No, when emulsion expires it loses the ability to react to light, so would not expose in the first place.
Emulsion can get locked in screen from reacting with ink and cleaning chemicals. This is much more likely to happen if the emulsion was not cured all the way through, as it remains reactive until fully cured by UV. Things that can contribute to undercuring: too thick a coat of emulsion, emulsion not dry enough when exposed, exposure too short/weak.
To get better results, improve any of the above that you can, do not use harsh chemicals not intended for screen printing, and post-expose the screen (after washing out the image, fully dry the screen and set it out in the sun for a few minutes or on the exposure unit for at least 2 or 3 times a normal exposure time).
Emulsion can get locked in screen from reacting with ink and cleaning chemicals. This is much more likely to happen if the emulsion was not cured all the way through, as it remains reactive until fully cured by UV. Things that can contribute to undercuring: too thick a coat of emulsion, emulsion not dry enough when exposed, exposure too short/weak.
To get better results, improve any of the above that you can, do not use harsh chemicals not intended for screen printing, and post-expose the screen (after washing out the image, fully dry the screen and set it out in the sun for a few minutes or on the exposure unit for at least 2 or 3 times a normal exposure time).
