Saturday, December 5, 2009

My first Extruder build and testing

I am all caught up on every ones Blogs caught up on all of the Forum posts with a Saturday with Midge off doing a Life Drawing class.

So without much else that I want to do today I'm going to make and test my Extruder !!!!
OK 1st tidy untouched work area!!! Charge 6 AAA batteries for temperature meter find the bits.

With 4/5 RepRap/CNC Machines I can fit it too and 2kg of ABS its about time I actually finish making an Extruder.

So here is where I start putting the bits I have already made together some over a year or more ago. New batteries in camera.

Pictures of the parts I have already made:-



Measuring the resistance of my meeter leads 0.3 ohms I have striped the back the insulation of 300mm of nichrome wire to 285mm measured as 6 ohms with the lead resistance subtracted from the measured 6.3ohms.

Using two brass inserts and the two screws from a 5A chocolate block connector with a red and a black moulded 4mm skt with 105mm of wire on each I have twisted together the12mm ends of the Nichrome wire and one of the power cables at each end of the heater element. Then screwed the two brass screws down very tight then I soldered this connection. I re checked the resistance of the heater element circuit between the brass connectors still at 6 ohms.

From blogpics


I then wrapped Kapton tape around each connection. I then taped the Black connection to the Peek insulator with Kapton tape. Wrapped a short length 22swg around the welding tip give an edge to wind the nichrome wire against wound the nichrome on ending just before the flat on the welding tip. Taped the red end of the element to the peek insulator then taped the nichrome coil to the welding tip.
Positioned my K type thermocouple on to the flat on the welding tip and taped with more Kapton tape. I then wrapped a layer of high temperature self amalgamating tape around the welding tip assembly and around the Peek insulator.

Ready to test... @ 5.16V and 804mA the measured temperature seems to be sitting at 200 C. (This was incorrect as the Thermocouple was reading low using the thermocouple supplied with the meter meant 200C was measured with 6.89V @ 1043mA on the element)



Little problem with the Maplin K type thermocouple and my Temperature meter as the meter goes out of range with the thermocouple at 200 C. So I have an Incompatibility with the meter from Deal Extreme and the Maplin K type thermocouple here seems to work ok with the meter tho. Nope it did not I reverted to using the Thermocouple supplied with the meter from this I will calibrated the maplin thermocouples in the Ardrion cct. Having now got an extruder heater that works it wont be long now.

The high temperature self amalgamating tape (pipe repair tape) from B&Q works ~Using 4 Cir clips to hold the Peek insulator to the aluminum angle works well. Next Jobs sorting out calibrating the thermocouples and control electronics. Trying to get the extruded plastic smaller ~Using a 0.6mm welding nozzle the extruded plastic was 0.9mm considerably more than I expected.

Photo are not very good getting a close up in focus with my camera was impossible.

I ran the Extruder on and off for at least an hour or more hand feeding 3mm ABS.
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