Graduation Year

2004

Document Type

Thesis

Degree

M.S.M.E.

Degree Granting Department

Mechanical Engineering

Major Professor

Crane, Roger.

Keywords

Molding, Cooling passages, Glass bottle

Abstract

Narrow Neck Press and Blow (NNPB) process is used to produce light weight bottles. The gob of molten glass is delivered to the blank mold and a specially designed narrow diameter plunger is used to form the finish or mouth and the parison as it presses upwards. Invert and final blow takes place followed by take-out and annealing. Anchor Glass Container Corp. (AGC) uses NNPB technology in their glass making plants. The problem experienced by AGC in the process is that the heat dissipation through out the mold is not uniform and hence there is a non uniform temperature distribution in the finished bottle extracted from it. Specifically the shoulder region of the bottle stays at a higher temperature when compared with the other regions, becoming the limiting factor in determining the rate of bottle production.

Excessive temperatures in any region leave the glass insufficiently rigid, allowing the bottle to sag or lean. An increased rate of production which demands faster and effective cooling of the bottle is desired and is the ultimate goal of this research effort. This problem can be effectively solved by increasing the amount of heat transferred from the mold to the cooling air, which can be done by increasing the surface area of the cooling passages. A mathematical model for calculating the amount of heat transferred to the cooling air is proposed in this thesis. The air properties at the exit of the mold and the amount of heat transferred by each cooling passage were obtained by using MATHCAD. A 2 dimensional numerical simulation for the final molding was carried out using ANSYS and the temperature distribution for the mold and glass were obtained.

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