How to Apply Lean Principles to Reduce Casting Costs
The lean manufacturing process focuses on ways to improve quality while reducing waste. Not surprisingly, companies that successfully implement that approach often find their costs dropping over time. Here are some proactive ways to use lean principles to reduce casting costs and keep expenses down in a foundry.
Encourage All Employees to Take Ownership
Making the transition to lean processes often doesn’t come naturally to employees. However, when company leaders emphasize that everyone plays a vital role in improving the organization, the team effort should become apparent in the results.
Consider the case of a Portuguese aluminum gravity die-casting plant that used the Lean Six Sigma method to reduce defects. The company moved ahead with a five-stage roadmap that included measures to identify the root cause of rejection rates, fix those issues, and develop a plan to minimize future problems.
One of the conclusions was that the processes used at the plant contributed to the failure rates. Additionally, the study’s authors emphasized that success happened due to executive buy-in coupled with active involvement from all team members.
When company leaders announce a lean transition, they must draw attention to how every person plays a vital role in helping it happen. It only takes one person to continually make mistakes or poor decisions that increase costs.
Process Maps to Reduce Costs and Identify Bottlenecks
People using the lean methodology consider waiting time a source of waste to eliminate. However, it’s difficult to know where delays or other inefficiencies exist without examining a full breakdown of the respective processes. The steps vary for different types of casting, but it’s easy to apply lean principles regardless of the method used.
One instance involved applying several lean techniques to sand-casting processes. Together, the changes reduced the rework rate from 20% to 11.33% and slashed the reduction rate from 7.3% to 4%. The seven lean techniques used in the paper cut the production time from 12.5 days to 6.66 days.
Moreover, the authors highlighted that there is a variety of ways to implement lean manufacturing. However, they called out 5S, kaizen, and kanban as being exceptionally instrumental to enhancing productivity. When the overall output goes up, costs tend to decline.
All types of casting involve primary steps. For example, the brass-casting process entails making a mold, heating and pouring the brass, and breaking open the mold after it cools. Some components also require smoothing depending on their intended uses.
Succeeding with the lean methodology means mapping out each process and looking for inefficient aspects within each step. The researchers above created a flow chart to scrutinize their processes.
Group Cells by Product to Reduce Casting Costs
Changing a foundry’s physical layout could also help a company embrace lean manufacturing principles and reduce casting costs overall. The FLEXICAST project involved 14 partners from five European Union countries. The main goal was to move from conventional batch-by-batch cast iron foundry processes to a more flexible mold-by-mold approach.
The people working on this initiative implemented lean manufacturing by grouping manufacturing cells according to the products or pieces made inside them. This option boosts efficiency by creating focused paths inside the relevant space. Moreover, it can minimize scrap and rework because people discover issues closer to the cells where the pieces originated.
Lean manufacturing also emphasizes the continuous pursuit of quality through ongoing improvement. The FLEXICAST team implemented smart sensors that assisted in gauging the quality of each piece. Another part of the system included a robot that automated some of the finishing processes.
The use of cells connects to lean manufacturing by letting people avoid unnecessary movement. This example also shows how connected sensors and automated machines can bring continuous improvement.
Minimizing Waste and Casting Costs Strategically
Using lean methodology to reduce waste can have a positive effect on cutting costs, too. However, it’s also true that some sources of waste are more costly to tackle than others. Cases also exist where getting rid of a type will not necessarily provide the expected payoffs — at least not immediately.
Thus, identifying the ideal ways to reduce casting costs may involve creating a numerical ranking system that suggests which ones to tackle first. A case study about high-pressure die-casting of aluminum alloys involved a company trying to reduce casting defects. However, representatives at the business did not attempt to achieve that goal haphazardly.
Instead, they examined three factors when deciding how to implement a generalized approach. They were the cost associated with removing the source of the waste, the ease of eliminating the waste, and the extent to which getting rid of it affected other parts of the process. Each factor had an associated value, and the researchers used them to make calculations that suggested the feasibility of making a particular change.
That data facilitated creating a three-phase implementation plan. The suggested actions in the first phase were those expected to be the cheapest, easiest, and most complementary to other processes. Those in the second and third stages cost more to do, were comparatively more complex, and did not have such positive effects on other processes.
This kind of tiered approach could work well when some decision-makers feel hesitant about moving ahead with lean principles. When they see the favorable outcomes associated with the first phase, they should become more open to proceeding with the later parts.
Additionally, such a gradual process makes it easier to connect certain improvements to the changes made and measure metrics associated with them.
View Lean Implementation as a Journey
The examples here show there is no universally best way to cut casting costs by applying lean principles. Succeeding requires taking a close look at a company’s most pressing challenges, becoming intimately familiar with all of its processes, and then looking at the most appropriate ways to reduce waste while enhancing quality.
Additionally, you should not treat the lean methodology as something you can fully adopt over a few weeks or months. Company leaders who are serious about using lean principles to reduce casting costs understand that lean is a long-term change that requires earnest participation from people at every level of the organization.
Since continuous improvement is one of the lean approach’s foundations, there should never be a time where you assume your company is the best it can get. Instead, making lean work for you means constantly looking for ways to make your company better — whether by boosting productivity, saving money, or achieving another desirable aim.
