I am about to purchase a 24v E3D V6 hot end for my K8200. I have also purchased a K type thermocouple and amplifier IC to suit. This in conjunction with a 24v 10A power supply to run the heated bed and hotend and some minor mods to the mainboard I/O will allow me to control the temp of my extruder up to 400deg C (the maximum recommended by E3D).
I want to start experimenting with some of the more exotic filaments out there.
Does anyone here have any experience printing high temp materials?
Well, i didn’t try high temp materials until now, but i also equipped both heatbed and e3d V6 hotend with
Thermocouple type K. I used the Adafruit breakout boards, so i could fit them to the board without changes.
I just made a new “thermistor” table to reflect the higher temp range of the thermocouples.
I don’t think you will need a 24v hotend. Mine reached 360°c easily in under 20 seconds during testing.
Even with sthe stock 15v and using the E3D supplied 12V heater cartridge.
I had already ordered the larger 24v supply and 24v hotend. Though upon hearing your advise, I think perhaps that was a bit of over kill.
I will be using some custom electronics of my own design (basically a pair of logic level MOSFET’s and associated components lower the input voltages from 15v to something more reasonable) for control the Bed/Hotend heaters.
I am interested in your solution for the thermocouple integration. Would you mind providing a link to the Adafruit breakout board you mentioned?
Do you know off hand the maximum recommended operating temperature of the heated bed?
Here is the link to the Thermocouple amplifier :https://www.adafruit.com/products/1778
You can connect it’s output directly to the THERM input instead of the thermistor. (Keep an EYE on the POLARITY!)
You will need to have a modified thermistor table to reflect the different temperature curve.
I can Post a link to my modified V 2.1.1 Firmware if you like.
I Don’t know what temp the Heatbed can take, burt i think up to 160°C should be possible with the PCB material.
I’m running 27VDC to my stock Velleman bed and get a temperature delta of about 100C, which means that I can reach about 120C in a room of ~18*C. My bed is on top of 4mm cork and under a Velleman glass plate. There are a lot of issues with higher temperatures.
Power dissipation from the copper traces drops significantly with the rise in temperature. A bed that measures 5 Ohms resistance at 12C presents a 7-Ohm load at 100C. My 27V supply drives 140+W through a cold bed, but only 104W at 100*C. I won’t use more power on a cold bed (raise voltage), don’t want to bother with the electrical complexity of a stepped supply, and hesitate to tackle the mechanical issues present with a NiChrome heater.
Assuming we could dissipate enough energy as heat to reach 135+C, new problems emerge. Chip thermistors are only rated to 135C - you’ll need a glass thermistor above that temperature. The glass transition temperature of FR4 (circuit board material) is about 140C. Then at 150C, the cellulose structure of cork starts to deteriorate.
Enclose the printer in a sealed chamber and you can probably reach 130*C without spending a fortune.