Friday, February 19, 2010

Heating element and relay arrived



The heating element from Omega arrived today. It's a thin silicone encased element that measures 6in by 6in and produces 10W per square in. The element maxes out at 450 degrees Farenheit but I goofed when I ordered it- I ordered it with the adhesive backing which limits the output to 250 degrees so that means using it for a surface mount soldering hotplate is out.....a bummer but not a deal breaker as it's still good for the heated bed build platform for 3D printing.

More info on the heaters here:
http://www.omega.com/ppt/pptsc.asp?ref=SRFR_SRFG&ttID=SRFR_SRFG&Nav=

Since the element uses 115v input it'll be connected to the PID controller via a solid state relay. 

 

Thursday, February 18, 2010

Extruder nozzle design



So here's the basic nozzle design- the drawing isn't exact but you get the idea. It's a stainless tube with a stainless stop washer welded to it and a machined brass nozzle. The O ring should help seal the nozzle to the stainless tube. I plan on using a load resistor to heat the nozzle and this is held in place using a small circlip (if this doesn't work I'll probably go the nichrome wire route.) The nozzle is held onto the stainless tube using small set screws that sit in a machined groove. Time will tell if this all works out....