04.04.08
Q&A: Design for Manufacturability
Manufacturing experts discuss the benefits of partnering early in product development.
By Jennifer Whitney
Editor
Working with a customer, Paul Barck (right) and John Ruggieri (center) perform a DFM exercise for an instrument in development. Photo courtesy of Seabrook International. |
In a recent conversation with Orthopedic Design & Technology, Paul Barck, president and CEO of Seabrook International, a contract manufacturing firm located in Seabrook, NH, and John Ruggieri, director of engineering, discussed the problems they often encounter in product designs today and how early attention to design for manufacturability (DFM) can offer savings in both time and money. Following are excerpts of that conversation.
ODT: How would you characterize your customers’ approach to DFM?
Paul Barck: While the practice is becoming more common, we continue to push for earlier involvement with DFM exercises. When they [engineers] are in the early stages of design, they have other goals and should not be constrained by how the parts will be made. At some point, however, it is important to factor in how the part will be manufactured. It is at this point where involving manufacturing partners becomes highly valuable. For example, a simple tight or corner radius dimension can force the use of difficult and time-consuming methods and tooling. Often times when considered early enough in the design and specification process, they can be modified or eliminated if if not a functional requirement.
John Ruggieri: The other item often overlooked is the cost associated with inspection and verification. We need to verify any given feature is what the design or specification calls for. Often times we have to match our customer’s methods used to verify part geometry and specifications. If you’re making parts that are hard to verify, it can become a quality issue for both parties consuming both time and money.
As a result, we continue to see engineers visit our facility to learn about our specific methods and capabilities. I think there has been a change from the “old school” days of “throw it over the wall” mentality where there was a major gap between design and manufacturing, sacrificing cost and lead time.
Cost and delivery pressures have made DFM more of a focus at higher levels of management in an effort to meet corporate goals and objectives.
ODT: How might a lack of due diligence with regard to DFM early in the design process impact a customer’s bottom line in terms of time and money?
Barck: In some new instrument programs, we (both design and manufacturing) have been forced to change specifications and rework production quantities of parts as a result of gaps between part specifications and manufacturing-related capabilities. In a well-managed DFM exercise, component function, use and application should be discussed. This process helps the manufacturing resources understand functional requirements as well as if there are mating parts or devices requiring functional gauging or special inspection methods. Recovery from these issues can be very costly both in time and resources.
Ruggieri: Early involvement with a contract manufacturer before the product is fully developed should be encouraged. Waiting until the design is finalized often makes changes to reduce manufacturing costs too difficult.
ODT: What are some other more common problems that may surface when DFM isn’t given much consideration early enough in the development process?
Barck: The primary focus of design engineering is typically functionality and not on manufacturing constraints. One of the inherent aspects of the development process worth mentioning is, the farther you get into the design process, the more difficult it is to make changes to reduce manufacturing costs. It’s always far more efficient to do it earlier. You certainly don’t want design engineers to be burdened by constraints when they’re performing their initial design work, but there is a trade-off, and if you wait too long the part or component might end up being very difficult and costly to manufacture. It’s really all about making sure that you find that right time where the design is mature enough to bring value with a DFM exercise and not so far into the process that making design changes becomes time or cost prohibitive.
ODT: It appears that shrinking timelines may be causing some OEMs to try to cut corners at times by not worrying upfront about how the product will get made—rather, it’s more about form and function. How is the time crunch to get a new product conceived and finished affecting your ability to get a product to come to fruition?
Barck: Our customers are always looking for shorter lead times to help with their tighter program timelines. In our industry, there have been large swings in demand, making it difficult to plan capacity and resources. From our perspective, the more information we have earlier on in the process (about things like launch dates, volume requirements etc.), the better we are able to help our customers meet their objectives.
ODT: We often hear from manufacturers that continuing enhancements to newer generations of CAD software have simplified the design process and subsequent manufacturing. How have these advances helped facilitate better manufacturability for customers?
Ruggieri: We often share files with our customers, especially for CAD solid modeling. It’s a huge time saver in getting ideas across quickly without requiring interpretation of part geometry and dimensions—it’s a lot easier for everyone involved to have this kind of information available. It also helps from the design side because they can see a three-dimensional solid versus a one-dimensional view. The features that are difficult and costly to manufacture are much more obvious and jump out a lot easier in a 3-D world versus a flat piece of paper.
ODT: In looking at DFM, what are some ways you approach a new product in determining how to make a product optimal in terms of manufacturability, cost and maybe factors such as enhanced aesthetics?
Barck: Knowing what geometries and features are easily generated without requiring costly manufacturing processes like complex 3-D profiling or multi-piece construction can greatly reduce the cost of the parts. Surface finishing, coatings and use of alternative materials (machined polymers, etc.) can also be considerations for color coding, enhanced aesthetics and ease of manufacture. We help our customers by suggesting alternative feature geometries and specifications that can be achieved most easily with our internal capabilities. To this end, we work hard to offer a wide range of capabilities, allowing us to create the wide variety of geometries required by today’s complex surgical instruments.
ODT: Can you recall a situation in which you worked with a customer using DFM exercises to achieve a specific goal?
Barck: We worked on a project with a customer whose cost target of a new product was 50% of its predecessor with equivalent functionality. We met with their engineering staff and, during that visit, reviewed the drawings as part of a formal DFM session. We were able to help them, through suggestions, to make the part more manufacturable and meet their cost targets. While the [original] design incorporated innovative solutions to reduce cost, the target would not have been met without the DFM exercise between the product designers and our manufacturing engineers.
Ruggieri: Partnering with manufacturing suppliers is key. At the time the DFM meeting took place, we were not yet selected to manufacture the parts under review, but having the relationship resulted in everyone meeting their objectives.
ODT: What are some of the other benefits of partnering early in the design process with a contract manufacturer experienced in DFM?
Barck: There are widely varying levels of experience both in design/development and manufacturing. Well-executed DFM exercises provide a lot of value and opportunity for learning in both disciplines. This provides returns well beyond the dollars saved during the one exercise.
In the larger view, the DFM process provides a forum for valuable cross training which only enhances an organization’s ability to bring new products to market more quickly and efficiently.