Different Hotends  

RE: Different Hotends

@jasii

I went with the copperhead. Chose your mount, great work. fits in there Like a charm.

Still trying to get Print quality Up to par, feels Like i have to go 5 degrees lower for petg to keep stringing at bay.

It is very reliable, no Jam yet. 

Thanks for Sharing again.

RE: Different Hotends

So I have read through this thread and others about the issues with hotend clogs and extruder clicking issues and the relationship between the two.

I have to say that I am pretty frustrated. I have rebuilt my extruder twice due to the clicking and filament getting trapped. I have now rebuilt my hotend four times. 

1st rebuild - While trying to clean out the nozzle, I damage the threads. I had to order a new nozzle that had less than 100 hours. 

2nd rebuild - I read about the short PTFE tube issue. Sure enough, mine was 1mm short. The extra Prusa provided was the correct length so I installed it. 

3rd rebuild - Discovered the PTFE tube had shrunk about .5mm. Cleaned everything up and reset the hotend to compress the tube properly at the shorter length.

4th rebuild - While cleaning everything and reassembling, I damaged a wire on the hotend heater cartridge..

So here I am, two months with the printer, and it is again, not usable and I have some decisions to make. I am frustrated having to spend money to fix the parts damaged while trying to rebuild the printer due to a known design issue. If the hotend was designed properly, I would never of dismantled it four times and would not have a damaged cartridge that now needs to be replaced.

But here is the worse part, replacing the cartridge only gets my printer back to heating, not working. Not replacing the cartridge means I can't even attempt to print upgrades to replace the hotend all together... I could also buy the Bondtech heatbreak, but I have heard some mixed reviews of it fixing the issue and now I have added another $15 (plus $18 in shipping) to the cost of the printer. Then do I still need the bondtech extruder? There is another $60... and at that point are my problems solved or do I need to upgrade the hotend, another $100+? 

And if I do all of that, why didn't I just buy a MK3s? I would be close to the cost. (btw, I cannot even print the casing to hold a new hotend without first fixing this hotend...)

So with that venting out of the way, where am I at with this printer? It is obviously useless as it sets with a broken heater cartridge. Do I buy a new cartridge and a replacement PTFE tube, and the bondtech heatbreak? 

I just don't want to keep pumping money into this printer for Band-Aids and would appreciate some input.

RE: Different Hotends

@outlawecho

well, I held off from buying this unit, and I am pleased I did. 

for me its not seeing much recognition from Prusa.  That alone worries me.

RE: Different Hotends

@outlawecho

Too bad - you seem to have little luck with your Mini.
I had good experiences with the E3d V6 hotend of the MK3 and therefore I equipped the Mini with it. It was obvious for me, because I had MK3 spare parts in stock and the costs were reasonable. I did not want to buy Bondtech, Mosquito or similar products.
For the conversion I only reprinted a few parts and mounted the E3D V6 hotend. There was nothing to change in the firmware. The whole thing looks like this and works very well:

I used the titanium heatbreak and a nickel-plated copper heaterblock. The standard (Alu and stainless steel) parts work as well.

If anybody wants to do the conversion as well, I will gladly provide the STL data.

RE: Different Hotends

@karl-herbert

Could we have the STL files please? Looks very neat!

RE: Different Hotends

@karl-herbert

Well, the looks excellent!

RE: Different Hotends

I would like the STL files also.

RE: Different Hotends

@karl-herbert

That looks really well done. I do have a few questions if you do not mind.

1) Does the additional weight on the x-axis have any negative affect on the gantry? Or otherwise, is there a significant weight increase? And how long have you been using this mod?

2) Did you upgrade the extruder as well or is it stock?

3) Why did you make this mod? Were you having hotend issues like many of us or was this always your plan?

4) Do you happen to have a list of components required to perform this upgrade? I am curious of the cost to do something like this and am pretty new to printing so it is sometimes difficult to know what components are required.

All that said, I am hesitant to spend much on the mini as if I put a couple hundred dollars extra in it, I would be around $600 all-in and at that point, I would of bought a MK3S in hindsight. Lastly, if I go this mod route, I either 1) have to get the mini working first to print the parts or 2) find someone to print them for me.

Thanks for sharing!

RE: Different Hotends

The weight has not changed significantly but rather decreased. We are talking about a difference of about 10 grams, so nothing significant that could affect the print quality or stability. The version shown in the picture above is V1 and I am currently working on V2. Here are some pictures:

I have also built a new extruder with incl. filament sensor for this purpose, which has already been in use for several weeks:

I have built extruders according to this template:

https://www.bernis-simple-bowden-extruder.com/v2-bernis-magnetic-alu-flexar-extruder/

The pressure on the filament can thus be adjusted very precisely. So far I have been able to print on various materials without any problems, including carbon (XT-CF20).

If variant 2 runs, I will publish this in the Prusa Prints. But this may still take some time.

I made the changes because, as I said, the MK3 runs smoothly and reliably with the E3D V6 and because I like to optimize and modify.

The variant 1, created by Tom Wilkie you can find and download here: https://www.prusaprinters.org/prints/31006-prusa-mini-v6-hotend-adapter

RE: Different Hotends

@karl-herbert

One question if I may, I'm sure that I read somewhere that Prusa used a different thermistor to standard V6 which I'm guessing would require a firmware change, probably wrong so disregard if you know you're getting true nozzle temperature or you reused the Prusa one.

+1 on the .stl's

RE: Different Hotends

@towlerg

I use the original MK3 components (thermistor and heater cartridge). The values of the thermistor table (5) of the Mini are identical to those of the MK3. Adjusting and change table values would be, if necessary, no problem.

@outlawecho

for information only:

RE: Different Hotends

Bottome line for me, I had to invest in a new hot end to get my Mini to function. It was not the greatest option since it was a design flaw, and negated the value of the mini for me. but I invested the extra money and have no problems anymore. 

RE: Different Hotends

@kevman

Then I hope that you have more luck with the new hotend and many successful prints 👍 

RE: Different Hotends

Posted by: @karl-herbert

@kevman

Then I hope that you have more luck with the new hotend and many successful prints 👍 

DEfinately, Its a hobby and certainly rewarding and frustrating at times, but I'm happy and won't look back.

RE: Different Hotends

@karl-herbert

Thanks for all the info. I think this is the route I am going. I can use the heater cartridge to repair my mini to print the parts needed to hold the new hotend and then rebuild with the upgrade.

The best I can tell, the E3D V6 hotend is a solid design without getting outrageous on cost.

Lastly, that aluminum extruder looks fantastic. It looks much stouter than the bondtech.  I was considering just buying it, but unfortunately they do not ship to the US. I look forward to seeing your designs uploaded.

Thanks again!

RE: Different Hotends

@outlawecho

The Alu Flexar extruder is precision work (5-axis milled) and does a good job. However, I had to do a lot of adaptation work to make it suitable for the Prusa Mini. V1 is without, V2 with integrated filament sensor (incl. control LED). The project is still in progress. I can't say yet if I will publish it, because the Flexar idea is not mine, I have only realized it for the Mini.
I will release the E3D hotend in the Prusa Prints in the next days/weeks as soon as the sensor works correctly.

RE: Different Hotends

@karl-herbert

I have to concur.  It is more applicable to the creality ender or CR-10

RE: Different Hotends

@karl-herbert

Completely understand. I will take a look at it once my printer is back up and running. I might attempt to make something similar. I really like the magnetic tensioner idea.

RE: Different Hotends

@outlawecho

If you want to rebuild the extruder, note the strength of the magnets. They are optimally dimensioned for the contact pressure of the filament. The developer has described it on his homepage:

If you have any questions, feel free to contact me.

RE: Different Hotends

@karl-herbert

Thanks for all the help Karl. I may reach out in the future. Browsing his website, I noticed that image and understood what was being shown although I will have to determine where to find those magnets once I get to that point.

First things first though. I have ordered my replacement heater cartridge and the e3D V6 hotend kit. So hopefully my printer will be back up and running soon.