What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)  

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

This is a great question and I have been wondering about this as well. Will be interesting to see what the experts say. I was thinking about spares for the parts that take the most wear and heat. perhaps:

Belts, nozzle, thermistor (due to the small wires and risk of damage when cleaning up Blob events), heater element

And I would print the "printable parts" set, while everything is working well.

Tom

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

If your pretty novice I'd recomend you buy the complete hotend built. Otherwise nozzle, thermistor, heater cartridge. As for the rest id say fan shroud, both fans, plenty of spare hotend ptfe tube, mmu data cable, belts if you do alot of printing,  heatbed thermistor, bearings and a spare pinda

Posted by: @chewie

Hi all

So I'm nearly 2 months into my 3D printing journey & it dawned on me today that I currently have no spare parts, other than what came with the printer & MMU3.

I think this is maybe a 2 part question really...

1. Which of the printed parts should I print to save buying on failure? Should I just print them all? Is there any I should have multiple of?
2. What purchase only parts should I keep? How many of each should I have?

I'm in the UK which appears to make life a little more complicated than expected for spares, so ensuring I have a good range of spares at home seems a good idea. I've found a few resellers & ebay shops for parts in the UK, but I think especially for the immediate future I'd like to keep things stock Prusa for now, just while I become a little more experienced with my new toy. I had a problem with a thermistor when I first got my printer, so I'm keen not to end up with substantial down times waiting for parts to arrive, so buying a few essentials now seems sensible.  

Many thanks

 

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

Posted by: @chewie

I think this is maybe a 2 part question really...

1. Which of the printed parts should I print to save buying on failure? Should I just print them all? Is there any I should have multiple of?
2. What purchase only parts should I keep? How many of each should I have?

I never bothered keeping spares for the 3d printed parts. However after 6 years fairly heavy operation the orange parts in my Prusa MK2 kit became really brittle. Some of the pieces snapped (like the z-axis holder) and I could literally crush parts in my bare hands, easier than crushing a beer can. I reprinted them in PETG and replaced them one-by-one. The printer chugged along until all the orange parts were replaced like the ship of Theseus. I wouldn't bother reprinting plastic parts until they break; in my experience the printer kept working even with some broken parts. The bed-slinger design is incredibly tolerant. 

For non-printed parts I keep spare nozzles, heaters, thermistors and belts. Except for nozzles I can't remember replacing any non-printed parts. The MK2 is a freaking tank. But nozzles do wear out and need to be replaced fairly regularly.

Keep spares of the spring steel sheets. I no longer use Smooth (aka PEI sticker) sheets. I only use powdercoated PEI sheets either Textured or Satin. The sheets do get scratched even if you baby them.

Keep spare bolts, nuts, magnets, bearings, etc. These get used for other projects too, not just for the printer, so buy 100s of each at a time. It's much cheaper when you buy in bulk from aliexpress.

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

Thank you for the replies so far, that's great. I'll start to put a list together at some point this week & post it up to see what has been missed off!

My Mk3 is coming up to 6 years old it has been printing over 30% of the time.  It has been extremely reliable and has needed very little attention. Inevitably the day my XL arrived it produced the first, small, blob-of-doom in over a year, so:

The most useful part to print in advance is a fan shroud, PETG is not ideal close to the hot end so these days I use Bio-Pro from 3DTomorrow.

I have replaced two idler pulleys and I have another spare in stock.

I have reprinted one idler carriage but the failure was slow and I printed the new while using the old.

One stepper motor failed, (an internal bearing collapsed), I consider this unlucky and unusual, it's not worth keeping spares.

And two print fans 'failed' - I replaced one then learned how to lubricate and rejuvenate them so now I have a part-used spare.

You will wear out nozzles, reckon on two a year, more if you use abrasive filaments.

You will eventually wear out or damage a print sheet but they have two sides so when the first goes you use the other side and order another.

And, not a part, print a belt tension meter to aid maintenance.

Cheerio,

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

Much useful input in this discussion. One thing I did not think of  checking - there is a "Spare Parts" kit in the PRUSA store.. Not surprised

I did not realize that some of the printable parts should not be made with PETG. Also I was surprised to hear that some of the Orange parts became brittle, although after 6 years. So I will be printing them and storing them for much later.

Thanks,

Tom

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

The first thing I did when I got a little good was print all the parts for my print head out of ASA.   A few months later, my print head went into a thermal runaway and melted the head.  Prusa sent me a new hot end under warranty but I used my ASA printed parts.  I had changed the fan shroud and that was partly damaged at the time.  My super Pinda was also damaged by the heat.  It took about 3 weeks to finally get a new one under warranty.  It passed the simple tests but I couldn't get an XYZ calibration to complete.

I have had my printer since March last year.

I have not even put my MMU2 together yet and am now printing the parts for the upgrade before doing it as part of my experience.

I now have spares for the hot end but will upgrade to a better hot as I get better.

RE: What spares should I carry for a Mk3S+ & MMU3? (Very inexperienced user!)

If you do not put a complete hotend aside, you might consider having a spare heaterblock (I use the nickel plated copper block from E3D), a heatbreak (I opted for a titan one), a heatsink and its collet. They helped me with heat creep. Apart from that, I once snapped a standard heatbreak at work when changing a nozzle. Its upper half was firmly baked into the heatsink, the lower thread in the heaterblock. The heating cartridge was also baked into the heaterblock. Fortunately, we already had the 3 parts as spare. I broke the block open to get the cartridge out, so that I did not have to fiddle with the cable bundle in order to change cardridge or thermistor which were both intact. For the grub screws of cartridge and thermistor a tiny bit of copper- or ceramic paste from the local hardware store.

Depending on how well your x-axis is lubricated and aligned, you might like to have a spare smooth rod for the x-axis apart from the linear bearings. I also once had a groove in the upper rod.

Some zipties of the original size.

As for the MMU: I just have the MMU2. One of its weak points some user reported was the left stud for the bearing. Mine held together though. I also drilled tiny holes coaxial to the holes for the 5 bearing axes in the idler, so that I can get those out with a pin if needed without breaking up the whole idler.