Hotend design & question about Wildseyed

Hello all.

So my previous hotend failed on me. It was simply a MIG tip screwed into a piece of Teflon, and because it was operating above the glass transition temperature of Teflon, it slowly creeped and the tip popped. So while I was on the search for a new hotend, I noticed something. Most of the hotends that I saw fell into two categories, either they were designed for people who had limited access to tools, or were professional made and needed to be purchased. While I did give some "ooh" 's & "aah" 's on group two, I didn't want to purchase something I could made myself, and I wanted to be a bit more precise than group one.

So my goal was to design a hotend for people with access to a small machine shop (Just a lathe, some drills and a tap & die), and to be easy to make even with little machining experience. I have a basic design which I will post later, but I have a question. My design is based off the Wildseyed hotend, as in the Teflon screws into the hotend and some of the dimensions are loosely based off of a MIG tip. But upon reading on hotends, I came across some posts saying that any design that uses Teflon as a support structure is bound to fail eventually, that

Quote
DeuxVis
all hotends who ever relied on it to attach itself are doomed to early failure

If this is true, how does the Wildseyed cope?

Good question. I made one with PTFE screwed into brass and it failed during the first layer.

---

[www.hydraraptor.blogspot.com]

FYI - I would consider my hot end design to fit nicely between those two categories. You do need a lathe to make the nozzle, but the design is otherwise very straight forward (and effective). I've been using V0.5 for months now and don't feel it needs any significant improvement. I will probably come back to this in the next month or so to play with some other materials, but you might find the info helpful at least.

[www.reprap.org]

U can try mine as well. It look litle more complicated then watsons wersion (two clamps instead one and more parts). But v 2.5 is realy good and as bonus it can be easily mounted/demounted, including heater element and thermistor. Plus two heater resistor can heat hotend realy fast.... U need only lathe and table drill. Milling machine is good but not necesarry...
hotend
Latest tests with ABS are realy interesting, i was able to get same results as profi printer udimension from my work...

Btw. one of my first designs used theraded PTFE too and it worked some time, before i need demount it...

Hi DeepBlue,

The Wildseyed Simple hot end is my design, just can't seem to interest any admin here in resetting my account.

My design copes just fine. If the PTFE is shaped properly, it will never slip out of the brass coupling. Since the couplings vary by region, it's best to keep a caliper on hand and measure the inner diameters and depth before shaping the rod. At the transition from small to large, I put a slight taper to help slip the threads over the rod. Also make sure the small end bottoms out on the MIG tip, or you won't get a good seal there.

The one thing to avoid is leaving the hot end at operating temperature without printing. This is the case for most designs. Eventually, the temperature inside the PTFE could get hot enough to soften the filament, and cause a jam.

Separation from the extruder body is a possibility if too much pressure is exerted by the stepper. This is remedied by using a nozzle opening no smaller than 0.5mm, and setting the stepper driver current such that it allows the motor to stall, rather than push at any cost.

On a Wade's or Greg's body, the PTFE rod should be clamped in tightly using four M3-8mm Set Screws. If it pinches the hole a little, it alright. Just run a 3mm bit in and out a couple of times.

I print with ABS only, but I do keep the temperature at 230C. This seems to give the best long term results.

I actually have the versions of this hot end, but I have not had the time lately to put up new instructions. If you want to get more info, and some pictures, drop me a line on my gmail wildseyed@...