Extruder Problems

Hello,

I've been working with my extruder for the past two weeks, and it has been one of the most frustrating experiences in this whole process. Everything else works wonderfully, and I was able to print three single layer items one evening, but the next evening it failed to print and I have been working to fix it since.

Current Situation:
-Makerbot V3 Plastruder
-White ABS 3mm plastic filament (from Makerbot)
-Arduino controlled electronics

Problems:
-Extruder initially worked great and printed on three occasions. Extrusion rate was almost too fast.
-Extruder currently does not push plastic through the nozzle, though it does come out slowly if I manually push it.
-Extruder must reach ~280C in order to extrude ABS at a reasonable rate and with reasonable force. Extruder starts smoking at 285C, and the white insulation begins to char.

I have stripped the system several times in order to see if backflow is a problem (it was but I believe I have solved that) or if there are other adjustments that I can make. I have realigned the idler wheel, but it slips away when the motor fails to generate enough torque to extrude.

Thank you for your time, and I appreciate any suggestions.

Brian

> -Extruder currently does not push plastic through
> the nozzle, though it does come out slowly if I
> manually push it.
> -Extruder must reach ~280C in order to extrude ABS
> at a reasonable rate and with reasonable force.
> Extruder starts smoking at 285C, and the white
> insulation begins to char.

I think 280ºC is a very high value! you should be ok with 220ºC +-10ºC.

Something is blocking your extrude process... try to find why. A good idea is to test just the heather brass barrel with the heater and push the filament by hand... it must work! I used a regulated PC PSU to try that, just put 12V and not measuring the temperature, just trying to heat the filament and try extrude using my hand to push it.

Yes, extruder can be a bit problematic. You should learn with that problems :-)

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By over-temping you are probably clogging your nozzle and may have destroyed or malformed your thermal barrier.

It's a common beginners mistake to keep upping the temperature. I kept doing the samething on mine, by not starting to extrude until it reached 240 and since my setup might have been off it was probally at a higher temperature so it kept jamming.

When I started trying temps around 220 I had better results.

Thanks guys. Thanks, I'll keep the temperature down in the future and make sure to start extruding once it hits the right temperature.

Any suggestions on how to remove solid ABS from my nozzle and barrel? I have it all stripped down, and I think there is may be some scorched material clogging the nozzle. Any suggestions on how to remove that, or should I just purchase a new nozzle?

Thanks for your input,

Brian

Hi Brian

Depends on how badly it is "coked" up. Soaking overnight in acetone somethings works.

Though if off on the chance you created your own nozzel, just run the drill bit though it again.

(Sorry of my bad english, use Google to translate)



-Extruder must reach ~280C in order to extrude ABS at a reasonable rate and with reasonable force. Extruder starts smoking at 285C, and the white insulation begins to char.


at a temperature greater than 255 degrees of the extruder by burning, because it will no longer regulated

// Clamp to byte
if (celsius > 255) celsius = 255;
else if (celsius < 0) celsius = 0;

The ABS should remain white, or you're too high with the temperature


Greetings from Cologne/Ger

Wolfgang

Hey,

This sounds a lot like our experience:

[spoolhead.blogspot.com]

The solution for us was to add a bit of oil into the extruder nozzle. Perhaps you'd like to try it too?

Also, for removing filament, try heating up the nozzle partway (perhaps 100 C) and then pulling it out by hand.

Wolfgang - Thats a good idea, and I've added that upper limit into the code

jbayless - Thanks for the advice. Sounds like you're making some good contributions to the community, and I'm looking forward to following your progress online.

I'm going to try fixing things tonight after class and hopefully it will all work out from there. I'll update with the status later this evening.

-Brian

Hi,

in the first times i had olways trouble with my Heaternozzle....i change some.

The brass i drill only with 3mm, and the isolator i drill with 2.8

there must no space between the brass-end and the 2.8 hole. the melt Material try to go into such a space, and after it is cold it never work again. round the isolator i put a hose clamp.... after that i have never trouble again.

understand ?


-Wolfgang

Well, I have very limited personal machining capabilities, so I really can't construct anything new for the extruder at the moment.

I was able to get a good 4-5 minutes of extrusion last night before I stopped it. Unfortunately, after I tried it again today, it has been a supreme effort to get anything out of it. So I'm going to try the oil option tomorrow.

After playing with some material that had not yet been heated, and some that I removed from the extruder, I have come to the conclusion that ABS displays some thermo-setting characteristics, such that it has different properties once it has been heated and cooled. After a cycle of heating, the stiffness of the ABS is much greater, and it is also more brittle. I would not be surprised to find that it has a slightly different melting point as well. Perhaps the best solution would be to clear out the nozzle and barrel each time and start with fresh ABS?

I appreciate everyone's help and feedback

A in ABS stands for acrylonitrile, which is a liquid at room temperature and boils at 77 celsius. When we melt the ABS, it probably loses some of this compound, altering the proportions of ingredients and therefore its physical properties. I haven't even checked the other components yet

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Wooden Mendel
Teacup Firmware

sorry brain, but i think your much to hot.

the termistors dont show the right temperatur, do not trust him !

you must look at the color and the surface of the ABS, it must be a little bit glossy and wite. if it is a little dark and tough, you are to hot.

more hot is not more Liquid ! to hot and the ABS get harder and smell


try it 10-20 degrees lower and push it with your hand. you will feel the right point of temperatur

better you start at 200° wait 10min... push and try and slowly higher the Temprature and try... you will feel and see it at the right point.


greetings from old Germany
Wolfgang

Yes I agree. If the ABS is going hard and brittle is has got too hot or it has been left hot in the presence of air.

It starts to change around 260C. At lower temperatures it will burn if you leave it exposed to air for a long time. For example bits stuck to the outside of the nozzle will burn black. Stuff inside the melt chamber will stay fine for much longer periods as no air can get in.

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[www.hydraraptor.blogspot.com]