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Peachy Printer - The world's first $100 3D Printer

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Re: Peachy Printer - The world's first $100 3D Printer

#31

Post by kevingadd »

anigbrowl wrote: post #21
kevingadd wrote: post #7

I wonder how much error is introduced by the use of the headphone jack to drive the printer - you've gotta deal with line noise from the computer's sound card, mixing latency/glitches from the OS, and the device sampling rate, along with any noise introduced on the audio cable. Does a 3D printer like this not actually require high-precision data to work correctly?

Line noise is a bit of an issue, but that's usually quite high frequency which means it can either be filtered or that the errors will be correspondingly small. Latency and glitches are not likely to be an issue at all, even the crappiest computer nowadays can handle multitrack audio and delays of a few milliseconds that would interfere with music performance are not going to have any impact here. Likewise sampling r…

Thanks for the points on how trivial it would be to handle line noise and playback glitches. Makes sense to me; I just don't know my hardware and analog circuits well enough to know how cheap it is to filter that stuff out.

Re: Peachy Printer - The world's first $100 3D Printer

#33

Post by maxerickson »

kevingadd wrote: post #13
SwellJoe wrote: post #12

Earlier quoted context omitted.

Audio output of modern computers is high precision. 16 bit resolution is pretty damned precise...even once converted to analog. I'm certain the mechanical parts being driven by it is a much, much, larger source of errors than any decent computer output would be. That said, there is measurable and audible differences between a stock audio output and a high end (or even prosumer) audio output. A nice 24 bit audio box c…

I'm not referring to 16 bit precision per sample, more to 44khz and the potential for multi-millisecond audio glitches on most modern PC configurations. Glitch-free audio is pretty tough, still.

Looking at the videos, a few milliseconds would correspond to ~1 drip, maybe 2. It isn't going to introduce a real significant flaw in anything.

Re: Peachy Printer - The world's first $100 3D Printer

#34

Post by jimktrains2 »

scotty79 wrote: post #29

Awesome idea. But isn't mirror inertia a problem? Also constant velocity of z-axis movement might pose some inefficiencies because if you want to print a box you have to set the rate of ascend low enough for the laser to create full bottom and you can't speed up when you are building sides of the box.

My wager is that, especially for this initial release, that's being tossed into the sure-but-adds-complexity bin. Perhaps later versions will have a variable drip rate to speed up the process, but the complexity isn't needed in this version.

Re: Peachy Printer - The world's first $100 3D Printer

#35

Post by maxerickson »

scotty79 wrote: post #29

Awesome idea. But isn't mirror inertia a problem? Also constant velocity of z-axis movement might pose some inefficiencies because if you want to print a box you have to set the rate of ascend low enough for the laser to create full bottom and you can't speed up when you are building sides of the box.

It's on a feedback loop, so you could probably manually twiddle the water valve to speed it up.

Re: Peachy Printer - The world's first $100 3D Printer

#36

Post by codehero »

I really like it and its entirely analog nature is refreshing. It makes sense to set aside something like a raspberry pi for it (I would never use a PC, especially on update tuesdays. And I would not want to set my PC audio to full blast so the output swings the full +-2.5V).

Mechanically delicate though. Vibrations disturbing the surface of the liquid will skew the print and cause poor layer adhesion. And you have to make sure your surface is perfectly level.

Re: Peachy Printer - The world's first $100 3D Printer

#37

Post by oakwhiz »

anigbrowl wrote: post #25
kevingadd wrote: post #13

Earlier quoted context omitted.

I'm not referring to 16 bit precision per sample, more to 44khz and the potential for multi-millisecond audio glitches on most modern PC configurations. Glitch-free audio is pretty tough, still.

That's not true at all and hasn't been for a long time. Maybe if you're mixing more than 8 tracks on a low-power CPU, but even a chromebook can do that sort of thing. Even my phone (several years old) can do that. Playing back stereo audio (which all that's required here) is something that can be done from a device that fits on your keyring. What you're arguing hasn't been true since the 90s. Certainly, it would be b…

I disagree on the premise that audio glitches can and do happen on non-realtime operating systems due to the lack of guaranteed scheduling. For this 3D printer, it doesn't really matter, but for a lot of other things, I would feel uncomfortable trusting a desktop PC soundcard, OS, and drivers to perform glitch-free audio I/O. I would much rather send self-clocking commands from a PC to a hardware device which takes care of the realtime task on its own.

Re: Peachy Printer - The world's first $100 3D Printer

#38

Post by DanBC »

> The software we wrote as an add on to blender takes the data from that 3D model and translates it into an audio waveform. It then plays the audio file out to the printer through the headphone jack in your computer. This waveform drives a pair of electro magnetic mirrors. The higher the volume, the higher the voltage, the more the mirrors move. The purpose of these mirrors is to reflect and control the path of the laser beam. By using the audio waveform generated from the 3D model data to drive the mirrors, we are able to get the laser beam to draw out the shape of the object. That's takes care of the X and Y axes.

I look forward to people doing weird interesting things with this!

I have no idea how lissajous figures could work, but they're cool and in 3d resin print they'd be cooler.

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