Buying one i3 MK3S+ or two mini to produce 9kg of print reliably  

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

Not an exact answer to your question, but FWIW I burned through more than 10Kg of PETG during the COVID PPE printing push earlier this year. My Prusa Mk3 was and continues to be a workhorse, working 24x7 without major issues. Watching it over video as I fell asleep and checking on it during the night was part of my routine, and I never had to scramble to deal with a problem in the middle of the night. I have a special fondness for the Mk3 based on its having not let me down even as other users with more expensive machines fell by the wayside. Other folks I was helping with Mk3s were similarly able to maintain production throughout the period.

I did take it offline briefly for lubrication and maintenance, but otherwise did nothing special. The Mk3 is a robust and reliable design.

That said, it is nice to have a second printer to fall back on. I don't have experience with the Mini myself, but reading through various threads here, it does sound like it needs more periodic maintenance (PTFE tubing, etc.)

I wound up with my Original Prusa i3 Mk3 and a cheap(er) Artillery Sidewinder simply because it was what I could get my hands on quickly. The Sidewinder is slowly being made into a reliable printer, but it was offline for a couple of critical months due to design and QA issues. A Mk3 and a Mini pushes your budget but might be worth considering, particularly if you're OK building kits.

I would recommend keeping spare hotend components on hand in case you end up with a Blob of Doom scenario. This would apply with any printer.

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

It basically boils down to how much time you have. For the sake of argument, let's say each piece takes one hour. If you have 100 printers (like Joe!) you could theoretically do it in an hour (after setup time). 50 printers, 2 hours, etc. If you can get 8 instances on a MK3 bed, it will take 100 hours. If you get 4 instances on each of two mini beds, it will take 50 hours. So now you have to analyze  bed size vs. future projects. If you think everything you might need to print after this project will fit on a Mini, definitely go for two Minis. If you will need the larger MK3 bed, go for it. A word of caution about multiple instances on either bed: If something goes wrong seven hours into an 8 hour/8 instance build, you have lost the time AND the material. Better, if you can space the instances appropriately to select sequential building. This takes some careful spatial planning, but may be useful. You will likely be able to place fewer instances on the bed, but you will only lose the time/material after the fault occurs, hopefully later in the job. It may still produce a spaghetti monster, of course. Has anyone ever built a spaghetti sensor that works? This also assumes you are starting the build and going to bed. If you can monitor the build in the daytime while doing other things, this concern lessens as you can still "save" instances that have completed building.

I REALLY wish Joe would come up with a dual extruder in the MK4 (?). With the same filament in both extruders you could print eight instances in four hours (with appropriate changes in the printer F/W and the slicer.)

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

What time constraints do you have?

If the build fits onto a mini, theoretically, you could print the models in half the time, by having two printers running simultaneously. However, given that the MK3S+ has a leadtime of 3-4 weeks, whereas the Mini+ has a leadtime of 9-10  weeks, getting the MK3S+ would net you 5-7 weeks of print time, before the Mini+ would even arrive.

As it stands right now, the Mini+ Firmware has enough features to function, while lacking many of the QOL features, the MK3S+ has. (Saving z-offset for textured and smooth PEI sheet, instructions during a print pause (e.g. insert 4x bearing),  total print time counter, etc.)

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

@teachtheprints

Excellent points. I had not considered the basic procurement times.

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

If I were you (but I'm not) 😉 I would get a single MK3S+ and use the Creality as a second and backup unit.

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

I have two MK3S and they are just fabulous, can’t compare to a mini as I haven’t got one.

I got curious about your choice of filament. I use almost exclusively addnorth’s filaments and find it to be extremely reliable, more so than any other that I’ve tried.

Have you used that textura filament? How was it?

I have been discouraged to try the textura filament because of their  ‘print quality guide’. I paste below:

• Nozzles: It works with standard nozzle size of 0.4mm, but it is recommended to use 0.5mm or bigger to avoid clogging issues. If you are printing big objects (5h+) with a small nozzle (0.4mm), it is important to print at the lower end of the temp spectrum (185-190°C), keep retractions at a minimum and turn off the fan. The material is not abrasive on metal nozzles, and can be printed on standard nozzles.

Misc: Remember to clean out the nozzle after the print to get rid of any fiber residues, and to keep the filament dry. Also, make sure the surrounding temp is not too high, 20°C is optimal. At 25°C+, some problems can occur.

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

Well I would contract some People who still have and know how to use a 3D Printer.

When you need them commercially the quality counts to.

RE: Buying one i3 MK3S+ or two mini to produce 9kg of print reliably

Thank you very much for your input. I ended up ordering two Mini+ with the expectation that I may be faced with sudden bursts of demand. Obviously I would love to add an MK3 to the "farm" but I guess I have to stay reasonable with the budget 😉 

@micke: I tested the filament on  my Ender 3 Pro with a 0.6mm Nozzle. The reason for using this particular filament is that I want to achieve a pleasing surface both to the eye and to the touch without post-processing (to save time). I tested PLA with XTC-3D before, but wasn't satisfied with the result and it took me way to much time to add two layers of it on every casing. The Add:North Textura is right from the print-bed beautiful to look at and to the touch. Unless you look very closely, you don't see any layer-lines and the rough surface has a bit the feeling of a natural material like wood or leather.