The Role of Heat Treating in Lean Manufacturing
April 4, 2006
Why Lean?The last ten years has seen the long-standing practice by furnace manufacturers of supplying "stand-alone" pieces of equipment change to that of building systems completely integrated into the manufacturing flow. Recognizing the reality of global competition, there is new emphasis being placed on improving the overall efficiency of manufacturing by using lean manufacturing strategies (Fig. 1).
The steps involved in a lean manufacturing strategy encompass an extended 5S strategy - to that of 5S+1. These steps are:
and, in addition, guarantee
Heat treating, a core competency as part of the success of any manufacturing strategy, means equipment manufacturers must adapt to this "on demand" philosophy. The 5S + 1 strategy for lean heat treating (Fig. 2) involves:
and, in addition, be sure to be able to
Why Conventional Heat Treat Technology FailsOne runs the risk in the manufacture of heat-treating equipment to ignore the needs of lean manufacturing and lean heat treatment by failing to design equipment with adequate flexibility to meet the demands of modern manufacturing operations. This ability to anticipate future need given the changing face of manufacturing is what separates an adequate supplier from a good one. Furnace and equipment design engineers must understand that changes in materials, manufacturing methods, processes, and even physical plant locations is a part of the new reality and an absolute part of their design strategy. The era of relying on what has been built in the past is over. Whether the heat treat system is large or small, simple or complex, the ability to rapidly alter the design to handle whatever may be required must be built into the system as supplied.
Today, corporate edicts are demanding lean manufacturing and lean heat treatment strategies; they require all manufacturing equipment to be environmentally responsible, conserve energy as well as other natural resources, produce small lot sizes quickly, and be mobile both within an existing facility and have the ability to move from site to site. Equipment must be engineered for use anywhere in the world. In addition, most companies are insisting that a furnace manufacturer support their equipment on a continuous basis no matter where it is located in the world. These demands are not unreasonable, and innovative companies have evolved strategies to support these needs.
Lean Heat Treat Equipment RequirementsLean manufacturing demands we apply multi-tasking skills to our heat-treating operations. We must have full control of all heat treatment equipment and process variables. The keys to achieving this involve designs with inherent:
Integration into the Manufacturing FlowThe ability to utilize a small footprint allows integration into cellular manufacturing so that product does not necessarily have to be moved from where it is being produced to a remote heat treatment operation. Both atmosphere and vacuum systems have been designed and successfully employed for in-line (Fig. 7), on-line (Fig. 8), and centralized ‘heart' cell (Fig. 9) manufacturing operations.
In-line systems service the needs of a single product as it is being produced in a dedicated manufacturing operation. On-line systems service a family of products having common heat treating requirements and receive parts from a number of operations simultaneously. Heart cell operations service the needs of an entire facility and often are the most demanding in terms of automation and flexibility. Many times multiple types of heat treating and ancillary equipment must be integrated into a single high throughput operation.
Lean ApplicationsLow pressure vacuum carburizing, a patented Hayes invention (Fig. 10), is a process with advantages that are now well recognized throughout the industry. Hayes has perfected and continues to advance the technology with their research into various carburizing gases, gas distribution methods and innovative designs such as continuous systems, which can be directly loaded while at operating temperature (Fig. 11).
Rules for Lean Manufacturing in Heat TreatmentThere are eight simple rules for success in heat treatment. They are:
1. To know, metallurgically, what it is you want to accomplish
2. To be able to predict the outcome of the heat treating operation
3. To have repeatability built into the process
4. To use state-of-the-art heat treating equipment and methods
5. To be able to adapt to changes in manufacturing operations
6. To understand and not compromise on quality control measures
7. To control costs
8. To use automation and equipment in a lean manufacturing environment
From Raw Material to Finished ProductModular engineering together with real time control methodology applied to both equipment and process variables allows us to integrate heat-treating systems directly into today's lean manufacturing strategies. Antiquated heat treating departments are being broken up and parts produced where they are being manufactured. Coupling similar operations together increases efficiency and continuous work flow. The future of heat treating as a competitive technology will be assured by equipment manufacturers willing to accept that lean manufacturing strategies apply to the heat treating operation as well as all other areas of manufacturing. IH
Additional related material may be found by searching for these (and other) key words/terms via BNP Media LINX at www.industrialheating.com: Heat treating, lean manufacturing, lean heat treatment, continuous vacuum, modular engineering