Shipulski On Design

Free Up Floor Space with Design for Assembly and Part Count Reduction

By Mike Shipulski, Director of Engineering, Hypertherm, Inc

Design for Assembly (DFA) methods have been around for over 25 years, but the number of companies using the methods is surprisingly low given that they are straight-forward, fast, and produce significant savings in traditional Value Added (VA) metrics: labor content and material cost. Now that LEAN has raised the world’s awareness of the importance of reducing Non-Value Added (NVA) activities, the true value of DFA methods can be appreciated.

As a first principle, Design for Assembly (DFA) methods focus on part count reduction. Part count reduction results in labor content reduction (fewer parts to assemble) and material cost reduction (fewer parts to buy). Part count reduction and labor reduction on the order of 40% are typical. My personal experience leading design teams is in-line with these numbers and I have achieved a 90% labor reduction on one design project. My personal rule of thumb is to set a goal of 50% reductions in part count and labor when using the methods to redesign a non-DFA design. Leaders of most companies would be thrilled with 50% reductions in VA activities (mine are), but the real savings lie elsewhere.

Counting the Savings

It is difficult to grasp the significance and far-reaching savings that come from reducing part count, but here are some examples to get you thinking. The size of a facility is strongly driven by the number of parts in your product, so reducing part count increases the number of products a facility can handle. Floor space is reduced because there are fewer parts to store and less storage space is needed for internal delivery resources (e.g., hand trucks, fork trucks) because there are fewer parts to move. Utilization of loading docks is reduced because there are fewer trucks to unload. Shipping costs are reduced because there are fewer parts to ship. So, if a 50% reduction in VA labor can’t get your company to reduce part count, you’ll have to retreat to a justification based on slashing floor space and putting more products through your factory.

If the savings are significant and far-reaching, why are so few using DFA methods to reduce part count? Before I get into the reasons, it’s important to understand my background and experience. I lead my company’s product development (Design Engineering) efforts and I have significant experience and education in Manufacturing (I still maintain my CMfgE certification – I’m proud of that). So, I understand what Design Engineering is asked to do and I know what Manufacturing is asked to do. Design Engineering is asked to design products and Manufacturing is asked to do LEAN. So, getting back to the reason why DFA methods aren’t used, the reason is simple: no one asks Design Engineering to reduce part count. And the reason is that company leaders don’t appreciate how significantly the product’s design governs Manufacturing’s LEAN work. To misquote a good friend, as a product designer I can design in more cost in a single afternoon than Manufacturing can take out in a lifetime.

There are few company leaders that have solid, fundamental understanding in both Product Design and Manufacturing, so strengthening the understanding of the design’s influence over Manufacturing’s LEAN work is difficult. The best, and most improbable, way to strengthen the link between a product’s design and LEAN is to ask the VP of Engineering and VP of Manufacturing to swap desks for six months. Getting back to reality, the next best way to get a company to reduce part count is use its fascination with reducing VA activities against itself. Beat the drum for 50% reductions in labor and you get to sneak in the real savings.

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Mike Shipulski is the Director of Engineering at Hypertherm, Inc., a privately-held company that designs and manufactures plasma arc cutting systems. Even though Mike has a Ph.D. in Manufacturing, Hypertherm still lets him design their products.