The Ultimate Guide to Metal Shears: Expert Tips

Sheet metal shears, as the name implies, is a machine used for cutting sheet metal.

The material selection is based on the general Q235 plate.

If cutting Q345 plate, then the model should be chosen 1.4 times larger. If cutting stainless steel, the model should be chosen 1.6-2 times larger. If cutting 10-40mm plate, a guillotine shear is a better choice.

Check out How to distinguish the steel plate from Q235 and Q345.

Overview

Metal shears are widely used in the sheet metal fabrication industry and can cut a variety of thicknesses of steel plate material. The machine used is called a squaring shear, power shear, or guillotine. It can be powered by foot, hand (less commonly), or mechanisms such as mechanics or hydraulics. The material is first clamped with a ram, and then a moving blade comes down across a fixed blade to shear the material.

Metal shears classification:

Generally, plate cutting machines can be divided into several types: foot-powered shears, mechanical shears, hydraulic swing beam shears, hydraulic guillotine shears, and hydraulic CNC-controlled shears.

Hydraulic shears work by moving the upper blade and the fixed blade with a reasonable blade gap to apply a shearing force to metal plates of various thicknesses, resulting in the plate being cut to the required size.

Sheet metal shears are often used to cut straight-edged blanks. The shearing process should ensure that the shearing surface is linear and parallel to the required specifications, and minimize sheet distortion to produce high-quality workpieces.

Metal cutting shears are a type of forging machinery, mainly used in the metal processing industry. These products are widely used in industries such as light industry, aviation, shipbuilding, metallurgy, instrumentation, electrical appliances, stainless steel products, steel construction, and decoration.

Definition of plate shear

According to the Machinery Industry Standard of the People’s Republic of China, a plate shear is defined as:

A machine that uses a blade that moves in a straight line against another blade to cut a sheet.

Classification

Special metal shears

Often, metal shears are used in conjunction with other equipment to fulfill specific purposes:

• Cold-formed line plate cutting machines: These shears are specially used in car longitudinal beam cold bending lines, car side baffle production lines, and color plate forming lines.
• Metal shears used in steel structure production lines: These are mainly used in angle steel and H-beam automatic production lines to complete the cutting process.
• Plate open line metal shears: These are designed for plate uncoiling lines to meet the requirements of fast production lines.

Thick plate lines mostly use hydraulic high-speed plate cutting machines, while thin plate lines are usually equipped with pneumatic metal cutting machines. High-speed lines use flying shear machines, which are known for their continuous production and high efficiency.

Inclined blade shear

The upper and lower blades of the metal shearing machine are angled, with the upper blade typically inclined at an angle of 1° to 6°.

The cutting force of an inclined blade shear is smaller than that of a flat blade shear, which leads to a reduction in motor power and the overall weight of the machine.

Flat blade shear

Shearing quality is good with minimal twisting deformation, but it requires a large shearing force and energy consumption. Most machines use mechanical transmission.

The cutting edges of the cutting machine are parallel to each other and are commonly used in rolling mills for hot billet and slab shearing. They can be divided into upper cutting and lower cutting methods.

Multi-purpose metal shears

Joint punching and shearing machine (ironworker machine): This machine is used to complete the shearing of plates, as well as cutting profiles, and is mainly used for the blanking process.

Sheet bending cutting machine: This machine can complete both the shearing and bending processes on the same machine.

Safety procedures for guillotine shears

Before operating the machine, wear tight protective clothing and fasten the cuffs. Do not wear loose clothing, remove clothing, or let clothing hang near the running machine to avoid injury.

Wear a helmet and tuck hair inside. Do not wear skirts, slippers, or gloves. The operator of the guillotine machine must be familiar with the main structure, performance, and use of the plate cutting machine.

This guillotine is suitable for cutting all kinds of steel plates, copper plates, aluminum plates, and non-metallic material plates within the rated thickness value. No hard marks, welding slag, slag, weld material, or ultra-thick material is allowed.

To use the metal guillotine shears: A. Adjust the blade gap according to the thickness of the material being cut. B. Adjust the mold or fixture according to the width of the material to be cut. C. Start the machine 1 to 3 times without material to ensure proper function, then begin using.

If the machine is not functioning normally during use, immediately cut off the power and check. Always cut off the power when adjusting the machine and be careful when moving the workpiece.

The machine parts should always be lubricated. The operator should add lubricant at the end of each shift, and the mechanic should add lubricating oil to the rolling bearing parts once every six months.

The following situation may arise:

Start the guillotine shears with a few empty runs to test the performance and try cutting different thicknesses of sheets, from thin to thick. Make sure the user is familiar with the shears’ performance.

Adjust the blade clearance for testing cuts with different thicknesses of plates. If the blade gap is not adjusted accordingly, it will affect the blade’s durability.

Open the pressure gauge switch to monitor the oil pressure during the cutting process. The pressure should be less than 20 MPa when cutting a 12mm plate. The factory setting is 20-22 MPa. The user must comply with this requirement and not cut material exceeding the specified thickness, as it will increase the pressure and cause damage to the machine.

The operation should be smooth and balanced. If there is any noise in the shears, it should be checked.

When the plate cutting machine is in use, the maximum temperature of the fuel tank should be less than 60 degrees. If the temperature exceeds this, stop the machine for a break.

In another blog post, you can check out Hydraulic Shearing Machine Operation Manual.

Hydraulic metal shears controller

1. E18 numerical control system

A domestically produced simple cutting plate CNC system with multi-step programming capability. It allows manual or automatic adjustment of the size of the back block and modification of parameters, making it easy to operate and use.

2. MD11 numerical control system

Developed and produced by Hong Kong Sanymicro Company, this economical simple CNC system is capable of multi-step programming and features manual or automatic back gauge adjustment and automatic retract function.

3. E20 CNC system

Nanjing Estun Manufacturing produces a special CNC controller for use on plate shearing machines. It features a double row 12-section LEC display, multi-step programming, automatic running, power memory function, and fast location teaching function. The system is stable and excellent.

4. E200-S numerical control system

Nanjing Estun produces a CNC controller with a 240×128 LCD display and a Chinese and English operation menu. It has multi-step programming and features a one-way positioning function and automatic position compensation function.

5. DAC-310 CNC system

The Netherlands DELEM company produces an imported CNC controller for metal plate cutting machines. It features a 275×48 high-definition LCD display and 100-step programming capabilities. It uses professional servo control technology for increased cutting accuracy.

6. DAC-360 CNC system

The CNC system for plate cutting machines is imported from the Netherlands and produced by DELEM. It features a high-brightness LCD display, automatic calculation of shearing pressure, automatic control of the back gauge, shearing stroke, shearing angle, and blade gap, and flexible definition of I/O ports.