-
The peachy printer: $100 photolithographic 3D printer?
Posted by
rs20
on 23 Sep, 2013 03:34
-
The link:
http://www.kickstarter.com/projects/117421627/the-peachy-printer-the-first-100-3d-printer-and-scI do like the photolithography approach as opposed to the extrusion technique used by most common 3d printers. Extrusion leads to weak, opaque products with voids stemming from a need to tune it to the Nth degree whereas photolithography produces the nice, continuous solid parts -- you can see from the example prints that it's almost clear-ish. For just $100, I'm actually very tempted.
What do we think?
-
#1 Reply
Posted by
EEVblog
on 23 Sep, 2013 04:15
-
I'll give him an A for thinking outside the box. But this thing just seems like it would be more trouble than it's worth.
Do you get the tanks and everything with it? or just the laser "cube"?
Sound card control onto a flimsy looking mirror on a string sounds troublesome. Then a Z axis measurement based on number of drips of a fluid? Maybe workable, but crikey.
It is nowhere near even the pre-production stage.
The "team" is huge (even includes a marketing guy!). If working on this full time, good luck feeding that many mouths until shipping.
There is no telling how much they will need to gild the lilly to get it into production.
If think it's probably a case of trying to think and go too cheap, and it may end up a troublesome unusable product. But that's just my initial gut feel., I haven't really thought about it.
-
#2 Reply
Posted by
marcan
on 23 Sep, 2013 04:50
-
Most sound cards are AC coupled - to build a laser scanner using sound card control you need to bypass the DC blocking caps. I have no idea how he plans to overcome that with an integrated sound card (people normally use a modified USB sound card for this). Along the same lines, what about feedback? Are the mirrors open loop? I've never seen an open loop laser scanner with any kind of reasonable performance. I've seen people build their own galvos, but still using closed loop control. Ah - I've just watched their demo video. That thing is *slow*. I still have no idea how they overcome the DC blocking issue though, considering the frequencies are definitely in the 1Hz range there (vs. more like 5-10kHz for a real galvo system). AM modulation with a cheapie detector, maybe?
The design has the same problem that extrusion based printers have: high X, Y, Z resolution, but a large "nozzle diameter" (or beam diameter in this case). You can't collimate a laser beam into a very thin beam (it won't stay thin for long, since the divergence becomes more pronounced the smaller you try to collimate the beam). And with varying distance between the scanner and the current resin level, you can't just use fixed focus. It doesn't matter that you can move your beam by 1um if it's 1mm in diameter. It also doesn't matter that you can move your Z axis by 1um if the beam is curing a 0.5mm deep resin layer.
Galvos move a beam to a given angle - to turn that into X,Y coordinates on the build volume, you need to use trig. That means you need to carefully calibrate the distance to the object or else you'll end up with trapezoid prints. Also, there are a bajillion variables here that would require calibration in order to build dimensionally accurate prints, and too many things that are likely to be unstable over time. Extrusion based 3D printers use belts and steppers that are very repeatable. Good photolithographic printers use constant distance to the print and/or a sturdy framework that provides repeatability. I don't think a simple jury-rigged design like this can manage that, which means at best it'll be good for decorative parts, not parts requiring accurate dimensions.
With uncontrolled Z feed, there's a limit to how complex a layer can be before you run out of time to print it. And you waste time on simple layers. All of their test objects seem to be very simple. Also, how do they turn the beam off to move between disjoin sections in a slice? Or do they just move it quickly and hope for the best? Their "Dave" print seems to show that they cannot print layers with disjoint parts.
This does feel way too cheap. I'm sure it'll print, but it's going to be at least as finicky as an extrusion based printer, for the same quality, if not more, and that's just for decorative parts. When I built an Ultimaker my very first print (with zero tuning) was crap by its standards, but it already looked better than the prints shown on that kickstarter page.
-
-
All technical arguments aside, just being able to say "3D printer" and "Less that $100" almost certainly guaranteed he'd hit his target.
Will be interesting to see if this prompts other similar style printers in the future. Even if it just spawns a new type of printer, then it'd be useful.
-
#4 Reply
Posted by
sleemanj
on 23 Sep, 2013 05:48
-
Saw it on Hackaday.
Not sure what I think really, on the one hand, it's a truly ingenious design in it's simplicity.
On the other hand, I'm not convinced of it's feasibility as a product, he has a working prototype but his self described best print is something loosely resembling a cube about a cm on each side.
There are campaigns from them running on both KS and IGG, I can't help but feel that they are getting in way too deep over their heads and that they just won't be able to complete the units to a good standard even if they end up with a good product.
I didn't see any mention of safety, any potential legal issues around the laser, or even the build volume. It has what appears to be a flat shipping charge internationally (for what may be quite bulky given that there are two fluid involved). These all indicate to me that they may not have thought their plan through completely.
-
#5 Reply
Posted by
Psi
on 23 Sep, 2013 05:58
-
Last time a company tried to make and sell a 3D printer that used the photolithography method they got hit with patents lawsuits.
I dunno what came of the company after that, but yeah photolithography seems to be a bit of a patent minefield.
-
-
Last time a company tried to make and sell a 3D printer that used the photolithography method they got hit with patents lawsuits.
I dunno what came of the company after that, but yeah photolithography seems to be a bit of a patent minefield.
ISTR reading that some major patents on PL are about to expire.
Some nice ideas there but I can see some potential issues with consistency and dynamics of the scanners, which look like they're open loop. I don't think AC coupling from the soundcards will be an issue as the mirrors can be kept moving.
The drip system is a nice idea but I don't like the contact detection as this will corrode over time (I'm assuming they're not using AC drive). An optical system would be more reliable and not much more expensive.
My guess is it will be a bit of a toy, but you can't really complain for the price.
Resin price & quality is probably the main issue.
The "team" is huge (even includes a marketing guy!). If working on this full time, good luck feeding that many mouths until shipping.
Looks like most of them have other businesses etc. so probably part time, or on a percentage
-
#7 Reply
Posted by
baljemmett
on 23 Sep, 2013 11:49
-
Last time a company tried to make and sell a 3D printer that used the photolithography method they got hit with patents lawsuits.
I dunno what came of the company after that, but yeah photolithography seems to be a bit of a patent minefield.
I think that was the Form printer? A quick look at the Kickstarter comments suggests Formlabs have started shipping some of the backers' machines now (compared to an early 2013 estimated ship date), and the website is still taking pre-orders, so maybe they're not quite dead...
-
#8 Reply
Posted by
EEVblog
on 23 Sep, 2013 13:07
-
Last time a company tried to make and sell a 3D printer that used the photolithography method they got hit with patents lawsuits.
I dunno what came of the company after that, but yeah photolithography seems to be a bit of a patent minefield.
IIRC they were either about to expire, or already have. The formlabs printer got hit with the patent slap because they were a year or two early to market. New companies should not have this issue.
-
#9 Reply
Posted by
Stonent
on 23 Sep, 2013 15:11
-
-
#10 Reply
Posted by
Marco
on 23 Sep, 2013 15:44
-
Formlabs was sued for patents concerning supporting posts ... if you just leave it to 3rd party coders to add supports then that patent won't be a problem.
Any way, as I see it you're paying for a resin which is optimized for resin on water stereolithography and you get a toy printer to go with it. Once the resin is out there better printers will follow.
-
#11 Reply
Posted by
tom66
on 23 Sep, 2013 18:19
-
Looks interesting.
Personally though I'd like to at least see it support e.g. connecting to a Raspi or Arduino for additional control like full Z-axis control using PWM as a DAC.
Have the headphone option at $100 and the extension board option at $150.
-
#12 Reply
Posted by
Tost
on 23 Sep, 2013 20:07
-
Marcan already mentioned the major points that will make it not compattable to other 3D printers. Open loop laser scanner doesn’t work well on high speed, but for low scanning speed they can be precise (Depending on the construction, temperature coefficients may be an issue, e.g. 1% per 10K if the coils are driven without resistor in series).
DC blocking caps can’t be ignored, when you drive the galvos directly. Every layer must be in some way symmetric in x and y direction. Otherwise the layers will drift away if the symmetry changes in z-direction. But that can be overcome by outputting a modulated high frequency AC signal and give the rectified and low pass filtered signal to the galvos.
Measuring a volume flow by counting drops… no that will not work properly, drop size depends on quite a lot of parameters that will drift slow but significantly during a print.
-
#13 Reply
Posted by
Rasz
on 23 Sep, 2013 23:50
-
If they can come up with good resins (they promise flexible and rubber one) then I see a future for a 3rd iteration of this printer
Its so simple Chinese could make them for $5-10, or just add for free to 2-5 liters of resin.
People currently funding the campaigns are just funding R&D, I wouldnt count on a working product from this.
-
-
It's a cute printer, and perhaps good for "play" but I don't think it has the accuracy, or consistency required for production work. I also find it somewhat shady as they are running dual campaigns, one on IGG and the other on KS... having said that they didn't select "flexible funding", which is a positive in their favour. [the 2nd campaign is not a copycat, they link to both on their official website]
-
#15 Reply
Posted by
tom66
on 24 Sep, 2013 23:54
-
For all it's limitations, it's a $100 3D printer. It's pretty impressive engineering. Reminds me of "An engineer can do for a dollar what any fool can do for two."
-
-
The pitch video features one of my most annoying pet peeves. Changing the camera angle on the guy randomly every couple seconds, making him stare into space for no reason. Ohhhhhh, dynamic camera! Edgy! Also, that music...
I like the concept. Probably won't have much precision, though, and it sounds messy. But I'm all for more types of 3D printers if it'll drive the cost down for all of them!
-
-
Measuring a volume flow by counting drops… no that will not work properly, drop size depends on quite a lot of parameters that will drift slow but significantly during a print.
What parameters ?
nozzle geometry will be constant, temperature isn't going to change much, density should be constant for a given mix and could be calibrated, change in pressure due to decreasing head if liquid could also be compensated for.
-
#18 Reply
Posted by
marcan
on 25 Sep, 2013 15:04
-
Going by the waveform displayed in the in-depth video, it's a very slow waveform, requiring DC coupling. I'm guessing his laptop has such a shitty sound card that it lacks the AC coupling caps.
Unfortunately, 99% of the soundcards out there have DC blocking caps and won't work. People who pledge are going to get a nasty surprise if they don't fix that.
There is no circuit - he's driving the coils directly from the audio jack, and the laser has no on/off control. Cheapest crappiest laser scanner ever. $100? That thing is $10 in parts, if that. $100
actually gets you a cheapo but real closed-loop laser galvo system in china these days, 12kpps or so, which an order of magnitude faster than what is demonstrated in the official promo video (assuming that isn't sped up) and two orders of magnitude faster than what was demoed in the in-depth video above. Add a modified USB sound card (sans blocking caps) and you already have a much better system than what is being demoed here. That's what I did for
OpenLase (
demo). That laser scanner was $300 in parts or so, including the 30kpps galvos, sound card, laser, and DIY laser driver and safety controller. That was in one-off quantities from eBay/Dealextreme. It'd be about $100 with the galvos linked above.
That in-depth video was quickly pulled. Why? That's a red flag right there.
Sorry, I'm not convinced. This is straying deep into "way too cheap for its own good" territory.
-
#19 Reply
Posted by
Stonent
on 25 Sep, 2013 19:09
-
Why does it seem that everyone on these sites has a video production service at their disposal but can't mock up a decent looking prototype?
Oh that's right, marketing guys. They have the idea and need the money for someone else to make it work (not picking on this project in particular but you know what I mean)
-
#20 Reply
Posted by
marshallh
on 25 Sep, 2013 21:37
-
How effing hard would it be to make a $10 pcb with a PIC and ADC/DACs.
-
#21 Reply
Posted by
c4757p
on 25 Sep, 2013 22:15
-
For a bunch of "software guys"? Well, I suppose they could probably operate the SparkFun shopping cart...
I kid... I think
-
#22 Reply
Posted by
Marco
on 25 Sep, 2013 22:37
-
nozzle geometry will be constant, temperature isn't going to change much, density should be constant for a given mix and could be calibrated, change in pressure due to decreasing head if liquid could also be compensated for.
I assume it uses a
Marriotte's bottle.
-
#23 Reply
Posted by
Rasz
on 26 Sep, 2013 00:33
-
How effing hard would it be to make a $10 pcb with a PIC and ADC/DACs.
but why if they can make it work without it? Simplicity of this thing is brilliant.
I just hope that some future iteration can also match FDM quality. Its just two speakers and a laser pointer - Chinese will make it for $5 with free shipping.
-
#24 Reply
Posted by
marcan
on 26 Sep, 2013 02:21
-
Also:
"Over the past year they have been working together to get the Peachy Printer to where it's at today."
Really? A year? Come on, I could've put this together in a weekend after having the idea. Maybe add another weekend for the software. What on earth have they been doing that it's been going on for a year and all they have to show is a jury-rigged prototype that looks like crap and some mediocre prints?
"Scott will be bringing his circuit designing experience to the table and helping with the R&D of the Peachy Pro."
Ha. So they already know it's going to be crappy and are designing one with real electronics. But that's Peachy Pro - not what the backers will get.
