225 holes to be precise!
The largest cause of failures for me has been builds falling off the plate. The holes really help prints stick to the plate - much better. It adds more surface area in contact, and greatly helps prevents slipping.
I also lined the holes up with the grid in PreForm, so even for small prints I know it will land on a hole.
If there is any interest, I have a CNC machine and can produce them for purchasing for a fair markup.
My problem is the opposite. Sometimes it takes a significant amount of effort to remove my prints. The only meaningful variable I can think of is the Z axis zero-reference, which will control how many base layers get printed “compressed” and adhered. If your prints are falling off, you might try tweaking the Z to be a little further down so more initial layers get printed compressed… FL recommended I increase the Z height to address my overly-stuck prints but I haven’t tried it yet. I’m OK with them being hard to remove so long as I know the bases will stick good.
When I used the regular resins (Formlabs Clear, Gray, etc.) the builds took significant effort to remove as well.
But all of the castable resins I have tried (which is what I got the printer for) just don’t seem to stick nearly as good.
Not sure how the hole would help because you will lose surface area for the parts to stick to. Best bet if your parts are falling off is to make sure the platform is a little scuffed up.
If you still have problems then it is possible you need to fine tune the platform so you have more pressure. It might be off just a little and enough so you your not getting good first few layers to adhere.
No you don’t - the holes are filled with resin that has been bonded - that translates to increased surface area. See:
In addition to more surface area, it gives the raft cleats which helps with the lateral peeling forces.
Already done that.
Done that as well. 
What resin is that? Doesn’t look like Formlabs. If it is a 3rd party resin then it might be slightly under exposed which would cause it not to adhere to the build platform. On the other hand that extends your tanks life.
Even filling the holes a little bit like that I think is still less surface area than without the holes. But it probably helps to have the grips since it has a sliding force to separate each layer from the tray during printing.
Actually they have slightly more surface area in contact. They fill about 0.6mm deep, and with a circumference of 2.29mm, that means they have about about 4.31 square mm in contact. Compared to the area of 4.15 square mm for the same circumference of the build platform.
To double the surface area where the cleats are, I should drill the holes only about 0.5mm deep. That way it would get full plate contact plus the additional area from the sides.
Not probably, definitely.
If there is any interest, I have a CNC machine and can produce them for purchasing for a fair markup.
Out of curiosity, what kind? I"ve got a little Taig 4 axis machine I’m quite fond of. Benchtop in size, but strong enough to cut steel (or even Titanium if I had a cutting lubricant system).
IMO, anyone who’s really serious about making stuff needs both additive and subtractive prototyping capabilities!
I have a rather large self-built machine that has a 4x8x2 foot usable area. I also have a Bolton 750 (Chinese import) converted to full CNC. The bolton has both a lathe and mill with cutting lubricant system installed.
The big machine can easily cut wood, foam, plastic, etc. and can cut metal if it takes its time (it doesn’t have cutting lubricant installed).
The biggy:
For sure. One project I have on my to-do list is print/cast the parts I need to get my big machine running 5 axes.
Nice!
Now that machine could be fun. Toss another axis on it and start mass producing totem poles 
