nanoDLP

Hello Dear Community,

This is my first post. I finally got my first successful print today and so I decided to subscribe to:
1) say a big thank to Shahin for it amazing piece of software and to make it free for DYIer like us. Thank to him, my dream to get a SLA 3D printer for less than 300euros became true.(I only bought the fullHD projector, the Raspberry Pi, the resin and the isopropyl alcohol)
2) to share my experience with users to help newcomers.
3) share a trick I've found to replace expensive FEP film by an alternate one.

So here a liste of pb found during building/testing and how I managed to solve them:

Top-down Vs Bottom-up:
I started to build a top-down printer to avoid the expensive VAT. (based on Gumroad tutorial with salt water to reduce resin volume). But after a few days trying to calibrate the machine (aligning the building plate with the resin surface, focusing projector on this same surface, etc.) and finding the Mandreas' post sharing his own experience (which lead to build a VAT anyway...), I switched to a bottom-up solution which is much much more easier to setup.
For those who still want to do a top-down solution, here 2 tricks:
- the end switch for the leadscrew shall be located on bottom (on top for the bottom-up configuration)
- the 4 pins of the step moor may need to be reversed to change the direction (as NanoDLP has no option to do it by software to my knowledge)

The WIFI stability:
First connection: it could be obvious but the first connection shall be done by ethernet in order to connect to Nano DLP (via browser) and entering the WIFI WPA key. (not alway simple when the printer is located at the second floor and the router at first one.. But you can still move only the raspberry Pi)
Stability: I have a lot of disconnection when using the Rasberry Pi3 wifi (less than 1 mn to a few minute stable connection). It is a nightmare to setup NanoDLP when you have to wait for each reconnection. I've found no solution for this pb at the moment (beside a 30m ethernet cable in the stairs ). I think the issue is shared between my router wifi stability and the raspberry Pi small antenna. But not sure (all other device in the house work with Wifi)

The 100000000 pulses:
During the very first Z axis test, the machine kept moving (the log were showing "100000000 pulses / about 40meters"). I wonder why NanoDLP sent this command until I understand that is was a normal high value (hard coded) to be sure to reach the end stop switch during printer power on. As I did not have a functional end stop at the beginning, the motor keep moving. And there is no mean to abort an ongoing execution line, even with the "force stop" function. I understood it is a normal behaviour to allow NanoDLP to restart a print after a fail. But it would be nice to have a real emergency stop button, especially during building phase .

The Shutter appetite:
I use a 6V servomotor for the shutter connected directly to the GPIO. I gave a try to that solution (beside the warning in NanoDLP mentioning the risk to damage the raspberry Pi) thinking that the servomotor was small (RDC-85B mini) and could not take so much current. I was wrong. the GPIO pin fried after a couple of test (weird behaviour of the RPi and HDMI display). Hopefully, only 1 GPIO pin seem to be dead. Listen NanoDLP warning!

And finally, the FEP alternative trick:
After I resign to build a VAT, I decided to build a flex type. But before purchasing FEP antistick film which is quiet expensive, I tried several alternative. First the food film: it is too stretchable. Could work with a supporting transparent plate (with hole on the surrounding to allow air to pass through and decrease suction effect). I did not investigate too much this solution but I saw a youtube video of someone who manage to do it. As a second attempt, I use the protection film of the Macbook ( the clear transparent hard film that Apple put around Ipad and Macbook). This film is very resistant and can be tightened a lot to get a tambourine. I sqeeze this film in between a toilet pipe () and a 100mm diameter check valve housing (). It was very tight and I thought that there will be no room for the film thickness. But actually it worked with a quiet high tension in the film and the famous tambourine sound.

Some picture of my printer:
https://drive.google.com/open?id=0B-v7r … I3bjVmdVVz
https://drive.google.com/open?id=0B-v7r … F6YnkzLVNn
https://drive.google.com/open?id=0B-v7r … xTa0xobDhF
https://drive.google.com/open?id=0B-v7r … t6MHJfd29N