HewlettHackard

This looks great! I’m super happy with my MK4, and have never had to do anything with it after the initial kit build and re-seating the LCD cable to fix some early screen-blanking issues.

I’ll probably skip this for my own printer since it seems like most (but not all) of the speed up comes from layer height, but $99 is not terrible for anyone who gets value from it. And anyone buying a new printer gets this stuff with no price increase, which is nice and makes the MK4/MK4S even easier to recommend.

I didn’t know how much more dimensionally accurate Prusa’s prints are compared to the competition, but it makes sense now why there are so many calibration models online if that just isn’t the way every printer works. I’ve designed some parts that need an 0.1mm first layer because I’ve never had any failures with that, but I guess if I share the STLs other people might have trouble.

Did you end up trying something?

I do think it’s important to be unassailable, because it’d be easy to say “the libs are making misleading claims” and then people not paying lots of attention will think there’s a “both sides” situation going on. I’m sure we all assumed it was literally on display as an exhibit; I was mislead. If you stick to transparent, honest language, the “both sides” stuff falls apart.

The MAGAs are unreachable, but the poorly-informed are out there too, and making them easier to confuse (by actually also spewing misleading-but-technically-true things) is not a good strategy.

Maybe, but that’s still insincere. When truth is on your side you don’t need to use weasel language.

It was sold in the gift shop, not on display. I know it’s not an enormous difference, but let’s try our best to keep the misinformation just on their side.

The best I have is to be careful to minimize dependencies, and minimize when I change the number of faces an object has, but of course that’s unavoidable sometimes. I don’t buy it that all CAD tools have the same problem or that this is how real professional CAD designers would work, though.

To minimize dependencies for example, instead of drawing the sketch for pad 2 directly on a face of pad 1, I might draw it on the base plane and transform the sketch to line up with pad 1’s face. The main consequence is that I need to manually move pad 2’s sketch if I change the size/position of pad 1. It’s a tradeoff, because I’m giving up some of the benefits of parametric CAD in exchange for easier fix-up.

I agree, mapping a datum plane to a face should have the same topo naming issue as just drawing on the face, so I don’t know why the guide would suggest that. The comment below about mapping datum planes to a simplified skeleton is interesting though.

The good news is that the next release (which sounds imminent) apparently improves it quite a bit.

They definitely don’t know what they’re doing. They featured this one, which is a death trap. It has a disclaimer that it might not be safe above 120V, but it’s absolutely unsafe and a code violation in the US, where we use 120V (and are very litigious). The disclaimer says they’re trying to get it approved which implies they believe it could be and that the design is sound, but fundamentally it cannot meet code in the US for mains voltage use.

Even if the design were sound, there are material requirements, and having seen the quality of prints some people find acceptable, there’s no chance allowing random people online to print their own boxes is safe.

I think they basically run the contests and feature things based on “ooh this is neat” and “this will excite people to use 3d printers”. It’s a marketing thing, and I guess I accept it because I have low expectations of even pretty-good businesses. But if it’s illegal…someone should probably let them know.

I don’t think I’d really view it as a typical first gen product; Kralyn has been working on it for quite a while and first showed it off 3 years ago. I saw a demo of LDO’s V3.2 at a RepRap Festival and it looks pretty solid.

I haven’t watched the videos in quite a while but I’m sure there are demos of bed leveling, which would be my only real concern with unpacking and repacking it frequently.

That said, since I haven’t owned one myself I can’t say “you should buy this!!1!”. Do you have the budget and time to start with another less-portable model at home to confirm you’re really into printing enough to spend the money on a positron? You don’t need a ton of space to store a Prusa MK4 when it’s not in use, and the robust frame plus fantastic bed probing mean there’s no calibration required after moving it.

If you think about bed adhesion, the forces on a light plastic part from gravity are negligible. Think of how much force it takes to pop a finished part off the bed compared to the weight of the part. When you have adhesion problems, I’m sure the plastic shrinkage is causing pretty large forces (or on a tall part the nozzle bumps the top of the print and has a long lever arm to pry the part off the build surface).

I haven’t bought used myself, but based on my own experiences with my printer (MK4; I love it) I don’t think there’s a ton to worry about buying a used quality printer. I would not buy a used low-end printer because the odds are much higher that the seller found it frustrating.

A used Prusa MK3S is probably an excellent choice if a Prusa MK4 kit is out of your budget and a Bambu printer is out of your budget or doesn’t meet your other requirements. The seller probably either realized they don’t actually print often, or upgraded to a MK4 (or XL if they had the budget). While you can upgrade a MK3S to MK4 with Prusa’s upgrade kit, the cost of the kit is so close to just buying an MK4 that it’s not worth doing (and Prusa admits this; they only offer it because of the flak they got for not doing such a kit in the past). The MK3.5 or 3.9 upgrade kits could make sense for some people…but in many cases someone looking to upgrade would likely leave the MK3S untouched and just buy an MK4.

Do you want the printer to be a tool, or a hobby (i.e. you don’t mind fiddling with the printer itself to improve the results, you don’t mind spending more to upgrade components, etc)?

If the printer itself is a hobby you can go cheap, but if you want something reliable you don’t have to mess with or upgrade, I’d suggest getting something as nice as you can afford, maybe a Prusa mini or Bambu A1 mini if you don’t care about open source. Also consider something like a used Prusa Mk3.x.

You’re affecting the hardness of the metals if you’re heating them to glowing point, because you’re heat treating them. The actual consequence is probably minimal, but you could potentially be softening the brass tip which could affect the rate of wear. From skimming a few random online sources, brass is only work-hardened, so if the nozzle was previously hardened, you’re un-hardening it (apparently quenching from high heat only hardens ferrous metals like iron and steel?).