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Improving Material Property in a Selected Area

IP.com Disclosure Number: IPCOM000080902D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Poynter, J: AUTHOR [+2]

Abstract

Physical characteristics of a molded part in a selected area are controlled, by dispersing or placing specific particles in the desired area of a mold. Material characteristics thus improved include wear resistance, electrical conductivity, magnetic properties etc. The process is particularly useful for fabricating thermoplastic parts which contain hard refractory particles in a selected area. Preferably the particles used do not react with the base material such as a polymer, but should be wetted by it. For instance, nickel coated powders can be dispersed in a mold cavity, attracted to the specific area to be improved such as by a magnet and the base material injected into the cavity.

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Improving Material Property in a Selected Area

Physical characteristics of a molded part in a selected area are controlled, by dispersing or placing specific particles in the desired area of a mold. Material characteristics thus improved include wear resistance, electrical conductivity, magnetic properties etc. The process is particularly useful for fabricating thermoplastic parts which contain hard refractory particles in a selected area. Preferably the particles used do not react with the base material such as a polymer, but should be wetted by it. For instance, nickel coated powders can be dispersed in a mold cavity, attracted to the specific area to be improved such as by a magnet and the base material injected into the cavity.

Shown is a mold 10 which can be used in this process. Cavity 11 is configured for forming a cam, with a permanent magnet or electromagnet 12 being located so as to define the tip area 13 of the cam. Magnetic powders such as nickel coated alumina are introduced to the cavity 11 and excess powder removed such as by forced air. The mold cover, not shown, is attached and the polymer such as nylon injected into port 15, using standard injection molding techniques. Nylon will wet nickel coated alumina and hold it in place after the nylon mixture has set. Cams formed by the mold shown will exhibit marked improvement in wear characteristics along the tip, which corresponds to area 13 where a cam frequently must withstand excessive friction loa...