Who are buying your drills from. Some mfgs have a large web thickness 
and a small % flute volume. Check it out. A large web can double 
drill wander.

> Date:          Mon, 26 Aug 96 14:52:41 EST
> From:          "Jim Spendow" <[log in to unmask]>
> To:            [log in to unmask]
> Subject:       Re[2]: Drilling shifted

>      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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