Polycarbonate print head

I have been extruding polycarbonate for about a month trying out various methods. I hit 605c at 24v and 3 amps with one prototype. Biggest issue was Getting the heat break small enough and sharp enough.

Today's tests we got 300c with a 2mm transition zone between hot and cold sections using 40 watt heater cartridge and k type thermocouple. Amazingly enough the cold end was touchable with bare fingers.

I use k type thermocouple board from the wiki.

The biggest hurdle once you perfect the filament drive mechanism is the print head being reliable. I use a bowden setup on my machine to get faster speeds.

Here is a short list of issues I have found:

Backlash in the filament drive. Yes there is backlash. This is one of the many things that causes oozing and filament jamming.

Heat transition zone too large or not sharp enough. I have one of the e3d that was shipped out around January. The suggested 30mm fan was not big enough and consequently had many issues. Upgraded to 40 mm fan and issues improved but still not satisfied with reliability. I'm looki g at 70 hour prints so reliability is huge issue for me.

Cooling cooling cooling. You need active cooling in the cold end AND you need a efficient hot end. Especially when you want to go to polycarbonate.

Temp stability and measuring. Thermocouples are your friend. Learn PID. Then Grok PID.

thermocouples are around 5-6 bucks. They are cheap and reliable.

Lastly. If you are a beginner in printing, you HAVE to follow all the pre printing procedures exactly. I can't tell you how many times I had to restart a pri t cause I forgot something g in the slicer, or didn't do the heat bed glue right. Attention to detail.

Edited 2 time(s). Last edit at 09/13/2014 09:34AM by metzindustries.

Took put the Bowden today and put in direct drive. 1mm retraction and very minimal ooze with the polycarbonate. I'm liking this polycarbonate with the water cooled print head.

Hey Metz,

Is your polycarb coming out clear? Mine is frosty.

Quote
metzindustries
Took put the Bowden today and put in direct drive. 1mm retraction and very minimal ooze with the polycarbonate. I'm liking this polycarbonate with the water cooled print head.

Depends on the speed, temp and layer height. It was really tricky to get clear prints.

My best results were .05mm layer heights and 270c running at 120mm sec.

Here is the print head.

I am using industrial temp controller with it and a DC SSR

1. Where did you get that head?
2. What are you using for a bed?

I make the heads myself.

At the moment using silicone heater, prob will go with some type of phenolic resin/silicone for the next batch and make myself.

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