In the manufacture of sheet metal, the first step is to cut the sheet to size, this function is performed by shears. These machines can be used for a variety of purposes cutting alloy or other sheet metal. Few shears use angular shearing action to cut metal into strips or sheets like scissors. In some larger machines, a straight shearing action is used, where the blade is held at an angle opposite to the angular motion.
Usually, the shearing operation is carried out with the help of two blades, one of which is fixed on the shearing bed, and the other is moved in a vertical direction with no or very little clearance. The shearing operation progresses from one side of the material to the other. In blades, the angular configuration is called a rake. Gap and slope are completely dependent on the thickness and type of material being cut. The following articles describe the types of shears in detail.
1. Mechanical shearing machine
The mechanical shearing machine consists of a flywheel, a motor, a worm shaft driven by the flywheel, a plunger driven by a connecting rod, an eccentric with the help of a driven shaft, and a clutch for connecting the worm gear drive and the driven shaft. Mechanical shears provide more spam (strokes per minute) than hydraulic shears under many operating conditions. Sometimes the cycle of mechanical shearing is about 100 times per minute.
In mechanical shearing, small motors are also used for intermittent shearing due to the energy stored in the flywheel.
2. Straight knife shearing machine
In this type of shearing, the workpiece is placed between a movable upper knife and a fixed lower knife. When the upper knife is pushed down, the upper knife cuts the metal into two parts. This type of shearing is economical for cutting straight edge blanks from the strip, sheet, and sheet thicknesses less than 50mm. This process is used to cut sheets in blanks that are subsequently drawn or formed.
The machines used for straight knife cutting are:
When efficient equipment is not available, press brakes and punches are used. Cornering shears are commonly used to cut and trim strips, plates, or sheets to the desired size, these shears are also known as guillotine or re-cornering shears and they are available in a variety of designs and sizes.
When the upper knife moves down, the strip, sheet, or plate is tightly grasped by the pressing device. Adjust the position of one knife to maintain the gap between the knives. The drive of the square shears is done hydraulically, mechanically, or pneumatically.
3. Pneumatic shearing machine
Pneumatic shears are most widely used for shearing thin metals less than 1.50mm thick and short pieces less than 1.5m thick. The shear blade beam is moved by the activation of the air cylinder to make the cut. Self-contained air or workshop compressed air is used to power the cylinders.
4. Rotary shearing machine
Circular shearing or rotary shearing is the process of cutting sheets and sheets into contours or straight lines using two rotary and tapered circular cutters. Shearing with rotary shears requires stationary fixtures to allow the workpiece to rotate to produce the desired circle. In rotary shears, for straight cuts, a straight edge clamp is required, which is mounted on the throat of the machine behind the cutter head.
5. Crocodile shearing machine
The shearing action of the alligator shears is similar to that of scissors. The upper knife is fixed on the arm and moves around the fulcrum pin, and the lower knife remains stationary. Alligator shears are commonly used for cutting profiles and bars and preparing scrap.
6. Hydraulic shearing machine
The driving of the hydraulic shearing machine is completed by a motor-driven pump, which presses the oil in the cylinder to the piston. The piston movement provides energy to the plunger that supports the upper knife. Compared with mechanical shears, hydraulic shears can withstand longer strokes. They are designed for fixed load capacity.
The above introduces the types of shears, if you plan to buy shears, please contact us
Hengli is a professional custom shearing line manufacturer. Our main products are synchronized with the world's advanced technologies and are widely used in the pillar industries of the national economy such as automobile manufacturing and parts processing, iron and steel metallurgy processing, electric power, and metal packaging.