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#1 2019-05-13 15:47:29

PhiMX
Member
Registered: 2019-05-10
Posts: 13

Resin exposure range finder

Ok, I come from the anycubic photon which has a fantastic community on facebook as well as a great resource page on github.
There they have made a resin exposure test which consists of a hack that mixes stl depth info with exposure time or something like that.
They use this stl file:
1.png

and as I said turn depth into exposure time, so that number 10 gets the highest exposure (i.e. is on all the time) and number 1 gets the least exposure
time (i.e. is on only 1/10th of the time). The depth info gets totally removed and so the staircase pattern disappears. What you are left with is a
flat version of the file with all the fields and numbers 1-10 are the same height.
Height and exposure range can be selected and tuned to what you need, so you can make the file 50um thick and exposure range from 1 to 10 seconds,
or 100um thick with exposure from 10 to 20 seconds.

what you end up with is this:
2.png

so you can easily spot what time is optimal for exposure in a certain resin/printer/settings setting.

I am sure such a similar thing can be easily implemented with nanodlp as well. It is unbelieveably useful to determine optimal resin settings, also as a
basis for dynamic resin exposure settings.

The way they do it with the photon is I believe turn off the z axis movements and so they get a flat piece with different exposures instead of stairs.
note also that first comes 100um fixed of full white exposure as a basis substrate layer and then the actual test gets put onto that.

I am not sure how it can be implemented with nanodlp but it should be baked into the main code and come as a tool together with nanodlp just because it is so incredibly useful.
3.png

When you implement it into nanodlp, maybe you can make the actual test pattern smaller and just concentrate on the values that make most sense and so combine
10 different exposure times with maybe 5 thicknesses in a 2 dimensional grid in one go and so harvest a wealth of resin info in one shot.
This could be extremely useful to make perfect dynamic resin settings.


Thank you for considering!

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#2 2019-05-14 08:04:08

Shahin
Administrator
Registered: 2016-02-17
Posts: 2,607

Re: Resin exposure range finder

As you know we have calibration method baked into nanodlp.
What you have described has two new advantages.
* Support for multi height calibration
* Empty areas to measure overcures more easily.

It will be difficult to make it dynamic but will try to add them.

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#3 2019-05-14 11:42:20

PhiMX
Member
Registered: 2019-05-10
Posts: 13

Re: Resin exposure range finder

What exactly do you mean by empty areas? The "negative spaces" as described in the picture?

Take a look, I made a mock-up of what I meant with 2D array of samples. From left to right the
exposure time is varied and from top to bottom the thickness. This way 30 Samples are made in one go.
Maybe even more thin and thick stripes could be removed, really interesting is the area around 0,5mm.
Would be awesome to have!
4.png

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#4 2019-05-14 14:48:35

Doug
Member
Registered: 2017-08-11
Posts: 86

Re: Resin exposure range finder

If you dont have a perfect mask this method doesnt  work.

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#5 2019-05-14 19:59:07

PhiMX
Member
Registered: 2019-05-10
Posts: 13

Re: Resin exposure range finder

You mean uneven light distribution? OK, that´s right, but why not compensate for this?
NanoDLP brings an option for it, I just printed a lattice this morning to measure my light distribution and then create
an greyscale file to compensate for this problem.
Or is there something I don´t think about at the moment? Because if you create your resin profiles after the data you get from
this test with your measured mask overlay displayed, you should be golden, right?

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