Can SLA printers produce strong engineered parts?

Question

I have an FDM printer, I printed ABS for years.

Since SLA printers became really cheap lately and are able to print finer details, are there resins out there as strong as ABS/PLA?

Answer 1

Not inherently

SLA prints are usually very glasslike in their internal structure and thus are often quite brittle: They tend to break with a very distinct, sharp failure mode. Their compression strength is often high but their tensile strength is limited, and their resistance to side loads is low.

Due to the printing method solidifying the resin layer by layer, there is an inherent stress pattern, resulting in the items having a much lower strength than monolithic casted resins that cured in shape.

Yes, as an intermediate step

However, their print resolution makes them an excellent solution to create a mold which then can be used to create the actual part. Due to the thermal properties, one can't melt SLA prints, making lost-model investment casting not available for many standard resins, though there are methods to burn out some resins and other specialty SLA materials are meltable.

Greensand casting isn't available for most resin or plastic materials. However, if the part is removable from the sand shells, it is a method that could make metal copies of your SLA printed masters.

As an alternative, rotary casting might be possible if the part can be removed from halves. Also, such prints are perfectly suited to making high detail silicone molds with limited undercuts, into which high durable liquid plastics (PVC) or 2-component casting resins can be cast for curing. In contrast to SLA resins, these cure into a monolithic product, which then is often much more durable to side loads.

Answer 2

I'm an owner of both an FDM printer and a resin one:

I've long searched a resin capable of printing durable objects even in tiny details but with poor luck. I've tried ABS-Like resins, and they provide a slightly better resistance than regular resin but do not expect great improvements; I've tryed the siraya tech Blue V2 that is for sure much more durable but eventually would fail on the smaller details...

In the end i think I'll try the flexible resins like the Liquicreate flexible X or the Siraya tech Tenacious because those (similarly to TPU in FDM) can better absorb energy from impacts and having a smaller young's modulus can help when under load.

Answer 3

^{The following was taken from this rejected suggested edit. If the edit's original poster, Kevin Tuber, posts their own (expanded upon and elaborated) answer, then this Wiki answer can be deleted.}

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Investment casting, or “lost-model” casting can be done with SLA resin - I do it every day at SpaceX, with the caveat that a furnace set to 730°C to 870°C could burn it out of a shell if one had a suitable process.

Due to the thermal properties, one can't melt SLA prints unless you’re using a burnout furnace set to around 730°C to 870°C and have a suitable process for shelling the resin, making lost-model investment casting unavailable.