Nordson Corporation

William R Coker

Charles H Scholl

Jan J Wydro

An apparatus (10) and method for reducing stringing of adhesive from a nozzle (20) of a dispensing apparatus (12) includes a pneumatically driven cylinder (50) which translates the source of adhesive co-linear with the translating substrate (100). The gun (14) is alternately translated at speeds equal to or greater than the substrate (100), with the object of causing the string (102) of adhesive to fall back onto the substrate (100) in a desired location rather than become airborne and fly away to undesirable locations.

Method for a reducing the stringing of adhesive from an applicator

A master control for preventing the operation of a hot melt adhesive pump motor in a hot melt adhesive dispensing system until the adhesive has reached a dispensable molten state. The hot melt adhesive dispensing system includes an adhesive melting tank and a heater for heating the tank, which in turn heats the adhesive. A heater control energizes the heater when the temperature of the tank falls below a predetermined temperature so that, after an initial 'on time', the heater control de-energizes the heater for periods of time of increasing length as the temperature of the adhesive increases. The master control enables the operation of the adhesive pump motor when the 'off time' of the heater exceeds a predetermined period of time. This predetermined period is selected so that at the corresponding adhesive temperature the adhesive is in a dispensable molten condition.

Pump motor master control

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.

Growing community of inventors

Lilburn, GA, United States of America

William R Coker