Life expectancy of the PDMS layer has typically been give in terms of liters of resin being used, however that number is extremely vague and should not be the measuring stick we use.
I think it’s time to actually put some meaningful numbers behind this.
We all know that different resins have different curing/exposure rates which affect the PDMS, but we don’t know what the actual numbers are behind them other than the tough or castable is harsher than white or grey.
Layer resolution will have a great impact on the life expectancy. As a simple example. take a 100mm solid cube; it’s approximately 1 liter of resin. Printing this cube at 01.mm without supports will expose the PDMS 1000 time (1000 layers), but printing it at 0.025mm will expose it 4000 times. Or put in other terms the equivalent of 4 liters at the lower resolution.
I think it’s about time that we get a more accurate idea of what to expect out of a tank based on empirical data which FormLabs already has and can provide.
They only offer 2 types of tanks with 2 types of materials, PDMS and FEP or whatever they have on the new LT model. So the life expectancy should be attached to the resins, rather than the tank. For example:
Grey v.4 (RS-F2-GPGR-04):
PDMS = 10,000 exposures
FEP = 100,000 exposures
Tough v.5 (RS-F2-TOTL-05):
PDMS = 3,000 exposures
FEP = 25,000 exposures
Obviously my numbers are just a place holder, but the actual numbers exist. FormLabs has already done this testing and knows exactly how many times you can print each and every one of their resins on the various surfaces they’ve used.
This way, we will know exactly what we should expect from every resin and tank we buy. I understand that one’s mileage may vary, but these types of numbers are certainly more useful than “your tank will last about 2 liters of resin”.