1 Topic by DBSDBS (edited by DBSDBS 2015-01-03 18:19:42)

  • DBSDBS
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Topic: A problem with PLA and Vertical setup

Hi,

I'm new here and may be this is already discussed, but I have very big troubles with my extruder.
It is not original Filastruder. It's home made, but the principles are absolutely the same. Just the extruder motor is from car wipers. It is a 7A DC motor and I can regulate the rotation speed of the screw from zero to 20-25 rpm.
The heater is powerfull enough and can run on over 200°C.
I tried with two nozzles: with 1.6 mm and with 2.8 mm. Both are 25-27 mm long.
The setup is vertical, because of lack of space. I tried too the horizontal ones but without success.
Thermocouple is a "K" type (up to 400°C), and the regulator is PID "REX C100".
Cooler setup is from two CPU fan's: DELL Model # DB9733-12HBTL (can't add a picture).
The fan's speed can be managed, from 0 up to 3500 rpm. The air flow is very impressive!

I'v got 25 kg "Ingeo Biopolymer 2003D" and try to receive 1.75 mm filament from it.

The problem is that I can't receive a stable filament diameter. I tried almost all variants:
- auger speed from 2 to 20 rpm
- temperature from 127 to 170°C
- cooler speed from 0 to max
- nozzle diameter 1.6 and 2.8 mm
... and all combinations between them. The result is always unpredictable!

The last almost stable result was at:
137°C, 13 rpm, middle airflow and 2.8 mm nozzle. The curious is that with the same setup, extrusion speed varies from 10-12 cm/min to 100-120 cm/min ?!?!? and the diameter varies from 0.5 mm to 2.5 mm.

With many efforts to pull the filament manually with constant speed, I received a filament with constant diameter of 1.5 mm for almost 2 meters.

I'm absolutely sure, that I have to add a FilaWinder for getting better results, but how to receive a ticker filament with a vertical setup?

Any critiques and advice are welcome.

2 Reply by IanJohnson

  • IanJohnson
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Re: A problem with PLA and Vertical setup

Maybe the pellets need to be dried.  Also, how is the vertical hopper set up?  Does it feed into the side of the pipe or the back?  If it feeds into the side, the angle may not be enough to provide a consistent flow of pellets into the barrel.

3 Reply by DBSDBS

  • DBSDBS
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Re: A problem with PLA and Vertical setup

Hi Ian,

Thank you for the reply.

The feeding is from the side of the pipe, but the quantity of the pellets is huge enough.

In fact, the problem is with the width of the filament. I can't receive a stable width for more than 20 cm.... I'm not sure that the feeding is important in this case. The process begins with a thick enough filament and when the weight of the extruded quantity exceed some value, it falls down and the filament becomes thin like hair. And the process is repeated from the start.

On the other site, I have no problems with the filament surface - it is flat without any bubbles in or on the surface. So may be the humidity is not so big problem.

When all purchased parts arrive, I'll try with automatic winding and hope this will help to receive a constant width.
The problem will stay only with the desired width. I use 2.8 mm nozzle and still receive not more than 1.5 mm good filament. I have to find a way to make it thicker. May be with lowering the auger speed and the temperature... But with lower temperature appears a problem with lack of pressure.

I'll report the results.

Best Regards.