Why do SLA printers pull each layer?

Is it not possible to continuously pull on the print and play the layers like a video? Is it that everyone just does the same thing or is this not a possibility?
In my weak, little mind, a continuous pull would speed up the print, as it would allow constant curing rather than 15%-50% of the time from the few videos I've seen. Get a good enough frame rate and a clean enough setup and you could essentially remove visibility of layers on curves and shallow slopes, right?
Just a few unresearched thoughts and questions.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Well would you look at that.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Remember even videos are made up of separate frames (like layers), they just display fast enough to fool our vision.

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MrDoctorDIV
Get a good enough frame rate and a clean enough setup and you could essentially remove visibility of layers on curves and shallow slopes, right?

Thought it was clear I knew what frames were by talking about them. I guess not. To be more clear, because the object is moving constantly you could play on the frame rate by increasing it rather than only using a frame per cleanly moveable distance. Of course you still run into the motor's capability of moving certain distances at a time at whatever stepping resolution you have.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

This was explained to me by a printer manufacturer a few weeks ago.
The laser comes up through the glass and sets the thin layer of resin that is right there on the glass.
It is necessary to move the printed object up and down to cool that layer or the print will stick to the glass.

... most of the 'stops' for every layer is caused by the limited energy density of the UV-lightsource -- you need a specific time to cure a layer ...

With laser-SLA the time per layer is defined by the time the laser needs to 'draw' the complete sheet.

I have a N2-TAE-laser, which emits extreme short pulses (200ps) with pretty much power (400kW) at 337nm, what would be perfect for curing UV-resin -- and too thought about "continuous printing" ... but could be, the slice has to be hardened before you can withdraw it from the glass surface, or the 'vacuum forces' while pulling the part will deform the soft volume ...

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Viktor
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Hi,
I'm trying to print with DLP printer but when I run the printing I the resin stick to the glass instead of plate, even I have used FTP for the glass but it's still doesn't work, can you help me and tell me what should I do for this problem?

I don't have much experience with SLA printers but when you print a layer it cures the resin which is between the bed or cured resin and the glass surface. This adheres quite well due to Van der Waals forces (someone correct me if I'm wrong here) and makes it very difficult to pull the object straight up. Companies like Formlabs or even mUVe3D make use of a peeling function where one side of the bed is lowered and then the next. This requires much less force and thus they can get away with using a weaker motor. There is also less risk of damaging the object.

This kind of approach could be possible with an SLA printed which works top down and lowers the printed object into a container of resin. I think there was some experimentation with one in the developers section of this forum but I can't find it at the moment.

And because I have no money, yet another of my ideas have been imagined and fulfilled by another person, namely Carbon3D.

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MrDoctorDIV
...a continuous pull would speed up the print...essentially remove visibility of layers on curves and shallow slopes, right?

With all of the benefits I had mentioned.

Edited 1 time(s). Last edit at 03/18/2015 06:54PM by MrDoctorDIV.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

... yes, this Oxygene-permeable window eliminates the problems with sticking on the glass while allowing the new resin to replace the drawn volumes.

Another 'endless' approach is a rotating disk or cylinder in a synchronous rotating vat, where you only cure a thin segment in an 'endless' stream, while the other areas performs the separating and wetting process while rotating out and in again ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

@VDX: Why do you think the Carbon3D can go so much faster than any other "endless" approach? Have we just not pushed the other methods to their limit? (I hope the answer is that we just haven't thrown the same amount of lumens/power at the problem as Carbon3D has. I hope this because I am sure Carbon3D have filed a patent and I don't want to wait a couple decades to have this kind of speed in my house.)

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ConceptFORGE
Wally, GUS Simpson, LISA Simpson, THOR Simpson, Sextupteron, CoreXZ

... with 'endless pulling' you have mainly two problems to overcome:

1. - curing speed (UV intensity + resin reaction time) - simply to solve with stronger lasers/LED's and resin chemistry

2. - refuelling speed of the 'drawn' or cured volume - this is the biggest problem with big flat structures -- and it's not solved until now, so you'll see only 'hollow' structures like the bucky-ball or Eiffel-tower, no solid volumes.

So this idea with Oxygene permeable windoe is good, but didn't solve the complete range ... here other 'simply mechanical' solutions could have a chance ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]