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Prusa MINI: Smart and compact 3D printer

blog.prusaprinters.org

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Re: Prusa MINI: Smart and compact 3D printer

#51

Post by _jal »

alphagrep12345 wrote: post #17

Why does everyone need a 3d printer? Maybe this statement would sound as ludicrous looking back as asking why does everyone need a PC in the 1980s. However, I still don't understand why would a regular person need a 3d printer? Mass marketed goods are always cheaper due to economies of scale. And would you really want to put in the effort to make your own chair, etc?

> Why does everyone need a 3d printer?

"Everyone" doesn't. If you don't make things, don't buy tools.

Metaphorically, you're comparing buying a radio to buying a piano. If you just want to listen to music, buying a piano is a very inefficient step to your goal.

Re: Prusa MINI: Smart and compact 3D printer

#52

Post by m0xte »

jrockway wrote: post #48
m0xte wrote: post #45

Earlier quoted context omitted.

Note: former EE. I’ve taken it and the provided power supply to bits before I even fired it up. 1. They’re IRLR3103PBF operated within their SOA. They’re fine. Most MOSFETs fail short due to the construction of the MOSFET. I’ve actually got a few scars on my arms from the buggers exploding on me misusing them on purpose as RF PA’s as a ham. I’ve seen them blow up in various bits of expensive US made kit too (tektroni…

I think he is referring to a step motor controller as a "stepper". People love the fact that Prusa uses Trinamic drivers instead of no-name drivers. I personally don't understand why step motor control is something that needs to be outsourced. Just stick an H-bridge between the microcontroller and the motor and improve the control algorithm with every release.

The “no name” drivers are a bit more complicated than an H bridge: https://www.pololu.com/file/0J450/a4988_DMOS_microstepping_d...

The typical H bridge has many failure modes and disadvantages which are handled by the controller ICs. Not to mention a lot less CPU overhead for the AVR running the show.

Re: Prusa MINI: Smart and compact 3D printer

#53

Post by Causality1 »

alphagrep12345 wrote: post #17

Why does everyone need a 3d printer? Maybe this statement would sound as ludicrous looking back as asking why does everyone need a PC in the 1980s. However, I still don't understand why would a regular person need a 3d printer? Mass marketed goods are always cheaper due to economies of scale. And would you really want to put in the effort to make your own chair, etc?

Even as a person with zero 3D modeling skills, I like making a printer because it lets me make little knick-knacks of things that aren't popular enough to warrant actual toys but someone bothered to model and put up on Thingiverse.

Re: Prusa MINI: Smart and compact 3D printer

#54

Post by j-pb »

jrockway wrote: post #50
j-pb wrote: post #8

I'm glad that prusa has stayed true to his open hardware pledge all these years, while continuing to push the reprap ideals. Everybody is complaining about the price, but c'mon this thing is designed printed and assembled in Prague, the EU. It creates local jobs for people with fair wages, social security and good quality of life, we should strive to have more of our stuff produced in the west. Happy to see him desig…

The price seems fine to me. This is going to print a lot of useful parts for people and comes with great software for both your computer and the printer that you can hack and modify. If this is anything like my i3, then it's going to have high quality parts (Noctua fans!) and come in kit form to let you assemble it yourself so you know where everything is if something breaks and you need to repair it. I am surprised…

My guess is that driving that big color display and more importantly ethernet/ip stack would be a huge PITA on an 8bitter.

Re: Prusa MINI: Smart and compact 3D printer

#55

Post by 2muchcoffeeman »

m0xte wrote: post #45
crankylinuxuser wrote: post #35

Earlier quoted context omitted.

Yeah, except for the things you can't see. 1. They use crappy MOSFETs that are known to fail closed. This means you can get a runaway heat on your hotend. A 40w cartridge can melt the alu heatspreader 2. The beds are anemic for heating. Not enough power 3. Crappy steppers 4. No features for jam detection, autoleveling, skipped step protection, filament runout 5. "Chinese" quality: good luck in getting any sort of tec…

Note: former EE. I’ve taken it and the provided power supply to bits before I even fired it up. 1. They’re IRLR3103PBF operated within their SOA. They’re fine. Most MOSFETs fail short due to the construction of the MOSFET. I’ve actually got a few scars on my arms from the buggers exploding on me misusing them on purpose as RF PA’s as a ham. I’ve seen them blow up in various bits of expensive US made kit too (tektroni…

This sort of attitude ignores the fact that a lot of people would rather spend time designing things and prototyping, rather than fix their printer.

I had the experience of getting and assembling a Prusa MK3 kit for myself, and getting access to a cheap Chinese printer at roughly the same time.

The Prusa cost more than twice as much and I've already made upgrades. Worked correctly right after assembly. I've already gone through several kilos of successful prints. And the frills just make it so much nicer to use: spring steel bed, auto mesh leveling, the Prusa fork of Slic3r just keeps getting better and better.

The Chinese printer required you to attach the gantry to the bed. But after weeks of tweaking. It still doesn't work correctly. It's completed prints. But none of them have been of decent quality. Now, some of the Chinese printers appear to be good. But do yourself a favour and research the specific models if you want to buy one.

Otherwise, if you really care about designing and prototyping, spend the extra cash and spend more time making things. There are a few brands out there. I reckon Prusa has the best kits if you swing that way.

Re: Prusa MINI: Smart and compact 3D printer

#56

Post by drudru11 »

j-pb wrote: post #8

I'm glad that prusa has stayed true to his open hardware pledge all these years, while continuing to push the reprap ideals. Everybody is complaining about the price, but c'mon this thing is designed printed and assembled in Prague, the EU. It creates local jobs for people with fair wages, social security and good quality of life, we should strive to have more of our stuff produced in the west. Happy to see him desig…

Price seems totally reasonable to me. Whenever I research the cheaper printers, I read about all the upgrades people have to implement. This ends up costing more time and $$.

Re: Prusa MINI: Smart and compact 3D printer

#57

Post by kbob »

tpmx wrote: post #39
jrockway wrote: post #38

Earlier quoted context omitted.

Dogfooding is valuable. If there is a fundamental flaw in their printers, they're going to find out about it firsthand. It is also nice to know that I can print replacement parts and that my replacement is pretty much identical to the original.

Sure, but they've kept doing it for many years now. At some point it shifts into some kind of "religion". Or, judging from your response, it's a part of their brand?

Keep in mind that the printers are getting regular upgrade cycles. A 2019 i3 MK3S is nothing like a 2015 i3. Firmware upgrades are released every couple of months. So continuous testing is still valuable.

Re: Prusa MINI: Smart and compact 3D printer

#58

Post by jrockway »

j-pb wrote: post #54
jrockway wrote: post #50

Earlier quoted context omitted.

The price seems fine to me. This is going to print a lot of useful parts for people and comes with great software for both your computer and the printer that you can hack and modify. If this is anything like my i3, then it's going to have high quality parts (Noctua fans!) and come in kit form to let you assemble it yourself so you know where everything is if something breaks and you need to repair it. I am surprised…

My guess is that driving that big color display and more importantly ethernet/ip stack would be a huge PITA on an 8bitter.

Yeah, I posted a few comments here without actually watching their marketing video, and didn't realize it had those two things. Upgrading to get those features seems like a good idea, to compete with the cheaper models.

I don't think I would have engineered a new board and control stack just to get a web interface and a screen. Their last model (the i3 MK3S) has headers to accept a Pi Zero, and that seems like a good approach modulo the bugs, which would be worth fixing. (Apparently the bugs are, the Pi Zero isn't fast enough to emit gcode to the UART and record a video stream from a camera at the same time. I kind of doubt it, but that's what I'm told. The other problem is that the i3 has one power switch, so it can't keep the RPi on when the printer is powered off. This means a lot of people are corrupting their SD card, which is probably why they complain about the setup randomly breaking.)

I just want a USB serial port that accepts gcode. I have plenty of computers with much better screens (and SSL stacks) around for doing something more powerful ;)

Re: Prusa MINI: Smart and compact 3D printer

#59

Post by dang »

omnimus wrote: post #36
dual_basis wrote: post #31

Earlier quoted context omitted.

Maybe, but quality is hard to measure. I just bought a Creality Ender 3 Pro for $180 and the print quality looks as good as anything I've seen from a Prusa or even the Ultimaker at my university. It's got a larger build volume than this mini as well. It doesn't have some of the comfort features, such as auto bed leveling or wifi, but if you really want these you can add them in and still be under the price of this mi…

Is this Creality Ender 3 Pro marketing team?

The site guidelines ask you not to post like this—would you mind reviewing them?

https://news.ycombinator.com/newsguidelines.html

Re: Prusa MINI: Smart and compact 3D printer

#60

Post by jrockway »

m0xte wrote: post #52
jrockway wrote: post #48

Earlier quoted context omitted.

I think he is referring to a step motor controller as a "stepper". People love the fact that Prusa uses Trinamic drivers instead of no-name drivers. I personally don't understand why step motor control is something that needs to be outsourced. Just stick an H-bridge between the microcontroller and the motor and improve the control algorithm with every release.

The “no name” drivers are a bit more complicated than an H bridge: https://www.pololu.com/file/0J450/a4988_DMOS_microstepping_d... The typical H bridge has many failure modes and disadvantages which are handled by the controller ICs. Not to mention a lot less CPU overhead for the AVR running the show.

Yeah, you can get some feedback from the controllers easily (and then omit physical endstops).

I am waiting for a 3D printer that uses servo motors, though. So many failed prints come from not knowing where the extruder is. But you can just measure exactly where it is, rather than guessing based on how much current the motor used.

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