There are six different edge types to choose from when completing deep drawn metal stamping. But before delving into edge types, it’s crucial to have a solid understanding of the stamping process itself, in which a blank, or sheet metal stock, is stretched over a plug.
First, the metal blank’s edges are held back while sliding between the blank holder and the die. Then the plug moves through the blank holder into the cavity of the die to a specific depth. This depth allows the blank to become the desired end form. The depth of the draw is typically greater than its diameter, which is what sets the process apart from other conventional stamping methods.
Several variables are inherent to the deep drawn stamping process, including plug shape, die shape, and depth of the draw. Different configurations will allow for different end results, with edge type playing an important role.
The following six edge types can be used in the deep drawn metal stamping process:
- Blank and Draw Untrimmed Flange — This edge type is often used as a cost-saving measure when designs require a flanged edge, but the flange dimensions are not critical. Blank and draw untrimmed flange edges require no additional tooling and result in irregular flange diameters.
- Blank and Draw No Flange — Used in applications in which side wall edges aren’t a top priority, this edge has the burr side facing the inside of the draw. No secondary tooling is needed.
- Blank and Draw Trimmed Flange — This produces ready-to-assemble products, though it can be expensive compared to other edge types.
- Pinch Trim Cut — When no flange is necessary and a slight flare is acceptable, this edge type is used. Secondary tooling may come into play, but this depends on diameter, depth, and burr direction. The burr side can be on either side of material thickness.
- Shimmy Die Cut — This edge is used for clean bottom cuts and/or when shapes or notches are necessary on the open side of the draw This method works well when secondary tooling is needed, since the inside of the draw faces the burr side.
- Flush Trim Cut — A more cost-effective alternative to the shimmy cut, this edge requires secondary tooling in order to get a small set radius. The burr side is to the cup side of the draw.
The Importance of Choosing the Right Edge Type
Taking the time to select the right edge type for a specific application will help ensure optimal part performance and cost savings, resulting in lightweight but very strong finished parts with exacting tolerances. These parts are usually much more expensive to produce using other stamping methods.
In fact, deep drawn metal stamping can result in significant cost savings for all types of high-volume applications. Upward of 2,000 precisely stamped parts per hour can be produced, and almost any material can be stamped, from steel to alloys to brass. And since deep drawn parts rarely need further processing thanks to the consistent, quality finish achieved, processes can be completed quickly and efficiently. Even secondary processes, such as notching and beading, can be completed within the initial draw.
Selecting the appropriate edge type for the particular application at hand is critical to ensure that your deep drawn metal stamped parts are as high-performing and reliable as possible. Whether cost savings are a top priority or having ready-to-assemble parts is the primary goal, take the time to compare the features and benefits of each edge type to determine which will work for you.
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