Design engineers, especially new engineering graduates, are always ready to come up with innovative and cool new products and ingenious systems. Yet, design for manufacturability (DFM) comes to dominate their creative process; their designs need to meet very specific terms for manufacturing. This can include everything from working with approved parts, to where a hole can and cannot be placed, to what types of materials can be used, to who needs to sign off on the design before it moves forward.

The responsibility for ease of manufacturing has moved higher on the list of design engineering responsibilities. "Design for manufacturing is a growing concern because the supply chain has become more complex with suppliers and contract manufacturing," Scott Reedy, director of product marketing for Arena Solutions, told Design News. "Everybody needs to deliver a product that can be easily manufactured."

Design It Fast with an Eye Toward Price

Nearly every new design project comes down to two primary concerns: design it faster and make it less expensive to manufacture. "Without applying the very basic concepts of design for manufacturing, you are doomed to create products with unnecessary cost overruns and quality and performance issues that can result in increased warranty and perhaps even recall costs," Alistair Munro, director of business development at Lean Design Canada, told Design News."You can also run into manufacturing and tooling costs that could have been completely eliminated in the design phase."

"Manufacturing is becoming more of a bottleneck, as manufacturing engineers are being asked to build more complex shapes and at the same time reduce the costs and speed up the process," Paul Sagar, VP of PTC Creo Product Management, told Design News. "To help reduce this time and cost, companies are asking their designers to take into account the manufacturing process." This is no small job for design engineers with little knowledge of manufacturing. "This is a difficult task for most designers, as they are not familiar with many of the manufacturing processes, principles, and intricacies," said Sagar.

Manufacturing Knowledge Is a Difficult Reach

For all the details engineering students learn during their university years, designing a product for manufacturing is not usually part of the curriculum. Craig Therrien, senior product manager at SolidWorks noted this is due in part to the fact that most universities don't have manufacturing plants in the classroom. Also, design for manufacturing is typically unique to the individual company and its machines, making it difficult to teach. So knowledge of DFM, which also extends to assembly (DFMA), tends to be a hit-and-miss experience with an individual designer mixed with his or her company's design rules.

"In a typical scenario a designer will develop a part and then hand this part over to manufacturing with little or no thought for how the product will be manufactured," said Sagar. "This forces endless loops to alter and refine the design for the specific manufacturing process."

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The lack of knowledge of manufacturing leads invariably to cost problems. "Although there is more of a focus on CAD in schools, there is less of a focus on manufacturing processes and actually making parts," Craig Therrien, senior product manager at SolidWorks, told Design News. "Because of this, many new engineers tend to design parts that may be expensive, or even impossible to manufacture using the methods of manufacturing available."

For many design engineers, the process of learning DFM requires on-the-job training -- mistake by mistake. "When I was 17, I worked in the printing industry, and I had difficulty getting a piece to fit right," Paul Brown, senior marketing manager at Siemens PLM, told Design News. "Finally, one of the experienced designers said, 'Go to the store, get a drill, and make the hole bigger.' It can be that simple, if you have the right information on how to makes things right for manufacturing."

Some manufacturers compile lists of approved parts. These parts are often selected by cost or by aggregated purchases. Compliance is another factor; some parts may throw the product out of compliance with internal or external standards. Design engineers are often guided in parts selection by tools developed by purchasing departments to manage parts.

The pace of materials innovations makes materials a moving target all the time. So the materials selected for a design need to adhere to both availability and approval.

For many large companies, parts management lives on a complicated algorithm for the sake of integrating part spec'ing and purchasing to make sure that there are multiple supply sources for each part.

"Split sourcing can apply to designers. You have to spread your risk. You can't put all your chips on green double-zero," Kent Killmer, VP of marketing at Arena Solutions, told Design News. "While those considerations were once the purview of purchasing, design needs to be in on the process of what parts can and cannot be spec'd into the design."

Tools for DFM

Most of the companies involved in product lifecycle management have developed tools to help the design engineer work manufacturability into the design process. Some of these tools track approved parts, while others manage constraints or compliance.

Collaboration is often part of the mix, as outside teams study product designs to ensure a product is well-geared to production. It also has become part of the internal process in order to make sure the design goes to production quickly. Collaboration through the design stage can reduce the time-consuming back- and-forth between teams.

"As we now move into a far more connected era, manufacturers will want to include many more organizational stakeholders in the design process to increase opportunities for innovation, growth, and cost reduction," Carl Smith, manager of professional services manufacturing at ImaginiT, told Design News."CAD tools can be configured to enforce and control design and documentation standards."

Design engineers also need to be aware of specific aspects of a company's manufacturing equipment and its impact on the product. "Designers need to understand imperfections in the manufacturing process, such as sink marks or weld lines," said Sagar from PTC. "Simple analysis tools need to be available to simulate the mold filling process to help determine and remove weld lines."

Ultimately, the more the design engineer understands about the company's manufacturing, the faster and less costly the design process. "In the past, the designer didn't always know what difficulties the design might have for manufacturing," said Brown from Siemens PLM. "When I first started as a designer, I spent time on the factory floor learning what all the machines could do, and that helped a great deal."

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Rob Spiegel has covered automation and control for 15 years, 12 of them for Design News. Other topics he has covered include supply chain technology, alternative energy, and cyber security. For 10 years he was owner and publisher of the food magazine Chile Pepper.