Quick response manufacturing of custom stampings requires that every aspect of the company operate efficiently. Every action from entering client orders properly to shipping on time works flawlessly. Our example shows how and why this happens. Computer integration of the entire process from customer request through die buildup and shipping the order is essential. The thing that makes money for the company is shipping what the customer wants on time. This requires an efficient dieroom. An efficient dieroom is neat and well organized. Our example illustrates a highly integrated machine shop and dieroom. Die Buildup Order Entry When an order arrives, it may be shipped from stock or require a die to be built up from components in stock. Quick response to special orders may require designing and CNC machining of new die details including wire EDM. Figure 1 illustrates workorder entry, which generates an instruction sheet that follows the job.
Figure 1. Workorders for both standard and custom stampings are entered into the system. The computer-generated workorder is also an instruction sheet that specifies the die components required. The workorder follows the job. Phoenix Specialty Mfg. Co. / Smith & Associates To accomplish custom stamping, most work orders are filled by first assembling a die in a standardized aluminum dieset from tool steel or carbide sections neatly stored in
indexed cabinets. The workorder specifies the parts needed and where they are obtained. An extensive machine shop produces both replacement and new die parts as needed. Using Machine Shop Capability Having a well-equipped machine shop is essential to build and maintain good dies. A variety of milling machines, grinders, lathes and EDM machines are needed. Machining centers and wire EDM machines operating under CNC control are essential to efficient diemaking. Figure 2 illustrates a diemaker entering barcode data into a networked computer system at a CNC machine workstation. This simple task assures accurate tracking of job status. Accuracy and speed are advantages of CNC machine tools. Achieving efficient use of the machines requires good die designs and everyone’s commitment to using these machine tools to produce the best possible fit and function of the dies. Here is where continuous improvement⎯a plant culture that is never satisfied with “good enough” uses everyone’s commitment to achieve true excellence. A die that just makes good parts is not the goal. Making the best possible parts at the lowest per part cost is the goal.
Figure 2. A diemaker enters barcode data into a networked computer system at a CNC machine workstation. This simple task assures accurate tracking of job status. Phoenix Specialty Mfg. Co. / Smith & Associates Continuous improvement also applies to the machine tools and plant computer integrated manufacturing systems being continuously refined and upgraded. Machine tools need software and hardware improvements to do the best possible work at the lowest total cost. For example, the job tracking and die maintenance software is upgraded as needed. Diemaking skills overlap with CNC machining. Operating a CNC machine to make die components requires a skilled craftsperson. This is not a job for “button pusher”. New
diemakers are trained in cooperation with the local community college in many skills of the trade. Training in diemaking theory and practice is met by on the job training by skilled supervisors and journeymen. How to Recognize a Good Plant Culture Efficient production and zero defects go hand in hand with cleanliness and organization of the workplace. A good plant frequently is a QS-9000, AS-9000 or ISO 9002 registered facility that practices continuous improvement. A good shop is also a “happy” shop. The writer is familiar with this plant by conducting two days of inplant die maintenance training there through the SME corporate training department. This training was similar to a popular SME public seminar given by the writer. A good company considers training important to keeping everyone thinking of ways to improve plant teamwork and operations. A variety of training is important and several days per year are devoted to in-plant updating of skills.
Figure 3. A clean workplace requires everyone’s cooperation. This Tool & Diemaker is keeping his CNC machine workcell clean. Phoenix Specialty Mfg. Co. / Smith & Associates A knowledgeable observer can make a quick audit of a plant’s efficiency just by walking around and observing work practices. Simple observation will tell a lot about the plant culture⎯how people work together and accomplish goals. For example, Figure 3 shows
a diemaker sweeping the floor in his work area. All employees work together to keep the workplace clean. There is no janitorial staff for this task. Some positive factors are:
1. Everyone is intent upon his or her task and working without obvious supervision.
2. The ratio of supervisors to craftpersons and machine operators is low e.g. 35 to 1.
3. Supervisors mainly instruct and provide hands on help⎯they do not spend a lot of time in their offices.
4. Everything is clean and organized⎯e.g. the machine shop, die storage racks,
pressroom and even the scrap recycling metal is kept separated to maximize value.
5. The support activities including engineering and scheduling are actively involved
on the plant floor learning how they may provide the best help.
6. The shop is a “happy shop”. Everyone is treated as “family” and there is no hesitation to lend a helping hand.
Figure 4. Standard die components are stored in cabinet drawers. The workorder routing sheet lists the location of the parts needed to build up the die. Phoenix Specialty Mfg. Co. / Smith & Associates Die Spare Part Storage Quick response manufacturing of custom stampings requires many die sections to keep on hand for quick retrieval and die buildup. Figure 4 shows a journeyperson picking the
required parts for a die buildup workorder from a drawer in a spare detail cabinet. The parts are located by looking at the workorder routing sheet lists, which tells the location of the parts needed to build up the die. Here, computer integration ties in with workorder generation, tracking exactly where each section is located, the condition of the sections and assures their correct return for storage or any required maintenance. Figure 5. The workorder routing sheet is checked to insure that all die parts and the correct empty aluminum dieset is placed in the tray for bench assembly. The use of aluminum diesets has ergonomic advantages because they weigh half as much as an equally strong steel dieset. Phoenix Specialty Mfg. Co. / Smith & Associates Ergonomic Considerations in the Workplace Avoiding excessive lifting, bending and other types of detrimental motion can avoid human injury. A properly designed workplace is important in both the dieroom and pressroom. Phoenix makes use of ball and roller conveyors for movement of their die sets and completed dies. This contributes to both efficient work flow and avoids awkward handling. Figure 5 illustrates the staging station where parts are placed with an aluminum dieset onto a plastic cafeteria tray. Here, the workorder routing sheet is checked to insure that all die parts and the correct empty dieset is placed in the tray for bench assembly. Using Aluminum Diesets Aluminum die sets have been in use for several decades. Superior Die Sets supplies Fortel™ aluminum alloy plate⎯a specially processed material optimized for die shoe applications. Some shops build their own aluminum die sets of Fortel™, 6061-T6 and 7075-T651plate. These alloys are physically hard, easy to machine, and suitable for applications where the light weight of an aluminum dieset is needed.
When substituting steel for aluminum in dieset construction first carefully consider the differences in the two materials. To obtain equal deflection an aluminum dieset must be made two fifths thicker than steel. This is because the modulus of elasticity of aluminum is only one third that of steel. With the additional thickness, the aluminum plate weighs approximately half that of steel for equal deflection. The coefficient of expansion of aluminum is approximately twice as great as that of steel. Warping and misalignment with temperature changes can occur if large steel sub plates are bolted to aluminum die shoes. In other words, the aluminum to steel bolted composite plate acts much like a bimetallic thermometer spring. Good designs consider this factor. To guideposts and ball bushing sleeves should not be pressed in. The shoe material may be displaced or sheared resulting in the pins and bushings being installed crooked. Shrink the pins and bushings in liquid nitrogen or dry ice before inserting them. This procedure is also excellent for steel or cast iron die shoes.
Figure 6. This diemaker is checking die block hole sizes with precision gages. Note the neat yet busy bench appearance with a calculator and other tools nearby. Phoenix Specialty Mfg. Co. / Smith & Associates Bench Die Build Up The die set and parts are moved from the conveyor to the bench where a diemaker builds the tool up and checks it manually for correct operation. The workorders with detailed instructions are on top of the diesets in the background on the roller conveyor. Workstations are placed next to roller conveyors at bench level permitting the light aluminum diesets to be moved easily without lifting.
Figure 6 shows a diemaker carefully checking a compound die section as a precision shim die is built up from interchangeable component parts. These dies are configured for cutting materials varying from cold rolled steel strip to beryllium copper, phosphor bronze and difficult materials including the Hastelloy series and elgiloy, a watch hairspring alloy. Stampings made from these materials find use in products from automobiles to defense and aerospace applications. Thin and hard materials require very close punch to die clearances. The diemaker shown in Figure 7 has completed making a tissue paper cut to verify proper cutting clearances and is double-checking the workorder to insure correct buildup of the die. Quick Die Change Capabilities The dieset has U-shaped tie down slots on the lower die and grooves along the side of the upper die shoe as shown in Figure 7. Many of the dies use a detachable shank or quill that attaches in the center of the upper die. The shank helps locate the die and incorporates a knockout pin needed for part ejection in compound dies. Most of these dies are run in inclined V&O high-speed precision presses. Timed air blowoff enables near perfect part ejection.
Figure 7. A diemaker has assembled a complete compound die and made a tissue paper cut to check for exact detail alignment. The final step is double-checking the workorder in the plastic protective sleeve. Phoenix Specialty Mfg. Co. / Smith & Associates Meet or exceed the requirements for safe die fastening by using two clamps to hold the upper die shoe in addition to shanks if used. Persons have expressed concerns that the use of die shanks is illegal under US OSHA power press safety law. Many shanks are illustrated in The SME Die Design Handbook, Quick Die Change and Fundamentals of Pressworking written or edited by the writer. Some diemakers are unfamiliar with why shanks are used with compound and combination press tooling. There is no known prohibition against using punch shanks with additional bolting to secure the upper die.
Keeping an Eye to the Future Wise management feels a strong civic responsibility as a major employer in their community. Expansion of capabilities includes increasing the amount of work produced in high-speed progressive dies. The company president is shown in Figure 8 checking out several new progressive dies built in house.
Figure 8. Phoenix president Robert Hurst, Jr. checks a new progressive die. In addition to compound and combination die work; high-speed progressive die stamping is a specialty at Phoenix. Phoenix Specialty Mfg. Co. / Smith & Associates Conclusion The metal stamping industry is essential to both national economic prosperity and that of the world economy. Fortunately, there are many companies like our example that add
value to metal by stamping while serving the community as a good employer, trainer of skilled workers and community leadership through active involvement in civic affairs. A well-organized dieroom and machine shop is essential to supporting an enterprise like Phoenix. Just as a die consists of many parts that work together to make a product, a wisely managed and partnered workforce team consists of individuals who contribute their best efforts to achieve outstanding excellence in manufacturing. Let’s all strive for excellence, because giving anything but our best is a commitment to mediocrity and failure in the marketplace. NOTES: _____________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________
