초록 ▼

An on-demand fast cycle mold for producing injection molded products such as polypropylene blister package bases. The on-demand fast cycle mold has a heated and cooled hot runner system which provides a short response time and optimal temperature control. On-demand injection molding is made possible

An on-demand fast cycle mold for producing injection molded products such as polypropylene blister package bases. The on-demand fast cycle mold has a heated and cooled hot runner system which provides a short response time and optimal temperature control. On-demand injection molding is made possible by a pulse modulated closed loop mold cooling system, the cooling design of brazed gate inserts, and an effective layout of the cooling channels. The programming of the software for a computer control system has also been designed to achieve on-demand injection molding. The design of the closed loop mold cooling system incorporates an advanced cooling circuit layout, and provides for easy maintenance and better quality control of the coolant which significantly reduces corrosion and scale buildup. Mold cooling is controlled by sensors installed inside the mold which are used in feedback control loops. The brazed gate inserts provide precise mold temperature control and improved cosmetic appearance of the molded packages. The use of a needle-valve injection nozzle results in reduced cycle time and improved moldability.

대표청구항 ▼

[ We claim:] [1.] An on-demand fast cycle mold system for producing injection molded products, comprising at least one mold, wherein the mold includes an upper bowl insert defining an upper surface of a bowl being molded and a lower bowl insert defining a lower surface of a bowl being molded, the up

[ We claim:] [1.] An on-demand fast cycle mold system for producing injection molded products, comprising at least one mold, wherein the mold includes an upper bowl insert defining an upper surface of a bowl being molded and a lower bowl insert defining a lower surface of a bowl being molded, the upper bowl insert includes a central coolant flow passage extending longitudinally centrally therein for conveying coolant for cooling the upper bowl insert, a hot runner system for supplying molten plastic to at least one injection nozzle, a high thermal conductivity gate insert surrounding said at least one injection nozzle and having an annular coolant flow passage therein positioned around said at least one injection nozzle to provide precise mold temperature control and improved cosmetic appearance of the molded product, and the mold system is both heated and cooled to provide a short response time and optimal temperature control, including a pulse modulated cooling system for cooling the mold system, wherein in operation of the pulse modulated cooling system, during each molding cycle, after the mold is filled with molten plastic the heat input of the molten plastic is matched by a timed pulse of coolant, after which the mold is allowed to dissipate heat gradients and seek equilibrium such that the molten plastic is cooled, an electric heating system for heating the mold system, a plurality of temperature sensors installed inside the mold system, which are used in control loops to control the flow of coolant through the pulse modulated cooling system.