PTFE insert breakthrough

After 5 months of frustration with my hot end(s) I have finally found a solution that works. All of my hot ends have been based on a PFTE insert, and they generally work well until ABS comes into the picture, it really does want more than 240c to print and this is where i have been failing for so long. PTFE does work well until you hit (or after) 250c, I don't care what anybody says it is bad news as part of a mendel- You need to constrain it, constrained it does what you want! PLA is great but I want to print in ABS, the quality is so much better but my PTFE is always letting me down though shrinkage. NO MORE - the attached picture speaks louder than words in in terms of a solution. With my new PTFE lip design I have printed a whole mendel without issues, not once have I had to clean the hobbed bolt - it works as I expected things to work in the first place.

I know not many people have access to a lathe for cutting this insert, but if you ask nicely i will machine you one (or two) to your measurements for modest sum - just PM me

It really does work, check out my mendel parts pics, these are all off the printer with no clean-up at at all. running my hot end at 250c 24mm/s (32 is possible but my heater does not keep up above that - arcol for you)

anyways, hope you find it useful, it has saved me at least two week of extra grey hairs.

sorry about quality of pics, my shed is dark and it's a phone so sorry about yping as well.

I can't really tell what part of your picture is the ptfe? It looks like a diagram or digital drawing. I have a design that uses a threaded coupler, with ptfe tubing inside, and the outside is a hollowed out wooden dongle. I'm willing to share pictures, if you can share your actual pictures of the object.

ptfe should work ok to at least 275deg c (standard ptfe goes to 260deg c), but it becomes structurally unstable, this is where the outside support comes in handy. I do think it does start to break down chemically around 260deg, so there will be some poisonous outgasing.

Edited 3 time(s). Last edit at 07/07/2011 09:39PM by jamesdanielv.

Sorry, the PTFE insert is the white part the brown bit is threaded peek that screws into the nozzel. Actual pictures are not possible unless i take it all apart. So, the PTFE is completely held in place - it can't move anywhere because the peek and nozzle are compressing the lip - no shrinkage!

Sound a bit like a mendel-parts v6, which I have great experience with.

---

--
-Nudel
Blog with RepRap Comic