What Is an Automatic Welding Helmet?
An automatic welding helmet is a type of protective gear worn by operators during arc welding, designed to automatically adjust the light transmission.
In arc welding, intense light harmful to the eyes is generated, and without protective measures, various hazards can occur to the eyes. Additionally, sparks generated during welding pose a risk of burns when they come into contact with the skin.
Therefore, operators engaged in arc welding are required to wear protective gear to safeguard their eyes and face. Types of protective gear include handheld, head-worn, and automatic welding helmets. The automatic welding helmet is a high-performance protective gear that reacts to the ignition of the arc, creating a shading film using a liquid Crystal Filter to protect the eyes from harmful light.
Uses of Automatic Welding Helmet
The automatic welding helmet is used to protect the eyes and face of workers during welding operations. Harmful effects on the human body during welding include damage to the eyes from intense spatter light, burns from spatter, and inhalation of welding fumes.
Spatter is metal particles that splatter when heated during arc welding, emitting intense light along with heat. Ultraviolet radiation in the wavelength range of 200nm to 380nm and visible light in the range of 400nm to 570nm are particularly harmful to the eyes. Additionally, spatter can cause burns to the skin due to its high temperature.
The automatic welding helmet is a head-worn facegear that covers the entire area above the neck, protecting the head and face. The facial shield automatically darkens upon sensing the arc light, protecting the head, face, and eyes from heat and harmful light.
Certain automatic welding helmets also offer protection against welding fumes.
Welding fumes are metal particles that become airborne when metal spatter during welding cools and forms clusters of metal microparticles. Welding fumes, appearing as white smoke, can accumulate in the body when inhaled, leading to severe health issues such as lung cancer and neurological disorders.
Principle of Automatic Welding Helmet
The automatic welding helmet includes sensors that detect the ignition of the arc, a facial shield with an embedded liquid crystal filter, and batteries, solar cells, or both for driving the system.
Sensors are mounted on the automatic welding helmet, ranging from one to several. When the sensors detect the ignition of the arc, a signal is instantly sent to the liquid crystal filter, forming a shading film to reduce the light transmission. The degree of shading varies among products, and some helmets allow adjustment to several levels of shading.
The faster the shading speed from the detection of the arc to the formation of the shading film, the shorter the time the eyes are exposed to potential damage. Shading speeds can be as fast as 0.1 milliseconds.
When the arc is no longer detected, the time taken for the shading film to disappear is called the return speed. The return speed is considerably slower, ranging from tens to about 200 milliseconds, compared to the shading speed.
Additionally, ultraviolet filters (UV filters) and infrared filters (IR filters) are stacked in front and behind the liquid crystal filter. This provides a certain level of eye protection even when the shading film is not active. As a result, the facial shield of the automatic welding helmet is tinted like sunglasses when the liquid crystal filter is not in operation, reducing the transmission of harmful light to some extent.
How to Choose an Automatic Welding Helmet
When selecting an automatic welding helmet, consider factors such as shading level, response speed, weight, and comfort.
The shading level must be chosen appropriately. Insufficient shading against arc light can lead to eye damage due to accumulated exposure. Conversely, excessive shading can make it difficult to see the work area, reducing efficiency. The selection should consider the intensity of the arc during work and the ambient lighting conditions.
Some automatic welding helmets come with a shading adjustment feature.
The faster the response speed, the shorter the time the eyes are exposed to potential damage. Therefore, it is advisable to choose a helmet with a fast response speed.
Furthermore, since automatic welding helmets are worn on the head and may not be frequently removed during extended work periods, it is essential to choose a lightweight helmet with good weight balance to minimize strain on the neck.