Hi Stefan
We are all quick to jump to possibly incorrect conclusions including myself, but what takes time is understanding the limitations of the printers we use, the models we are trying to make, and most important of all how to read a failed print.
For example the formlabs printers are not designed as heavy weight industrial printers, so when designing a large solid model you will be possibly placing the printer and part under great stress during the printing process and possibly trying to make the printer or resin work beyond its ordinal design specifications. If you have a large surface area to peal off the PDMS the level of suction between the part and bed increases exponentially. I had a part that failed and could slide it around the PDMS but getting it to release took some doing.
The next thing to think about with solid model parts is that as the resin post cures you will increase the risk of cracking due to the way the UV rays penetrate the resin, as I had with four ships funnels of 100mm X 25mm in size that cracked. This was resolved by redesigning the model and making them hollow using a 2mm wall, thus having a two fold effect of reducing the stress on the printer/part and the post UV curing challenge.
Another point to think about is print stability, most people think that a part needs to be rock hard and is finished once removed from the printer, this is a misconception. A part should be stable for handling and once cleaned the part is fully cured during the post curing process be it a UV chamber or left in strong sunlight, and depending on the resin colour and model size will determine the time required to complete this process.
Deck gun using Prototype F1+ black resin at 50 microns
During the testing process of the F1+ blends I learnt so much more about reading a failed print and making adjustments to correct the issues caused (even just tilting a part by 1 degree), and was testing the F1+ resins over a 5 month period in my form1+. The final blend was used to create a 1 metre long model ship to commemorate those lost at sea in WW1, the full story is at hmshampshire.peediemodels.com.
HMS Hampshire - 1 metre long at a scale of 2mm to the foot
Looking at your frog print there are some things to consider:
- Solid vs hollow, was the model solid? Looking at the way it has cracked I would suspect this was the case and hence the stress fractures on the leg.
- Orientation, the way you made the print may not have been the best option, maybe printing the body first then legs afterwards could help reduce the stress on the more delicate items.
- Support material, using more supports at the same level and above the front legs on the body may have reduced the fracture, also orientation of the model as mentioned above may have helped?
- Layer height, F1+ has been designed for fine detail, so 50 or 25 microns may have been a better option? This family of resin is a completely different blend to the DLP blends as it has a reduced reactivity to make it work successfully in the form1 & form1+ printers as it was heavily tested on these units. With DLP printers you can change the exposure times to suit the resin in use, in the formlabs printers this has to be done through the chemical formulation and hence this blend has been designed from the ground up for these units.
- Layer banding, if this is common in all your prints this could be due to a misalignment of the galvo mirrors which is what happened to my form1+, if this is the case I would submit a support ticket.
- Damage to PDMS, this could be caused by the first layer being too thin. Any resin will potentially heat up slightly from the chemical reaction during the printing process resulting in an increased vacuum between the part and PDMS thus resulting in part sticking to the PDMS and possible failures, this also applies to the layers of large solid models (larger the surface area, higher the vacuum).
When I design a new model kit I use the form1+ for all the small detailing parts and any casting or injection points required or medium sized hollow parts, and a commercial DLP printer for the large solid items such as the walls of a building as it has a build area twice the size of a form2 and more flexibility with the exposure control, lift speed and distance. Both printers have had a lot time spent on trial and error to find the limitations of each machine and the resins on the market.
With these points in mind, hopefully this will help you analyse a failed print and increase your success rate with this excellent family of resins.