Design for Manufacture and Assembly

designing for the lowest manufacturing cost

take into account how the product is going to be produced requires an entirely different mindset.

Pure Prime Design for Manufacture and Assembly process

When developing new or redesigning old products, you have to take into account how the how the product is going to be produced, and that requires an entirely different mindset.

Designing your product to be manufactured consistently with quality is a challenge. Having components that are difficult to build or are time-consuming to assemble adds unnecessary cost.

To minimize costs and warranty issues and to ensure quality remains high, all products need to follow Design for Manufacture and Assembly (DFMA) principles. The DFMA process leads to the lowest cost of manufacturing. There is nearly 3X a difference in the cost as compared to poor designs and inefficient manufacturingĀ processes. Over time, as technology advances, what determines a good DFMA design from a poor one changesā€”resulting in DFMA a valuable part of the continuous improvement process.

PurePrime Web Mob DFMA GraphA v2
Figure 1 The effect of design on manufacturing cost. (Source: Data reduced from ā€œAssessing the Importance of Design through Product Archaeology,ā€ Management Science, Vol. 44, No. 3, pp. 352ā€“369, March 1998, by K. Ulrich and S. A. Pearson.)

What is Design for Manufacture and Assembly?

Design for Manufacture (DFM) involves designing for the lowest manufacturing cost of parts that make up a product. DFM is achieved by selecting cost-effective materials and manufacturing processes that minimize the complexity of manufacturing operations.

Design for Assembly (DFA) involves designing parts for the lowest cost of assembly. DFM is achieved by reducing product assembly costs and minimizing the number of assembly operations.

Effective DFM and DFA reduce material, overhead, and labor costs, and overall production time while maintaining quality.


Ensuring effective DFMA requires that the process occurs at the beginning of the design process. The verification of the concept design with simulation (CFD FEA). Effectively-executed DFMA requires all the stakeholders ā€” engineers, designers, manufacturers, mold builders, and material suppliers.

The purpose of this cross-functional team is to challenge the design from a manufacturing process. Because what you’re going to build is nothing without how you’re going to build it.Ā 

PurePrime Web Mob DFMA GraphB v2750

This holistic approach validates the design is optimized for manufacturing and does not have any unnecessary cost embedded in it. The following graph provides a visual representation of the difficulties and the cost of making design changes late in the development process.

The following graph provides a visual representation of the difficulties and the cost of making design changes late in the development process. The graph also demonstrates how ineffective continuous improvement processes are for design improvements during and after the production phase of a product life cycle. As you can see from the figure, there are many limitations as the design progresses through the product lifecycle. Changes become exponentially become more expensive (factor of 10 rule). The ability to change the design is exponentially decreasing. Additionally, as the design moves from stage to stage, a percentage of the product’s cost has been consumed.

  • Minimize The Number Of Product Parts.

    • Limiting The Number Of Parts In Your Products Is An Effective Way To Lower The Cost Of Any Product. This Results In Less Material, Assembly Labor, And Inventory.
  • Standardized Parts.
    • Customization Is Expensive And Time-Consuming. Standardized Parts Allow For Significant Production Efficacy Providing Scale And Lower Production Cost.
  • Create Modular Designs.
    • Using Modules Or Subassemblies Simplifies The Future Product Redesigns And Allows For The Use Of Standard Components For The Re-Use Of Modules In Other Products. Reducing Product Development And Production Cost.
  • Design Multi-Functional Parts.
    • Design Parts With More Than One Function; Multi-Functional Parts Are Produced Through A Clear Understanding Of The Design Intent.
  • Design Multi-Use Products.
    • Different Products Share Parts Or Subassemblies That Are Designed For Multi-Use.
  • Design For Ease Of Fabrication.
    • Selecting The Best Combination Of Material And Manufacturing Processes Minimizes Production Costs. Avoid Expensive And Labor Extensive Final Operations Like Painting, Polishing, Or Finish Machining.
  • Design Your Product To Join Without Using Screws, Fasteners, Or Adhesives.
    • Snap-Fit Design Is Used Every Day For Many Products To Interlock Or Clip Together. Screws Add Only About 5% To The Material Cost, But 75% To The Assembly Labor.
  • Minimizes Fastenerā€™s Selection, The Amount Needed, And Removes Washers.
    • Keep The Size, Number, And Type To A Minimum. Use Standard Fasteners Whenever Possible And Select Fasteners With The Washers Integrated. When Integrated Washers Are Used, It Minimizes Handling, Production And Assembly, And Inventory.
  • Handling Includes Positioning, Orienting, And Fastening The Part Into Place.
    • For Orientation Purposes, Use Symmetrical Parts Wherever Possible. Minimize Assembly Direction.
  • Your Parts Should Assemble From One Direction.
    • Ideally, Parts Should Be Assembled From Above. Assembly Is Facilitated By Gravity Rather Than Fighting It.