Only extruding a tiny amount

[GordonB]

Hi

Finished building my Geeetech Prusa i3 Pro C.

Build went well and all axis are running smoothly. My problem is that I cannot get anything to extrude. Everything goes to plan until it approaches the hotend and does not seem to reach a fluid temperature. On repetier I have had the temp at many different levels from 220 to 270 to try to melt varying types of pla and abs but none make it through the 0.3mm hole.

I am using 1.7 PLA, 3mm nozzle, heating to say 230 and manually pressing the filament into the feed motor, the filament obviously goes right inside but does not melt!

If I check the temperature of the aluminium heat blocks they are at approx 150 when on repetier I have the temperature at 240..

Been at this for a week, stripped the hot end to bits, built it up about 30 times, can't get to the bottom of it, any help would be appreciated...

Thanks

Gordon.

[Jaran]

Could it be a faulty thermostat?

[GordonB]

Hi Jaran

It is a twin extruded head. And the symptom is the same on both.

I have removed the thermostats from the block and tested them with my hand at 29 degrees c, then dipped in boiling water and got 94 degrees so the thermostats (termisters) are ok.

I have ordered 0.4mm nozzles as I think this might be part of it, but I can't understand how others can extrude even through 0.2mm...

Gordon

[William]

I think there's something wrong with the connection between the thermistor and the hotend.

[William]

make sure the thermistor body is completely in the hotend. They tend to slip out.If it has slipped out of the block, even a little bit, it will read too low and the machine will keep heating.

[GordonB]

Hi William

Thanks for the comments. I have to date retested the thermistors a few times as I have been checking them for temp accuracy.

I have stripped the full hot end out, cleaned it and soaked the nozzles in acetone. They are clean as a whistle and I can see light through the hole and can pass a 0.3mm wire through the hole. Reassembled the kit with high temp teflon PTFE tape on joints and all nice and tight.

In Arduino I changed the max temp to 325 to allow a greater top end temp.

In repetier, I have raised the temp to 240 degrees c, and let the temp raise up. I let it sit for 5 mins to heat well then passed some 1.7mm filament through. The motor loads it and pulls it down the threaded tube ok, but stops at the nozzle and does not extrude...

I have raised the temperature to 280 degrees too, but still no extrusion..

Totally stuck, laser thermometer says 220 degrees at the aluminium block..

When it is hot and I remove the filament it stretches out to a fine thread, and after it all cools, if I remove the nozzle it is bunged up.. the nozzles are just not letting the filament through..

I have ordered new heater units, new thermometers, new ptfe tubing and some 0.4mm nozzles..

So none the wiser.

Thanks.

Gordon.

[m_kramar]

This was my problem

viewtopic.php?f=19&t=19063

[GordonB]

Well.. I sorted my problem out.

Replaced the thermostats, nozzles, heater blocks, threaded collard and heater units.

All working now, although slow at heating to temperature.

Disappointed that both were not working from the factory kit though, this cost me so much time and through trying all different ideas ended up damaging most of the hot end, but I wanted to close this post in case anyone finds the same problem in future.

Thanks for your help William and Jaran.

Cheers

G