UM2 "socks" - well it turned out to look more like spandex

[foehnsturm 970]

There's one point with the new E3D stuff which I found interesting: Preventing material buildup on the nozzle surface.

I recently did some dual extrusion prints with PETG and while the wiper is working flawlessly this stuff sometimes sticks to the nozzle, carbonizes and then drops down at some time.

First try wasn't that bad, so rev1 is printing the mold for rev2 now.

Edited September 8, 2016 by Guest

[neotko 1,417]

Was thinking of doing the same but with PVA as a mold. Filling molt with hightemp silicon / solid resins

I think I have an unopened PVA spool somewhere and this morning did order some 500C resistant stuff.

[neotko 1,417]

https://www.amazon.es/Sellador-Escapes-Pattex-Selladora-Escape/dp/B00LUKCXYU/ref=sr_1_6?ie=UTF8&qid=1472818467&sr=8-6&keywords=MASILLA+SELLADORA+alta+temperatura

I'm gonna give this a try, it can go up to 1000C, but I need to design the mold first ofc

Should not be too hard now that the step files of the olsson block are on the github of um2+

Edited September 2, 2016 by Guest

[korneel 176]

awesome!

seriously, if someone makes these, I'll buy 6..

I've had to cancel so many prints of NGEN Clear or XT Clear where the nozzle was just dragging junk over the print and leaving a brown smudge..

neotko.. let me know how I can help same to you @foehnstrum!

[eldrick 65]

I'd also buy several. I have the same issue with white ABS.

[neotko 1,417]

Well my idea isn't to sell them, sure would be nice if someone can just make it. I want to check the diy route.

[foehnsturm 970]

Finally, rev 9 looks promising. The press fit in the fan bracket stills needs some fine tuning.

[neotko 1,417]

Oh I see you where already doing it. What material you use for it?

[foehnsturm 970]

For now just 2K silicone, shore 45 A.

Won't withstand the temperature forever I suppose. Also, a little less soft material would be nice.

[Labern 775]

I love it. This would be really great.

Have you notice much of a difference during the print with plastic build up?

Any post print photos?

[foehnsturm 970]

I'm waiting for some silicone sheet material now. Casting seems possible but the critical thing is the tiny hole around the nozzle. You need a perfect edge there. Otherwise some material can make its way between the sock and the nozzle, especially after dual extrusion wiping moves. So I ordered 2 to 4 mm hollow punches as well.

[Labern 775]

Looks like you have the silicon go right up to the tip of the nozzle. If it was up about a mm it may help stop it from going in between.

Like you said. It needs to be quite stiff.

[foehnsturm 970]

Looks like you have the silicon go right up to the tip of the nozzle. If it was up about a mm it may help stop it from going in between.

Like you said. It needs to be quite stiff.

 

True, a little more clearance will help. Anyway, I think it's not a big issue with single extrusion printing if the hole is cut well.

A possible wiping move is a different story as the wiping blade will catch the plastic and drag it over the nozzle tip an that edge onto the silicone surface where it will fall down.

[korneel 176]

offering to test this for you

[mastory 44]

Oh I see you where already doing it. What material you use for it?

 

I made a silicone boot for my one-off heater block and nozzle.  Mine was intended for containing heat but it turned out really nice.  I built a mold out of pla printed parts.  I lubed the mold with olive oil and use high temp automotive silicone RTV (the red kind generic brand seems fine) for the boot itself.  I found instructions for mixing cornstarch with the silicone to cause fast curing.  It has been holding up to the heat for over 3 years. I think it took a couple hours or less to cure.  I used a syringe to fill the mold cavity.

Looks like I could use a sock too.

Edited September 5, 2016 by Guest
added pics

[neotko 1,417]

Cool. I have the design finish for the e3d and ultimaker nozzles, but I need time to do it

I think the key of this being helpful to avoid materials sticking to it might be to use a specially slippery silicon, curiously the one I found its blue like the one e3d uses. But it's expensive and the delivery would take a while.

I think for the first molds I'll just use pla, fill with silicon, leave to cure 24h and then remove the pla with a hairdryer

Edited September 5, 2016 by Guest

[geert_2 558]

If you want "non-stick" silicone, make sure to use mould-making silicone, but *not* sanitary silicone (which may be very sticky).

Silicone for mould making and casting is available from dental laboratory suppliers (dental labs use it to make casts of teeth models), or from special-effects suppliers for the film and theatre industry for their masks and props.

There do exist liquid versions, where you have to mix liquid A and B in correct ratios, and versions that you can paste-on, but liquids are better as they give much more detail. But these silicones are not strong: they tear easily. They do exist in very soft (skin-like) and harder versions.

Just make sure that you have a mechanical way to fix the model after casting (screwing, clamping,...), since it will not stick...  :-)

Edit: spraying a bit of silicone mould release spray on the silicone moulds, makes them even less sticky, and it increases their life. Silicone is heat resistant to about 250°C.

As a quick fix to existing items, you could also consider spraying them with silicone mould release spray to prevent anything from sticking to it. Just do *not* spray on the glass print bed...

Edited September 5, 2016 by Guest

[foehnsturm 970]

First test, benchy scaled down to 50%. Everything looks clean afterwards.

If it works with PET, I will try to get a batch manufactured.

Intended price target: some 25 € for 5 covers and 2 mounting brackets

Edited September 8, 2016 by Guest

[tinkergnome 927]

If it works with PET, I will try to get a batch manufactured.

Intended price target: some 25 € for 5 covers and 2 mounting brackets

 

Cool, this looks inviting... What about durability?

Seriously - can i place a pre-order?

[neotko 1,417]

Seems it's really hard to print a mold for this, but with some hard fan and good temps it printed nicely. I'll have the 295C flexible silicone product tomorrow, but this stuff isn't cheap, 40€ for 1kilo. Down, side each print will be for just one sock. If works I'll release the files, but this isn't as easy as just printing...

Edited September 8, 2016 by Guest

[foehnsturm 970]

Seems to help with PETG & Flexifil. No brown junk anywhere.

[eldrick 65]

Why not just wipe the nozzle with some silicone before printing to avoid material sticking to it?

[foehnsturm 970]

That's what I'm already doing. But over time nozzles start to get dirty during printing and then no wiper will be able to remove this stuff again.

[neotko 1,417]

So far it works, I don't have much nasty filaments (that could stick to the nozzle) but as soon I finish the design I'll do a carbonfill test (it always makes a big chunk of goo on the nozzle after 1h) that should be a decent test.

The first test I did was printing one of my keychains (something I have printed easily over and over 500 times) with faber pink. For this filament/temp I always had to go 222-225 to get a gloss finish, anything below made the finish matte (something quite handy sometimes) but it was something that always did bother me since on umo+ hotend I was able to print at 210 with gloss effect). So first test was at 215C and the print did had a nice and cool gloss effect on the big top flat layers. So my early theory it's that having the nozzle cover with this helps to keep a more uniform heat all around, so the filament exists 'hotter' than without the socket.

It's too early to open the champange but I'm quite surprised and happy by this sideeffect.

[neotko 1,417]

Next test will be to make just a nozzle shock, something easier to remove and that 'should' work more or less the same. But I never did a mold of anything so it's been a fun learning experience, also I only have a week and a few days to do more test before the 40€ silicon starts to die after opening it.