Looks like Form1 has some competition now


#61

I mean the key difference of resolution is not just caused by the Z axis layer thickness. It also involves the XY resolution. A LCD 2k screen can get to 47um as the pixel size compared to 140um of the laser beam size of Form2 machine.

When you go down to small things, there is a huge difference in printing quality.


#62

Hey,

If you buy those LCD resin more than 50kg a time, it can get lower to around $15/kg.


#63

well, the 13" size 4k is the next.

Not sure about the 8k.

The biggest challenge to go bigger with this LCD screen is the tension force from the FEP film won’t be strong enough to hold it from deformation during the printing. It fails into a problem that if you print a big item in the center, the cured resin area will create a strong suction force and pull the film up and form up a dome shape until it peels off and bounces back to the screen. This will cause a big dimensional inaccuracy problem or print failures. I think to solve the problem, you will need to replace the FEP film with a hard surface tank like silicone coated or very tightly stretched film like the new form3 tank. But this will increase the cost obviously.

But I agree with you if you just load a whole platform of small things, it actually print all of them in the same speed as you print one piece. So it is very fast and efficient.

I mean, in general speaking, the upside down printing way always has problems if it goes bigger print size. How to offset the grip from the gravity is always a challenge.


#64

Why just small things like figures. I used my Photon (the small one) to print many things where I needed dimensional accuracy. My Form 1+ had a tendency to skew things side to side, and because the skew was more pronounced as you got to the edges, no amount of software compensation could fix it. I could print a cylinder of about 1.5" ~2" without any meaningful distortion but beyond that it started to become an ellipse. Not necessarily obvious, but certainly measurable.

On the other hand, on the Photon, everything was exactly as it needed to be. I printed many pieces that fit together with very small or no gaps, things like battery covers, boxes with sliding covers and even Phone cases. 2 years later they are still the same size, they didn’t shrink or swell.


#65

I think we are just having different understanding towards small this definition.

What I am trying to say is when you print small things, the shrinkage/deformation is easy to be ignored and the details/quality you gained from LCD machine is much obvious.

I don’t want to argue with you and I agree with you everything.

End of the discussion.


#66

As soon as it is available again in the EU i will take an Elegoo Saturn to complement my F2, I think it is a good compromise between quality and print size.


#67

Whenever I see someone spout bollox like this I know there is an agender.

The laser point size has no relevance to the resolution. If anything its only relevance is to the minimum wall thickness.


#68

What Ashtree said is technically accurate, not BS.

While the XY resolution of a mSLA printer is easy to define, as it is given by the actual resolution of the LCD panel, it’s the laser SLA XY resolution that is harder to define.

Anycubic Photon or any other mSLA printer with a 5.5" screen has a resolution of 2560 x 1440 has a print area that is120 x 68mm. That translates into 0.0468mm pixels (~47μm). Yes, being that this is a color LCD, each pixel is really a pixel group made of 3 subpixels, R, G and B, and there is a mask between pixels groups, but those would only be visible under a microscope.

Nevertheless, a 47μm resolution means the minimum feature size could be 47μm. You could draw a line that is a single pixel (47μm) wide and skip a pixel and draw another line next to it. So really the XY resolution in the mSLA is pretty cut and dry. The real issue is the resin properties. Is the resin being used capable of curing a 47μm feature without either bleeding into the next feature or overcuring the surrounding area?

On the other hand, a laser SLA like the Form printers has a relatively coarse laser spot at 140μm. So if you were trying to simply draw the finest line you could, it’s width would be 140μm. What complicates the equation on the laser technology (and gives the laser SLA an edge), is the accuracy of the galvos, the ability to position the laser spot with pinpoint accuracy. I don’t know how accurate the galvos on the Form printers are, as Formlabs doesn’t really give that information out, but assuming they can be within 30μm, you now have this situation:

You can only cure a path that is 140μm wide, but you can place another one 30μm next to it. So depending on the type of details you have, the positioning/orientation of the part and the resin being used you could resolve features that are much smaller than the 140μm diameter of the laser spot.

The the reality is that both technologies have their advantages, but to say that “laser spot has no relevance to resolution”, now that is simply uninformed.


#69

A picture may best explain the difference.

Purple is printed on Form3 25um Layerthickness with So-called 25um XY resolution.
Orange is printed on a LCD printer with 25 layer thickness and 47um XY reolution.

The size is around 1" in height. I understand not everyone needs this resolution.

One machine costs $3500 plus all the resin cost ($300/liter for the purple)
The other machine costs $299 and the resin costs $50/liter.

Just watch the eyes.



#70

@Dudemeister the main thrust of your explanation is correct, but heads up there are some mistakes in that math. One is you switched units from micrometers (47μm) to nanometers (47nm) without doing a conversion. I think you meant to say μm throughout. Should also be noted while the Form 2 spot is 140μm, the Form 3 spot is smaller at 85μm. Still not as small as an Anycubic Photon pixel, but closer. Of course (as you pointed out) actual achievable minimum feature sizes on both printers will be coarser than the idealized, calculated result. I’d love to get my hands on a printer that could reliably make 30μm gaps precisely where I tell it every time ;-).


#71

You’re right, I meant μm (Micrometer/Micron) throughout the post. I’m not sure why I put nm (nanometer). I’ll fix the post.

Thanks