3D Printing: Filament Runout Sensor False Trips

This is one for the books. On my Creality Ender 5 Plus 3D Printer I moved the extruder and filament sensor unit from the back of the printer to the front. I tore my rotator cuff and couldn’t reach to the back to load filament (the printer is on a shelf against the wall) and I was scheduled for surgery but wanted to continue printing while recuperating.

Well something went south. Every time I tried to print, after a while the controller thought it ran out of filament when there was still plenty. I’d tell it to continue and it would do it again. Tried different filament sensors, different extension cables, still kept doing it. Started to wonder if the motherboard was having a problem.

Fast forward ~9 weeks to yesterday where I could finally lift and move the printer to troubleshoot. Opened up the controller, reseated the filament sensor connector, closed it up, tried it again. Nope. Still false trips. Didn’t really think that would fix it but process of elimination…

So then I started thinking about the cabling, specifically it’s routing. I routed and bundled the filament sensor’s cable using Ty-wraps running it with two servo cables. Having read about an issue a while back with some BLTouch’s getting interference from heater cartridges (probably due to PWM control) , there even happens to be a setting in Marlin to turn off the heaters during probing, I wondered if the filament sensor was getting noise from the servo cables.

I wasn’t convinced it was a motherboard problem and didn’t have any other ideas at the moment so I unbundled the filament sensor cable from the two servo cables. I let the filament sensor cable hang out in open air and ran a 3+ hour test print. Not really printing though, no filament being pushed to the hotend just a short piece of filament stuck through the sensor. This same test would get false trips before.

No. False. Trips. Just to be sure I ran the 3+ hour print test again. No. False. Trips. It would not make it through this test print process before without tripping…

So the electromagnetic field generated by the current in the servo cables was enough to induce a voltage/current, noise, in the filament sensors cable to make it look like the sensor tripped due to a out of filament condition.

Seriously I was really starting to wonder if the motherboard went bad, but turns out that was not the case. Now I wonder if wrapping the filament cable around a ferrite torrid/ring core right by the motherboard would be enough to eliminate the induced noise.

But I’m not curious enough to try it… Happy Printing!

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…