Multilith 1250 Vacuume problems

[Tanner121]

Heyo! So, I'm not very experienced with offset printing, I've had a little bit of learning but it's all really bare minimum stuff. One of the offset presses I run is a Multilith 1250, usually it doesn't give me too much trouble, but I'm having a lot of trouble right now getting it to pick up a set of envelopes I'm trying to run. The envelopes themselves are digi-clear, I'm not sure if that matters, they were just stock that was on hand so I figured why not use it. But, whenever I get the press running and ready to go, the vacuume just doesn't pick up the envelopes to send them through. I've tried fiddling with the air blowers to see if I can position them better, but it doesn't seem to be helping, it'll send some through sporadically, but it isn't consistent and the lag between picking them up causes ink to build up on the plate.

 

[SteveSuffRIT]

I would try increasing vacuum to almost maximum.
You shouldn't have to worry about picking up doubles if separator fingers are positioned properly.
Keep pile height low, maybe add a block to keep front edge of envelope higher than back edge.