Combining additive fabrication and conventional machining technologies to develop a hybrid tooling approach

Abstract

South Africa is constantly loosing contracts for the manufacturing of innovative projects to the East, due to its non-competitive mould-making industry. The paper will report on progress made in a specific focus area in mould-making, namely Hybrid Moulds for injection moulding. Hybrid Moulds refers to a hybrid between Additive Fabrication and conventional methods through the use of amongst others, Direct Metal Laser Sintering techniques, combined with conventional CNC machining (High Speed) techniques. Although the emphasis is on an economically viable process for limited production runs, once the moulds have been developed, it normally is pushed to its limits to realize production quantities. One of the competitive edges is the cutting of lead-times, which obviously impacts on production costs. Another aspect is the ability to manufacture short runs of injection moulded parts in the required engineering material Realising that Laser Sintering of metals is an expensive manufacturing process, a concurrent manufacturing process was developed. Intricate mould details, which normally are time-consuming to manufacture through EDM processes, were grown as inserts, while the less-complex parts of the mould is machined in Aluminium through 3 and 5 Axis High Speed CNC Machining. Using a 3-axis CNC wire cutter, pockets will be created where the more complex Laser Sintered Metal inserts will be fitted. One of the competitive edges is the cutting of lead-times, which obviously impacts on production costs. Another aspect is the ability to manufacture short runs of injection moulded parts in the required engineering material.