ShellMould
A new concept of integrating mold to maximize the production of glass packaging to the international market affirmation

Challenge

The main challenge currently facing the glass industry is to solve the heterogeneity of temperatures that occur on the moulding surface of the moulds. The use of different materials for the construction of the bulk part of the moulds and the application of new coatings on its moulding surface significantly changed the cooling conditions inside the mould. These modifications in the moulds associated with poorly developed cooling processes (basically cooling is done by blowing air outside the mould or through linear channels positioned at different distances from the moulding surface), led to a harder and more difficult homogenization of the temperatures in the mould surfaces. In addition to the variations in mechanical properties that may occur due to different cooling speeds (reason why the surface temperature is not homogeneous), the problem is aggravated, since during blowing of the containers, the different temperatures will lead to different values of thickness on that container. The efficient control of the mould cooling rate is, at the moment, the most attractive action to be optimized by the companies that manufacture moulds for glass containers production. In fact, knowing that the problems of premature wear and lubrication are solved, if the cooling system allows maximizing the extraction of heat, associated with a homogenization of temperatures in the moulding surface (or better saying an effective control of the temperature in all areas of the mould), it could easily compensate the higher costs of surface engineering solutions through the:
i) increasing production rates;
ii) decrease of the glass raw material provided ensuring their homogeneous distribution according to the necessities, iii) lighter products/containers with better properties;
iv) energetic improvement of the entire production process.

Solution

Contribute to the manufacture of glass packaging moulds that allow the elimination of problems inherent to cracking, oxidation, corrosion, glass adhesion to the moulding surface, heterogeneous thickness distribution in the final product, all without having a negative impact on production costs, productivity, energy consumption, consumption of expensive raw materials, working conditions and the environment. In this way, it is intended to develop new engineering solutions for moulds used in the glass industry, using a concept that simultaneously allows to integrate the already achieved developments, in which respects to the bulk materials and the surface engineering solutions, and to create the conditions to reduce the costs involved with the acquisition of such material and, at the same time, optimizing an effective cooling system from the point of view of heat extraction and temperature control in the moulding surface.

Objectives, Activities and Results expected / achieved

Goals:
a) Develop a new concept for the manufacture of glass moulds that allows incorporating solutions already developed to combat wear and corrosion of moulds at high temperatures, avoid external lubrication and improve the rate of heat extraction from the mould. This concept will be based on a multicomponent mould formed by a base structure, the bulk in low-cost material, which will support a shell manufactured with the materials already developed in previous projects, namely, a high thermal conductivity alloy as a base, coated with hard coatings with anti-stick characteristics;

b) Analyse and develop the engineering of the interface between the bulk and the shell in order to control the localized extraction of heat during cooling. The materials and the geometry of the interface will be the main factors to be studied. It should be noted that the multicomponent concept of the mould allows, in an efficient and economical way, to change the geometry and constitution of the interface;

c) Conceptualize and develop a model for simulating the thermal behaviour of a glass mould with the characteristics of the concept previously presented. This model should, depending on the production conditions, allow the evaluation of heat flows during cooling and determine the temperature distribution on the moulding surface during the glass packaging production process;

d) Adaptation of the mould manufacturing processes, compared to those currently followed, due to the developments that will be made with respect to new materials and new geometries. It will be necessary to design new moulds that can incorporate the shells and coatings already developed under other projects. It is intended to master the techniques of machining and casting, for the manufacture of moulds with the new concept.

Expected results:
a) Develop a multicomponent mould (bulk + shell) that allows the interface zone to incorporate cooling channels optimally distributed and on the surface of the shell allows coatings with low friction, in a way that together allow the manufacture of defect-free packaging with increases in production rate.

b) To develop a simulation model of the thermal behaviour of a solid mould / shell that, depending on the production conditions, should allow the design of cooling channels that promote an efficient and homogeneous heat extraction and that allows determining the temperature distribution on the moulding surface in depending on cooling conditions and glass packaging production.

c) Reduce the amount of material that has high thermal conductivity, usually quite expensive and apply coatings already developed in other projects to improve the tribological, thermal, lubricating and mechanical properties of the shell surface.

d) Optimization of the machining, sintering and casting strategies, aiming at reducing the manufacturing phases, increasing quality and reducing costs. In the end, the prototypes produced should guarantee a 10% decrease in cycle time, a 20% decrease in raw material use (same goal for the final product mass), a 20% decrease in energy consumption and a 50% decrease in the bounce rate.