printerModelsOverride>Robo3D_R1.stl</printerModelsOverride>
<startingGcode>G28 ; home all axes,G1 Z5 F5000 ; lift Z by 5mm,M201 X500 Y500 ; slows acceleration,M565 Z-1 ; set the offset for auto-leveling mechanism,G29 ; run auto-level</startingGcode>
<layerChangeGcode></layerChangeGcode>
<retractionGcode></retractionGcode>
<toolChangeGcode></toolChangeGcode>
<endingGcode>M104 S0 ; turn off extruder,M140 S0 ; turn off bed,G28 X0 ; home X axis,M84 ; disable motors</endingGcode>
<createX3G>0</createX3G>
<celebration>0</celebration>
<celebrationSong>Star Wars</celebrationSong>
<createMB5G>0</createMB5G>
<postProcessing></postProcessing>
<defaultSpeed>5400</defaultSpeed>
<outlineUnderspeed>0.5</outlineUnderspeed>
<solidInfillUnderspeed>0.8</solidInfillUnderspeed>
<supportUnderspeed>0.8</supportUnderspeed>
<rapidXYspeed>8400</rapidXYspeed>
<rapidZspeed>1000</rapidZspeed>
<minBridgingArea>10</minBridgingArea>
<bridgingExtraInflation>0</bridgingExtraInflation>
<bridgingExtrusionMultiplier>0.8</bridgingExtrusionMultiplier>
<bridgingSpeedMultiplier>0.5</bridgingSpeedMultiplier>
<filamentDiameter>1.75</filamentDiameter>
<filamentPricePerKg>46</filamentPricePerKg>
<filamentDensity>1.25</filamentDensity>
<useMinPrintHeight>0</useMinPrintHeight>
<minPrintHeight>0</minPrintHeight>
<useMaxPrintHeight>0</useMaxPrintHeight>
<maxPrintHeight>0</maxPrintHeight>
<useDiaphragm>0</useDiaphragm>
<diaphragmLayerInterval>20</diaphragmLayerInterval>
<robustSlicing>1</robustSlicing>
<mergeAllIntoSolid>0</mergeAllIntoSolid>
<onlyRetractWhenCrossingOutline>1</onlyRetractWhenCrossingOutline>
<retractBetweenLayers>1</retractBetweenLayers>
<useRetractionMinTravel>0</useRetractionMinTravel>
<retractionMinTravel>1</retractionMinTravel>
<retractWhileWiping>0</retractWhileWiping>
<onlyWipeOutlines>1</onlyWipeOutlines>
<avoidCrossingOutline>0</avoidCrossingOutline>
<maxMovementDetourFactor>3</maxMovementDetourFactor>
<toolChangeRetractionDistance>12</toolChangeRetractionDistance>
<toolChangeExtraRestartDistance>-0.5</toolChangeExtraRestartDistance>
<toolChangeRetractionSpeed>600</toolChangeRetractionSpeed>
<allowThinWallGapFill>1</allowThinWallGapFill>
<thinWallAllowedOverlapPercentage>10</thinWallAllowedOverlapPercentage>
<horizontalSizeCompensation>0</horizontalSizeCompensation>
<autoConfigureMaterial name="PLA">
<globalExtruderTemperature>195</globalExtruderTemperature>
<globalBedTemperature>60</globalBedTemperature>
<globalExtrusionMultiplier>0.9</globalExtrusionMultiplier>
<fanSpeed>
<setpoint layer="1" speed="0"/>
<setpoint layer="2" speed="100"/>
</fanSpeed>
</autoConfigureMaterial>
<autoConfigureMaterial name="ABS">
<globalExtruderTemperature>230</globalExtruderTemperature>
<globalBedTemperature>80</globalBedTemperature>
<globalExtrusionMultiplier>1</globalExtrusionMultiplier>
<fanSpeed>
<setpoint layer="1" speed="0"/>
</fanSpeed>
</autoConfigureMaterial>
<autoConfigureMaterial name="PVA">
<globalExtruderTemperature>195</globalExtruderTemperature>
<globalBedTemperature>80</globalBedTemperature>
<globalExtrusionMultiplier>1</globalExtrusionMultiplier>
<fanSpeed>
<setpoint layer="1" speed="0"/>
<setpoint layer="2" speed="100"/>
</fanSpeed>
</autoConfigureMaterial>
<autoConfigureMaterial name="Nylon">
<globalExtruderTemperature>220</globalExtruderTemperature>
<globalBedTemperature>80</globalBedTemperature>
<globalExtrusionMultiplier>1</globalExtrusionMultiplier>
<fanSpeed>
<setpoint layer="1" speed="0"/>
</fanSpeed>
</autoConfigureMaterial>
<autoConfigureQuality name="Fast">
<layerHeight>0.3</layerHeight>
<topSolidLayers>3</topSolidLayers>
<bottomSolidLayers>3</bottomSolidLayers>
<skirtLayers>1</skirtLayers>
<infillPercentage>15</infillPercentage>
<supportInfillPercentage>25</supportInfillPercentage>
</autoConfigureQuality>
<autoConfigureQuality name="Medium">
<layerHeight>0.2</layerHeight>
<topSolidLayers>3</topSolidLayers>
<bottomSolidLayers>3</bottomSolidLayers>
<skirtLayers>1</skirtLayers>
<infillPercentage>30</infillPercentage>
<supportInfillPercentage>30</supportInfillPercentage>
</autoConfigureQuality>
<autoConfigureQuality name="High">
<layerHeight>0.1</layerHeight>
<topSolidLayers>4</topSolidLayers>
<bottomSolidLayers>4</bottomSolidLayers>
<skirtLayers>2</skirtLayers>
<infillPercentage>30</infillPercentage>
<supportInfillPercentage>40</supportInfillPercentage>
</autoConfigureQuality>
<autoConfigureMaterial name="PETG">
<temperatureController name="Primary Extruder">
<temperatureNumber>0</temperatureNumber>
<isHeatedBed>0</isHeatedBed>
<relayBetweenLayers>0</relayBetweenLayers>
<relayBetweenLoops>0</relayBetweenLoops>
<stabilizeAtStartup>1</stabilizeAtStartup>
<setpoint layer="1" temperature="243"/>
<setpoint layer="2" temperature="238"/>
</temperatureController>
<globalBedTemperature>1</globalBedTemperature>
<globalExtrusionMultiplier>0.9</globalExtrusionMultiplier>
<fanSpeed>
<setpoint layer="1" speed="0"/>
<setpoint layer="2" speed="100"/>
</fanSpeed>
</autoConfigureMaterial>
</profile>

[dorgeman]

jimc had very helpful info - that the burned pieces are not really from the hairs, but rather because of overextrusion. Although I tried reducing the extrusion until it was clearly too low, I was only paying attention to the hairs while I was doing that test. Lower extrusion did nothing to reduce the hairs. It did, it turns out, reduce the brown droppings in the print. So reducing the extrusion has helped with the burned pieces - which was the main reason that I cared about the hairs in the first place. Thanks for that.

I still find myself wondering what causes the hairs and if they can be reduced - though it is no longer as important as I thought it was before when I thought it was destroying prints. I did try one of the coated nozzles from P3-d (one of the Apollo ones for E3Dv6). I like it a lot - much easier to clean up - but it doesn't do anything about the hairs. I also tried a Titan extruder. That seemed to work better than the one I had previously, but it again didn't do anything about the hair.

I might be getting a bit more hair just because I have been printing at a low layer height (0.1mm). I notice that most are printing more like 0.2mm or 0.25mm. That is one of the very few differences of any significance in the config that lafaspot posted. Is the low layer height something that maybe is more of a problem with PETG?

[jimc]

petg is just a sticky plastic when it melts. i have been printing petg for prob 2.5 years and can say those couple few hairs i see in your pic is totally normal and for the most part you have them under control about as best as your prob gonna get. i have done some prints in the past where the hairs almost overtook the model. looks like i pulled apart a cotton ball and stretched it around the print. that would be abnormal.