DFM Strategy in Sheet Metal Product Design Bridges the Gap between Exact and Real World

It will be too redundant to say that getting the product designs right the first time is the top most priority for manufacturers. Businesses that have not recognized and adapted the right technologies have already been outpaced by early-adopters and survived the competition successfully.

The reason why technologies have helped so much is because they enable businesses to bring down the cost and time on design rework and preventable engineering mistakes. It is estimated that 30-50% of time is spent on design rework and fixing errors and almost 24% of these errors are related to manufacturability.

The prime reason why these errors occur is due to ignoring the gap between exact and real world scenarios. This can be best understood considering the example of sheet metal products. These products are made up from metal blanks or stocks that are formed to required shapes using press.

There are numerous design parameters like tolerances, hole spacing, hole dia., bend allowances, etc. to be taken care of. With virtual CAD tools, designing sheet metal components is fairly easy and look good on screen, but it is equally important to ensure the manufacturability of these components.

Exact World and Real World in Sheet Metal

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Bridging the Gap

Above mentioned differences are only few; but there’s enough to understand why real world scenario is always different and must be taken into account right from the designing stage itself. From all the product development stages, design is the only stage that consumes most of the time and cost. Optimizing the design phase to reduce the rework and errors in such situations can be successfully implemented using Design for Manufacturing (DFM) strategy.

DFM helps designers to consider important manufacturability factors while designing the component and thereby reduces the possibility of engineering change orders at the last moment. It thus helps in bridging the gap between exact and real world scenarios.

For a sheet metal product design case, applying following strategy during the design phase can turn out to be beneficial both in terms of cost and time.

• Chamfering can help in avoiding metal tear at corners
• The sides and edges of the sheet metal component if provided with bends and beads can improve stiffness and reduce the spring back effect
• Applying collar around the pierced area also helps in adding the stiffness
• Using embossing for clamping area helps in improving the strength of the overall design. It also helps in maintaining flatness.
• Spacing between two holes if kept two times the stock thickness can help in maintaining the strength
• The location of hole or slot from the edge must be 1 ½ times the thickness of the stock
• Bend allowances must be applied in the design to avoid misalignment
• Design containing lugs must be cut perpendicular or at 45 degrees to grain structure to avoid cracking

DFM is a strategy that designers can learn and implement with practice and experience. However, to incorporate the changes in the design, you should also need the right CAD tool that helps in keeping the sheet metal design process smooth and alerts whenever there is a difference sensed between exact and real.

About Author: Kashyap Vyas is an Engineer at Hitech and holds a Master’s degree in Thermal Engineering with several research papers to his credit. He covers CAD and CAE topics for the engineering industry. His contributions are primarily focused on encouraging manufacturers and suppliers to adopt virtual product development tools to build efficient products with reduced time-to-market.