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Is there any way to purchase a tested extruder assembly?  

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GregB
(@gregb)
Trusted Member
Is there any way to purchase a tested extruder assembly?

Is there any way to purchase an extruder assembly?  Not the entire printer, just the bit where the plastic squirts out of.

I recently purchased an I3 Mk3 kit and had a lot of fun assembling it.  I originally considered a LulzBot but then discovered Prusa.  Prusa clearly leads the desktop 3D community and what I sacrificed for convenience I made up for in education.  The latter is particularly important as I'll start an online AM degree program this fall.

However, as I am new to the 3D/Maker community there have been problems.  Fun problems mostly, but still problems.  The largest problem is that whenever I fix anything with my printer something else goes off.  I love learning but need things to work.  A recent nozzle change was a good experience but somehow negatively affected the print quality.  How can I get this thing working while having something that's safe to break?

Posted : 12/05/2019 1:55 pm
Peter M
(@peter-m)
Noble Member
RE: Is there any way to purchase a tested extruder assembly?

You give no info over your problem?

 

For repairs, before you do this, check the prusa website for info(manual), and because prusa could also make a mistake(prusa has very good manuals), check the same info on youtube on how to repair things.

Then you have, more then 1 howto, then start repairing, and combining the manuals.

If you make a mistake, yes you can fix your problem, but also kill something else, cables will get bad or brake fast.

 

Try to ask the prusa helpdesk, I do not know if they do?

Posted : 12/05/2019 4:31 pm
bobstro
(@bobstro)
Illustrious Member
RE: Is there any way to purchase a tested extruder assembly?
Posted by: gregory.b10

[...] A recent nozzle change was a good experience but somehow negatively affected the print quality.  How can I get this thing working while having something that's safe to break?

If you changed nozzles, you need to repeat the Live-Z calibration. It's also highly probably that your PEI surface was contaminated in the process. Best is to treat the 2 most common causes of adhesion problems.

Here's some copypasta...
 
Adhesion issues are usually caused by 2 main problems:
  • A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. Take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails, and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent to give it a very light buff, but only infrequently.
  • If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. 
And above all else, avoid touching the PEI print surface.
 
Try those 2 steps. If you're uncertain of the Live-Z results, post pics here of the 75x75 print bottom and you'll get quick help. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When it's right, you should be able to gently rub it without it coming loose. Then start lowering (more negative) the level until there are no gaps between layers. 
My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 12/05/2019 5:44 pm
Vojtěch
(@vojtech)
Honorable Member
RE: Is there any way to purchase a tested extruder assembly?

The E3D v6 assembly guide is fairly straightforward and if you follow it carefully, you should be fine. Nevertheless, if you want a properly assembled hot-end, you can buy one for the Mk3 from the Prusa shop. It isn't particularly cheap, though. You can also buy any of the individual parts of the hot-end there.

Perhaps if you mentioned what your issues are, people on the forum, me included, could give you advice on what's wrong with your assembly.

Posted : 12/05/2019 5:48 pm
--
 --
(@)
Illustrious Member
RE: Is there any way to purchase a tested extruder assembly?

One of the more common errors people make when changing nozzle is they do it cold; and second they fail to properly torque the nozzle against the heat break: instead they try to bottom the nozzle into the heater block.  The HEX of the nozzle should not (must not) hit the heater block. The E3D-V6 guide explains how to properly change the nozzle, and should be followed to the letter.

Hex position when installed correctly:

 

ps: I purchased an entire hot end from Prusa ... assembled.  You can also buy an assembled hot end from E3D.  The Prusa version has the correct cable lengths.  Then again - maybe you mean complete Extruder Assembly... that would be hard to do because of many factors, like bearings generally need to be on the rods when assembling, cables need to be routed above and below rods, etc.

This post was modified 5 years ago 2 times by --
Posted : 12/05/2019 5:53 pm
GregB
(@gregb)
Trusted Member
Topic starter answered:
RE: Is there any way to purchase a tested extruder assembly?

 Posted by: peter.m26

You give no info over your problem?

 

For repairs, before you do this, check the prusa website for info(manual), and because prusa could also make a mistake(prusa has very good manuals), check the same info on youtube on how to repair things.

Then you have, more then 1 howto, then start repairing, and combining the manuals.

If you make a mistake, yes you can fix your problem, but also kill something else, cables will get bad or brake fast.

 

Try to ask the prusa helpdesk, I do not know if they do?

Not so much looking to fix this problem but cause other problems.  Right now it's too stressful and time consuming to experiment, which is no good for anyone.  Having two nearly identical assemblies to compare would be fun, informative, and allow for increased risktaking.  I could buy a MMU 2 kit but that’s not the point.

 

Posted by: bobstro

If you changed nozzles, you need to repeat the Live-Z calibration. It's also highly probably that your PEI surface was contaminated in the process. Best is to treat the 2 most common causes of adhesion problems.

Did all that but now Benchy looks a little drunk.  Like the above, to feel comfortable experimenting, I need a backup.

 

Posted by: Vojtěch

The E3D v6 assembly guide is fairly straightforward and if you follow it carefully, you should be fine. Nevertheless, if you want a properly assembled hot-end, you can buy one for the Mk3 from the Prusa shop. It isn't particularly cheap, though. You can also buy any of the individual parts of the hot-end there.

Perhaps if you mentioned what your issues are, people on the forum, me included, could give you advice on what's wrong with your assembly.

Yea all the Prusa instructions are great but it’s not just the hotend.  While having the option to purchase just that is good, it’s not the entire assembly with printed parts.  If the MMU is available in a kit maybe the I3S is as well.

 

Posted by: Tim

ps: I purchased an entire hot end from Prusa ... assembled.  You can also buy an assembled hot end from E3D.  The Prusa version has the correct cable lengths.  Then again - maybe you mean complete Extruder Assembly... that would be hard to do because of many factors, like bearings generally need to be on the rods when assembling, cables need to be routed above and below rods, etc.

 

Yes, the complete assembly.  That way if I want to experiment with a new fan, have an assembly dedicated to high temperature/exotic filaments, etc., I can do so.  You bring up a good point though.  From memory and the instruction manual replacing assemblies should be a straightforward process.  A few zip ties and cable management are worth it.

Posted : 13/05/2019 12:29 pm
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