Sunday, March 25, 2012

Extruders and Hot Ends

When I initially started building my Prusa Mendel, I decided to go with the standard  Wade's Extruder (Thing:1794 from thingiverse.com) and a hot end called the Budaschnozzle 1.0 from  Lulzbot.com. Because it was my first setup, I  spent a lot of my learning curve with it. 

Wade's Extruder and Budaschnozzle


The second setup I acquired was the Bruthead filament drive and hot end from MakerGear.com. 

MakerGear


The third setup I've used is Greg's Accessible Extruder (Thing: 6713 from Thingiverse.com) and the J Head MKIV-B Hot-End from hotends.com.

Greg's Accessible Extruder and J Head



Here are my impressions:

First, I should clarify that I am using 3mm ABS filament. I haven't used 1.75mm or PLA.  I don't have plans to until later and then, only when I experiment with a dual extruder system using PLA as a support material.
    
(1)
Wade's Extruder:  I don't like it. I have spent more time removing the larger gear so that I could remove the motor and get to the screws that attaches the extruder on the x-carriage.  This is not fun when calibrating a machine for the first time.  Also,  I am not a fan of the hobbed bolt as a means of gripping the filament.  It easily becomes filled with filament particles and slips.

The Budaschnozzle 1.0 is no longer available and is now 1.1 (the difference being that the nozzle is more accessible for removal). I have version 1.0 and overall it is a good hot end. I have successfully used the .35mm and .5mm nozzles and questionable results with the .25mm and .75mm nozzles. My only dislike for the hot end is that the heater block and nozzles are made of aluminum and because of this they are fragile when cleaning glassified ABS (I recently had to re-tap the heater block because I over heated it while cleaning).

(2)
The Bruthead filament drive is the best! The geared stepper (with a 5:1 reduction) is easily dismantled for clearing jams.  The filament drive gear grips the filament well without tearing into it.  This is the most expensive of all three setups, but well worth it.

The MakerGear hot end uses a nichrome wire heat core, unlike the other two hot ends which use heat resistors. I find this to be fine. I personally have had less serious jams in the hot end system than the others ( I have been able to run it at a lower temperature).  Both the .35mm and .5mm have been equally successful.

(3)
Greg's Accessible Extruder is a vast improvement over Wade's. Getting to the motor mount screws without having to remove the larger gear saves considerable time.  But the hobbed bolt kills it for me.

The J Head MKIV-B hot end is still intriguing to me and deserves more experimenting.  Initially, I ordered the .35mm setup and couldn't ever get a print started with it.  I could extrude a very fine thread and that's it.  I don't have any way of accurately measuring it,  but I think the nozzle is bored incorrectly and is much smaller than .35mm. I have printed a number of successful prints with the .5mm nozzle.  My main dislike is the shape of the nozzle end.  It's not blunt or flat like the MakerGear or Budaschnozzle nozzles, but has a sharp nose.  I think this digs into the filament layer rather than pressing it to the required depth.


.35mm J Head Nozzle

.5mm MakerGear Nozzle

I don't have any similar print samples from each hot end to compare.  I don't have the time or the interest.  I think all three basically would give equal results.  What I am concerned about is longevity.  I need a trustworthy system that will give me a 2 day print time without jamming.  From my experiences to date, I feel only the MakerGear setup will be able to accomplish this.  And because of my confidence in it,  I plan to adapt it for dual extrusion in the future.




2 comments:

  1. Thank you, your info was very helpful. Throughout my many searches, I've found very few comparison reviews of different hotends. And of the few that do exist, they all only discuss printing with PLA. Like you, I also started with a Budaschnozzle 1.0 and only print with 3mm ABS.

    My Budaschnozzle recently broke and I've been trying to choose between repairing it, upgrading to a Budaschnozzle 1.1, or switching to a Makergear or J-Head hotend. I still haven't made a firm decision, but I'm leaning towards the Makergear hotend at this point. I believe my original Budaschnozzle failed due to the PEEK melting and it seems that the Makergear hotend can print at a lower temperature than the others, which might make it last longer.

    Regarding the filament drive, I'm reasonably happy with my Greg's Accessible Extruder and I just purchased an Arcol Hyena hobbed bolt (which seems extremely strong and likely contributed to blowing out the bottom of my Budaschnozzle), so I'm considering just purchasing the Makergear hotend by itself without the Bruthead. One concern that I have with the Bruthead is that it looks like the motor sticking out straight to the side would cause a decent loss of print space. Would you agree with this conclusion or does it look worse in the picture than in reality?

    Are you still happy with your Makergear setup since you made this post? Have you changed your mind about any of the hotends since writing it?

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  2. I'm glad you found it helpful, Chang. I'll try to answer your other concerns. My impressions about the MakerGear Extruder and hotend have not changed, my convictions have only grown stronger. It's a very good design. The only fault I can see surrounds the switching out of different nozzles. I plan to just have different hotends for each size I would like to use. I know that the Budaschnozzel 1.1 would probably be better for this. I actually didn't know that the MakerGear hotend was known to run cooler. That would explain why I run mine at 200 degrees C. This definitely appeals to me.
    I think I came across the Arcol hobbled bolt on eBay recently, or something similar. I would like to try this for my Greg's accessible Extruder.
    Yes. X axis movement is hindered by the MakerGear Extruder. I actually pulled my Z motor holder out further on one end to gain some of this back. The entire bed could be accessed if I did more dismantling, but I'm not up for that now. I'm getting 187mm of travel along the X axis since my adjustment.
    Good luck with everything!

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