Extruder Fails To Melt PLA

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Extruder Fails To Melt PLA

Postby Colin » 28 Aug 2014, 23:14

This is really weird.

I'm using Pronterface and setting the extruder temperature for PLA at 200, then 220 and finally 250 degrees.

Pronterface tells me the extruder temperatures are rising to 200, 220 and 250 degrees.

Then I try to print and the PLA fails to melt.

The filament softens a little, balls up above the print bed and gets dragged around by the tip.

Help?
Colin
 
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Joined: 06 May 2014, 06:42

Re: Extruder Fails To Melt PLA

Postby mavgrab302 » 29 Aug 2014, 12:22

huh, weird...only thing i can think of is being your thermister is directly taking reading from the heat block and not the nozzle I'm thinking maybe your nozzle could be loose?? It shouldn't even start a print without the temp being correct..also try using a laser thermometer to check nozzle, block, thermister, and cartridge..
mavgrab302
 
Posts: 65
Joined: 17 Aug 2014, 04:06
Location: conroe,tx

Re: Extruder Fails To Melt PLA

Postby Colin » 29 Aug 2014, 19:04

The nozzle seems to be tight.

The printer does wait until temperatures are correct before it starts printing.

The filament just fails to melt.

I tried slowing the filament feed rate so it would be inside the heated chamber a little longer, but I still don't get melt.

The plastic is not liquid when it comes out of the nozzle, so all I get is a tangled mess dragged all around the bed.
Colin
 
Posts: 10
Joined: 06 May 2014, 06:42

Re: Extruder Fails To Melt PLA

Postby Scatterplot » 02 Sep 2014, 17:40

Your thermistor is reporting the wrong temperature. This means one of a few things:

1: your nozzle/heat chamber/heater/*something* is loose, and heat isn't transferring properly.
2: thermistor has wrong calibration values in firmware
3: thermistor is broken (either the thermistor itself or the wiring somewhere else)

There could be other issues, but those three spring to mind as my first thoughts.
Scatterplot
 
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Joined: 10 Jul 2014, 23:16

Re: Extruder Fails To Melt PLA

Postby Faye » 21 Sep 2014, 07:20

If plastic is coming through the nozzle, it is melting. The nozzle is .4mm wide and the filament is 1.75 approx, so it can't come through unless it melts.. You are expecting it to liquefy, it does not. It forms a gel, like piped icing and is extruded in a similar way. If you are dragging a mass of filament around then the bed is not adhering, possibly because it is too far from the tip of the nozzle, but possibly you also need to calibrate the feed. I did this using the cold extrude command with the nozzle removed. Google gcode cold extrude. I found that I was extruding 11.1mm of filament when ordering 10mm and that was causing my prints to blob. I still get drooping during overhangs but I am hoping to fix that with a part fan.
Faye
 
Posts: 8
Joined: 05 Aug 2014, 06:58

Re: Extruder Fails To Melt PLA

Postby mavgrab302 » 22 Sep 2014, 22:44

Have you tried to take the temp with a laser thermometer? I know my heater cartridge went out after a few hours of use so I got on ebay and ordered 10...lol
As far as you doing a cold extrude if you measure right..I believe if you change fr% on lcd screen will change it regardless of pronterface etc???flow rate is what it stands for??I know it changes it being I have tinkered with it while printing practice bs
mavgrab302
 
Posts: 65
Joined: 17 Aug 2014, 04:06
Location: conroe,tx


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