With all due respect to Bob the Builder, too often our answer to the question posed in the title of this article is “no, we can’t.” This response requires a bit of explanation. Consider the following dialog – not quite verbatim to a single conversation, but a synthesis of several very similar conversations:
Joe Design Engineer (to Author Hamlen): “…and so that is the design and the process I want manufacturing to use to perform this manufacturing task.”
Author Hamlen: “Umm… I am not sure if that is a viable process to take in to manufacturing.”
Joe Design Engineer: “I don’t see any problem with it.”
Author Hamlen: “Well, the process is rally rather ‘fidgety” – you need to get the parts oriented just right, and it could be easy to get the orientation wrong.”
Joe Design Engineer: “So? Just back off and re-orient them until they are right.”
Author Hamlen: “Yes, but that takes time. On top of it, this design and assembly process has a lot of parts and many sequential steps. If you make a mistake on any one of those steps, the entire assembly is scrap.”
Joe Design Engineer: “Again, I don’t see the problem. Just go slow and be careful and the product can be assembled.”
Author Hamlen: “In the manufacturing environment with a lot of pressure to get product built quickly and get it out the door, taking that time presents a lot of problems.
Joe Design Engineer: “I don’t see any problems – I have no trouble performing this assembly on my laboratory bench top.”
Author Hamlen: “But in manufacturing, you are not in a lab environment, and time is king. With this design, throughput will be slow, and if the workers are forced to hurry, there will be more mistakes and the scrap rate will go up.”
Joe Design Engineer: “Again, I don’t have any problem assembling this design. We just need to train the workers more. Besides, our profit margin will be so good on this product that a little scrap is not a problem.”
Our guess is that many of you have had this, or similar conversations.
The first point to make here is that the manufacturing environment is not the same as the development environment. Most anyone who has worked in both environments will echo that statement. In manufacturing there is: considerable time pressure to complete product assembly; turnover in the workforce; and movement of workers between differing assembly tasks which reduces their focus on a single process. Also, the parts used to assemble product are more variable in their characteristics (dimensions, mechanical modulus, surface roughness, etc.) than those parts used during the development process.
Aside from the pure cost associated with “scrap” is the relationship between scrap and quality. One of the fundamental teachings of Six Sigma, borne out by experience, is the relationship between scrap rate and quality of released product. The higher the scrap rate in manufacturing, the lower the quality of the released product. This is the case even if there is a final inspection of an assembled product. If you want to produce high-quality product, reduce your scrap rate.
How low a scrap rate is acceptable? The answer to this is complicated, and often businesses will not explicitly define it – instead offering that “if I am still making a profit, I am ok.” This appears to work in the short term, but fails when another organization steals your market share and profits by producing a product that they can sell less expensively, or which is recognized as having higher quality and reliability. Examples abound: the US auto industry versus the Japanese in the 70’s and 80’s, the race towards smaller and cheaper computer disk drives, the first drug eluting stent approved for use in the US (it could not keep up with competition in cost and quality, and its manufacturer is now out of the market), and more.
Again, how low a scrap rate is acceptable? We might take a clue from those industries that are operating effectively – the most notable of which is the electronics industry. There, the overall yield rates are often in the high 80% and can be well up in to the 90’s. This is remarkable given that final yield is often the product of the sequential assembly steps. For example, for five assembly steps, each individual step having a yield of 90%, the yield of the overall process is: 0.9 * 0.9 * 0.9 * 0.9 * 0.9 = 59%. That is with only 5 assembly steps. Hopefully, with that example, the drive to achieve “Six Sigma” yield levels on individual manufacturing steps becomes clearer.
The main point of all this is: the ability to achieve high throughput with low scrap rates in manufacturing is driven by the design. If this point is not paid attention to during the design process, then no amount of “continuation engineering” will really fix a problem. We simply cannot afford to continue to have more dialogs like the example one given at the start of this article.
On the regulatory front, organizations often struggle with satisfying, for example, 21 CFR Part 820.30 (h), Design Transfer: “Each manufacturer shall establish and maintain procedures to ensure that the device design is correctly translated into production specifications.” We will repeat here our much earlier statement: a quality system is not enough. Focusing on the regulations, which appear to require procedures for “handing a design off to manufacturing” entirely misses the point: effective design transfer starts with a design that is manufacturable in the first place.
So, by saying in the first paragraph that “no, we can’t (build it)” we mean that we often do not build our products in a way that is high-yield, high-quality, and can continue to beat out the competition. We accept what we believe is “good enough” without real regard to the downstream problems that acceptance causes.
In the vignette in the first article of this series, we saw this play out by a rushed development effort, followed by a hand off to manufacturing that resulted in obsolete components, and overly tight component tolerances that drove up both cost and scrap rates.
Which brings us to … design for manufacturability.
This is a topic that today is often taught in association with lean practices. However, this subject really goes back, to the authors’ knowledge, to W. Edwards Deming. No one who ever had the privilege to hear Dr. Deming speak can ever doubt his passion and sincerity for his subject. Among the many points he made was the need to include the people involved in manufacture in the design process. And he specifically meant both the engineers, as well as the manufacturing line employees. It is those people who do assembly up close and every day that really understand what the pitfalls are, and what many of the potential solutions are. These are resources and sources of wisdom that we would be foolish to ignore.
In Deming’s era, this translated into the use of “quality circles.” In the current lexicon of Lean, we speak of “the wisdom of the team,” or “the wisdom of the organization.” Closely aligned with this is the Lean directive to “go to the Gemba.” Because our intent here is not to teach Lean or Six Sigma, we will leave it to the readers to research these terms if not already familiar with them. But we will make the point that the terms all represent methodologies that have at least one thing in common: actively drawing on the experiences, activities, and perspectives of those individuals who are closest to a specific activity or procedure.
In the context of product design, this translates into what we believe is the first and most important step in design for manufacturability: include on the design team significant representation by people who have had appropriate experience in the manufacturing environment. Do not limit this to engineers: include representation by the manufacturing team itself.
With that perspective in place, we can then start to effectively use the tools and methodologies that are currently being taught as “design for manufacturing.”
These methodologies are widely known, and readily available by search on the internet. They include; “design for assembly” (DFA) guidelines such as “reduce the number of parts” and “minimize assembly directions”; scoring methods to enable semi-quantitative estimation of time to perform an assembly process (typically known as “DFMA” – Design for Manufacturing and Assembly); Lean Design, teachings from Lean to “poka-yoke” a part or process (i.e. make it literally mistake-proof so it is not possible to do or be used incorrectly); and teachings from Lean to mock-up and practice a manufacturing line or process as part of the design cycle. Many other such methodologies and teachings are out there.
The purpose here is not to teach these methods, but rather to reinforce awareness of their existence. Many or most of them are accessible to learn on the Web via straightforward searching. It is likely more effective to first actually practice them under the tutelage of someone experienced in them – but lacking that opportunity it is still feasible to simply start out on your own from what can be learned on line.
We conclude this article with a list of recommendations that are either stated above, or logically flow from that discussion. None of these points are really new, and all of them are executable should an organization decide to do so:
- Demand that any individual has experience in manufacturing before they are allowed on a design team. Actually doing this does demand breaking down “silos” and reducing biases between organizational functions and their leadership – but it can be done.
- Lacking the above, include significant manufacturing representation on the design team. Listen to them (their perspectives are golden).
- Apply, as part of the design process, design for assembly, design for manufacturing and assembly, assembly process mock-ups, and other appropriate teachings from Lean. Be willing to change the design based on what you learn from these practices.
- Do not accept low yield (i.e. low capability) processes. Low capability processes lead to high scrap costs, and reduced quality even in the released product. If you accept these low capability processes, you may get your product out sooner, but your organization will pay a significant price downstream.
© DPMInsight, LLC 2017 All Rights Reserved
About the Authors:
Over 27 years of experience in industry, including 20 years with Medtronic, where he worked and consulted with many organizational functions, including research, systems engineering, product design, process design, manufacturing, and vendor management. He has also worked with development, regulatory submission, and clinical trials of combination products using the pharma (IND) regulatory pathway. He has been extensively involved with quality system (FDA and ISO) use and design, and is particularly concerned about effective understanding and use of product requirements and design controls. He has formally taught elements of systems engineering, design for Six Sigma, Lean, and Six Sigma. Cushing has degrees in chemistry and chemical engineering, is certified as a Project Management Professional, is certified as a Master Black Belt in Lean Sigma, and is the owner/member of DPMInsight, LLC (www.dpmillc.com).
Over 26 years of experience in leading Quality Assurance, Validation and remediation efforts in FDA regulated Medical Device and Pharmaceutical industry. Experience includes product development life cycle management from initial VOC through New Product Introductions (NPI), sustainable manufacturing, and end of life product management. Technical expertise in quality system gap assessment, system enhancement, alignment and implementation of all quality elements including design controls, risk management, purchasing controls, change control and post-market surveillance. Regulatory experience includes; ISO 13485, 9001 and 14971 certification, providing guidance for FDA PMA/510K and CE clearance, designated Management Representative, company representative and lead during FDA and ISO audits, 483 and warning letter resolution with experience working within consent-decree environments.
Michael B. Falkow
Michael Falkow is a Quality Specialist with Raland Compliance Partners. He has served as a regulatory compliance and quality assurance executive with multi-facility/international companies and was an FDA Compliance Officer and Senior Investigator/Drug Specialist. Michael has subject matter expertise for quality and regulatory compliance, quality auditing, quality assurance, quality control, supplier evaluation and certification, and compliance remediation. He has been approved by FDA as a GMP certifying authority and is qualified to provide Expert Witness testimony for GMPs.
Currently – Adjunct Professor at Mercer County Community College – teaching courses on Clinical Development for Certificate Program in Clinical Research as part of Drexel University’s Masters Degree in Clinical Development.
 “Bob the Builder” is an animated children’s television show produced and copyrighted by HIT Entertainment Limited and Keith Chapman. The iconic question and response from the show that many kids (now young adults) and parents will remember is: “Can we fix it? … Yes we can!”
 “J&J to quite struggling heart stent business.” http://www.reuters.com/article/us-johnsonandjohnson-idUSTRE75E2PK20110615
 Out of the Crisis. W. Edwards Deming. The MIT Press, Cambridge, Massachusetts. 2000.
 Software and information available from Boothroyd Dewhurst, Inc. http://www.dfma.com/software/dfma.htm