Some DLP printers can even do 25 micron XY, although the print area becomes small. Enough for jewelry though. 
Which one? I thought I had a list of them all and lowest was 37.
Also, does 25 micron projected pixel result in a 25 micron cured resin?
One thing that is also bothering me with DLP as opposed to SLA is with DLP you have light spots close to each other (pixels), whereas with SLA you have a light spot (laser) moving along a path so thereās no āgapā between or at least the top and bottom edges of each light spot unlike with pixels. Or not quite?
Minimum Feature Size(DLP) != Minimum Feature Size(SLA). You just canāt realistically compare them. Think of it like this. With DLP each layer is like a rasterized bitmap with a given pixel size and on SLA itās like a vector with a given stroke width, so if you want a sharp corner DLP at higher minimum feature size can be better. If you want a smooth curve SLA even compared to a DLP with a smaller minimum feature size can be better. SLA works more like FFM in this regard. Meanwhile DLP is kinda like really tiny Minecraft structures.
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X/Y resolution and minimum feature size are quite different. X/Y resolution is the smallest step that the print mechanism (laser spot, nozzle, etc) can make in the X/Y direction. I would be much more interested in X/Y repeatability than the actual resolution itself. Systems used to control X/Y movement of a print mechanism are likely far more resolved than the process itself can reveal in a finished part, so repeatability is more important.
Minimum feature size is the smallest feature that the print mechanism can create. Think of a thin vertical wall. How thin can that be? The width of this wall is the minimum feature size. Measuring the nozzle opening (FDM) or laser spot (SLA) does not tell you minimum feature size. There are too many other variables.
Laser profiles are Gaussian. There is no such thing as a laser that goes from 0-100% intensity over an infinitesimal distance. A photo of a laser spot is misleading because exposure time can make it seem like the effective spot is much larger than what is actually true. Analogous to this is the laserās effect on resin.
The best way to determine minimum feature size is experimentally. The Formlabs Form 1+ is quite capable of features that are 300 microns, as we say in our specifications.
As with any manufacturing process, nothing is perfect! There are ways, as some users have discovered, to expose the SLA process. As with any process, leveraging its strengths, and working around weaknesses is how you become an expert. The Form 1+ makes it easy to print nearly anything if you respect the limitations of the light based print process.
Obviously I am biased as a Formlabs employee, but I think we have a fantastic combination of value, quality, performance, after-sale support, and community that makes our printer a fantastic purchase.
Lastly, a simple coating of paint or another UV blocking coating can eliminate any issues caused by prolonged UV exposure over time in finished parts.
Hope this helps you to determine whether you think a Formlabs printer could fulfill your needs. If you have any questions, feel free to ask here or reach out to our support/sales teams.
-Aaron
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Re: nozzlesā¦
One thing people forget is that you can actually print with widths smaller than your nozzle diameter on FDM machines. The extrusion does not have to be the diameter of the nozzle - it stretches. If the extruder goes slower than necessary to lay down a full width pancake of plastic at a given speed, youāll get a thinner trace.
Alright, now iām annoyed. On my prints, my 635 MICRON square holes where NON-EXISTENT when printing on the Form1+. So the advertised specs are incorrect. The same print from i.materialize.com had a crisp and beautiful square hole.
I was being very optimistic before with 1000 microns. So letās look at the real Form1+ laser profile. This machine was better than the replacement I was sent to replace it, so even this should be optimistic.
As you can see the laser spot is 3,900 microns! That is 3.9mm. And of that, 1200 microns (1.2mm) is the core.
I am disappointed that you were not happy with our printer. My coworkers at Formlabs can tell you how vocally frustrated I get when things do not perform flawlessly 100% of the time. I truly do understand your frustration. Please stay peaceful and keep the swears off of the Forum (swearing always follows frustration for me, so once again, I get it ) .
Moving on with one of my favorite things, an analogyā¦
By altering driving habits to take advantage of strengths and weaknesses of each vehicle platform, superb or terrible MPG can be achieved. Advertised MPG ratings come from an EPA test cycle meant to represent a typical driver on typical roads in typical weather and is usually pretty darn close to what most drivers will achieve. A very poor number does not mean the MPG rating is āBSā. Our 300um minimum feature size is is analogous in that, in our experience, it is representative of what is possible in most use cases of a Form 1+.
Nothing in life (or SLA) is black or white. While you may have been unhappy with the printerās performance, that does not mean it will not work for most customers, or that our specifications are āBSā.
@aarsh, there are a lot of variables between actual laser profile and digital images of a static laser spot that would make measuring effective spot size difficult at best. The best indication of typical Form 1+ performance is parts that it produces and the fact that most customers are extremely satisfied with their printers. Please let us know if you have any more questions or concerns.
Cars are rated in AVERAGE MPG highway and city. (And MPG lawsuits surround Ford). The Form1+ specs donāt say āaverageā minimum feature size. Which would still be wrong. What you are counting on is the guy that is post-processing the part being able to ERODE the part down to features that are 300 micron. With the holes the only thing I could do was try to press a needle though, but there was nothing there to work with.
@Aaron_Silidker this is all more complicated than just learning the advantages of the platform, and that viewpoint is unnecessarily dismissive and a bit condescending. First off the Form1+ seems to have a very wide range of laser profiles. To be clear Iām not talking about what the spot looks like in a picture but instead by what the results of the same print being printed on different printers. The quality varies from great to awful. This has been well explored and documented on the forums. @JoshK got a couple printers on the awful end of the scale and had pretty terrible support experiences. This is also well documented on the forums. As for the 300um smallest detail size on the Form1 I just donāt buy it. My FFM printer with a 350um nozzle and set to 350um extrusion width produces clearer X and Y details than any of the Form1s I have owned, and I do know how to get the best out of my FFMs and my Form1.
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@Aaron_Silidker
Iāve calculated the average minimum feature size for the machines I had. I was able to do this because I had to maintain separate models that were dimensionally WRONG so they would work on the Form1+.
The Form1+ average minimum feature size is 900 micron. That was discovered through experimentation like you requested. Please update the webpage.
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Okay, I understand that.
My question is, does 25 micron projected pixel result in a 25 micron cured resin?
Laser seem to have a problem as the beam profile is a gaussian beam, not a sharp circle or rectangle, so I guess the edges are less cured, which I guess means after some time under sunlight or UV light it will cure completely, so it is honest to state the āfeature sizeā the whole beam diameter, including the āflareā around the brighter middle. So if the āflareā or as I call them, āfeathersā are not counted in the diameter, then itās not really 300 micron resolution in X and Y as claimed.
What is the case with projected pixels from a DLP?
Well, not quite. I mean yes, you can print smaller diameter than the nozzle hole diameter. That is how support is printed on FFF printers and easier to remove.
I can print 100 micron width plastic from my 400 micron nozzle. In fact I do it for flat surfaces to almost hide the low quality texture of current FFF prints.
The question is, how good does it work for everything?
I surprisingly havenāt found any discussion or article on this, as you can print the inner (invisible) walls of your print at higher microns and outher (visible) walls at much lower micron widths and you get a very smooth looking print without an extremely long print time, in theory.
Truth is, from my tests, if you let the printer squish the printed plastic by extruding less while moving the nozzle on the previous layer, the plastic is smaller than the hole, it gets dragged around while changing direction while printing. Being left behind is ābacklashā. Itās not a problem with printing a flat surface as the backlash is there for only one step when the extruder quickly changes direction, but when when it happens more smoothly backlash is a pain of an issue.
hereās an illustration. Imagine the yellow ring is the nozzle and blue is the extruded and squished plastic. The nozzle is what is moving, the plastic gets ādraggedā or left behind in the opposite side of the side the nozzle is moving.
I hope this makes sense.
This is not normal and unacceptable. Either the optics arenāt calibrated in the factory the same way, or the lasers themselves are poor quality and differ so much. Whatever the case, thereās no excuse for this.
Not really.
Iāll need some info to explain how eaxctly you determine the āfeature sizeā and āeffective spotā and some results as proof of it (ruler next to a print like some other companies). If you have it then please link to it. Thank you.
As for post processing, except for support material areas, if I had the time to postprocess, I wouldnāt be here. FDM printed ABS can already be post-processed with or a combination of the following: acetone vapor, laquer coating, spray or acrylic painting, sanding, sandblasting and rotatory/vibratory rock thumblers.
And maybe ultrasonic cleaners. Havenāt tried myself.
If these additive or subtractive postprocessings were done on a 25 micron print, many tiny details would be gone which are the reason youād want to print at 25 microns, to have tiny details.
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I compleatly agree. See the threads on laser flare for details. And read āA response to Sam Jacoby for a summary of my opinion.ā It is however currently the reality. The good machines are quite good however I have not seen the supposed 300um X/Y resolution hold up to a very well tuned FFM. On the other hand their Z resolution and far superior overhang handling and clean layer edge usually results in a much better end product than an FFM.
@aarsh ā I suggest that you contact our sales team (sales@formlabs.com), who (depending on your location), can arrange to have a small custom part printed for you on one of your machines. Then you can assess first-hand whether or not the resolution fits or your needs, or whether youād like to go another route, as others are suggesting. I know that some of our other users, like @Monger_Designs, often print sample parts for potential customers as well.
We are working on a more substantial design guide, similar to what Shapeways has here, which sounds like that youāre after, but itās not completed yet.
Beyond that, this thread is taking a accusatory & prosecutorial tone that I donāt find conducive to conversation or the well-being of myself and others on the forum, so Iām going to lock it. @aarsh ā feel free to start a new thread focused on your questions above, and weāll see if we can keep it a bit more focused.