Companies embrace Lean or Flow Manufacturing primarily because of the benefits that can be achieved. Foremost among them is a reduction in Manufacturing Cycle Time, but there are many others, summarized in this lesson.
WHY IS MANUFACTURING CYCLE TIME SHORTER IN A FLOW LINE?
The main reason is that the processes necessary to build the product are Linked and Balanced. When processes are linked and balanced, the product moves from process to process in an uninterrupted manner. That uninterrupted movement we call Flow.
When products are built to Work Orders that reflect the Bills of Materials, you build subassemblies that are moved from department to department accumulating standard minutes. After the work order has been scheduled and has waited on the floor to be worked on, the actual work or production time takes place. If you look at the relative duration of those three elements, Schedule, Wait, and Production, you can confidently say Days, Days, and Minutes.
The idea behind establishing a flow line is to eliminate the department-level scheduling to replace it with work signals. Then, through the linking and balancing of processes eliminate the wait time, leaving just the production time. It is common to see improvements of 70% or 80% or even 90% when a manufacturer goes from traditional batch scheduling to flow.
Let’s look at the many other benefits derived from implementing Flow Manufacturing. Many of the benefits we are about to discuss are derived from the shorter Manufacturing Cycle Time that results from linking and balancing manufacturing processes.
FASTER CUSTOMER RESPONSE
By reducing the time it takes you to make the product, the Manufacturing Cycle Time or MCT, you can significantly improve your ability to deliver the product faster to the customer. The Customer Response Time is the time from the receipt of the order, to delivery of the order.
By arranging workstations to work progressively, flow lines facilitate the implementation of quality steps that double check critical product features. These quality checks are aided with the use of Operator Method Sheets that indicate when to perform those checks and in what sequence. You probably know these checks as TQC and Verify.
REDUCED FLOOR SPACE
Embracing a Flow Manufacturing strategy means that all those batches go away and especially the warehouse of Work in Process becomes unnecessary. All that floor space can now be used for making product rather than storing it. As important, if not more, is that the inventory that went away, became cash, cash that does not have to be reinvested in materials. A better cash position makes your company much stronger.
ONE LINE MANY PRODUCTS
A Mixed Model flow line is designed to build a family of products using the same manufacturing resources. The advantages of mixing products in one line are many including the capacity to absorb swings in customer demand.
Arranging workstations in a sequential manner opens the door to implementing a tool know as Operator Flexibility or “Flexing”. Flexing means to move to where there is a blockage in the flow. This is done in a very structured manner based on demand signals. Flexing is not “moving around looking for something to do”.
Many forms of waste are eliminated when processes are linked and balanced and the product flows from process to process in an uninterrupted manner. But one that is clear and very evident to the naked eye is the substantial reduction in the amount of walking that takes place in the new line.
LOWER INVENTORY REQUIREMENTS
By eliminating batch-building, the many piles of partially completed products that litter the floor of a traditional factory are not longer necessary and all that floor space that was occupied by those piles can be reclaimed for more useful uses, like building products.
REDUCED WORKING CAPITAL
Working Capital is a measure of how much cash is tied into the factory’s daily operations. By linking and balancing processes there will be a substantial reduction in Work In Process inventory followed by reductions in Raw Materials and improved labor utilization. All these will contribute to better asset management.
These are just a sampling of the many benefits of implementing a Mixed Model Flow Line.