Manufacturers have a lot of options when it comes to working with aluminum. One of the most common processes is shearing, and it is used in a variety of industries. When you are making decisions about your manufacturing operations, shearing offers many benefits, but it’s important to be aware of the many variables that come into play, in particular selecting the best alloy for your application.
For those who are new to the manufacturing process, it can be easy to get confused about the various terms involved with cutting and shaping metal. For instance, what’s the difference between shearing, slitting, and blanking metal? What is a die and is it different from a shear? Even among experts, these terms will often be interchanged in a confusing manner.
What is metal shearing?
Shearing is defined as a process in which a material is cut by using a punch (the moving blade) to push it against the die (the fixed blade). As the material is pushed, it will experience highly localized shear stresses between the punch and die, until it finally reaches a breaking point. The material fails when the punch has pushed far enough that the stresses are greater than the shear strength of the material, resulting in a clean tear along the length of the piece. One major benefit of shearing in this manner is there is no formation of chips, nor does it require burning or melting the material.
Strictly speaking, to be called shearing, the cutting blades need to be straight. When the cutting blades are curved, then it is a shearing-type operation. These include blanking, piercing, roll slitting, and trimming. Another term that is commonly used to describe shearing is die cutting. Other similar processes are clicking, dinking, and kiss cutting, though these terms are less common in metalworking industries.
The materials that are most commonly sheared are sheet metal or plates, along with rods on occasion. In addition to metal, paper, plastics, and leather are commonly sheared as well.
What are the common types of metal shearing?
There are many varieties of shearing machines and benches that can be found in metal working shops. One of the most recognizable is the alligator shear, also referred to as a lever shear or crocodile shear. It is used to cut metal and it consists of a hinged jaw, which is pushed using a flywheel or hydraulic cylinder. These jaws will range in size from 4 to 36 inches in length. If you’ve seen one, you will definitely understand how they got the name alligator. They are primarily employed for cutting steel and aluminum pieces, including rebar, pipe, angle iron, or I-beams.
Also prevalent is the bench shear, sometimes called the lever shear. As the names suggest, it is a shear that has been mounted to a bench and which is operated with a lever to increase the mechanical advantage. It is capable of cutting medium-sized pieces of sheet metal. Because of its light weight and ease of use, it can be employed in many different manufacturing scenarios at a low cost. Even so, these benches tend to be very sturdily constructed. Some lever shears can even cut sheet bar and flat bar up that is up to 10mm in thickness.
A step up in complexity, the shearing machine known as the guillotine may be powered by foot, hand, mechanically, or hydraulically. The material is first clamped to the ram, and a moving blade is then lowered across a fixed blade, which shears the piece at the desired point. When dealing with larger shears, the moving blade can be set at an angle so that the metal is sheared in a progressive manner from one side to the other. A typical guillotine is comprised of the shear table, a device to hold the material that will be cut, the upper and lower blades, and a gauging device.
Finally, many machine shops will have power shears, an electrical (or pneumatic) hand tool that can blank large sheets of metal without any size limit. They have been specially designed to ensure straight lines and relatively large radius curves. The largest models can cut up to 12-gauge sheet metal. They are especially convenient for cutting metal that is too large for transport or that is found in remote areas.
What Aluminum Alloys Are Readily Available For Shearing?
The aluminum alloys that Clinton Aluminum regularly stocks in sheet form include all of the major commercial grades. Sheet metal is an indispensible material in many technologically advanced industries, in particular aerospace and automotive. The method of producing this aluminum sheet involves passing the aluminum ingot through high-pressure rollers, which will flatten the metal to the desired thickness. Another benefit of aluminum sheet is that it is easily recycled, offering tremendous energy savings, as recycling sheet aluminum requires ten percent of the energy needed to produce new aluminum.
Among the most popular alloys, 5052 and 3003 followed by 6061 are sold in sheet form. The former is prized for its admirable combination of strength, toughness, and corrosion resistance, and it is truthfully among the most versatile aluminum alloys commercially available. 6061 is readily weldable and machinable, while offering the highest resistance to corrosion of the heat treated aluminums. For this reason it is commonly found in marine environments.
Summary
New techniques are being developed that allow for the shearing of specialty alloys that might suffer from burring or other defects when sheared by traditional means. These advances allow for the efficient cutting of materials that previously required cost prohibitive or inefficient processes. Please contact us with any questions regarding your specific application needs and we’ll work with you to find a solution. Our friendly and knowledgeable technicians will be more than happy to help in any way they can.
