I just finished a wooden parts tray made from 3 mm MDF and 0.8 mm Tough Wood. It is a little challange to glue it together but it is fast and cheap to make compared with 3D printing or milling from feedstock.
The little notches in the ruler parts every 10 parts help to align the ruler on top of the 3 mm parts devider. Some of the ruler ticks are not perfectly lasered because I did it to fast. Will do it better in the future.
You can place white and black paper strips under the parts to get a good contrast in the hole.
I have not tested it in the p&p machine jet because mine is still under construction. So I will use this for my first tests...
Rainer
from Hannover, Germany