A Guide to Preventing Sheet Metal Shearing Defects

 

Metal shearing is a popular process used in sheet metal fabrication. It involves cutting a piece of metal along its length to create a specific shape or size. Unfortunately, this process can sometimes lead to defects in the product - an issue that no sheet metal fabricator wants to encounter. The good news is that these sheet metal shearing defects can be avoided!

 

This article will provide a comprehensive guide to preventing common sheet metal shearing defects. We will look at those defects, their causes, and the necessary preventative measures. However, before we dive into the details, let's first take a look at the metal shearing in Albuquerque, New Mexico Metals can provide to help you better understand how and why defects occur.

 

Let's get started!

The Shearing Process

This metal fabrication process involves using a special machine to cut sheets and plates of metal into different desired shapes and sizes. It works kind of like a giant pair of scissors, with an upper blade that moves down and a lower blade that remains stationary.

 

The location of the cut takes place on a shear table (or bed) with a squaring arm, which helps ensure that the cut is straight and precise.

 

Once the material is placed on the squaring arm and in position to cut,, the upper blade moves down and compresses the sheet metal against the lower blade, cutting through it. The result is a perfectly straight and accurate cut.

Sheet metal shearing defects

1.    Deformed edges

When the sheet metal (being sheared) is not held firmly in place, it tends to wobble or dislodge during the shearing process, resulting in a deformed edge.

 

To prevent this from happening, operators must ensure that the hold-downs (clamps) are securely holding the metal in place during the entire shearing cycle and that the shearing blades are sharp and in good condition.

2.    Burred edges

Burred edges are rough and jagged protrusions that occur along the cut edge of a metal. They usually occur when the shearing blades are not sharp enough or the gap between the lower and upper blades is too big or too small for the material being cut.

 

To prevent burred edges, make sure that your shear blades are properly sharpened and that the gap between the blades is adjusted to suit the type and thickness of the metal being sheared.

3.    Bowing

This defect slightly curves the cut edge of the metal - making it look like a bow (hence its name), and happens quite often when shearing long, narrow strips of metal.

 

And although bowing is caused by the stresses inherent in the metal itself and not as a result of a faulty shearing machine, you can minimize it by taking a trim cut to release the grain stress from the edge where typically a higher amount of stress exists.  Bowing can also be minimized when shearing across the grain instead of along the grain.

4.    Twisting

This happens when a fabricated metal curls into a spiral, right after the shearing process. Twisting is caused by excessive rake angle. And just like bowing, twisting can be minimized by taking a trim cut.  Also, it can be minimized when shearing across the grains instead of with the grains when possible.

5.    Cambering

In some cases, a metal workpiece can have varying thickness along its width or excessive internal stress which can lead to the material not remaining straight when sheared; even when the piece lays flat. In the case where the thickness varies edge to center, it is called a crown and can cause camber when shearing. .  Excessive internal grain stress as described above can also lead to camber.  As with twist and bow, camber can be minimized by trim cutting or cross grain shearing when possible.   

Key Takeaway

Sheet metal shearing defects can be avoided or at the very least, minimized if the right preventative measures are taken. By following the tips outlined in this guide, you can ensure that your shearing process is accurate and produces high-quality results.

However, if you're looking for a more reliable and efficient metal shearing solution in Albuquerque, New Mexico Metals LLC can help! We offer high-quality metal shearing services that guarantee accuracy and precision.

So, don't wait any longer! Contact us today, and let us help you get the perfect cut for your next project.

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