Becoming Disillusioned With the Utility of Resin Printed Components

[cliffyk]

As the subject states, I find my self becoming increasingly disappointed in the utility/usefullness of resin printing. As the FDM crowd are quick to point out i find printed components to be absurdly brittle, with low overall tensile strength (the claimed TS for most strikes me as wishful thinking). Any prolonged exposure to daylight--or even moderately strong higher color temperature artificial light seems to exacerbate this to the point of making resin printed structural components completely unreliable. Time seems to be a factor as well, as though a "self-destruct" clock is set at the end of the printing process.

FWIW I am post-curing in a modified 0.7 ft³ microwave oven fitted with a 30 W 405 nm LED.

I have tried numerous different resins, having best luck with Phrozen's Beige Flex Functional Resin--not cheap @ $54 per litre from Amazon (but it's been unavailable there and elsewhere [typically @ $100/litre] for over 6 months). Has anyone found any other resin that comes close to it's characteristics:

Tensile Stress (Break): 40 MPa
Elongation: 50-60 %
Tensile Modulus: 192 MPa
Hardness: Shore 65D
Heat Deflection Temperature @0.45MPa: 100C

The FDM guys routinely print compliant mechanisms with materials like PETT and Nylon--I don't think that is possible with any SLA resin; but I'd be happy just to print an occasional 2-piece pinned hinge or other hanger/support component that could be trusted to support even 3 or 4 pounds.

Custom peg-board clips are popular with the FDM folks, those that I have printed can barely support 1/10 of their design goal load, and degrade further as they age (a couple weeks seems to be how long resin printed stuff remains usable).

The system does not seem to be especially good at producing even modestly robust mechanical components with more than a 30-day useful life. 

I tried making an IC test clip like this; using Siraya Tech's "Sculpt" resin (one of the better I've used):



I had made the hinged sections 25% or so larger and increased the pivot pin diameter. It still failed miserably, barely surviving assembly and breaking on first use.

Quite disappointing.

Thoughts anyone?