Bondtech Extruder for Prusa MINI  

RE: Bondtech Extruder for Prusa MINI

@cendrizzi

Go for it, you'll never look back, it's also also helped with the very light string I was getting as stock 🙂 

RE: Bondtech Extruder for Prusa MINI

I totally agree with @jeffnicol.  

My stock Mini worked great for about 15 hours total print time with multiple different models and then the nozzle(s) began to jam.  The first was the stock brass, then a couple of aftermarket brass nozzles and then a tungsten carbide nozzle which I had purchased so I could print glow-in-the-dark filament which is very abrasive.  Cold pulls were only a temporary fix.

With all of the nozzles I was only getting a few minutes of printing before they would clog. I had purchased both the Bondtech heat break and the Dual Extruder (to do flexible filaments) before the printer arrived and figured I would change them out after I got the hang of the Mini.  After the clogging started I just went ahead and installed both at the same time.  The Mini now prints with no problems.   As and example, I just finished the huge spider on Thingiverse (Giant Poseable Halloween Spider w/ Split Abdomen by HeroXero August 27, 2018 - sized to 90% to fit the Mini) where each of the five prints took between 7 and 9 hours, with NO clogs or other problems.  

Yes, you do have to insert the custom G-code in the slicer and after the warranty expires I will flash that into the firmware, but until then putting it in the slicer works fine.  I trust the Mini enough now to just watch to be sure the first layer goes down correctly, and then I let it go, even overnight.

The only thing I would have liked Bondtech to do was build in an exit port below the hobbed gears.  Over time there will be little bits of filament building up in the cavity and there is no place for it to go.  Sure, a blast of canned air will blow it out, but then it will go all over the room.  With a properly positioned hole, it would just drop out and could be routinely vacuumed up with all the other bits.

RE: Bondtech Extruder for Prusa MINI

I just got the Bondtech Heat-break kit. Hopefully, I'll have time this weekend to install it. I actually don't think I've had as many problems you @vazovsky. However, I have had mine fail at the nozzle jam several times for no reason.

RE: Bondtech Extruder for Prusa MINI

cendrizzi:  I think all of my issues with the nozzles were caused by the Prusa heat break. It’s poor design without the thin section of other hot ends allows the PTFE tube to get too hot and shrink slightly. It’s just enough that the melted filament sneaks around the end and the filament forms a bulb that once formed is cooler than the melted filament and partially jams the feed path. At one point,  I put the replacement tube that came as part of the spares and it worked .....for a few hours.  A properly designed heat break and the Capricorn cured the jams. 

Looking back on it now, it is possible that just swapping out the Prusa PTFE tube in the hot end with some higher temp rated Capricorn Tubing may well have done the same thing.  

RE: Bondtech Extruder for Prusa MINI

Dear all,

I am new to the hobby and unfortunately I have no one to ask, so please be patient with the following questions.

If I use both upgrades I will probably have to enter both codes into the PrusaSlicer. Does the order play a role or it is irrelevant which code is inserted first?

I have the MK3s in addition to the Mini and had a lot of fun with the setup and the prints are also perfect. Unfortunately this is not the case with the Mini, the printings are not that good as from the MK3s. That's the reason why I bought the Heatbreak Upgrade and the Feeder Upgrade (and I love to strip down the Machine too 🙂

Thanks for your support and feedback.

RE: Bondtech Extruder for Prusa MINI

Also I would like to know if changeing the G-Code for the Mini, does it affect the Profile of the MK3s too? As far as I understood this should not be the case....?

RE: Bondtech Extruder for Prusa MINI

@oliver-andre-u

I could also compile the latest firmware and removed  the appendix from the board.

But flash failed with "firmware signature verification failed!"

What am I doing wrong?

RE: Bondtech Extruder for Prusa MINI

@richard-alpert

You can create a separate start/end etc. code for each printer profile. Depending on which printer you select in the printer profile, the gcode settings of the printer will be active.

RE: Bondtech Extruder for Prusa MINI

@buy-uh,

this message always appears with a modified firmware. Just "ignore" and flash.

RE: Bondtech Extruder for Prusa MINI

When installing the Bondtech Heatbreak, should there still be a 0.5mm gap between the nozzle and heater block?  Or do you install the nozzle tight against the heater block?

RE: Bondtech Extruder for Prusa MINI

@tbn319

No matter which heatbreak you use, the nozzle must always seal flush with the heatbreak. There should always be a distance of about 0.5mm between the block and the nozzles hexagon.

https://help.prusa3d.com/en/article/changing-replacing-the-nozzle-mini_134235

RE: Bondtech Extruder for Prusa MINI

Understood.  I was confused by the instructions here ( https://support.bondtech.se/Guide/0.1+Heat-break+Upgrade+Kit/60).   Step 17 has you tighten the nozzle to the heatblock, then back it off 1/2 a turn.  Then Step 33 has you tighten the nozzle.  I thought that backing the nozzle off 1/2 a turn (Step 17) would create the 0.5mm gap.  Unsure if that gap still remains after tightening in Step 33.

RE: Bondtech Extruder for Prusa MINI

Curious question - why? To allow for hot tightening, or for thermal expansion of block?

RE: Bondtech Extruder for Prusa MINI

@crawlerin

If the threaded part of a new nozzle is e.g. 0.1mm shorter during a nozzle change, it is no longer guaranteed that the collar seals at the heatsink. 0.5mm offers enough security, but probably 0.2mm would be sufficient.

RE: Bondtech Extruder for Prusa MINI

@richard-alpert

have been printing with both upgrades.  Below in bold you can see the order I have them.  as far as I know, the order does not matter.

I always suggest to leave a comment explaining the change as in the examples in bold below

G1 Y-2.0 X179 F2400
G1 Z3 F720
M109 S[first_layer_temperature] ; wait for extruder temp
M92 E415 ; Bondtech ESTEP change for extruder upgrade
M301 P13.54 I0.98 D46.58 ; Bondtech Change for Heatbreak Upgrade

; intro line
G1 X170 F1000
G1 Z0.2 F720
G1 X110.0 E8.0 F900

RE: Bondtech Extruder for Prusa MINI

@bryan-b7

Thank you for your Information, this is a good Idea leaving a comment after each Line. Didn't knew that this is possible without disturbing the Codefunction.

Are you satisfied with the results? Which issues did you had and which of them has been solved with the upgrades?

Thanks for sharing.

RE: Bondtech Extruder for Prusa MINI

I just purchased a bondtech extruded and heatbreak. I’ll be printing Sainsmart TPU for drone parts  90% of the time so I figured it makes sense. I can print TPU now but cannot get rid of that last little bit of stringing. 

RE: Bondtech Extruder for Prusa MINI

@oliver-andre-u

I made an adapted version of bondtech feeder, compatible with BMG parts and save old connections.

https://www.thingiverse.com/thing:4655132

RE: Bondtech Extruder for Prusa MINI

@f12ank_pelayo

I'll be interested to hear about your experience with stringing post upgrade.

RE: Bondtech Extruder for Prusa MINI

I received my Mini second week of October 2020. I am mainly printing drone parts (TPU,) so I had preemptively purchased the extruder, and heatbreak. I believe I have over 20 hours printing accumulated now, and I am really impressed. I have not installed the Bondtech parts, and the printer seems handle Filamentum 98A beautifully. Sainsmart TPU prints kinda look like the filament does on the spool, imperfect. The Filamentum however appears perfect on the spool, no kinks, bends, etc., and results in beautiful prints. There is minor stinging that I personally cannot consider an issue, and some of it may even result from a less than optimal slice job. I am a noob, but I have no problems with the clean up of light stringing, and I am getting better with the slicer.

A bigger challenge has been unreliable bed adhesion, resulting in minor curling at the base. This is my environment I believe, drafty, and I plan to address it with an enclosure. Zero distance skirt/brim of 4mm, and 3 layers has addressed the problem almost entirely, for the time being.

My only real pain is removing TPU support material. Thankfully the latest beta of PrusaSlicer has some impressive controls for designating support enforcement/block zones. This has allowed me the chance to minimize extraneous supports on a print. Ill add that I've had some TPU prints with pretty big overhangs, as well as minimal surface area in contact with the print bed, come out looking just excellent. For me, this result really gives the machine a sense of magic, or science fiction, as it's printing these objects practically into mid-air. Fascinating!

I wont soon be installing this alternative extruder, and heatbreak because I don't have any issues with my prints. For the sake of contributing data to the thread, I very much would like to install them, but I won't do this until I have a clear picture on how to confidently return it to the original configuration (should I desire,) after testing. You can be sure that when I achieve this, the first thing I'll do is post some photographs of actual prints from each configuration for comparison. This thread is a little light on evidence, and that's mainly what I'd prefer to see here. If there were more photos, it would establish something of a standard with which I could compare my own results. I may not personally have a problem with my print quality, which i would call excellent in comparison to some TPU parts I previously had to purchase, but having a standard established by other actual users of the same device, for comparison, I might then find some critique with my prints. For now though, I'll just be pumping out the prints. I got this to assist with existing projects, rather than add it to the current list of them, and I feel I received what I expected.  ..actually better than expected, because I thought Id have to tinker to print with FLEX materials.