Print layers drifting towards rear

[cliffyk]

Another thought I had while driving today. In your diligence you are running close to exhausting the pool of potential mechanical alignment issues. So let's consider the overall process.

It occurred to me that any consistently uneven intensity, phase, or wavelength of the curing light across the field would cause deviations in the cured thickness of each layer. a deviation that would logically be cumulative as the number of printed layers increased.

Not quite certain how to gauge this though.

At 405 nm the sensitivity of our eyes is pretty damned poor and Intensity/phase/wavelength variations that might be sufficient to cause such cumulative variances over 50 to 110 layers may well be below our unaided ability to visualize. I know from recent observations with Elegoo's water washable resin that a 12.5% increase in exposure (8 s to 9s) made the difference between hangers breaking from the main body of a print and not. +12.5% change in exposure is not a whole lot.

Perhaps some sort of pattern analysis of a digital image of the LCDs transmission could spot such variations.

I know this has to be intensely frustrating for you, nonetheless I enjoy our ability to discuss the issue--too bad we cannot be tossing back pints while doing so...