I started this thread several weeks ago but due to work commitments couldn’t follow up on progress until now. Re-igniting the thread following some tests. Big thanks to @DavidRosenfeld for your help. Also thanks to @KevinHolmes - I have replaced my large mirror with help from your resources. Works great.
This was the original thread All prints fail after a certain time/height
To cut a long story short I am an experienced Form 1+ user and keep my machine very clean at all times, including vats and resin. I have replaced the large mirror and cleaned galvo mirrors as and when needed.
Despite this all of my prints drastically fail at a certain height almost as if cut off suddenly, and quality is poor to terrible with flakes everywhere.
I have now conducted a flare test and taken some pictures of my most recent spectacular fail. To my eye it looks like my laser is ok - no major flare, a very faint square outline when the cover is open.
Laser Spot Tests:
Example of Failed Part:
So it seems to me I have a reasonably good laser, a clean machine, new mirrors and catastrophic fails!
Any suggestions as to what could be causing this would be greatly appreciated. @DavidRosenfeld I still need to check for issues with the travel of the build platform along the screw thread - this is on my list.