Welcome to the SeeMeCNC Community

Hey all you beta testers, this is the topic that we will be using for feedback/comments etc... of the DropLit. Please try and keep posts in this topic specifically about the assembly/hardware/electronics of the machine, general talk should go in the other topics to keep this less cluttered. You'll be getting an email shortly if you were chosen as one of the beta testers! WooHoo!

Woot! Ordered.

Now to get the rest of the parts!!!

Congrats to all those who received emails this morning!

Reminders to people buying the extra parts...


M5 Nut Anti-Backlash (Printable): http://repables.com/r/349/

Projectors Tested:
*ACER P1283 (Mod Guide: https://www.dropbox.com/sh/9swmwuq1t0mq ... ca3ywj5t3a" onclick="window.open(this.href);return false;)
*INFOCUS IN116a

Projector Specs

We have tested the DropLit™ with a projector with the following specs:

1024x768 or better native resolution

17,000:1 contrast ratio

3,000 Lumens output

DLP only, LCD will not work

Uses Osram 190w P-VIP lamp (removal of the UV filter required)

Ok, first up is the parts we need to print. There are 3 of them on the GitHub. I just confirmed with John how many we need of each:

Anti-backlash nut: 1
Bearing Bushing: 6
Eccentric Bushing: 4

John recommends printing a few extras of each of the last 2. I'm printing at 50% fill in PLA and they are coming out great. I'll post a photo when complete.

cheers,
Michael

YES, MAKE SURE you print the parts in PLA not ABS, as the resin can break down ABS parts if it gets soaked in the resin.

And for all you accepted ones, there wasn't any shipping on the beta kits on the website, surprise! Lucky you guys!

I had read that about the resins and I had white PLA already loaded so I went with it!

Thanks for the free shipping, make sure to put a 10# hunk of lead in my box!

cheers,
Michael

Who said you weren't?

1 each of the parts to print.

Hi guys! I got the email this afternoon and I've started printing the parts now - I've also submitted a couple of pull requests to the GitHub repo; I'm moving some money around and I'll buy the beta kit ASAP.

Thanks for the opportunity!

ordered! Eagerly awaiting!

jdiez wrote:Hi guys! I got the email this afternoon and I've started printing the parts now - I've also submitted a couple of pull requests to the GitHub repo; I'm moving some money around and I'll buy the beta kit ASAP.

Thanks for the opportunity!

Yay Jose!

Printed the parts. They look tiny but hey!

https://cdn.mediacru.sh/b2lnwYRpoAw1.jpg

Missed the boat, but will be following along....
Wonder how long it will be before someone slaps a larger vat on it. After the beta test that is......

Anyone debating the P1283 and x1240? Similar price, similar specs.
http://www.amazon.com/Acer-P1283-3000-L ... B00IJ400E0" onclick="window.open(this.href);return false;
http://www.amazon.com/Acer-X1240-DLP-Pr ... B009KG8VNS" onclick="window.open(this.href);return false;

DavidF, there may be a little wiggle room for larger prints but resolution will be sacrificed. The resolution of the print is directly proportional to the resolution of the projector output and the inversely proportional to the distance the projector is from the vat/build plate. So, if the ideal print resolution for a 1024x768 projector at 6" from the vat moving the projector further away to increase the image size lowers the resolution (in X-Y) of the part and also decreases the intensity of the light which will require a longer exposure time. I think I got that right!

For example, lets just look at the resolution for the Droplit. The Droplit does a 3" build diameter. If the projector can output 1024x768pixels/in the lowest lowest resolution will be the 768pixles/in. So for a 3" part that is 1/256" per pixel (0.004") which is 0.1mm or 100 microns. Moving the projector closer to create an image/part 2" wide increases the resolution by two, or 50 microns. Moving it back increases the part size but decreases resolution.

Regards,
Michael

An easily repeatable projector calibration process will need to be developed as well. I 'm thinking a laser printed target made out of card stock that will sit in the vat. You adjust the projector until a test image aligns with the points/shapes on the calibration card and you're done.

g.

Having never used one of these printers I have no idea what I'm talking about but that won't stop me!

Doesn't the projector have to focus on the build plate surface? Granted, it might only be a cm or so from the bottom of the vat but that might be a few % of the focal point. But the technique applies and makes sense. The points should be at the extremes to get the best calibration I think.

The focus isn't the issue I was referring to. It's the scale of the image being "displayed" on the bottom of the vat. If your focus is perfect, but the projector is too close, your 1" part is going to come in at .75" or smaller.

g.

Good point.

geneb wrote:I 'm thinking a laser printed target made out of card stock that will sit in the vat. You adjust the projector until a test image aligns with the points/shapes on the calibration card and you're done.

g.

That's exactly what I do with my resin printer. Having multiple cards is handy if you want to change xy resolution. And you don't even have to do points or shapes or anything fancy, just have a rectangle on the cards for the full image area, and have the projector show a white screen. Line up the two, and tadaa, all set.

geneb wrote:An easily repeatable projector calibration process will need to be developed as well. I 'm thinking a laser printed target made out of card stock that will sit in the vat. You adjust the projector until a test image aligns with the points/shapes on the calibration card and you're done.

g.

Maybe some clear plastic with a grid etched into it??? Will a laser etch glass? does the petri dish fit into any type of register?

Might be overkill David. Card stock is cheap and it would be pretty easy to print a disc that would fit in the vat and have a circle cutout in the center as the calibration shape. That way not matter how it went in, it's always correct.

g.

Just ordered my kit! Hopefully it doesn't take long to make it to the land of maple syrup and igloos.

Folks, I initiated a discussion in the email list of beta users on a problem with one of the STL files we need to print.

John, I noticed that there may be an issue with the STL for the eccentric bushing. It prints a small "pad" for the first layer and then prints a longer layer for layer 2 that extends out over air.

I opened the STL in my CAD and discovered that the bushing is not laying flat on the X-Y plane. I've corrected the STL and it is attached here.