What is Manufacturing or DFM Design?

What is Manufacturing or DFM Design?

Design for Manufacturing (DFM) is the process of designing parts, components or products for ease of manufacture with the ultimate goal of making a better product at lower cost. This is done by simplifying, optimizing and refining the product design. The acronym DFMA (Design for Manufacturing and Assembly) is sometimes used interchangeably with DFM.

Five principles are examined during DFM. They are:

1. process

2. Design

3. material

4. the environment

5. Compliance/Testing

Ideally, DFM needs to occur early in the design process, before the tooling is started. Additionally, a properly executed DFM should include all stakeholders – engineers, designers, contract manufacturers, mold builders and material suppliers. The purpose of this "cross-functional" DFM is to challenge design – looking at design at all levels: component, sub-system, system and integrated levels – to ensure that design is optimized and does not incur unnecessary costs.

The chart below gives an excellent visual representation of the effect of initial DFM. As the design progresses through the product life cycle, changes become more expensive, as well as more difficult to implement. Initial DFM allows design changes to be implemented quickly, at a low cost location.

It is easy to pull stakeholders together in the design process if you are developing a new product, but if you are dealing with an established product, challenging the original design is an essential element of the entire DFM. Often, mistakes in design are repeated by repeating the previous design. Question every aspect of your design.

• See original drawings.

• Disassemble the product.

• Look at competing and nearby products, as well as key end users such as medical and automotive.

• Talk to your contract manufacturer - who may have solved the problem with other customers?

• Has anyone else solved this problem in a different way?

• Is there a way to make it better?

A lot of thought, time and effort goes into DFM. Jeff Tadin, our Senior Product Development Engineer, has nearly 30 years of experience in product development, design and manufacturing. Today, he's going to walk us through a hypothetical DFM process using an original computer mouse (this mouse was not made by East West Manufacturing.)

1 | process

The manufacturing process selected must be right for the part or product. You don't want to use a highly-capitalized process like injection molding that involves building tools and dies to make a low-volume part that can be manufactured using a less-capitalized method like thermoforming. That's the equivalent of using a tank to squash an anthill - a classic case of overkill. Let's see what Jeff has to say about choosing the right manufacturing process:

The manufacturing process selected must be right for the part or product. You don't want to use a highly-capitalized process like injection molding that involves building tools and dies to make a low-volume part that can be manufactured using a less-capitalized method like thermoforming. That's the equivalent of using a tank to squash an anthill - a classic case of overkill. Let's see what Jeff has to say about choosing the right manufacturing process:

Jeff said that in determining the manufacturing process, DFM takes into consideration the amount of parts being made, the material being used, the complexity of the surfaces, the tolerances required and whether there are any secondary processes required. You will notice that many of the questions they ask regarding the process fall under the heading 'design'.

2 | Design

Design is essential. The actual drawing of the part or product must conform to good manufacturing principles for the manufacturing process you have chosen. Jeff talks about mouse design:

In the case of plastic injection molding, for example, the following principles apply:

• Constant wall thickness, which allows for consistent and rapid part cooling

• Appropriate draft (1 - 2 degrees is generally acceptable)

• Texture – 1 degree is required for every 0.001” of texture depth on textured sidewalls.

• Ribs = 60 percent of nominal wall as a rule of thumb

• Simple transitions from thick to thin features

• The wall thickness is not too small - this increases the injection pressure

• No undercuts or features requiring cross action - all features "in line with pull / mold opening"

• Specify the loosest tolerances that allow for a good product - and consult with the trade organization for your manufacturing process about what is reasonable for that process.

Be sure to discuss your design with your contract manufacturer to ensure your design conforms to good manufacturing principles for the chosen process.

3 | material

Choosing the right material for your part/product is important. In this video, Jeff talks about some of the criteria that go into that decision:

Some material properties to consider during DFM include:

• Mechanical Properties – How strong should the material be?

• Optical properties – is the material reflective or transparent?

• Thermal properties – how heat resistant should it be?

• Color - What color should the part be?

• Electrical properties – Does the material need to act as a dielectric (act as an insulator rather than a conductor)?

• Flammability – How flame/burn resistant should the material be?

Again, be sure to discuss the matter with your contract manufacturer, who may have access to existing materials in their portfolio that will allow you to secure a lower material price.

4 | the environment

Your part/product must be designed to withstand the environment it will be exposed to. All the looks in the world don't matter if the part doesn't function properly under its normal operating conditions:

5 | Compliance/Testing

All products must comply with safety and quality standards. Sometimes these are industry standards, others are third-party standards, and some are internal, company-specific standards.