Types of Design Analyses possible with User Process Flowcharts

Flowcharting isn’t just useful for manufacturing processes. We can use them in lots of ways to help us with design of products and to identify quality characteristics. After all, products are used by people, and the way in which they use them is a process.

• compare ideal vs. actual flowcharts
• identify where there is disagreement about correct sequence or steps
• identify common mistakes/problems at each step to mistake-proof the process and design
• look for holds or delays, find the critical path

We also talk about specific flowchart analyses and how they can be used to analyze the user process for design.

• Cost-of-Poor-Quality
• Critical-to-Quality
• Value-Added Analysis
• Deployment Flowchart

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Design Tolerances Based on Economics (Using the Taguchi Loss Function)

Defining tolerances for our quality characteristics is sometimes not an easy task. If we set tight tolerances, it could be costly to make with a lot of rejects and rework in the future. If we’re too sloppy with our tolerances, then it can affect the functionality of our product, leading to unhappy customers, and also possible rework and scrap. There’s economics involved in setting-up tolerances.

Genichi Taguchi related his measure of quality (variation from the target spec) with economics, called the Taguchi Loss Function. It’s used to calculate the cost (in money) of a certain deviation from a target value. It assumes that the farther our quality characteristic is from our target value, the more costly it is to us.

We talk about how we can use the Taguchi Loss Functions as a way for us to set tolerances for our designs. Scroll lower to get an interactive tool and the equations.

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