3m Innovative Properties Company

Michael J Tichy

James M Nelson

Robert A Yapel

Robert B Secor

Raghunath Padiyath

Mark J Stevenson

Jennifer L Trice

Charles N DeVore

Keith R Bruesewitz

William R Dudley

Chris J Tanley

Bruce D Shalles

Andrzej P Jaworski

Lori T Holmes

A center-fed single cavity slot die () for coating particulate suspensions without creating the coating defect known as center banding. The die has a flow obstruction device () located in the die cavity () in a position such that the flow obstruction device blocks undisturbed straight-line flow of coating composition from the feed inlet to the die coating slot. Also, a coating process that employs the disclosed coating die. Types, shapes, sizes, and compositions of particles that may be used, and viscoities and particle concentrations of the coating composition which may be used.

Die for coating suspensions with flow obstruction device and method of use

Computer implemented method for making a die includes: selecting coating uniformity required to produce a particular coated product with the die and a value for one or more dimensions of the die; determining (using a mathematical model determined by regression analysis) total indicated run-out (TIR) of a die surface and dimensions of the die not having a user specified value; and machining die part or parts to the determined TIR and dimensions. A thermal treatment process for reducing the number of finishing (e.g., grinding) cycles needed to produce a desired die flatness is provided. A coating fluid rheological characteristic can be an input to the method.

System and method for designing a die to yield a desired coating uniformity

The invention is a method of forming extrudate having substantially uniform thickness. A shim is formed which has a thickness variation of less than or equal to about 0.5 mil (13 microns) total indicated runout. This shim is disposed between a first die portion having a first surface and a second die portion having a second surface. A slot is formed between the first surface and the second surface. The slot has a height dimension substantially the same as the shim thickness. Flowable material is extruded through the slot.

Method of improving coating uniformity

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Henning, MN, United States of America

Michael J Tichy