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Operational Excellence in metal AM
Fig. 7 Systematic approach to loss reduction encompassing all aspects of production
Typically in these situations, we observe that manufacturers tend to keep busy in order to fully utilise machine uptime without defining what their organisation represents. In the early stages of learning by doing, this is understandable. However, as organisational experience and competence mature, these projects should be scaled down and a manufacturing specialisation developed. Suppliers at this stage have a difficult, but absolutely necessary need to change their mindset, either by charging for the lost opportunity cost to make up for 100% system efficiency in the short term, by improving the CPP through cheaper systems and part redesign, or by simply refusing such business in order to focus on a more profitable niche.
Invisible output losses The final invisible waste category that we continuously notice with customers is the challenge in identifying the opportunity cost related to machine output. Every time a part or batch is rejected due to non-conformities, these losses are not quantified, since scrap rates are difficult to track in a variable production. Because AM offers the ability to customise every product, we see that rejected product costs are difficult to compare with the true costs of other efficiency losses like
machine downtime or parameter inefficiency. Without holistic metrics, these wastes are ignored and not accounted for in terms of overall production efficiency. The approach with rejection waste is similar to downtime and parameter inefficiencies, in that we compare the losses from rejected parts and try to strike a balance with other metrics. Slowing down the process is typically effective in reducing these rejections and leads to better overall AMI. After all, if a system is running at maximum capacity, but the output is of no value to the end-user, it is the same thing as not manufacturing anything in the first place. What needs to be considered here are the two major reasons for these losses: first rejections are a result of the steep learning curve in utilising this technology, while the remainder of rejections are related to process limitations connected with specific geometries, materials and machines.
How do we systematise our work? Coming back to the bigger picture, companies are missing a systematic approach to solving these problems within their organisational structure. To address this, they need to convey to individual team members the quality that their production represents and have a systematic approach to solving these issues.
Metal Additive Manufacturing | Summer 2020
These guiding principles need to be written in a simple structure that encompasses every production variability so that the whole organisation can participate. As organisations define this structure, they tend to struggle with conveying to individuals the process because of gaps in terms of metrics as well as specific problems that arise. If individuals feel that their concerns are not included in the corrective strategy discussion, the acceptance of such practices is mostly ignored, at which point the only solution is non-flexible rules within the manufacturing process. This results in additional invisible losses. What we propose to a general problem-solving schematic is to divide all of the issues in production into three categories and then systematically solve them. Through this approach and with metrics that keep track of all process shortcomings, we can convey to individuals the importance of their tasks in the larger picture of the value chain. To begin with, organisations need to be open about their approach and goals. With goals, we refer to the simple focus of output, profitability and strategy and their alignment with individual incentives. If these are communicated correctly, team members will be forthcoming with issues in production, because it will eliminate the â&#x20AC;&#x2DC;us vs themâ&#x20AC;&#x2122; mentality in an organisation. If
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Vol. 6 No. 2