27 July 2013

First tests with high temp extruder

I did some testing with hp_'s ceramic hotend
It came with a 24V/30W heater cartridge.

Read on after the break.

I also had my new extruder electronics ready, which supports k-type thermocouples.
so theoretically I could go up to 1100 degrees Celsius.

As you can see in the photo above, 1st thing I did was clamp the hotend in a vice and put a good radial blower on top of the hotend.

As The circuit to control the K- type thermocouple was a AD597 and it basically outputs 1V for 100 degrees Celsius, I could "only" go up to 500 degrees Celsius as the AD597 was powered by 5V.

First I set it to 250 degrees, that took about 30 seconds to reach.

Then I upped it with 50 degrees increments, and everything was fine till 400 degrees Celsius.
When I set it to 450 it went to 430 with reasonable speed, but after that, it started to take forever.
I eventually got it to 434 and that was it. The limit of the heater cartridge was reached.

So I set it to 425 and that held perfectly.
The top of the hotend that was actively cooled could be touched.
Everything below that was HOT!!

There is however a 24V/40W heater, so there is room for improvement.

If you are asking yourself : Why would you want to go that hot?
Same answer as ever : Because I can :)