I would also look into how many you have up in a stack. Stack drilling 
     has its height limitations for small holes.


______________________________ Reply Separator _________________________________
Subject: Re: Drilling shifted
Author:  [log in to unmask] at SMTPpost
Date:    8/26/96 2:44 PM


     Sounds like drill "wander".  This can be caused by several 
     things.
     Here are a few basic places to start checking:
     
     1.  Make sure panels lay flat on the drill table.
     
     2.  Make sure there is no movement in back-up, or tooling plates.
     
     3.  Make sure tooling pins fit snugly into tooling holes.
     
     4.  If the problem can be traced to one (or more) particular      
         spindle(s), it may be from excessive spindle runout.
     
     5.  Try changing entry material.  
     
     Mark Dowding
     Multek, Irvine
     [log in to unmask]
______________________________ Reply Separator _________________________________
Subject: Drilling shifted
Author:  [log in to unmask] at INTERNET_GATEWAY 
Date:    8/26/96 7:55 AM
     
     
I am in the manufacturing of bare pcb boards. Lately I have been having shifting
problem in the drilling section. Sometimes its just a few holes that's
shifted. Sometimes its random shift. Observation shows the shifting happens 
more on the smaller diameter holes, 0.65mm to 0.80mm. Glad to hear any 
suggestion that can help me overcome this problem. Thanks
     
Bobby
     
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