The working principle of safety light curtain/safety grating and safety light curtain solution
In modern factories, humans and machines work together on some potentially dangerous mechanical equipment, such as stamping machinery, shearing equipment, metal cutting equipment, automated assembly lines, automated welding lines, mechanical transmission and handling equipment, and hazardous areas (toxic, High pressure, high temperature, etc.), it is easy to cause personal injury to operators. The photoelectric safety device generates a protective light curtain by emitting infrared rays. When the light curtain is blocked, the device sends out a light-shielding signal to control potentially dangerous mechanical equipment to stop working and avoid safety accidents. The installation of photoelectric safety protection devices can effectively avoid safety accidents, avoid the dangers of operators and third parties, reduce the overall cost of accidents, and benefit the company itself, operators and society. The price of the safety light curtain depends on: protection height, resolution, and safety level. The world's first safety light curtain product was born in 1952, and it has a history of more than 60 years. The time when safety light curtain products officially entered the mainland was concentrated in the early 1990s. From 2007 to 2008, the market share of China's safety light curtains was close to 220 million yuan, the sales volume was close to 80,000 sets, and the market size increased by 32.3% year-on-year. Safety light curtains are mainly used in the automotive industry, packaging industry, electronics industry, rubber and plastics industry in China. Among them, the automotive industry, rubber and plastics industry, and the electronics industry are the key application industries, with sales accounting for 67% of the total scale and supporting volume accounting for the total 62% of sales.
How the safety light curtain works
The safety light curtain consists of two parts: a light projector and a light receiver. The emitter emits modulated infrared light, which is received by the receiver to form a protection net. When an object enters the protection net, when light is blocked by the object, through the internal control circuit, the receiver circuit immediately responds, that is, the output Part of the output is a signal for emergency braking of machine tools such as punches and presses.
Light curtains have a very wide range of applications. For example, in the stamping equipment that requires continuous feeding and retrieving, if a contact safety protection door is installed, the operator needs to open and close the protection door frequently, which not only increases the workload of the operator, but also reduces Increased production efficiency. In this case, the use of gratings and light curtains is a good choice. When the operator is sending and reclaiming materials, as long as any part of the body blocks the light, the machine will enter a safe state without causing injury to the operator.
The density of the light beam determines how large the body part can be detected through the light curtain. According to ergonomic data, the diameter of the fingers of an adult should be no less than 14mm, the thickness of the palm should be no less than 30mm, and the diameter of the wrist should be no less than 40mm. For example: if the optical axis spacing of the light curtain used is 40mm, the optical axis diameter is 20mm, its resolution is 40+20=60mm, then the hand value, palm, wrist and arm may pass through the light curtain without being detected. Therefore, if you want to obtain higher security, you need to use a higher resolution light curtain.
When using gratings and light curtains, there are certain requirements for installation. People are not allowed to bypass the gratings and light curtains and enter the dangerous area, and it is also not allowed to have surfaces reflecting light near the gratings and light curtains so that the receiver can receive The safety switch signal cannot be output due to the reflected light. In addition, there are certain requirements for the use environment of gratings and light curtains. If the dust in the environment is too large, it will affect the emission of light, thereby affecting the use of gratings and light curtains.
