nanoDLP

PhiMX

Member

Registered: 2019-05-10

Posts: 21

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:

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:

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.

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!

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

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.

PhiMX

Member

Registered: 2019-05-10

Posts: 21

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!

Doug

Member

Registered: 2017-08-11

Posts: 100

Re: Resin exposure range finder

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

PhiMX

Member

Registered: 2019-05-10

Posts: 21

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?

elliot

Member

Registered: 2016-04-28

Posts: 109

Re: Resin exposure range finder

Following:

Has there been any more interest in this method. It is quite interesting take on the exposure test.

I do see the issue with the mask, however, if you are using dimming greater possibility that the dimming settings outweigh the mask alterations. Example 25% reduction in pixel brightness is more than likely higher than a reduction in mask curve over the DLP.

Thanks all, great idea, discussion and consideration Shahin!

macdarren

Member

Registered: 2017-03-20

Posts: 411

Re: Resin exposure range finder

I  am watching this thread....I would love to get even exposures but somehow none of my masking efforts seem to be really successful.  Perhaps my ShuffleXL is just doesn't need much in the way of masking just better time tuning.....Getting a good base line as this method might provide would be helpful, especially to avoid over/under cure issues.  I am thinking to improve it slightly would be to do four separate prints one set then reversing it and going the other direction...in theory same result if like is fairly even...I would then additionally rotate it 90 and do two passes that direction too....maybe some even more complex variant of the pattern could reduce the number of passes but making four is not that hard.

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: Resin exposure range finder

New multicure feature might help

elliot

Member

Registered: 2016-04-28

Posts: 109

Re: Resin exposure range finder

Shahin,
Is there the potential you might change the difference in spacing between objects on multi-cure. I would like to be able to fit more objects for testing. If it could be user defined, we could design and fit objects by known packing.

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: Resin exposure range finder

Multi cure gap setting added to profile on the latest beta version.

PhiMX

Member

Registered: 2019-05-10

Posts: 21

Re: Resin exposure range finder

Dear Sahin,

let me thank you for implementing multicure into nanoDLP!

elliot

Member

Registered: 2016-04-28

Posts: 109

Re: Resin exposure range finder

Hi Shahin, I'm wondering if there is a base set of instructions for multi-cure. I'm not able to get it to work anymore on the previous build or the new nano releases. Correct me if I am wrong but the only controls are in the resin profile - for space between prints, and in the advanced features of the pate. If those two are set, then a generated model should be shown on the preview.

my exposure test is 1x21mm, 1mm spacing between objects so should be plenty of room to double everything up.

Thanks!

Shahin

Administrator

Registered: 2016-02-17

Posts: 3,541

Re: Resin exposure range finder

You are correct. https://docs.nanodlp.com/manual/multicure/
1mm is margin as far as I remember it is from side or any close object so between two objects you will have 2mm gap.