August 3, 2017 / best practices, continuous improvement, lean manufacturing, LIT, production planning, productivity, strategic planning, workflow process
Over the last 20 years, lean manufacturing, Six Sigma, and other improvement techniques have changed the face of manufacturing. Kaizen programs, 5S, value-stream mapping, and other lean strategies have rendered impressive results in high-volume manufacturing plants around the world. However, not every lean principle is an off-the-shelf solution for operational efficiency. This is especially true for high-mix, low-volume manufacturing environments.
Industrial metal-cutting shops are often juggling multiple jobs—many of them custom and almost none of them the same. Production requirements, lead times, and due dates can vary, which makes forecasting and traditional lean concepts difficult to apply. In fact, according to the eBook, Five Performance-Boosting Best Practices for Your Industrial Metal-Cutting Organization, many small, high-mix operations don’t even attempt to implement traditional lean techniques because they are typically more successful in higher production environments.
The good news, however, is that lean manufacturing is evolving. “A growing number of high-mix, low-volume operations are tweaking traditional lean methodologies to their specific situation,” the eBook notes. “Lean manufacturing techniques can be modified to increase efficiency in even the most customized metal-cutting operations.”
For example, according to an article from Canadian Metalworking, one way to achieve operational excellence in a high-mix manufacturing environment is to create a mixed-model value stream. This begins by creating “product families” or groups of products that have similar process flow and work content. “The next step is to create one current-state map per product family and then a future-state design for that family that can achieve operational excellence,” the article states.
There is no question that this task can be complicated when dealing with a variable product mix. To help managers successfully achieve operational excellence in mixed model production, Canadian Metalworking offers the following 10 guidelines: (You can read the full article here.)
- Do you have the right product families? Create product families based on similar processing steps and work content, not brainstorming.
- What is the takt time at the pacemaker? Determine how often the pacemaker must produce a part to keep up with customer demand for the product family.
- Can the equipment support takt time? Determine if existing machine capacity can support the product family within the established takt time.
- What is the interval? Calculate how often the pacemaker will cycle through and produce all the parts in the product family.
- What are the balance charts for the products? Balance the work content, per operator, to takt time to create continuous flow through the pacemaker process. There will be different balance profiles for each product within the family.
- How will we balance flow for the mix? Determine how variation within customer demand and the product family will be handled, either by adjusting labor, sequencing, or work balancing.
- How will we create standard work for the mix? Standard work means establishing one standard way to build the products in the family, and then having everyone follow that method.
- How will we create pitch at the pacemaker? Pitch is a visual time frame that tells everyone in the value stream if they are on time to customer demand. The pitch created is tied to how often work is released to and taken away from the pacemaker.
- How will we schedule the mix at the pacemaker? Determine the mix that can be supported at the pacemaker, and schedule the pacemaker to handle variation within the product family.
- How do we deal with changes in customer demand? Customer demand can vary, and we need to pre-establish a Plan B to use when it does. Plan B might involve pulling a product or rebalancing the pacemaker.
Of course, this is just one example of how lean can be applied to smaller, variable manufacturing environments. For more strategies, check out the book Made to Order Lean by Greg Lane or these links of archived case studies published by Modern Machine Shop and The Fabricator.
While high-mix, low-volume operations certainly present a unique set of production challenges, there are several custom methods managers can put in place to reduce waste, optimize flow, and improve productivity. It may take a little research and some creativity, but leading-edge shops are finding that in today’s competitive market, the benefits are well worth the investment.