Successful 3D Printing PETG Filament

  • This is based on Simplify3D settings.

PETG printed item highlighting no stringing. Information below describes how that is accomplished. This is done on Creality CR-10S, CR-10 S5, and Ender 5 Plus printers.

I do a lot of things to print PETG successfully. First off for the first layer the width and height are never increased, both are kept at 100%. What is done instead is to increase Extrusion Multiplier by 10%, sometimes 15% for the first layer to lay down a thicker layer. I’ve increased EM by as much as 25% successfully.

For this item that was done for the first 2 layers. Subsequent layers are at the calc’d EM. The first layer printing speed is slowed a lot. Printing speed is 2700mm/min, first layer speed at 33% of that.

A 40x40x40mm topless test cube in vase mode is printed to calculate Extrusion Multiplier. These EM calc’s are done a lot, there is a spreadsheet for each spool/filament Mfg/type/color. 12 points are measured, 3 per side, and the spreadsheet calc’s the EM value. In each spreadsheet the previous calc’d values are recorded to note any trending.

The filament is dried before printing in a big Chard stainless steel dehydrator for at least 6 hours or so, a lot of times overnight. The spool is also placed in a Sunlu single spool dehydrator while printing that has been modified by installing a circulation fan. Below there is a picture of an object printed with dried verses not dried filament, you’ll be amazed…

Display shows current Temperature of 64.7C and Relative Humidity of 5.5% in the Dehydrator. Average Humidity where I am is in the range of high 60% to low 70% so filament left out for any amount of time needs drying.

Sunlu Dehydrator below. You can see the circulation fan on the left behind the spool. It blows downward creating a circular airflow around the spool.

Shown are two backlit 40x40x40mm Extrusion Multiplier test cubes, guess which one’s filament wasn’t dried first before printing… Same spool. Not dried and dried.

First 2 layers have the support infill set at 65%, subsequent layers are at 35%. Support horizontal spacing is set at 0.2mm, support vertical spacing 1 layer when layer height is 0.15mm to 0.20mm, 2 layers for 0.10mm layer heights.

When using 0.30mm layer heights or higher 1 layer separation is too much. With layer heights above 0.20mm use split processing to get a 0.15mm separation layer. This is more important then it sounds due to PETG sagging.

Surfaces including front, left/right extensions and top are where the supports contacted the item. Unretouched item after support removal i.e. not cleaned up at all.

Bottom view of item after removal from printer bed. Note spacing/gaps in the support structure to foster clean/easy release.

Retraction with a Micro Swiss All Metal hotend is 4mm, no coast, no wipe retraction speed is 2700mm/min. Too fast a retraction speed can be just as bad as too slow.

Outline/Infill/Support Underspeeds are 70%, 80%, and 80% respectively.

X/Y Axis Movement Speed 12,000mm/min.

Only retract when crossing open spaces.
Minimum travel for Retraction 1.0mm.
Avoid crossing outline for travel movements.

No Cooling. Ever. Cooling can weaken the PETG object and it’s flat out not necessary.

Temp 245C/80C and that’s for eSun and 3D Maker Engineering PETG. Hotend temp might be a bit high(er) then usual due to Micro Swiss All Metal hotend.

Even after using a 4 stroke priming wipe on the edge of the bed a Brim is used to prime near the object, 1 Layer, 3 Outlines, 3mm Offset. Eliminates any stringing from the prime getting under the object’s first layer. Although it appears that string has finally been eliminated also, just to be safe.

Object Infill is what ever is needed.

Never use Dense Support for PETG. It’s great for PLA and ABS but the supports will become part of the object if you use it with a high percentage setting with PETG because of PETG’s propensity to sag.

That’s all folks HTH…

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