Lean manufacturing refers to developing the right processes to achieve high quality results.  For contract manufacturing involving coating and converting, the techniques are essential to high quality product and relationships. Derived from the Toyota Production System (TPS), the goal of lean manufacturing is to achieve “more value with less work” by eliminating waste anywhere in the process. Lean defines waste as activity that does not create value for the customer.

Lean philosophy includes employee involvement, Jikoda, just-in-time manufacturing, kanban use, and a relentless pursuit of eliminating waste. Success in meeting objectives delivers a safe working environment and a robust and sustainable manufacturing operation.

Jikoda

Success in meeting objectives depends primarily on the two pillars of the lean manufacturing system: Jikoda and “Just-in-Time.” Jikoda refers to the ability to stop production lines immediately upon the occurrence of a problem. In Jikoda, immediate efforts are taken to correct the problem through timely countermeasures. The Jikoda principle is designed to diagnose problems quickly, as well as to prevent defects and continually verify the quality of production.

A five-layer approach to quality is used to implement Jikoda for a variety of manufacturing operations:

• Prevention processes, designed to make errors as close to impossible as they can be, based on checking input and process conditions;
• Detection, which mandates checking the outputs of the actual manufacturing process;
• Successive Inspection with checks to the outputs a second time, using different personnel or methods
• Process Control, where administrators confirm that process steps, prevention, detection, and successive inspection countermeasures are all working;
• System Verification, which confirms that the complete system is working properly.

In the coating industry, an example of prevention efforts includes the use of an official barcode to verify that the correct base roll and chemicals are loaded onto the coater. Once confirmed, a color sensor verifies 100 percent of the product (layer two) through continuous detection during the coating process. At layer three, the coating undergoes inspection via a functional check. This inspection is followed by a fourth layer, in which statistic process control charting verifies the entire process before the finished coated material is verified alongside the complete quality system (layer 5).

Problems detected during this process are reported visually to operators to make changes and suspend machine operation until the materials are present and/or the defect fixed. Most importantly, these problems are escalated to the open forum for process evaluation and recap so the root cause is determined, countermeasures are implemented, and verification of countermeasures’ success and standardization are documented and confirmed.

Just-in-Time

The “Just-in-Time” principle requires that manufacturing operations produce only what is needed, in the amount needed, and when it is needed. In coating and converting operations at Carestream, for example, components such as product packaging, product chemicals, and consumable process components are set up using “kanban” or signal cards. As they are consumed, kanban cards are removed and returned to the supplier to “signal” for more product to be sent to Carestream.  Only after items are used at Carestream does the supplier make and deliver more. Determining just how many kanbans are needed depends on a number of factors. Manufacturing lead time, variation of supply, the reliability of the manufacturing process, customer demand, and demand changes all play a role in kanban sizing. And in order to deliver on these production requirements without straining resources and creating inefficiencies, leveling production, or achieving “Heijunka,” is necessary. Heijunka is a technique to reduce waste, finished good inventories, and production lead times.

Kaizen

Successfully leveling production for maximum efficiency and minimal waste depends on attacking bottlenecks utilizing Kaizen events. Kaizen refers to a philosophy or practices focusing on continuous improvement in manufacturing activities, including activities that continually improve all functions of a business. Particularly important to lean manufacturing is to make Kaizen events routine as employees become in-house-certified and trained in Kaizen techniques in order to deliver the utmost in customer satisfaction and service levels.

In a coating operation, for example, three different products at differing volumes and with differing lead times may need to be produced during a single shift. In order to minimize lead time and cut down on logistics costs, however, manufacturers can level the shipping of these goods to reduce overall expenses.

For successful lean manufacturing, the rule is simple and finite. Eliminate waste. The result is higher quality product delivered faster to our customers.