Nordson Corporation

Jan J Wydro

Charles H Scholl

Raymond M Fetcenko

William R Coker

Ralph P Zuponcic

A method and apparatus for applying hot melt adhesive to the parting surfaces of sections of a foam pattern employed in the lost foam metal casting process includes an adhesive applicator operable to dispense a layer of adhesive in a desired pattern onto a transfer surface. The parting surface of a section of a foam pattern is then brought into engagement with the transfer surface so that at least a portion of the adhesive adheres to the parting surface for assembly with a mating section of the foam pattern. The adhesive remaining on the transfer surface after engagement with the parting surface is scraped off and a new layer of adhesive applied in preparation for another section of the foam pattern.

Apparatus for adhesive transfer

A method and apparatus are disclosed for controlling the density of dispensed hot melt thermoplastic adhesive foam in order to assure uniform foam characteristics. In order to create the hot melt adhesive foam, air or any relatively inert gas is mixed with the thermoplastic adhesive while the adhesive is in the molten state, and the mixture is then pressurized so as to force the gas into solution with the molten adhesive. As the molten adhesive/gas solution is dispensed at atmospheric pressure, the gas is released from solution and becomes entrapped in the adhesive so as to form a homogenous closed cellular adhesive foam. According to the practice of this invention, the supply of gas is periodically discontinued so as to prevent an excess volume of gas from being admixed with the molten adhesive whenever foamed adhesive is not being dispensed, thereby stabilizing the density of the adhesive foam.

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Lilburn, GA, United States of America

Jan J Wydro