Which Prusa to choose for 400+ hours of monthly printing  

RE: Which Prusa to choose for 400+ hours of monthly printing

Frankly, after a few weeks of using my new Mk4, I'd go with another Mk3s+ if I were you. While I like a lot of things about the Mk4 — like the much improved access to the nozzle — I'm not super enamored with the "always perfect" first layer. Maybe true for PLA on a smooth sheet but in my hands I have to babysit it for PETG on satin or textured sheets (which is most of my usage) and manually adjust live Z. I hope a future firmware upgrade will address this somehow  

I also love my Minis but would rather get the Mk3 for the build volume. But you can't get a Mk3 or Mk4 with Prusameters… 😢

RE:

As far as nozzles are concerned, I have tungsten carbide on all my Mk3s and Minis, with Dragon hotends. On the Mk4 I now use the Obxidian nozzles (bad experience with TC and the nozzle adapter). Will hopefully last as long as the TC nozzles, i.e., forever. 

RE: Which Prusa to choose for 400+ hours of monthly printing

Go for mk3 we all know there super reliable and you can connect octoprint with ai fail detection if need be for spare parts I'd go heater block thermistor heaters and nozzles oh and a spare print sheet

Posted by: @ralfr68

Hi there,

allow me to share my thoughts and ask for advise. I am setting up a small business and will need to constantly print a volume of about 20 hours per working day (PLA only). I use my Prusa i3 MK3 for 5 years now (with only few printing hours per week) and I am more than happy with it. For redundancy (and to have a spare printer for further development), I will need to buy a new printer (or two). In future I cannot afford to have a downtime of more than a week. (And I don't want to look into other brands, since I am 100% satisfied with Prusa). 

My first question is, which model I should choose for this "non-stop" job. I would LOVE to go for the MK4 (newest model, yeah!) or two Prusa MINI+ (two Mini are about the price of one MK4, and together they should have a similar throughput). If I buy two Mini, failure of one printer does not completely stop my manufacturing while waiting for spare parts. Which way would you go?

And my second question is, what tear and wear should I expect in this extreme workload? I mean, I did not have a single failure on my MK4 so far, but with 400+ printing hours per month, I think I should order some spare parts upfront. Some Nozzles, okay. But what else? Is there some common calculation like "a printbed lasts 12345 hours, the heatbed is good for 54321 hours, etc.)"?

Thanks for sharing your thoughts!

-Ralf

what tear and wear should I expect in this extreme workload?

This isn't an extreme workload, it's under 60% average duty cycle; the default state of a 3D printer is - printing.  Prusa's own print farms run at a much higher duty cycle and looking back my own Mk3 averaged over 40% for the first three years.

Mini's appear to be almost as reliable and I would expect both the Mk4 and XL to be similar in the long run but of course its too soon to be sure.

With ordinary PLA you would use about two brass nozzles a year.  My original smooth buildsheet is still useable if a little scruffy 'though I have others now.  The parts that have failed most?  I have had to replace three belt-idler bearings in five and a half years at roughly 33% use and I am now on my third hot-end PTFE tube.

As you are used to the Mk3 printers I would suggest buying one or two more as kits - the price has dropped since you bought yours.  The only advantage of the Mk4 is that it is slightly easier to use and significantly faster - but the extra speed is likely to be at the expense of part strength so unless your product is purely decorative you probably wouldn't be taking much advantage of the speed.

With two or three machines of the same model you can keep a common pool of spares or even canabbalise one to keep the others going in emergencies.

Cheerio,

RE: Which Prusa to choose for 400+ hours of monthly printing

Posted by: @fuchsr

As far as nozzles are concerned, I have tungsten carbide on all my Mk3s and Minis, with Dragon hotends. On the Mk4 I now use the Obxidian nozzles (bad experience with TC and the nozzle adapter). Will hopefully last as long as the TC nozzles, i.e., forever. 

If you have trouble with TC nozzles getting loose on the V6 adapter, maybe  a nickel plated copper nozzle with a TC insert would be the solution ?. I purchased a couple of these from Triangle labs for my MK3S+. So long, they work as well as a nozzle made totally from TC. I print often PA-CF and I haven't noticed any wear on the tip. No need to recheck the Z offset of the first layer every now and then.

On the other part, Obxidian nozzles are basically copper nozzles with a hardened steel insert. They should last forever printing non abrasive filaments. If you print abrasive stuff on a regular basis, it's a different story. Nozzles with TC, ruby or diamond tips will outlast hardened steel by a long run.

RE: Which Prusa to choose for 400+ hours of monthly printing

Thank you all for sharing your thoughs! I think it will be another MK3 to team up with my existing MK3, and later that year I would add a MK4 when it gets a bit cheaper. This way I have two MK3 work horses for production, and a MK4 for new development (and to help out if a MK3 should fail).

Cheers

RE: Which Prusa to choose for 400+ hours of monthly printing

^^ Sounds like a good plan.