The number that jumped out at me: a circular gasket designed to be 50 mm across measured 52.06 mm on a caliper before drying. That is a couple of millimetres of growth from nothing but isopropyl alcohol soaking into the material during washing. Ember Prototypes built a whole explainer around this, and the scale of the swelling is the part I cannot stop thinking about.
The way the piece is put together is thorough. There are bar charts tracking dimensional percent error across the wash, air dry, dehydrator, and cure stages, and weight-gain figures from resin data sheets are laid alongside the measurements. Flexible resin is listed at 39.2 percent weight gain in solvent, tough resin at 4.21 percent, and a standard black resin at just 0.3 percent. That spread explains why some printers chase this problem for years and others never meet it. The shop setup is all there too, with SLA printers, a wash and cure station, and a stainless steel dehydrator doing the drying work.
The core recommendation is to run washed parts through a dehydrator at 30 to 35 degrees Celsius for roughly three hours before UV curing. In the comparison, dehydrated specimens stayed straight while air-dried and blown-dry ones warped considerably. Parts that look flawless going into the cure can come out twisted if solvent is still trapped inside, and curing or support removal while swollen locks those stresses in.
The obvious trade-off is the wait: three hours of drying added to every batch is real time. There is also a bonus section on rescuing parts that have already warped, and apparently this took six years to finish, which shows in the patience of the testing.
Project by Ember Prototypes. Watch it on their YouTube channel: