DESIGN FOR MANUFACTURABILITY

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New article everyone needs now:  How to avoid most shortages now 
AND design new products for unlimited scalability.

 

Since this is the worst possible time to "fire-fight" production or ramp problems  
"on the floor," companies should . design products for manufacturability, 
which can be done in remote teams, using Zoom or M.S. Team.

If this is not widely understood,  arrange DFM webinar training or 
distribute the
600 page 2020 DFM book.

DESIGN FOR MANUFACTURABILITY ARTICLE

from the Book: "Design for Manufacturability: How to Use Concurrent Engineering to
Rapidly Develop Low-Cost, High-Quality Products for Lean Production" (2014, Productivity Press

Copyright © 2020 by David M. Anderson

Design for manufacturability (DFM) is the process of proactively designing products to (1) optimize all the manufacturing functions: fabrication, assembly, test, procurement, shipping, delivery, service, and repair, and (2) assure the best cost, quality, reliability, regulatory compliance, safety, time-to-market, and customer satisfaction.

Concurrent Engineering is the practice of concurrently developing products and their manufacturing processes.
If existing processes are to be utilized, then the product must be design for these processes.
If new processes are to be utilized, then the product and the process must be developed concurrently.

Design for Manufacturability and Concurrent Engineering are proven design methodologies that work for any size company. Early consideration of manufacturing issues shortens product development time, minimizes development cost, and ensures a smooth transition into production for quick time to market.  These techniques can be used to commercialize prototypes and research.

Quality can be designed in with optimal part selection and proper integration of parts, for minimum interaction problems. By considering the cumulative effect of part quality on product quality, designers are encouraged to carefully specify part quality.

Design for Manufacturability can reduce many costs, since products can be quickly assembled from fewer parts. Thus, products are easier to build and assemble, in less time, with better quality. Parts are designed for ease of fabrication and commonality with other designs. DFM encourages standardization of parts, maximum use of purchased parts, modular design, and standard design features. Designers will save time and money by not having to "re-invent the wheel." The result is a broader product line that is responsive to customer needs. Click here for article on standardization.

Companies that have applied DFM have realized substantial benefits. Costs and time-to-market are often cut in half with significant improvements in quality, reliability, serviceability, product line breadth, delivery, customer acceptance and, in general, competitive posture.

These practical methodologies are taught through Dr. Anderson's in-house seminars and lower-cost webinars.  He helps with implementation through his leading-edge consulting.

Designing Products for Manufacturability

In order to design for manufacturability, everyone in product development team needs to:

C In general, understand how products are manufactured through experience in manufacturing, training, rules/guidelines, and/or multi-functional design teams with manufacturing participation.

C Specifically, design for the processes to be used to build the product you are designing: If products will be built by standard processes, design teams must understand them and design for them. If processes are new, then design teams must concurrently design the new processes as they design the product.

The Bad Old Days

Before DFM, the motto was "I designed it; you build it!" Design engineers worked alone or only in the company of other design engineers in "The Engineering Department." Designs were then thrown over the wall leaving manufacturing people with the dilemma of either objecting (but its to late to change the design!) or struggling to launch a product that was not designed for manufacturability. Often this delayed the both the product launch and the time to ramp up to full production, which is the only meaningful measure of time-to-market.

The Good New Days of Product Development Teams

One way that manufacturability can be assured is by developing products in multi-functional teams with early and active participation from Manufacturing, Marketing (and even customers), Finance, Industrial Designers, Quality, Service, Purchasing, Vendors, Regulation Compliance specialists, Lawyers, and factory works. The team works together to not only design for functionality, but also to optimize cost, delivery, quality, reliability, ease of assembly, testability, ease of service, shipping, human factors, styling, safety, customization, expandability, and various regulatory and environmental compliance.

The Importance of Early Concept & Product Architecture Decisions

By the time a product has been designed, only 8% of the total product budget has been spent. By that time, the design has determined 80% of the cost of the product! See graph from the book, Design for Manufacturability. 1 The design determines the manufacturability which determines a significant part of the introduction and production cost (the 80%) of the product. Once this cost is locked in, it is difficult for manufacturing to remove it. Note that the concept or architecture alone determines 60% of the cost!

Similarly, thorough up-front work cuts in half, the time to stable production.  See article on half the time.

Off-the-Shelf Parts

Paradoxically, one of the first decisions the team has to make is the optimal use of off-the-shelf parts. In many cases, the architecture may have to literally be designed around the off-the-shelf components, but this can provide substantial benefits to the product and the product development process:

Off-the-shelf parts are less expensive to design considering the cost of design, documentation, prototyping, testing, the overhead cost of purchasing all the constituent parts, and the cost of non-core-competency manufacturing. Off-the-shelf parts save time considering the time to design, document, administer, and build, test, and fix prototype parts.

Suppliers of off-the-shelf parts are more efficient at their specialty, because they are more experienced on their products, continuously improve quality, have proven track records on reliability, design parts better for DFM, dedicate production facilities, produce parts at lower cost, offer standardized parts, and sometimes pick up warrantee/service costs.

Finally, off-the-shelf part utilization helps internal resources focus on their real missions: designing products and building products

Some Key Design for Manufacturability Guidelines

DFM Guideline A1) Understand manufacturing problems/issues of current/past products

In order to learn from the past and not repeat old mistakes, it is important to understand all problems and issues with current and past products with respect to manufacturability, introduction into production, quality, repairability, serviceability, regulatory test performance, and so forth. This is especially true if previous engineering is being "leveraged" into new designs.

DFM Guideline A3) Eliminate overconstraints to minimize tolerance demands.  An overconstraint happens whenever there are more constraints than the minimum necessary, for instance guiding a rigid platform on four rigidly mounted bearings or trying to precisely align two parts with multiple round pins inserted into round holes (the solutions for both are shown below).

• For critical alignment of parts use round/diamond pins. Use pairs of inexpensive but tight-tolerance dowel pins to locate critical parts. Matching tight-tolerance hole diameters can be made with reamers. To eliminate the tolerance match problem between holes, use one round pin to locate in “x” and “y” dimensions and a diamond pin to locate the angle from the round pin. The diamond is precision ground to locate in the angle direction, but is relieved in the direction of the hole spacing. Aligned parts are held together with bolts, with ample clearance holes so the bolts do not try to align the parts. This technique was developed to locate tooling, but it can also be useful for aligning parts for assembly.



Assembling Parts Together with Pins. Parts that are already aligned can be pinned together by drilling and reaming holes through all the parts and then pinning them with all round pins.
 

DFM Guideline P1) Adhere to specific process design guidelines.

It is very important to use specific design guidelines for parts to be produced by specific processes such as welding, casting, forging, extruding, forming, stamping, turning, milling, grinding, powdered metallurgy (sintering), plastic molding, etc. Some reference books are available that give a summary of design guidelines for many specific processes. Many specialized books are available devoted to single processes.

DFM Guideline P2) Avoid right/left hand parts.

Avoid designing mirror image (right or left hand) parts. Design the product so the same part can function in both right or left hand modes. If identical parts can not perform both functions, add features to both right and left hand parts to make them the same.

Another way of saying this is to use "paired" parts instead of right and left hand parts. Purchasing of paired parts (plus all the internal material supply functions) is for twice the quantity and half the number of types of parts. This can have a significant impact with many paired parts at high volume.

At one time or another, everyone has opened a brief case or suit case upside down because the top looks like the bottom. The reason for this is that top and bottom are identical parts used in pairs.

DFM Guideline P3) Design parts with symmetry.

Design each part to be symmetrical from every "view" (in a drafting sense) so that the part does not have to be oriented for assembly. In manual assembly, symmetrical parts can not be installed backwards, a major potential quality problem associated with manual assembly. In automatic assembly, symmetrical parts do not require special sensors or mechanisms to orient them correctly. The extra cost of making the part symmetrical (the extra holes or whatever other feature is necessary) will probably be saved many times over by not having to develop complex orienting mechanisms and by avoiding quality problems.

It is a little know fact that in felt-tipped pens, the felt is pointed on both ends so that automatic assembly machines do not have to orient the felt.

DFM Guideline P4) If part symmetry is not possible, make parts very asymmetrical.

The best part for assembly is one that is symmetrical in all views. The worst part is one that is slightly asymmetrical which may be installed wrong because the worker or robot could not notice the asymmetry. Or worse, the part may be forced in the wrong orientation by a worker (that thinks the tolerance is wrong) or by a robot (that does not know any better).

So, if symmetry can not be achieved, make the parts very asymmetrical. Then workers will less likely install the part backward because it will not fit backward. Automation machinery may be able to orient the part with less expensive sensors and intelligence.

In fact, very asymmetrical parts may even be able to be oriented by simple stationary guides over conveyor belts.

DFM Guideline P5) Design for fixturing.

Understand the manufacturing process well enough to be able to design parts and dimension them for fixturing. Parts designed for automation or mechanization need registration features for fixturing. Machine tools, assembly stations, automatic transfers and automatic assembly equipment need to be able to grip or fixture the part in a known position for subsequent operations. This requires registration locations on which the part will be gripped or fixtured while part is being transferred, machined, processed or assembled.

DFM Guideline P6) Minimize tooling complexity by concurrently designing tooling.

Use concurrent engineering of parts and tooling to minimize tooling complexity, cost, delivery leadtime and maximize throughput, quality and flexibility.

DFM Guideline P7) Make part differences very obvious for different parts.

Different materials or internal features may not be obvious to workers. Make sure that part differences are obvious. This is especially important in rapid assembly situations where workers handle many different parts. To distinguish different parts, use markings, labels, color, or different packaging if they come individually packaged. One company uses different (but functionally equivalent) coatings to distinguish metric from English fasteners.

DFM Guideline P8) Specify optimal tolerances for a Robust Design.

Design of Experiments can be used to determine the effect of variations in all tolerances on part or system quality. The result is that all tolerances can be optimized to provide a robust design to provide high quality at low cost.

DFM Guideline P9) Specify quality parts from reliable sources.

The "rule of ten" specifies that it costs 10 times more to find and repair a defect at the next stage of assembly. Thus, it costs 10 times more cost to find a part defect at a sub-assembly; 10 times more to find a sub-assembly defect at final assembly; 10 times more in the distribution channel; and so forth. All parts must have reliable sources that can deliver consistent quality over time in the volumes required.

The Rule of 10

Level of completion     Cost to find & repair defect

    the part itself                     X

    at sub-assembly               10 X

    at final assembly             100 X

    at the dealer/distributor 1,000 X

    at the customer             10,000 X

DFM Guideline P10) Minimize Setups. For machined parts, ensure accuracy by designing parts and fixturing so all key dimensions are all cut in the same setup (chucking). Removing the part to re-position for subsequent cutting lowers accuracy relative to cuts made in the original position. Single setup machining is less expensive too.

DFM Guideline P11) Minimize Cutting Tools. For machined parts, minimize cost by designing parts to be machined with the minimum number of cutting tools. For CNC "hog out" material removal, specify radii that match the preferred cutting tools (avoid arbitrary decisions). Keep tool variety within the capability of the tool changer.

DFM Guideline P12) Understand tolerance step functions and specify tolerances wisely. The type of process depends on the tolerance. Each process has its practical "limit" to how close a tolerance could be held for a given skill level on the production line. If the tolerance is tighter than the limit, the next most precise (and expensive) process must be used. Designers must understand these "step functions" and know the tolerance limit for each process.

The Importance of Good Product Development

C Good product development is a potent competitive advantage.

C Product design establishes the feature set, how well the features work, and, hence, the marketability of the product.

C The design determines 80% of the cost and has significant influence on quality, reliability and serviceability.

C The product development process determines how quickly a new product can be introduced into the market place.

C The product design determines how easily the product is manufactured and how easy it will be to introduce manufacturing improvements like just-in-time and flexible manufacturing.

C The immense cost saving potential of good product design is even becoming a viable alternative to automation and off-shore manufacturing.

C True concurrent engineering of versatile product families and flexible processes determines how well companies will handle product variety and benefit from Build-to-Order and Mass Customization.2

 

Section 3.11 in the 600 page DFM boo a  sub-section in the Preface that summarizes:

 

Generating Interest in DFM (Section 3.11).   This new section shows individuals, DFM champions, (who could be you)  and project team leaders what they can do to help generate interest in DFM, with respect to the following:

 

Change. Finally, here is a book that presents the most effective product development methodology that will achieve any cost goals needed in half the time to stable production with quality designed in right-the-first-time. This elevates “DFM” from a “tool” to be given to engineers to make them responsible for all the goals listed below, often without trying any empowerment or change to the company itself, really supporting product development, or changing any counter-productive policies summarized in Section 11.5 with “links” to all the sections that show what the policies should be changed to. 

        If individuals, team leaders, or champions can trace the sources of any counter-productive policies, they should send this book to anyone who may need to learn these principles, with post-it notes on applicable pages (which are recommended in the text of Section 11.5).

        If DFM training (Section 11.3) cannot be arranged before the next product development effort, buy this book for everyone on the team and management, with the Manufacturable Research section (3.9) applied immediately to research efforts before the  training

Cost. This section encourages DFM champions in all departments to develop plans to use DFM to greatly save cost in all the categories presented in the book, not just part cost as done in most companies. Champions must help eliminate fallacies about cost, like ‘“cost is 85% parts –it’s a “parts play”’ (heard at more than one company big on cost reduction), and beliefs that cost can easily be reduced later, or that cost can be easily reduced by Mass Production, sheer volume, automation, or robotics.

 

Time to Stable Production. All team members need to apply the principles of concurrent engineering to work together early in complete multifunctional teams. Also, team members must make sure that their projects have enough time so that the timelines look like the lower “advanced” timelines in Figures 2.1 and 3.1. If this is not automatically forthcoming, teams and champions must campaign for a higher proportion of up-front work (use these words instead of asking for “more time”).

 

Prioritization of Resources. Everyone in the company who is aware of the sales force “taking all orders” or “accepting all customizations” and its effects on resource utilization should speak up now to ensure that resources and adequate timelines are sufficient for success. 

         Section 2.2.17, titled “Don’t Lose Team Completeness or Critical Talent,” strongly emphasizes the importance of complete multifunctional teams with a list of 60 specialties needed to complete  multifunctional teams! Sub-sections show Management, Champions, and Team Leaders many ways to do this:

 

Don’t Let Essential Team Members Be Laid Off. This sub-section starts with a citation from the author’s other book, Build-to-Order & Mass Customization (described in Appendix D.2) from the “Don’t Lay Off People” section on page 429, which starts with a side-bar quote from Jim Collins: “Great companies don’t lay off people.” The need and value of complete multifunctional teams is a big reason why champions and team leaders need to campaign to prevent layoffs affecting any of the 60 specialties cited in Section 2.2.17. In one DFM seminar, the author said, “You need to have your Regulation specialist on that team,” to which the team said, “we just laid him off.”         Interviews with human resource experts point out that the firing/rehiring cycle has a 1.5- to 2-year breakeven point, meaning that if the market rebounds in less than that time, the company would be ahead by saving all the severance and rehiring costs and simply keep the people on salary, even if they theoretically had nothing to do! Of course, the company can deploy them in improvement programs and training.

 

Don’t outsource engineering. In addition to the obvious loss of   alent and accessibility challenges, there are resource challenges for the survivors in that workloads will increase to fill in for people who are gone or whose functions are no longer working at the same time, all of which cause more resource gaps for the remaining teams. Further, morale and efficiency will drop, and the best engineers may leave, thus weakening engineering efforts and making product development even less efficient—all for the illusion of saving money.

 

Don’t waste your MEs on draining ventures, such as taking in “contract manufacturing” work (which can increase ME demands several times), offshoring production (which will literally remove most MEs from multifunctional development teams and use them to work for other companies).  Accepting any money-losing business like low-volume builds,  “taking all orders,” accepting all customizations, or developing  all discrete products for all markets.

Infrastructure demands on valuable NPD resources, like big MRP/ERP IT implementation projects that may be made obsolete by Lean Production (Section 4.1). Build-to-Order  Projects (Section 4.2) with Spontaneous Supply Chains (Section 4.2.1) that don’t need to manage inventory (Sections 3.8.11, 3.8.12, and 3.8.13). If those projects are as good as they say, the IT Department should be able to pay for their entire implementations.  That overall section opens with the advice: “Team leaders and program managers need to be astute enough to keep multifunctional teams complete and preserve critical talent

 

Help Make the Case for DFM. This section advises individuals and champions to compile their observations about what makes their products hard-to-build and what improvements to the product development process would mostly improve manufacturability in the company or on your project.   The first step would be to measure, or, at least estimate, the problems caused by lack of DFM.  The next step would be to propose DFM improvements in your sphere of influence, your department, or your project, not waiting for a company-wide product development initiatives.  

       Two high-profile DFM demonstrations would be to show the nearterm value in DFM: • One would be to immediately apply DFM to a project where all the principles of this book or DFM training are applied for a product development project in its own microclimate as proposed in Section 3.11.6.1, which would be enhanced if the project had its own project room, as recommended.  • The other would be a design team can redesign a backward-compatible “drop-in” replacement that can immediately reduce the cost of an expensive sub-assembly on current and legacy products and then become the foundation of next-generation products. This is proposed in Section 3.11.6.2.


How to be taught the  most practical  DFM principles

Dr. Anderson's DFM class is the most effective and practical class available because:

So the this is the best DFM course out there  and is far better than  the usual "canned material taught by staff  trainers" who  only teach engineers  guidelines, sometimes using tools that may use software that look for “opportunities” after something is designed, which is discouraged, as shown in the articles “Why it is so hard to reduce cost or "implement" DFM after design” at http://www.halfcostproducts.com/how_not_to_lower_cost.htm   and “7 Reasons Why “Cost Reduction” Attempts after Design Doesn’t Work;' at: http://design4manufacturability.com/cost_reduction.htm'                 

       See the  most frequently  updated page on on this site; which is on  on Strategy.   

 

 

See new section at end of Cost Reduction article:
 
What to Do About Existing Products that Cost Too Much 
 

All of these principles on DFM can be included in
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Dr. Anderson is a California-based consultant specializing in training and consulting on build-to-order, mass customization, lean/flow production, design for manufacturability, and cost reduction. He is the author of "Design for Manufacturability" (2014, 486 pages; Productivity Press) and  "Build-to-Order & Mass Customization, The Ultimate Supply Chain Management and Lean Manufacturing Strategy for Low-Cost On-Demand Production without Forecasts or Inventory" (2008, 520 pages; CIM Press, 1-805-924-0200, www.build-to-order-consulting.com/books.htm).   He can be reached at (805) 924-0100 or anderson@build-to-order-consulting.com; BTO web-site: www.build-to-order-consulting.com.

Endnotes/References

1. David M. Anderson, "Design for Manufacturability; How to Use Concurrent Engineering to Rapidly Develop Low-Cost, High-Quality Products for Lean Production" (2014, 486 pages; Productivity Press) www.design4manufacturability.com/books.htm).  Click here for the DFM book description and order information.

2. David M. Anderson, Build-to-Order & Mass Customization; The Ultimate Supply Chain Management and Lean Manufacturing Strategy for Low-Cost On-Demand Production without Forecasts or Inventory," (2008, 520 pages; CIM Press phone/fax: 805- 924-0200, www.build-to-order-consulting.com/books.htm;  ISBN 1-878072-30-7).  Click here for the Build-to-Order book description.


Dr. David M. Anderson, P.E., CMC
Management Consultant
www.design4manufacturability.com
phone: 1-805-924-0100
fax: 1-805-924-0200

e-mail: anderson@build-to-order-consulting.com
 

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