Spiral Punching synthetic paper

[SoggyWinter]

My team is producing a run of outdoor textbooks books on 161gsm synthetic paper that we are punching for spiral binding. The bottom sheets of each spiral bundle do not punch clean unless we put a couple of pieces of cover paper underneath the stack getting punched. Is there any way to avoid the extra material use like a different punch pattern (we're using 4:1 spiral) or new punch dies that are sharper? thanks.

 

[kslight]

Are you oiling your dies?

Also I know you say you’d rather not, but you can replace the pins without replacing the whole die..it’s not that expensive. I was quoted a few bucks per pin on my machine.

 

[namelessentity]

Oiling helps, but punching plastic usually causes flare out on the final sheet.

 

[SoggyWinter]

Thanks. Negative on the oiling. Where did you buy replacement pins?