Evening sir!
I started a pretty extensive thread on the Form 4 a while ago My experience with the Form 4(B) so far/ Semi-Review from a Semi-Industrial User Perspective, I hypothesize the dimensional inaccuracies you have experienced being from what I have experienced, as a result from immature print profile settings and material limitations from what I have seen. Very disappointing indeed to see the Form 4 not able to achieve 0.2 tolerances, we have found this as well extensively. If it’s fitting two printed parts together you’ll probably have to allot for 0.2mm each side or play with 0.2-0.5mm if you are going to mate with another machined part/ fastener. This is of course assuming the part does not warp during printing and afterwards…
4 reprints and ultimately having to hack the part with a dremel to get this to work is a lot of wasted time and material indeed, and in my opinion far from acceptable for a $5000 printer advertised to be a hands off industrial system. I do not actually believe you are doing anything wrong, I think your .form file 1 and 2 should have made imperfect but reasonable results, and .form file 3 should have definitely mostly printed fine. I believe the current Formlabs guidelines of just orienting flat surfaces 10-15 degrees is severely deficient, and Form 4 cannot achieve the “knifeedge” overhangs and steep/ 90 degree overhangs like other industrial DLP printers. Somethings that I found to kind of work around this from my experience:
- 30-45 degrees is your friend, angle a flat part up BOTH X and Y axis. The printer really cannot do any steeper overhangs even like 15-20 degrees well, long/ straight sections attached from nothing to supports will really suffer as well.
- Pretty much the auto orient is junk, at least orient the part yourself and then using auto support is reasonable. You can then edit the part to avoid nubs on critical areas.
- It unfortunately will take time and a lot of repetition (took me 6 months to 1 year) to fully able to learn orienting and supporting. There is a lot of nuance and is very often not intuitive like FDM printing, and now I do every support and orient by hand.
Here is how I personally would go about printing this and most flat profiled things:
Orientation_Example.form (902.6 KB)
Here I purposely kept tips on edges so they can be easily sanded down. After a mineral oil dab/ polish (total black magic) on the sanded areas you will usually not be able to tell anything was there.
Some additional considerations:
- I have pretty much currently given up on getting general purpose materials, especially grey V5, to work reliably. I experience significant warping during printing with initial 5-10mm of the part warping significantly from the rest of the model with overall poor accuracy. You can read all about this in my thread I linked to. Again, I hypothesized this being the result of not fully developed print profile and material limitation, currently still waiting for a fix from Formlabs. Tough engineering materials are way worse.
- Precision model material is about the same material properties as Grey v5 and general purpose v5 material including grey, but is far more accurate. Not perfect, but I am currently printing everything in this due to less warping during and after printing.
- You can read the datasheets yourself, but general purpose v5 and precision model are ultimately as strong as generic PLA plastic in terms of tensile and impact strength practically from what I have experienced. Not terrible, but not great. Printing in the Tough materials (1500/ 2000) are way more finnicky and prone to failure so I will not recommend them personally at this point in time. For what it’s worth, seems like you are making enclosures for electronics and none of these materials are ESD safe. I haven’t seen like a microcontroller getting fried from static electricity or anything inside these prints, but on paper that is a risk. Formlabs ESD resin exists, but I never used it and have no knowledge of its reliability on Form 4. You may want to try depending on how important this electronic/ your client is.