Oops, posted this in the general forum but just found this forum...


Hi all,

I have a multi-purpose 3-axis robotic workcell, that I need to add an extruder head to, in order to make it a 3D printer. I've been working with some high-schoolers who have built the machine...
Workcell
PnP config

They also built an extruder feed mechanism (pics overdue), and we started engineering a hot end using chassis-mount power resistors for the heater (similar to the plastruder mk5), but it seems that's a very bad thing to do -- as even within max temp spec externally, these resistors can fail since the internal core temp can be much higher. And apparently they can fail violently. So I'm looking for a new hot end, but confused about all the versions/variations/tweaks etc. Of all the designs, which one really works best? "Best" meaning getting the finest extrusion, and reliable.

At this point, I'm leaning towards buying the parts and assembling it, or perhaps buying the hot end already-built.

Thanks,
-Neil.

Hello,

I make the J-Head nozzles and hot-ends. Thus far, nobody has reported any issues with the heater resistors that are used. However, unlike the chassis-mount resistors, these are inserted in a hole in the heater block. The resistors are basically used as small nichrome heater cartridges. At this point, 6 out of 8 reliable hot-ends that are regularly sold use the heater resistors. The other two use different methods. Once uses a heater cartridge, and you have to wrap nichrome wire and use some ceramic putty with the other.

The J-Head nozzle has been proven to work reliably with both ABS and PLA.

Regards,

Brian

Edited 1 time(s). Last edit at 10/25/2011 09:32AM by reifsnyderb.

I built my hotend for $10 but you will need a lathe to do it.