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.
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.
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.
a) Manufacture of a new functional two-component mould based on a shell + moulding core type;
b) Development of a numerical model adaptable to the geometry and constitution of the new cooling system, which simulates the thermal flows and the distribution of temperatures on the molding surface;
c) Development and application of a thin coating with self-lubricating properties that reduced wear caused by melted glass.
Thus, as a main result, the efficiency of the new mould in an industrial environment stands out, which from the point of view of cooling, compared to the traditional mould, revealed a temperature decrease of 30ºC on the surface of the mould during the production of glass packaging , estimating a significant impact on reducing energy costs in the medium term. In this way, it is possible to foresee important gains in productivity and national and international competitiveness of the companies involved.
From the point of view of exploring the results, we highlight the publication of 3 scientific articles (one already submitted and two in the final stage) and the submission of a provisional patent application regarding the innovative cooling system, developed for the new concept of mold.