Taking a new hotend into operation (cleaning, forming, etc)

Question

When installing and using a new hotend for the first time, which steps of action should be taken before. This will probably be more applicable to chinese clones than to authentic products (is the statement true?): Should a certain cleaning procedure be carried out (removing swarf/shavings for example)? Should mechanical precision be controlled and if necessary improved (de-edging and nozzle size are two things I could think of)?

I know the topic How should I clean my extruder when changing materials?, which is a nice addon read, but I am concerned about brand-new extruders.

Answer 1

I haven't done anything special to set up mine. But it's probably worth doing a general cleaning. I'd swab it off with alcohol, including running a q-tip or similar inside the fiber feed path. Then blow out the nozzle with compressed air to make sure it's clear.

You could measure the nozzle diameter by fitting fine drill bits in to see which is the largest one the passes through freely. Be sure to measure how much fiber your extruder really takes in when you ask it to extrude a certain length -- but that's about the extruder, not the hotend per se.

Finally, I'd check the insulation, if any. I got a couple hot ends that had big gaps in/around the insulation. I've found that "high-temperature gasket maker" is great for improving insulation (depends, of course, on the shape and design of the specific hot end.

Answer 2

I heard some people are using silver polish on a pipe-rag (not sure what the English word is, it's a long metal wire with threads on it to clean a pipe (for smoking). Then put the pipe-cleaner in a cordless drill and spin it around to polish the inside the hotend to have it silky smooth inside.

Also i heard some people put a hotend in canola oil and cook it, supposedly the canola gets on the hotend (like baking in a new chinese wok pan, you put oil and heat it to create a nice oily film).

I always bought original J-heads and switched to E3D only for my Delta printer. Never had to clean anything, but heard the chinese clones sometimes lack the finish the "real" products have.

Answer 3

So far, these are my experiences to make a new hotend work properly.

• Read the instructions. The ones of the 'original' if it is a clone.
• Check the parts. Is everything included you need?
• and check the design, if it is a clone. It might not be the same as the one they're trying to copy. Figure out the differences (as far as I encountered mainly the heatbreak/inliner design)
• There is no immediate need to mechanically check the nozzle if it passes an optical check. You will be calibrating the extrusion anyway and unless you're unhappy with the results, there are most likely more severe impacts than the accuracy of the nozzle diameter.
• Cleaning should be done to some extent. You wouldn't want any visible leftover products from the hotend's production in the extrusion path. Anything that you can't see will most likely be removed easily by the filament and should only be a problem when there are other more significant flaws.
• You maybe want to install a heatbreak into the heatsink with lots of thermal paste to transfer the heat as effectively as possible. A defined and short meltzone is key for reliable operation.
• You also maybe want to add some thermal paste for the thermistor/thermocouple to ensure quick heat transfer here.
• You maybe want to insulate your hotend thermally to not lose heat by dissipation. I asked a question about that process here: Efficient and easy way to thermally insulate the heat block of the hotend?
• Test whether the filament is easily guided into the heatbreak, so that it doesn't stop being extruded by catching an edge or deforming over one.
• Check the two valuable answers of TextGeek and Dimitri Modderman, there's good information in them!

This answer is most likely not complete and totally up for discussion. I appreciate any addtional answers and comments to improve on the topic!