The peachy printer: $100 photolithographic 3D printer? - Page 1
Forum section: electronics / general

author: rs20
author_rank: Super Contributor
timestamp: September 23, 2013, 03:34:19 am
content: 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?

author: EEVblog
author_rank: Unknown
timestamp: September 23, 2013, 04:15:07 am
content: 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.

author: marcan
author_rank: Regular Contributor
timestamp: September 23, 2013, 04:50:43 am
content: 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.

author: ChrisGammell
author_rank: Unknown
timestamp: September 23, 2013, 04:52:01 am
content: 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.

author: sleemanj
author_rank: Super Contributor
timestamp: September 23, 2013, 05:48:06 am
content: 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.

author: Psi
author_rank: Super Contributor
timestamp: September 23, 2013, 05:58:54 am
content: 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.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 23, 2013, 09:12:13 am
content: Quote from: Psi on September 23, 2013, 05:58:54 amISTR 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.QuoteLooks like most of them have other businesses etc. so probably part time, or on a percentage

author: baljemmett
author_rank: Unknown
timestamp: September 23, 2013, 11:49:14 am
content: Quote from: Psi on September 23, 2013, 05:58:54 amI 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...

author: EEVblog
author_rank: Unknown
timestamp: September 23, 2013, 01:07:22 pm
content: Quote from: Psi on September 23, 2013, 05:58:54 amIIRC 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.

author: Stonent
author_rank: Super Contributor
timestamp: September 23, 2013, 03:11:23 pm
content: Well he certainly has a good understanding of the X axis.

author: Marco
author_rank: Super Contributor
timestamp: September 23, 2013, 03:44:17 pm
content: 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.

author: tom66
author_rank: Super Contributor
timestamp: September 23, 2013, 06:19:05 pm
content: 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.

author: Tost
author_rank: Contributor
timestamp: September 23, 2013, 08:07:01 pm
content: 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.

author: Rasz
author_rank: Super Contributor
timestamp: September 23, 2013, 11:50:55 pm
content: 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 printerIts 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.

author: CanadianAvenger
author_rank: Regular Contributor
timestamp: September 24, 2013, 03:33:00 pm
content: 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]

author: tom66
author_rank: Super Contributor
timestamp: September 24, 2013, 11:54:10 pm
content: 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."

author: cloudscapes
author_rank: Regular Contributor
timestamp: September 25, 2013, 12:27:25 pm
content: 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!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 25, 2013, 01:09:18 pm
content: Quote from: Tost on September 23, 2013, 08:07:01 pmWhat 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.

author: marcan
author_rank: Regular Contributor
timestamp: September 25, 2013, 03:04:48 pm
content: 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. $100actually gets youa 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 forOpenLase(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.

author: Stonent
author_rank: Super Contributor
timestamp: September 25, 2013, 07:09:40 pm
content: 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)

author: marshallh
author_rank: Unknown
timestamp: September 25, 2013, 09:37:20 pm
content: How effing hard would it be to make a $10 pcb with a PIC and ADC/DACs.

author: c4757p
author_rank: Super Contributor
timestamp: September 25, 2013, 10:15:32 pm
content: For a bunch of "software guys"? Well, I suppose they could probably operate the SparkFun shopping cart...I kid... I think

author: Marco
author_rank: Super Contributor
timestamp: September 25, 2013, 10:37:43 pm
content: Quote from: mikeselectricstuff on September 25, 2013, 01:09:18 pmI assume it uses aMarriotte's bottle.

author: Rasz
author_rank: Super Contributor
timestamp: September 26, 2013, 12:33:14 am
content: Quote from: marshallh on September 25, 2013, 09:37:20 pmbut 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.

author: marcan
author_rank: Regular Contributor
timestamp: September 26, 2013, 02:21:40 am
content: 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.

author: cloudscapes
author_rank: Regular Contributor
timestamp: September 26, 2013, 02:57:16 am
content: Am I right to assume that there's liquid trapped inside closed models?

author: MFX
author_rank: Regular Contributor
timestamp: September 26, 2013, 09:37:59 pm
content: I think the general idea of the Z axis is inspired thinking. A different high density liquid may be better than salt water (maybe glycerine?), that said I'm not sure any drift in drop size will be a major issue, some drops may be slightly over, some slightly under so there's a good chance they will even up to an extent over time. If you were really worried then a simple sensor strip in the tank could zero the count every 1cm or so . Give it some decent galvos with feedback (loads of Chinese ones on Ebay) and could be a winner. Trying to churn it out for $100 is a mistake though, a $300/400 would still be cheap and probably produce much higher quality prints.Martin.

author: casinada
author_rank: Frequent Contributor
timestamp: September 28, 2013, 06:07:09 am
content: The formlabs product is shipping, is real, and looks solid but it is not cheap$3299http://formlabs.com/products/our-printerI don't see anything about a lawsuit on their site.The peachy product looks too imaginary and flaky. Why don't they show a full working prototype. They only show bits and pieces and some fancy 3D simulations. Even the purchase options look weird to me.

author: pickle9000
author_rank: Super Contributor
timestamp: September 28, 2013, 07:43:55 am
content: The specs on the formlabs unit are amazing, as are the sample outputs.

author: MFX
author_rank: Regular Contributor
timestamp: September 28, 2013, 11:03:11 am
content: Quote from: casinada on September 28, 2013, 06:07:09 amEr. "Form 1 Pre-order (January)"

author: Marco
author_rank: Super Contributor
timestamp: September 28, 2013, 03:22:33 pm
content: Formlabs shipped kickstarter units.

author: Tost
author_rank: Contributor
timestamp: September 29, 2013, 10:10:55 am
content: Quote from: mikeselectricstuff on September 25, 2013, 01:09:18 pmRight, fluid density will not be an issue and surface tension of water which is much more sensitive to temperature and contamination (e.g. deposit of tensides from cleaning) may be acceptable too.But the contact angle at the nozzle/liquid interface will be an issue. The nozzle surface will change significantly over time, especially with water because of a growing biofilm (high NaCl-concentrations will impede that but will not prevent).It is to consider that the droplet size depends on vibrations too. Even quite small vibrations will cause an earlier droplet release and therefore a smaller average droplet volume.Furthermore there is strong evidence that this concept will not be practice: nobody used that concept before where precisian better than 20% was required.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: September 29, 2013, 10:18:38 am
content: Quote from: Tost on September 29, 2013, 10:10:55 amLong-term effects like this can be calibrated out. probably do want a biocide there to to avoid ickinessQuotevibrations should avarage out as there will be a vary large number if drops for any meaningful Z axis movement. There are no motors to produce any synchronous vibrations that could cause offsets

author: Tost
author_rank: Contributor
timestamp: September 29, 2013, 11:18:17 am
content: Quote from: mikeselectricstuff on September 29, 2013, 10:18:38 amSure you can use a toxic water mixture (If you want). But still you have a lot of other effects that can change the surface (e.g. absorption, adsorption, oxidation, dust). Even if it wouldn’t be an issue during the print, I guess a proper calibration without precision scale will not work below a hour (for better than 5% error).Quote from: mikeselectricstuff on September 29, 2013, 10:18:38 amVibrations will make the drop only smaller never bigger, so the average drop size will depend on the vibration amplitude and frequency which can change significantly during a print (e.g. Street Trafic is quite time depended). There is a reason you have to spend quite some money for a decent flow meter.A much better low budget solution would be in my option a pressure sensor that measures the level of liquid. It will give no precision short term changes but that should be quite easily to predict by extrapolating last measurements in a smart fashion.

author: CanadianAvenger
author_rank: Regular Contributor
timestamp: September 30, 2013, 03:55:34 pm
content: Quote from: Marco on September 28, 2013, 03:22:33 pmThey are still shipping them. They have completed shipping to all their US and Canadian backers, and are currently working on all the international ones. I got mine back in August, the print quality [when it works] is amazing, but you do get a lot of failures. I also believe my unit may have a bit of a calibration issue. But otherwise I am quite happy with it, and am sure any issues my printer has will be worked out.

author: filip_cro
author_rank: Regular Contributor
timestamp: October 07, 2013, 09:40:29 am
content: Quote from: CanadianAvenger on September 30, 2013, 03:55:34 pmCan you find some good review of it? Or post some pics of your prints?

author: CanadianAvenger
author_rank: Regular Contributor
timestamp: October 07, 2013, 06:31:03 pm
content: https://support.formlabs.com/entries/27382436-My-Form1-PrintsNot mine, but is an impressive example. If you brows around the support forums, you'll find many more.

author: filip_cro
author_rank: Regular Contributor
timestamp: October 08, 2013, 10:22:00 am
content: Are you sure that we talk about same 3D printer???

author: Marco
author_rank: Super Contributor
timestamp: October 09, 2013, 02:20:08 pm
content: Quote from: filip_cro on October 08, 2013, 10:22:00 amYour original question has a quote block mentioning Formlabs ... his example is from a Formlabs printer.

author: filip_cro
author_rank: Regular Contributor
timestamp: October 09, 2013, 03:13:21 pm
content: Quote from: Marco on October 09, 2013, 02:20:08 pmUpsI didn't read full thread.

author: Marco
author_rank: Super Contributor
timestamp: April 13, 2014, 02:08:58 pm
content: They have a Youtube video up showing the construction of their beta kit ... the Galvo assembly is an amazing piece of work, it's extremely low mass. The construction however is extremely fiddly, a lot of kit buyers are going to screw that up

author: Kean
author_rank: Unknown
timestamp: April 13, 2014, 02:36:05 pm
content: Wow, that looks neat but awfully fiddly!I wonder what percentage of the 4000+ backers are going to be able to make a working assembly.

author: miguelvp
author_rank: Super Contributor
timestamp: April 13, 2014, 11:34:05 pm
content: What will worry me more is that they don't address the safety of the resin at all, or at least I didn't see anything about it.IIRC the resins are highly carcinogenic, maybe they have found safer resins. In any event, proper protection equipment has to be used when handling those resins. Once cured is safe AFAIK.

author: Marco
author_rank: Super Contributor
timestamp: April 14, 2014, 12:26:03 am
content: Quote from: miguelvp on April 13, 2014, 11:34:05 pmI'm sure there will be some which are, but as far as I know epoxy and acrylic monomers are generally just allergenic ... I'd worry more about the dye.

author: Muxr
author_rank: Super Contributor
timestamp: May 11, 2016, 06:00:31 pm
content: So it turns out this was a long con all along:Prepare for some truly terrible acting:

author: sswift
author_rank: Contributor
timestamp: May 11, 2016, 11:13:09 pm
content: He could win an oscar!Well maybe not.

author: Rasz
author_rank: Super Contributor
timestamp: May 12, 2016, 02:21:13 am
content: that performance alone was worth $100