Browse Prior Art Database

Green Sheet Punch Simulator

IP.com Disclosure Number: IPCOM000051956D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Fredriks, RM: AUTHOR [+2]

Abstract

A tool and technique are described here to quantify adhesion between a green sheet slug and the punch. This is a direct measurement of the propensity of the slug to stick to the retracting punch and clog the hole.

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Green Sheet Punch Simulator

A tool and technique are described here to quantify adhesion between a green sheet slug and the punch. This is a direct measurement of the propensity of the slug to stick to the retracting punch and clog the hole.

This technique can be used to: (1) optimize green sheet parameters for punching (drying composition, burden, etc.); (2) study the effect of punch process parameters on adhesion (punch speed, surface finish, geometry, clearance, etc.); (3) possibly serve as quality control tool for green sheet batches; and (4) possibly evaluate the punch dynamics to eliminate hole clogging from slugs ("trailer" cam for appropriate internal force).

The procedure for operation is as follows:

1. With vacuum on, punch sheet at controlled velocity. Punch force may be read from the transducer output. The vacuum force holds the slug to the carbide tip.

2. Reduce vacuum slowly. If the slug falls off before the vacuum is reduced to zero A = W-pi r/2/ nu

where A = adhesion (dynes)

W = weight of slug (dynes)

r = effective radius of small center hole in

carbide tip

nu = pressure below atmosphere pressure at which

slug drops.

3. If slug is still on, impose a sinusoidal motion on rod of frequency f and amplitude delta. Increase delta (or f) gradually until slug drops. Then A = W (2 pi f)/2/delta.

Extrapolation from lab slugs (typically 1/4" Phi) to product slugs (typically
.005" phi) can be made theoretically and/or experimentally, for instance, by punching...