Designing for Dollars
Do your die-design and forming-simulation efforts, or those of the companies you select to undertake these tasks, keep up with the times?
Thirty years ago, lead time from tool-design start to first-part off stretched from 14 to 20 weeks, even for simple parts and tooling. Today, with a huge assist from die-design and forming-simulation software, eight weeks is the norm, with four weeks not unheard of.
Lead-time reduction is just one area of evolution in the software realm. Accuracy is another, and the list goes on. With such software going mainstream, how can it be best employed moving forward?
Each spring, MetalForming presents a roundup of the latest and greatest in die design and simulation for the metal-stamping process. The articles show that as these technologies continue to improve, they deliver huge cost savings to metal stampers. We present these articles in conjunction with our annual Die Design and Simulation Software Experience (www.metalformingmagazine.com/diedesign), organized by MetalForming and slated for May 28-29, 2014, in Rosemont (Chicago), IL.
Given the ever-challenging business environment for manufacturers, we’ve surveyed leading software suppliers on how improved die-design and simulation processes can influence the bottom line of tool builders and stampers, and their customers.
Hire This Guy
Consider investing in software for the design-build process, urges Ray Proeber, president of Accurate Die Design Inc., New Berlin, WI, the North American technical center and master distributor for Logopress3 3D die-design software from Logopress Corp. and also a reseller of forming-simulation software from Forming Technologies Inc.
Says Proeber: “We as humans don’t think as efficiently or as accurately as computers. Some very seasoned toolmakers do an admirable job of predicting the future based on their experience along. But plenty of smart people have conducted mounds of research and performed years of testing, and they’ve programmed software with more accurate parameters than anyone can pull out of their brains. With advanced software available today, you are using proven science.”
Wear your human-resources hat, instructs Proeber, and the case for die-design and simulation software strengthens.
That’s a compelling argument, and Proeber shares an experience highlighting the value of a ‘hire’ like this.
“Suppose you interview someone who is unbelievably accurate about toolmaking and forming predictions, and knows if something is formable just by looking at a part print,” he says, “and also can accurately predict the flat-blank size. If you could hire this person, who will positively affect every employee and process in the shop and can predict the future, for $25,000 per year (roughly the cost of a formidable simulation/design software setup), would you do it? You can have the software for half the cost of a human employee. In addition, the software makes employees and processes, even quoting, much more accurate and efficient.”
This thickness map, provided by ETA, shows how software can predict the thickness of a stamped part—just one of many capabilities available in forming-simulation software.
“A metal stamper quoted a die to make a part complete in a progressive die, and when it tried to stamp the part it had major problems,” he relates. “The part could not be produced with the planned process in the die. Plans called for a draw station after material had already been cut away. But, in reality the material needed to be cut away after drawing. The tool builder had to rework and simplify the progressive die, and add a four-station secondary die to complete the part. More than $100,000 was lost by the tool-and-die builder, the stamper and the OEM customer. Meanwhile, a $5000 simulation-software package (equivalent to a part-time employee, or perhaps a summer intern) would have caught the problem upfront and enabled the designer to develop an ideal process instead.”
This employee also works well with others, Proeber points out.
Work with Any File
Next on the list of software advancements: improved file management. In a manufacturing setting, file snags, or the requirement to adapt or recreate files for different formats, burn up dollars quickly.
“Many parametric products—those using a parametric tree—may require tool builders to redesign the part from the provided file in order to paramatize it for their own use,” explains Jack Thompson, sales engineer at TST Tooling Software Technology LLC, Clarkston, MI. TST offers VISI software for tool, die and mold design and build. “Redrawing the part in order to proceed with the tooling side of the build can be a huge undertaking. The ability to use a native file (a VISI feature) saves time and eliminates these opportunities for error.”
For example, suppose a part designer provides a file to the tool designer/builder who then has to redraw, or reparamatize, the part. In most cases, according to Thompson, accomplishing this can take a couple of days. That means days lost on design time. Redrawing or reparamatizing also introduces the opportunity for errors that may cause significant challenges down the line during tool design, build and tryout.
“In these situations, the tool designer/builder may recreate a part that is not identical,” Thompson says. “But using the file provided by the customer ensures that you are working with exactly what it provided, without the risk of errors in translation and the resulting costs.”
Working with multiple files also present challenges.
“Some software systems undertake a large amount of file management in working with assembly and individual files,” says Thompson. “Imagine a die that may have 1000 features. Each of these features may be a separate file in some systems, which then save the files together in an assembly. Doing so requires complicated file management. If someone removes or deletes one file, the assembly won’t open properly. Some shops may have one employee who spends all day maintaining these files. A single file, compressed to make it manageable, provides an ideal solution.”
Another advantage that offers bottom-line payoff for stampers and tool builders: The ability to employ a fully integrated software package from design to manufacture.“If machining of the tool occurs in a different package, someone must translate and transfer the files into another format,” Thompson explains. “Even if the separate machining software can read the design format from the other software, the files still must be transferred and kept current should any changes occur down the line.
“Full systems using one file format,” he continues, “allows shopfloor personnel to look at the part, decide what information is needed and move forward without going back to engineering and asking about design intention or requesting a section view because data were not included in what was sent. These time-wasting interactions are eliminated.”
Opportunities to Enhance Profitability
Studies show that during economic recovery, companies stress returning to profitability. How to do that separates winners from losers. For die shops and stampers, simulation may offer the ideal answer, says Charles Hayden III. Hayden works in technical sales for Engineering Technology Associates, Inc. (ETA), Troy, MI, provider of the Dynaform die-system simulation suite.
Hayden offers the example of a customer that throughout the recent recovery has improved profitability two to three times due to controlling and understanding fixed assets and direct labor, because it can predict tool performance and perform precise scheduling.
“Productivity and efficiency leads to profitability,” he says, “and this technology allows users to better determine per-piece price so that they have confidence in their costs beforehand.”
Gaining confidence in the analysis and accuracy of simulation tools enables expansion into new markets and projects.
“Companies can bid on more complex parts and grow their comfort zone, perhaps expanding from automotive to appliance or aerospace,” Hayden explains. “Capabilities in simulation systems can help open doors to new processes that enable entry into new types of businesses.
“Tool-and-die is constantly evolving,” continues Hayden, “so players in this arena must be conscious of the new high-strength steels and other new alloys, and need a tool such as simulation to deal with what’s new. Standing pat will put you behind the eight ball.”
Springback in the new materials Hayden references offers an area where simulation pays big dividends, allowing users to predict how materials will react to force. This leads to improved tool performance and higher-quality parts from the start.
Not only does new simulation technology enable new-market and new-process entry, it continues to quicken development time upfront. Optimization is a case in point. “Proper draw-bead placement for medium or large stampings had not long ago been a week-long testing project,” says Hayden. “Now, it can be done in one day.”
Complementing Designer Expertise
Placed in the hands of an experienced designer, die-design software reaches its pinnacle and provides an excellent cost- and time-saving tool.
For example, “two designers can proceed with part nesting in two different ways,” explains David Lindemann, application engineer for Cimatron Technologies Inc., Novi, MI. “One approach is to eliminate as much scrap as possible and form as tightly as you can. The other considers the tool, noting that parts placed tightly together results in fragile tooling. Some software may provide every possible nesting configuration along with scrap-percentage factors, and the designer can choose with the goal of achieving the optimal scrap-percentage factor while retaining good tooling conditions.
“But an experienced designer who understands what process is necessary for making the proper, most-stable tooling in the shortest amount of time can enter a minimum set of conditions based on knowledge and experience,” Lindemann continues. “He knows, for example, that the hunk of tool steel should not be less than 1 in. thick given the grade of material to be stamped, so he enters that as a minimum condition. He sees that a certain angle is needed in a certain location, so he sets a condition there. Throughout all of this, the experienced designer can see the scrap-percentage factor change on the screen as the software automatically calculates it.”
At this intersection of expertise between designer and software, conditions are optimized, yielding an ideal balance of scrap generation and tool robustness.
“Designers can use their experience, and through that the software helps them arrive at the best solution,” Lindemann says.
Die-design software also assists experienced tool designers and adds efficiency by thinking like designers think.
“They know that they must punch holes in the steel before forming,” Lindemann adds. “They know that when pulling a punch it must go through a particular piece of steel with so much clearance and then go through another piece of steel with even more clearance, and then go into another piece of steel and hold it. The software stores that in job memory, making it repeatable and ensuring a proper design while saving time in trying to recreate everything.”
Through such interactions, the experienced designer adds to the knowledge base in the software system, and through the system makes that knowledge available to those who are less experienced—junior designers, for example, or those in the quote department.
“Good designers know what different features and operations will cost,” concludes Lindemann, “and can build up the knowledge database inside of the quote system, for example. Less experienced personnel draw from that, leading to more accurate quotes.”
Consider the Big Picture
With simulation software gaining acceptance throughout the industry, lead-time-reduction arguments are losing some luster. Going forward, users of simulation software can differentiate themselves if they leverage its capabilities to see the bigger picture. So stresses Eric Kam, product manager at AutoForm Engineering USA, Troy, MI.
“We challenge people in that, because since computers are so fast and simulation tools have automated things to a high degree, don’t we owe it to ourselves to simulate the road not taken?” Kam asks. “Look, for example, at cam trimming versus direct trimming and then flanging down in a later operation. A designer may choose to eliminate the cam and go with the second option, saving money on the initial tooling investment. But how much are you really saving? If eliminating the cam can be shown to save $20,000, is doing so justified? Try simulating with and without a cam, and predicting the cost of both processes. Robust simulation may show that employing the cam-trim operation results in better overall production repeatability, with a 0.1-percent scrap-rate prediction as compared with a 0.5-percent rate by eliminating the cam. The reduction in downtime due to increased repeatability could save tens or hundreds of thousands of dollars over the life of the job. You saved $20,000 upfront but spent perhaps $100,000 more overall. What was the correct decision?
“The future goes beyond feasibility simulation,” Kam continues, “and uses simulation results as a factor when considering the overall comprehensive cost for forming the product in a process.”
Eliminating process concepts without sufficient justification can be a danger when only using simulation for feasibility, Kam cautions.
“Take, for example, a three-die process that draws, trims and flanges,” he says. “Simulation might say, ‘yes, that works.’ Then, upon springback analysis and other testing, designers decide that they must modify the part to fit into the process window, and allow for a certain amount of part variation due to striking only three times. By simulating an alternative, made possible due to advancements in simulation technology, designers may find that part quality improves enormously without modifications in a four-hit process using a cam. Not modifying the product design could save tens of thousands of dollars over what the simplified process saves upfront.
“So now,” Kam continues, “some designers use simulation to validate a suggestion for customers to change the product. They might say to the customer, ‘You need a product concession for the part to be makeable, and I have simulation to prove it.’ But changing the product can cost hundreds of thousands of dollars in assembly costs if, for example, a carryover mating component won’t fit the new part and that component must be redesigned, too.”
The Conclusion?“People must think in a larger, more holistic way,” Kam says. “That is the next rung on the ladder for finding cost savings through simulation. Quantify the potential costs of the tools, blank material and production. Then factor in the potential repeatability of not only the ‘leading process,’ but also those that we traditionally eliminate due to subjective opinions about costs. Finally, make a balanced decision about the quality, cost and repeatability of the processes we choose and those we eliminate. Many in the industry are just not there yet.” MF
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