While 90% of all orders are bespoke, each follows the same lost wax investment casting process, irrespective of whether the alloy used is cobalt, steel or aluminium. The process begins with making the required wax components via tool injection, with these individual components being assembled onto an appropriate runner (wax frame) which may contain from one to over 500 individual components depending on design and weight factors. Each runner, complete with individual components forms a mould which is then repeatedly ‘shelled’ with a mixture of ceramic coating and special bonding agents. Once a thick ceramic coat or shell is formed around the wax mould it undergoes de-waxing in a boilerclave (steam cabinet) in order to melt the wax out of the thick ceramic shell. A further firing stage is required to remove any remaining traces of wax and this precedes the actual casting where the appropriate molten alloy is poured into the mould. Once cooled, the mould is de-shelled leaving the rough cast components from which the metal parts are cut before being cleaned and then subcontracted out for any specialised finishing requirements.
Rigorous quality control according to customer specification and high internal standards follows before orders are despatched. Monitoring and managing every step from order entry, acknowledgment, materials and works order management is EFACS E/8. For traceability, which is integral to this industry, touchscreen PC’s running the EFACS E/8 Touchscreen module are used strategically throughout the production line.
As Liberty Gwitira, McKenna’s IT Manager explains, while this may seem relatively straightforward, the reality is much more complicated. “While our customers value the fact we can turn around high quality product in a relatively short space of time, often weeks quicker than other foundries, the majority of them work on a forecast and supply basis, which might extend a number of years into the future. The theory is that they then call off agreed order amounts over a set period, but this in practice can change, often with short notice, which leaves us having to make quick and accurate planning and production decisions. While we do have a minimum order level, our larger customers will often provide orders of multiple products worth hundreds of thousands of pounds.” Given the continual production line approach that exists in the company where there is a snaking list of live orders from start to finish in varying degrees of work in progress, any change, especially one involving due dates, has a knock on effect across the entire production area.
In addition to this, there are a number of day to day challenges that McKenna has to overcome in order to remain competitive. According to Gwitira, the two key challenges involve scrap/rework, and production planning. “It is the nature of our business that there will always be a degree of scrap/rework involved. But as our material costs are by far the greatest costs, having accurate visibility of what these are, plus the means to minimise scrap/rework rates, really makes a huge difference, possibly the difference between making a profit or a loss on a job.” He continues, “It’s the same when it comes to production planning. At any time there may be 200 live orders in progress and knowing where each order physically is and at which process stage they are at is essential to determine whether we are going to make our all-important due dates. Knowing when to start each order as well as each individual process is also central to making sure we meet our deadlines.”
Given that 70% of all products require an element of sub-contracted finishing this also has to be factored in accurately to achieve any sense of a realistic production plan. This in turn means being able to accurately track what products are where, and more importantly, when they are due back and ties in with the company’s overall high level of traceability requirements. Gwitira again, “Given the exacting nature of our customers, we need to be able to trace not just who did what and when, but also what material was used, from which batch, and from which supplier.” He continues, “From a customer perspective, they also need a potentially wide range of documentation/certification covering everything, especially when it comes to assured quality control.” It’s not just the customers who need access to information, from a management perspective, McKenna ideally needs real-time access to a range of production and management data such as WIP reports, scrap/rework reports etc., as Gwitira notes, “All of these have a direct bearing on our ability to supply the right product to the right customer at the right price at the right time.”
McKenna has long since recognised the value of IT in helping to most effectively address these issues and when Gwitira joined the company in 2000, he was confronted with a Unix system complete with DOS-like screens and significant reliance on manual data input with all the inherent issues that this brings, it was also far from user friendly. To this was added a simple barcoding system in 2001 which enabled basic start/stop process information to be recorded at each step. But as Gwitira explains, it couldn’t record other important information. “When it came to scrap/rework information, this still had to be written manually onto the order route card and time sheet then entered manually on the system from the time sheet some considerable time later.”
The acquisition of Finecast brought with it a dedicated foundry processing software package called Synchro 32. This was adopted by McKenna and while this contained a range of functionality suited to the foundry aspect of the business, including tools/die management, contract reviews & sales, and an element of scrap/rework recording, it all rested on an Access database which was far from ideal. At that time it was also incapable of working in real-time and was not compatible with the company’s barcoding technology. Consequently people had to start manually filling in time sheets which then had to be manually entered into the system by two clerks, one day after the actual operation process date.
Two years later and not satisfied with existing systems, McKenna decided to invest in a new real-time solution from Manusoft. Although Gwitira admits that many aspects of the new system were not as good as the previous Synchro system, a key feature of the new system was that it offered a touchscreen interface for the shop floor. After going live, with what seemed to be a fantastic solution, over a relatively short period of time the system quickly began to lag behind McKenna’s evolving businessrequirements, as Gwitira explains. “For example, we began to require better document control and retention for our FDA approved customers, and changes in EU traceability laws meant we also needed to keep more product details and subcontractor certifications as well as material traceability.” The company increasingly had to rely on workarounds in order to meet these growing needs and at one time had 36 databases and 7 spreadsheets simply to achieve this.