techzone extruder

hello all,

ive been posting on here for a good amount of time. i have finally gotten my reprap mendel to move around and recognize limit switches. now my weakest point seems to be my wade style extruder with techzone parts. it seems i cannot keep the temperature high enough during printing. i was wondering if anyone else has this same setup and how they improved it. i think i just need more of the black goop to smear around the brass screw tip.



Morrist

What happens during the print that makes you think that you're not keeping the nozzle hot enough? Does it stop extruding plastic even though the extruder motor is running?

yes it does, after 25 seconds or so, the temperature is reading aroung 118 c



morrist

Is the LED indicator for the heater on or off when the temperature goes down? Are you using a thermocouple with TZ onewire AD or thermistor?

What software are you running? What electronics? How are you creating your Gcode? Can you post a picture of your extruder?

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Experimenting in 3D in New Zealand

Morrist, I had a similar problem with my Techzone extruder, which stemmed from problems with the thermocouple.

As it turns out, Techzone's thermocouple is very sensitive to noise on the line. If you're often seeing very high (and obviously wrong) temperatures (1970 or greater) it indicates that noise on the thermocouple communication line is making it difficult to read. This, in turn, will mess up the temperature control resulting in low temperatures. The worst of my communication problems stemmed from inductive coupling between the communications line and the heater power. To deal with it, I finally ended up replacing the Ethernet cable with 2 runs of shielded cable - one for power and the other for communications.

Also, if you think you need more "black goop", you're looking for Loctite 598 Black High Performance RTV Silicon Gasket Maker or something similar. You should be able to find it at an auto parts store.

i seemed to have the temperature thing kinda under control. it seems to need to be paused in the beginning of the print, then gains temperature and has no more problems. however, i am using repsnapper and it does strange things sometimes. it will zigzag along the print surface instead of printing the part. this happened when i tried to print the 40mm test cube from thingiverse this happened to me. also, is there a list of codes that flash in the temperature box. is there a listing anywhere of what they mean?



morrist

RepSnapper sometimes has a command in the Start G-Code section that sets the temperature to 70C. If this is the case, and you are doing the STL to G-code conversion in RepSnapper (instead of SkeinForge), then this little bit of code is being put into the header of all your prints, which means the temperature begins to drop as soon as you start printing. Just change the command G104 S70 to G104 Sxxx, and SAVE the settings to make it permanent. xxx should be your temperature: 230-250 for ABS, 180-210 for PLA. THose are just recommended temperatures. There will be variations.

thank you, that is actually very helpful. any idea on why it randomly might have zig zagged on a few of those prints? should i create the g code with skeinforge instead?



morrist

Hi,

I have recently got all my axes, end-stops, and temperature measurement working (sort of). By sort of I mean it often reports back wrong temperature which I've been told may be to do with RS-485 requests from motherboard to extruder controller timing out.

Anyway my problem at the moment is I don't know how to get the extruder started up. I've used a thermocouple that came with my multimeter to check the tip temperature and it seems to be being controlled quite well; but the temperature at the top of the extruder where I'm feeding in the plastic is cold; so plastic is not melting to start the extrusion. Are there any tricks to starting off the extrusion process. I think that perhaps once the plastic is melted through there will be better conductivity from the tip and so once started it should be able to continue extruding OK.

I may be missing something obvious.

Any help appreciated.

- Khalid

khalid,

The end of the thermocouple is kind of exposed. is it possible it is making connection with the nichrome wire or the brass tip? can you read the resistances for me.

1.) between the heater wires
2.) between the thermocouple wires
3.) between one of the thermocouple wires and one of the heater wires. Doesnt matter which ones. one of each is fine.

also, what electronics are you using?

The top of the extruder should be cold. The solid plastic should pass through it and melt when it gets close to the tip.

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[www.hydraraptor.blogspot.com]

Thanks for the quick responses!

morrist:
Thanks for the hint. I've previously checked the resistances along these wires; and was happy that they were ok. I got the following
1) Between heater wires ~6 Ohm
2) Between thermocouple wires ~ 3 Ohm
3) > 17MOhm
I am using the generation 3 electronics which came with the laser cut mendel from Techzone as a kit from their site - v1.2 motherboard, v2.2 extruder, 3 x v2.3 motor controller, thermocouple A/D with oneWire temperature control.


nophead:
Thanks for the advice. The way my extruder went together there is not space for the solid plastic to get past the extruder machined bolt; as it is hard up against the bearing. I will try backing off the bearing so that I can slide the plastic filament down past the bolt and to the tip; and see if the extruder then works.

khalid: To test your hot end, just remove the idle bearing completely and then push the filament in with your hand into the hot end. You should see plastic coming out of the hot end this way without too much effort.

All,

Thanks for the help. Have now been able to test my extruder and it worked fine.
I was also able to print my first calibration cube; which went pretty well... at last!

Then the next time I'm plugged in the 12V supply out of the blue one of the motor driver chips on the extruder controller board started smoking; and is now toast. Argh - just when I though it was coming together.

Through some surface mount soldering (which I'm pretty useless at) I've got the dead ship off and am in the process of ordering a replacement Allegro A3949SLBT. Has anyone had this chip blow on their extruder controller before? Any ideas why it might of gone. The extruder motor was a little warm to the touch so the pot might've been set too high? - I'd set it at the lowest which would keep the gears spinning so don't think that's it. Would anyone recommend switching to using something other than the Techzone extruder controller board?

I have previously fried one of the A3982SLBT's on the motor controller boards - so perhaps I just have a gift for breaking these things. I guess I don't have the knack! - [www.youtube.com]

You should contact techzone. They might be willing to replace the stepper controller board or fix it.

I actually changed my stepper controllers to Pololu 1201's using a 4-axis board. But for the price of the board, it's probably more cost effective to go to RAMPS which I eventually ended up doing since the TZ Gen 3 remix motherboard and extruder controller kept giving me problems. It would occasionally lose the tip temperature or stop a print before finishing. These problems went away with RAMPS. I don't know for sure if it's a TZ or gen 3 issue.

khalid, sorry to not follow up this post. number 3 i listed, there should be an open load between the heater wires and the thermocouple. could be on eof the problems. let us know if you figure it out

Have you had success contacting techzone? They appear to have gone dark (without shipping my extruder). Did you get one of their stainless extruders?

morrist:
I measured 17 megaOhm between the wires of the heater and those of the thermocouple; and the reading from the multi-meter was creeping up so I took this to mean it was an open circuit and it was a limitation of the multi-meter in reading large resistances.

brnrd:
Thanks for the tip; will get in touch with techzone regarding a replacement extruder controller board and post back about how I get on.

bjmckenz
No; I am using the oak block extruder with metal (brass?) tip and nylon insert. I have not tried contacting techzone but will do and will report back.

khalid,

good point, didnt really consider it. sometimes i cannot think outside of the box. i have a cheap multi meter from radio shack, maybe like 10$ figured they all said OL . il keep checking to see if i can help you any further