Public Funding for Pecm Systems Ltd

Silicon carbide (SiC) is a ceramic, typically sintered-multicrystalline. Single-crystal SiC has semi-conducting properties superior to silicon allowing smaller and thinner transistors and integrated circuits (Semi-Conductors), able to work at higher temperature and higher current/frequency. A key application is power electronics, which are important for electric cars, etc. The SiC-Semi-Conductor market is large and growing rapidly; value £1.3bn in 2023 growing to £6bn in 2030 (CAGR 23.5%). However, SiC is hard to cut leading to reject rates of up to 50% when conventional diamond machining is used. We propose applying experience of electro-chemical -machining to improve the quality of SiC cutting and increase yield leading to a significant commercial potential in global markets.

Many industries, including electronics and medical are interested in miniaturisation, but this requires the ability to machine increasingly small components with superior geometries and surface topologies. Our conventional electro-chemical machining (ECM) machines are sold to customers globally and operate at the macro-scale, attaining surface roughness ~0.2 micro-metre Ra (depending on material grain). Although high-quality, our customers state this intricacy is not conducive for machining at the sub-micro scale and does not deliver the array of 3D geometries modern industries aspire to. Our new approach will address these short-comings and have profound industrial and social benefits. PECM (in collaboration with Brunel University & Faraday Motion Control) wish to engineer a 4-axis micro-pulsed electro-chemical machine (micro-pECM) capable of fabricating sub-micro scale multi-dimensionally in a single machining iteration; with Ra down to 5-nano-metres. Brunel University have proven the concept by building a laboratory single-axis prototype through two FP7-projects. Brunel University now wish to build upon this success and partner with PECM-Systems and Faraday Motion Control to develop the above proposed test machine. BENEFITS: (1) customers can develop new, miniaturised products to drive sales; (2) cost effective system (relatively cheap technology and no specialist tooling required); (3) reduced material consumption (environmental benefit. . Key technical risks are associated with: (1) producing desired rate of electrical pulses; (2) Real-time inter electrode adaptive gap monitoring, control of multi-axis and material removal rates not achievable in a commercial machine; (3) ensuring motion control specification and operational mode is developed coherently to ECM hardware and power supply system.

In addition to our original scope, we now also wish to also investigate the following in our final quarter: Credit cards require a security secure holographic hot foil print on the reverse side of the card. The hot foil printing on to a rigid substrate is extremely difficult and holographic foil compounds this difficulty. We wish to investigate in this final quarter whether our punches could be applicable for the latter purpose. We are confident that we have sufficient funds available in our existing grant to make this investigation and to manufacture the necessary tooling to produce sample dies for examination and testing by our credit card customer. To achieve this, we wish to move funds from categories, ’other’, ‘subcontract’ and ‘travel’, into, ‘labour + overheads’ and ‘materials’. Costs allocated to subcontract and capital usage are not affected by this request. Formal signed letter supplied.

Current art electrochemical machines (ECM) are: (1) High cost; (2) Single axis; (3) Not modular i.e. additional axis modules and associated bearing rails/gears cannot be implemented limiting a diverse range of components that can be manufactured from a single ECM machine. (4) Current operations waste expensive material as 2-3 solid metal cathodes are manufactured before final tolerance is achieved. The above issues impact the ability for small companies to tender for lucrative manufacturing contracts. And remain competitive. We aim to engineer novel methods to allow high quality components to be manufactured with intricate geometries to smaller tolerances with greater precision. BENEFITS: (a) Low lead-time component manufacture; and (b) Very little material wastage.

Electro Chemical Machining (ECM) has advantages over conventional manufacturing (milling/turning) i.e. less material waste, able to machine any conductive metal & higher quality surface finish. pECM systems Ltd (PSL) believe ECM technology could be advanced. Current cathode development is lengthy & high cost, machined to high surface finish from materials like copper/tungsten, requires much iteration till final production cathode geometry is achieved capable of producing finished components. There are few manufacturers of ECM equipment; machines are typically single axis (machine one side at a time) & custom built to repeatedly manufacture identical components. ECM process requires 2-3mm additional material on roughed components, enabling removal of defects after ECM to achieve final geometry, wasting expensive material. Pulsed ECM (PECM) offers increased efficiency, improved energy use, better surface finishing allows components to be nearer net shape pre process, thus less wasteful of expensive material. This is critical for industries such as aerospace, where expensive alloys are used. The problem facing PECM/ECM is that machine tools are bespoke & single axis. PSL believe that current art can be significantly advanced with the proposed project.

Pulsed Electrochemical Machining (pECM) uses the principles of ECM but pulsed voltage/current providing; lower current improving energy usage, lower material removal rate & better surface finish, vastly improved dimensional accuracy machining hard/high strength, temperature resistant materials, smaller machining gaps between cathode & workpiece to produce finer detail, follows geometry of the cathode reducing cathode reshaping/regeneration, has less metal Hydroxide waste (hard to dispose of). The problem facing the conventional ECM market is components must have 2-3mm additional material prior to machining to enable removal of defects/achieve final geometry, wasting expensive materials. Components can be nearer net shape if manufactured using pECM. Typically compressor/turbine blades are forged to oversized dimensions, machined by conventional methods (milling/turning) or, one side at a time using single cathode (axis) ECM leaving a “pip” which needs removing via tumbling /hand grinding/polishing with no control over accuracy of final geometry/dimensions. A twin cathode (axis) ECM would machine both sides of the blade simultaneously, leaving no pip. There is no known production of twin axis ECM machine tools in the world nor any twin axis pECM. A twin axis pECM would be the ideal machining method to complete manufacture of compressor/turbine blades to final tolerances/geometries & surface finish. If twin axis pECM could be developed, it would have a huge impact on the global aerospace/turbine market. The proposed study involves exploration of the ECM market in aerospace (civil & military) for the manufacture of compressor/turbine blades & to see if development of a modularised platform technology of pECM machines, capable of duel sided machining (twin axis/multi axis) can be adapted to meet industrial applications at a competitive price & be viable, research & investigate the use of metal dipped plastic as cathodes to provide cheaper tooling/manufacturing costs