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scottmayson

Cracked brass printer head

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So I have been having continual problems with my printer head leaking back up through the thread and through the heater block. To try and stop this I added high temp plumbers tape 6631648845_8f4c378e2e_b.jpg This worked for some time however, I notices a crack appear in the print head and then it pealed apart on disassembly :( .

The nominal wall thickness of the UM 0.4mm print head where the brass tube bottoms-out is 0.34 mm! Print head Failure

Have ordered several 0.4mm print heads, teflon coated MB http://store.makerbot.com/makerbot-mk6-nozzle-teflon-coated-0-40mm-width.html 'new heater block required' and MakerGear http://www.makergear.com/products/nozzles. will post images when finished.

Also I am re designing the head for drop in/out interchangeable heads that will be one piece design and compression "surface" clamped in a new PEEK component. The Fortus 900c http://www.fortus.com/products/fortus-900mc.aspx uses a similar method. will post images when finished.

Thoughts anyone?

Scott

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'new heater block required'

Eh?

The MB nozzles have a M10(???) male thread, while the UM and Makergear nozzles have a M6 female thread, hence a new heater block is necessary for the MB nozzles... I personally would stick with the UM/MG nozzles for now, and not go through the trouble making a new heater block (unless it's induction :-) )

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My thoughts are:

 

  • [*:3tordj21]So the MakerGear nozzles fit on the Ultimaker without issue?
    [*:3tordj21]How much more fine quality would I get from a 0.25mm nozzle compared to the stock (0.4mm?) nozzle? Because I noticed I want to print really small things and some details go missing then.
    [*:3tordj21]Changing the nozzle scares me. So a quick interchangeable heads sounds like a really good thing! Cannot wait to see the results.

 

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My thoughts are:

 

  • [*:282n8yvy]So the MakerGear nozzles fit on the Ultimaker without issue?

    [*:282n8yvy]How much more fine quality would I get from a 0.25mm nozzle compared to the stock (0.4mm?) nozzle? Because I noticed I want to print really small things and some details go missing then.

    [*:282n8yvy]Changing the nozzle scares me. So a quick interchangeable heads sounds like a really good thing! Cannot wait to see the results.

 

Yes, the makergear nozzles fit easily. the only difference is a sightly different throat depth: UM nozzle 8.5mm, makergear nozzle is 8mm, which means you need to adjust the heater block down by 0.5mm (180 deg) to maintain a good seal and good heat contact between the nozzle and the heater block.

I don't think that changing the nozzle is such a big problem... I print with a 0.5mm nozzle, since speed is more important than detail at the moment, and pushing enough PLA through keeps the UM sprinting. but I bought the complete makergear nozzle set, and changing hot nozzles isn't so bad.

using a 0.25mm nozzle will definetly/probably cause more pressure in the head (and the print profile needs to be adjusted to avoid "large volume" situations), but should make really nice details.

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How much more fine quality would I get from a 0.25mm nozzle compared to the stock (0.4mm?) nozzle? Because I noticed I want to print really small things and some details go missing then.

Unless you're really pushing the limits of your current nozzle by dropping the thread width down to 0.35mm (and then trying to get even thinner), a smaller nozzle isn't going to get you any improvement - if anything, it will just make things more difficult because, like Joergan says, smaller nozzles increase the internal pressure.

If you've already pushed the thread width down as low as the stock nozzle will handle and it still isn't enough, fine - absolutely go for a smaller nozzle. If you haven't, a smaller nozzle is a waste at this point.

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How much more fine quality would I get from a 0.25mm nozzle compared to the stock (0.4mm?) nozzle? Because I noticed I want to print really small things and some details go missing then.

Unless you're really pushing the limits of your current nozzle by dropping the thread width down to 0.35mm (and then trying to get even thinner), a smaller nozzle isn't going to get you any improvement - if anything, it will just make things more difficult because, like Joergan says, smaller nozzles increase the internal pressure.

If you've already pushed the thread width down as low as the stock nozzle will handle and it still isn't enough, fine - absolutely go for a smaller nozzle. If you haven't, a smaller nozzle is a waste at this point.

Well, my thread wide is on 0.4mm. But when I say small things I really want small things. For example this photo:

http://daid.eu/~daid/IMG_20111212_194956.jpeg

It's a bad print, with 0.2mm layers, a to high temperature and problems with support removal. But that's not the point. The point is, that this print is still 40% to large for my goal.

I cut the model in half, printing only up to the waist, so I didn't need support, I also scaled it to 50% size and used 0.1mm layers. I still need to photo it (taking photos from small objects with my phone doesn't work very well) but you can see it has oozing problems. And the 0.4mm nozzle is not cutting it.

I'm just trying to see what the machine is capable off. With prints that small you are not printing fast, because cooling becomes a real issue. But that also solves the pressure problem I think?

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I haven't had my machine for very long but I've had problems with small details since the start. My temperature is already pretty low (around 185-195C) but it still gets quite "blobby" on very small details. Print too fast and it gets messy because it doesn't get enough time to cool, print slow and you get issues with oozing, print multiple objects you get stringing... it's a pain to say the least. From my very limited experience it seems that what we really need is reliable filament retraction and push back and I don't see that happening with the bowden really.

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If I put the temperature at 195 my filament grinds to a halt. I guess my sensor has quite an error. 205 seems to be my safe temperature. (The above picture was printed at 230)

I should get access to a PrintrBot somewhere within the next few months. As it doesn't have a bowden tube. I guess I know the difference between a bowden and not once we get that up and running. (Friend of mine ordered one after seeing the results of my Ultimaker)

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I'm just trying to see what the machine is capable off. With prints that small you are not printing fast, because cooling becomes a real issue. But that also solves the pressure problem I think?

Keep working at it!!

Check out the tiny stuff this guy's done, apparently with an Ultimaker:

http://monocircus.com/en/news_post/tag/3D_printing/

Not sure how he's doing it but it's looking quite nice...

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3cm or so? That's pretty doable with an ultimaker. But I'm going a bit smaller then that:

IMG_20120107_214334.small.jpeg

Click for larger image

The left one is the famous Octocat at 50% scale. To the right is the smallest thing I ever printed. It has imperfections that also have to due with settings. However, that's the size that I'm wondering at if a smaller nozzle will help.

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