Ideas on why models render as oblong or at an angle!

[Zypher]

Hello! Man you guys are awsome! Peachy is an insane approach to 3d printing! So Friggin Elegant! Well I just bumped into the Peachy site and this blows my mind! I cant wait to sign up and Back this. I noticed that your models are oblong and and also canting at an angle the steeper they go. Not 100% sure, but I suggest maybe if you dont mind, to remember that your laser is building at or from a reflected source, I mean that it is not always building directly overhead at each point. That the incline or degree of your reflected beam travels at different pitches of degrees dependent where your curing the resin. Since your height or Z axis is fixed at the laser and rising in the resin tank, you need to compensate for the growing incline, suggest an algorithimn that varies according to the slice increment as the model grows closer to the laser, also the distance of deflection might be looked into since this also may be causing your oblong results. As a visual example, try thinking of drilling an angular hole into a piece of wood as opposed to drilling strait down..now you see the difference in the aspect of your mirror deflection as opposed to the overhead aspect of the common 3d printer..Rylan man you are an awesome visionary! But if you havent already dont rewrite blender dude..make a file exporter plugin for a custom format to protect your Genius proprietary software. If you put your wav. format algorithmn in blender its open source project and anyone can use what you release the code I mean. Keep that genius protected! OMG! Who thinks like that? Man did a Giant Apple fall and hit you on the head!! God Loves you! Hit me up anytime bcosola@outlook.com


Oh I noticed your mirrors are rectangular which is probably why your circular dimensions render oblong...thats what i meant earlier, also Scot awsome catch on the on the laser charge delay..maybe a heatsink or fan can help with the temperature spike and James super catch with the laser tests! super fix!

[Zypher]

Hmm was thinking of your switch in the signal modulation to create a power shut down for the laser...if you added the am modulation to create the stop...dont forget that am modulation is amplitude modulation and it will affect your ampres and directly affect your voltage. am grows and decreases in gain..maybe this may be an attribute to the squish or unexplained power loss and surge.

[jstrack2]

Hey welcome to the forum!

The effect that I think you are describing where the laser is shining at an angle (so that the max volume would be a pyramid shape) is already corrected for in software. However things do need to be properly calibrated for it to work properly. One thing that will help with that is I know there is work on having the Peachy continuously measure the resin height. Of course with very careful calibration very good results are still achievable. Also I don't think that the rectangle shape of the mirrors should be causing problems either. This is because both mirrors are rotating with respect to the long axis of the mirrors.

I too am curious what the problems are with the circuit. I think that just adding more calibration options to the software will also help with prints. For example if for a small mirror deflection the mirror moves easily but not as much for a large mirror deflection (or vice versa) then software could help with this. However ultimately I think that circuit problems definitely need to be addressed.

Anyway thanks for the suggestions. I think that the more people suggests stuff the better the printer will be. Even if some suggestions don't lead to anything others can. Sometimes very unexpectedly. I personally got interested in being active on this forum after I saw some ideas about how to actively measure the resin level.

[Zypher]

I was wondering if the bulges occured in the general areas of the print or if they appeared randomly in different places, what I mean is if your laser is fixed, the laser dimension at the curing point would be larger at the lowest point since the resin climbs toward the laser.
lased.jpg
with out actually knowing where the bulges appear, tell the truth feel kind of dumb saying this cuz you have probably already fixed this issue, since my only experience with lasers is a laser pointer I torture my cat with. But every little micron the print climbs toward the laser, the size of the beam should be diminishing in size and I would expect the print to be thicker at the bottom. But with a small print this is probably unnoticible a neglible difference. But something to be addressed with taller prints. Have you thought of using Phase modulation?

[rylangrayston]

I was wondering if the bulges occured in the general areas of the print or if they appeared randomly in different places, what I mean is if your laser is fixed, the laser dimension at the curing point would be larger at the lowest point since the resin climbs toward the laser.
lased.jpg
with out actually knowing where the bulges appear, tell the truth feel kind of dumb saying this cuz you have probably already fixed this issue, since my only experience with lasers is a laser pointer I torture my cat with. But every little micron the print climbs toward the laser, the size of the beam should be diminishing in size and I would expect the print to be thicker at the bottom. But with a small print this is probably unnoticible a neglible difference. But something to be addressed with taller prints. Have you thought of using Phase modulation?

As for the spot size of the laser changing with z height, we typically just try to focus the laser beam at infinity so that this is not a big problem

The oblong shape of the laser spot has many causes ( the biggest one is actually the angle at which the beam hits the resin surface )
Thanks for bringing this up, this is something we have talked about at peachy and certainly the more deflection we move the mirrors too the more of a problem it will be.
We have done nothing about this problem yet, mostly because we have been doing small prints at low deflections like within 20 degres (ether side of zero).
When we try printing at higher deflections we expect to run into this issue and we think that slowing the speed we print at when the laser dot is size is larger will be helpfull.

The dot does become oblong for many reasons so it will draw layers like a calligraphy pen. To account for this I think we will need a function that takes spot shape(at xy zero), the deflection and direction, and laser wattage, and outputs a speed that keeps the light per cubic aria of resin exposed at a constant. ( we dont think that the refraction index of the resin will have a large effect because the layer height is only around 10 microns in a typical peachy printer print at this time)

We are very very lucky that there is a huge range of exposure the resin will preform well with, It seems that we can print well with double and even triple the light needed to cure an object. By printing with more light than we need to the printer may be able to survive this problem without us doing anything to counter it. For example if we print with double the light needed and the most the aria of the laser dot grows by is double, then altho some walls will be thicker than others, the printer will still print all the walls.

Thanks again for bringing this up Zypher! Laser spot shape may become an important problem to think about as we push the limits of the printer,
and its nice to have lots of brains working on a problem, looking forward to hereing more of your ideas esp if they come with more descriptive pics