Die Science: Reducing die cost

“How much?” “You have got to be kidding, right?” “What is this die made of? Gold?” It’s almost comical to watch the person responsible for getting quotes receive them. Facial expressions resemble those from a Three Stooges movie. Emotions from total joy to total disbelief are not uncommon.

To stay competitive, die builders must use every method possible to reduce tooling cost. This doesn’t mean you should mean you should make the dies cheaply, just less expensive. There are many ways to make tooling at a low cost without sacrificing quality. In some cases, the quality of the tool can increase while the manufacturing and tooling cost decrease.

Cost Versus Value

For stampers, nothing is worse than a cheaply, poorly made die. The resulting downtime an poor product quality are major profit killers.

Often that poorly made die was bought form the die shop that submitted the lowest bid. Its bid was low because the die is made of poor-quality steel, and poor processing and contraction methods were used.

This doesn’t mean that the lowest bidder cannot produce a value added, quality tool, but keep in mind that a die builder must ensure that the die can effectively produce the stamper’s piece part for the duration needed.

High-quality tooling is an influential investment that gives stampers the means to be successful.Very simply, sometimes stampers have to spend money to make money. Spending $20,000 for a die that rarely results in downtime is a much better investment than a $10,000 die that produces 5 percent scrap and a marginal part.

Stampers should make no sacrifices with respect to the die’s function, regardless of the cost. If they can’t afford to buy a tool that can effectively produce the piece part, they should not attempt to produce that part.

Tool Steel Selection

With new types of sheet materials being used, such as dual- and triple-phase, ultrahigh-strength steel, and aluminum, it often is necessary to use premium tool steels to form and cut them. Unfortunately, premium-performance tool steel usually comes at a premium price.

When a die wears out abrasively and breaks down (galling), it usually is in a very small, confined area. One way to reduce your tool steel investment and reduce the die cost is to insert small amounts of premium tool steel in these small problem areas, which usually can be identified during the processing and designing stages.

Stamping applications such as creating compression flanges; severe drawing or ironing; and bending heavy, high-strength metal warrant dies that contain some premium tool steel. The rest of the die can be made of a less expensive material.

Using small inserts not only reduces tool steel cost, but also for easy replacement. In addition, if the insert needs to be coated, it is far less expensive to coat a small section than a larger tool steel section.

Die builders need to work with their customers to determine where lower-quality tool steel or cast iron can be used. Avoid using across-the-board die standards.

For example, a stamper might stipulate that D2 tool steel be used in all of the die forming stations. The stamper may have specified this because of previous galling problems that occurred with lower-quality tool steel. If the stamper has researched the galling, however, it likely would have found the problem occurring in very small, isolated areas, and that inserting D2 or a higher-quality tool steel such as vanadium or a PM grade just in those areas would have been more effective.

Lower grades of tool steel, such as 4140 or hardenable cast iron, could be used for the remainder of the section. Because pockets would have to be milled into the larger die section, machining time would be increased somewhat, but this additional cost would be far outweighed by the tool steel cost. Using this commonsense method not only reduces die cost, but makes it easier for the die maintenance crew to do their jobs.

Die Components

Whenever possible, avoid using custom die components. These components will have to be made in a die builder’s shop, usually at a high cost and a substantial amount of time.

Instead, consider using purchased components such as cams. These components can be purchased from a variety of suppliers, and they are available in many shapes and types and serve different functions. Because the vendors make only these components, they can make these less expensively and, in some cases, more accurately than a die shop can.

Fit and Function

Die don’t have to be pretty; they just have to work properly and be easily maintained. Die components such as stops or setup blocks often are unnecessarily ground on six sides, with the perimeter of a riser fully machined, and finished and polished to give them a brilliant appearance. Although grinding all of the die components makes them look great, it does nothing to increase the performance of the tool.

Die are built to fit and function. Period. Don’t put a great deal of effort into making the die pretty unless doing so adds value to the die quality of your customer’s sense of professionalism. This is not to suggest you do sloppy work. The die sections must fit together well, the dowels must fit, and components that travel must do smoothly.

Avoid both overbuilding and underbuilding tooling. Working with your customers to define the necessary die geometry and construction techniques is an important first step toward reducing tooling cost without sacrificing quality.

Until next time… Best of luck!