Poke Yoke

Jon M Quigley

There are a set of tools and techniques that come with developing products for the automotive industry and are part of the Advanced Product Quality Planning for the product.  We have written about APQP or some years and have decades of experience in this approach to product development.  In general, the phases of the project are described as:

1. Voice of Customer
2. Product Development
3. Process Development
4. Product Validation
5. Process Validation
6. Launch
7. Feedback

Automotive Industry Action Group APQP Graphic

We have a discussion board that supports questions you may have regarding APQP.  Today, we will ruminate on the technique known as Poke Yoke, which I heard an Supplier Quality Assurance professional refer to as “goof proofing”.  While largely benefiting manufacturing, these considerations and implementation is achieved in the development work, otherwise we end up doing considerable rework of the developed product to optimize manufacturing or field service work. Rather, we will use design for manufacturing (DFM) or design for manufacturing and assembly (DFMA) to provide manufacturing feedback to the development work.  As more is learned about the product and how it is to be manufactured and serviced, opportunities for mistakes are discovered. Consider, for example, an electronic component that has two identical connectors.  Which mating connector applies to which connector of the component.

Poke Yoke are the actions we will take to ensure the product can be consistently produced and assembled.  In our example above, we can color code the connectors or change the pin count, or connector type and shape.  Doing so, differentiates which mating connector will go to which connection point on the product.  These alternatives will have costs associated, and the best cost value solution is often selected, in this case changing the color of the connector body and the mating connector will ensure the appropriate connector is connected, baring color-blind personnel, perhaps.

There are many ways to accomplish assembling the product in only one way. Besides connectors shapes, sizes, we can have parts labeled with corresponding mating surfaces, we can have special screw or fastening mechanisms for the assembly.  There can be specific jigs or tools that are employed on the manufacturing line to ensure the appropriate orientation of the assembly. These fixtures, for example, can block out part of the product to ensure the correct portion of the product is exposed for this step in the assembly.

So how do we learn what areas may be the source of the greatest mistakes? Well, we can look at our historical record when it comes to manufacturing of products, even our clients may have some input in this regard if they have had similar products built.  As we work our way through the product and process development portions of the APQP process, we will see thing that we can identify as potential areas of contention or opportunities for a mistake to enter the manufacturing of the product.  This is the reason for product and process development overlapping.

We need not wait until the end of the product development in fact it is not in our best interest to do so. We should be exploring how to make the product as effectively and as error free as possible, considering the cost of poor quality and rework.  Check out our APQP section of the website.