Teflon spacer replacement

[randyinla 14]

The problem i see with spacers is that some material could go between it and the insulator, it will then cause a nice clog that would be hard to clean, i really feel that it's better to have the insulator in one piece

 

Maybe. But wouldn't that already happen between the hot end and the spacer now? both are flat at the mating point. The spring above keeps pressure on it so material doesn't get in between. If the washer was flat, then it seems to me that it shouldn't be any different.

 

(... )So, if you changed it reguarly it would help the Teflon coupler live much longer, yes. But the point for many is to avoid the "hot end rebuilds" in the first place: (...)

(...) Like Didier is indicating: is your washer is not really the right shape you will have a leak, and swamp the whole hot end.

Meanwhile the I2K works well, 500hours/260C and counting.

 

Yes, taking the hot end apart can be a pain, but it seems like more people are complaining about the high cost of ordering a replacement (if they are not entitled to a free one).

 

And yes, the shape has to be correct or it will fail.

[swordriff 119]

I messed up by sending UltiArjan a PTFE coupler I had purchased from China, because he really needed one fast.

He swamped his whole (Olsson Block) lower hot end completely. Turned out the PTFE coupler (had one left with me) was off by less than 10 micron (!), 6.38 instead of 6.32-34, which caused leak due to lack of downpressure. To machine the washer is a lot more fiddly, Anders Olsson recently used a scalpel / sharp knife to manually correct some after lathing. puh... (Anders; are you still so young so you have eyes for this?)

 

[densohax 0]

Just wanted to chime in! So my setup finally failed (burnt plastic formed between the hotend and the PTFE coupler) .. So I am now using the vespel spacer between the teflon part and hotend..

 

[densohax 0]

So it's not going very nicely... I have under extrusion problems, the feeder motor started skipping and I am at 250 celsius with ABS using the vespel spacer + teflon spacer.

It looks like I might have to drill the inside diameter a little, or maybe the head is not heating as it should, I am a bit tired of this issue, I hope Ultimaker will find a good solution.

 

[swordriff 119]

Did you put a new Teflon coupler when you inserted the vespel spacer?

[densohax 0]

Yes I did.

It feels like there is not enough heat in the plastic. There is no smell now and the plastic is not very fluid... My heat sensor might be bad, although it boils water at 100 celsius.. I have to find a better way to test it...

[swordriff 119]

there is a video somehere, possibly by gr5, with a simple, non-scientific test of nozzle tip temp. It involves touching the tip with a piece og filament and see how deep an impression it leaves... try to find it!

I think there is a bigger chance of loose connector on main PCB, both sensor and heater, , then heater failure, least temp sensor failure..

[densohax 0]

Yeah I saw this video, I'll give it a try..

Actually, I had to change the PT100 on my heatbed recently, maybe there's actually a problem with the PCB connections, because the PT100 was reporting temps correctly but sometimes after the print there was the temp sensor error, although the bed was correctly heated..

 

[densohax 0]

Ok so my problem is that the vespel spacer didn't sit on the hot end tip and it went up and so it plugged between the vespel and hot tip..

Really a simple issue after all, but I broke the vespel. So I'm back with the original teflon spacer.

 

[JohnTrail 0]

In what way does lowering the nozzle reduce pressure on the spring? The spring starts at the top plate of the print head and pushes the teflon isolator, which pushes on the stainless steel collar, which spins on the aluminum plate of the print head. The nozzle is BELOW that. Thats how its removeable to clean.

 

Stainless steel would be good as it's not very heat conductive.

UM has a "new" glass infused teflon isolator but if you got the printer less than 3 months ago (you said 2 months) then I suspect you might already have it.

There is a spring pushing on that isolator from the top - very obvious when you look at it.  You can reduce deformation by reducing the pressure of that spring by lowering the nozzle as low as you can.  That's all I got.

I usually print at 220C and the isolator withstands 220C MUCH better than 240C.

 

[ultiarjan 1,223]

Actually the Teflon sits on the top of the nozzle.... inside the hot-end-isolator... rotate the hot end isolator and the nozzle block goes down and the teflon goes deeper into the hot end isolator.