PEEK Tube.

[Mac The Knife]

From reading the forums, the weak link with the supplied hot end is the PEEK tube. I don't see them available in the store, and I haven't seen a clear drawing of the tube itself. Has anyone looked at using machinable ceramics to replace the PEEK Tube? Way more expensive then PEEK, but you would still be using all the standard parts of the stock hot end.

[Mac The Knife]

http://www.mcmaster.com/#standard-ceramic-rods/=s51eet

[Captain Starfish]

Or even get them made. http://www.industrialceramic.com

Or - hang on - does anyone have a paste extruder and a kiln available, and wants to PRINT them for us?

[Mac The Knife]

So you're saying I just need to buy a fancier hotend.

[Captain Starfish]

Lol

Not at all.

If someone posted on here something along the lines of "hey guys, I've been playing with my ceramic paste extruder and have now got this thingy for sale which replaces the PEEK heat break and the tygon hot end internal barrel tube liner whatsit in the stock hot ends with a ceramic job that will happily run to 400ºC or more", I'd be very interested. Nice to be able to continue using the hot ends, nozzles etc I already have.

Or SeeMe might consider drawing and pricing up a commercially cast and cooked version as an option for purchase time or as a retrofit.

It's a bit sad that we presently buy a hotend and then end up buying another one to do the good stuff.

[precisionpete]

I'll go way off into left field here.
They make castable ceramics.
Why not print a hot end and cast it?
Not going into all the details here, but temp is 3000 deg C for the stuff we use so would handle anything we throw at it.

Project #397

[Max]

I'm actually working on design where the PEEK part is ceramic, but it doesn't directly replace the current PEEK piece. It requires 2(or 3) screws to squeeze the ceramic piece in place. You still have the PEEK fan, but it pulls air throw a hollow section of the ceramic to cool the PETF tube in the middle.

I want to get printing ninja flex so I can make a reusable mold to cast this piece, just because it's soft and will release easier.. Print the part in Ninja flex, cast in plaster, let dry, and then cast the ceramic in the plaster. Then fire... It's a lot of steps. Then you will probably have to finish the top and bottom pieces to make sure they are flat, and parallel. Or at least parallel, a thick gasket could make up the difference in some flatness.

Ceramic is an option, but refectory cement is another, and you don't have to fire it. It sounds heavy, but there are light weight versions, and you might be able to add micro balloons to help with insulation, and weight.

Another option that I'm looking at is just using a dense plaster, sometimes call mold plaster. USG has a formula for casting metal parts, that can handle 1200C. But I have no idea how well it will work in a hotend. Worried about the vibrations from the steppers, and any dusting of plaster getting on the parts.

Like are pete said, project #397

[Mac The Knife]

your idea of pulling air through it should work with with a piece of stainless steel,,, drilling a bunch of holes in the side of it.

[JohnStack]

If you have a standard heater block like the E3D and make it screw into a ceramic head piece that's a 1" cylinder with a 1.75mm hole down the center, wouldn't that solve the world's ills? Seems to me, all you would have to worry about is how brittle the ceramic is.

[Max]

I was thinking something like this.

This would be a drop in replacement. The problem is the top doesn't have a wide enough brim to drill holes in to put screws. But you could put a washer there and drill holes in that. I have a old stock hot end that the peek melted a bit on. So I was looking to mod it.

The air channel is just a mock up to give an idea of the concept. It would need to get modeled to match a fan, and fan shroud.

[Max]

I just realized I could probably 3d print that top piece... if I keep a fan on for the middle I'm sure it would work.

[Captain Starfish]

Sounds like an excellent project. The ceramic part could be printed in PLA as a female mould and plug, filled with clay and fired - the PLA will burn away leaving the clay part behind.