Currently, most laser cutting of thin plate materials is still manually lifted, and at least three people are needed to lift a 3m long, 1.5m wide, and 3mm thick plate. In recent years, manual material handling mechanisms have begun to be promoted, usually using a lifting mechanism + electric hoist + vacuum suction pad system to achieve material handling.
The vacuum suction pad, also known as the suction cup gripper, uses vacuum pressure to hold and grasp the plate. The plate surface is relatively flat, and the lip edge of the suction pad is relatively soft and thin, which can stick to the plate.
When the vacuum pump extracts vacuum, the cavity of the suction pad also produces a vacuum, forming a negative pressure. The suction force of the vacuum suction pad is proportional to the pressure (vacuum degree, pressure difference between the inside and outside of the suction pad) and the area of the suction pad. That is, the higher the vacuum degree, the greater the suction force; the larger the suction pad size, the greater the suction force.
According to data tested by a foreign professional vacuum company, the safety factor of vacuum pressure requires 2 times the acceleration generated by a conventional electric hoist.
To ensure safety, the theoretical suction force of vacuum suction cups is calculated under the condition of 60% vacuum degree and then divided by 2 to obtain the required safe suction force.
The theoretical safe suction force refers to the condition where the suction pad is not aging and hardening, the suction pad is not damaged or cracked, the suction pad surface is clean, and the plate surface quality is relatively good.
The lip edge of the vacuum suction pad is well-matched with the plate surface, and the air leakage is small, so the vacuum degree can reach 60% or more. Therefore, to ensure the safe use of the vacuum suction pad system for material handling, please pay attention to :
Regularly clean the suction pad lip surface (the side that is in contact with the plate), and regularly inspect whether the suction pad is scratched, cracked, or aged. If there is any issue, replace the suction pad immediately. In fact, many companies are using unsafe suction pads, which have hidden safety hazards.
When the plate surface rusts severely and is very uneven, the safety factor should be increased, otherwise it may not be firmly suctioned.
Material handling with vacuum suction pads is a manual assistance method, and it is necessary to ensure the safety of personnel. The vacuum degree of the vacuum generator is lower than that of the vacuum pump, so the vacuum pump is usually used as the vacuum pressure source for safety.
Professional material handling system companies do not use vacuum generators, and another factor is that they have requirements for high-pressure gases. Some factories have insufficient or unstable gas sources, and the arrangement of gas pipes is also inconvenient.
There are also two types of vacuum pumps : one uses three/two-phase electricity and needs to be connected to the control cabinet of the vacuum suction pad system from the workshop's electrical control box. If the customer's crane is too high and inconvenient to connect to electricity, a diaphragm pump can be used, which can be powered by a 12V battery and timed for charging.
Based on the above practical situations, we can summarize the following conclusions :
Material handling with vacuum suction pads is safe as long as the correct configuration and use are selected ;
The less the plate shakes, the safer it is. Choose vacuum mechanical hands that reduce shaking ;
The worse the plate surface quality, the more likely it is not to be firmly suctioned. Choose vacuum mechanical hands with high safety configuration ;
Cracks or dirt on the suction pad lip surface may cause poor suction. Please pay attention to checking ;
The vacuum degree of the power source is an important factor that determines the vacuum pressure. The vacuum pump is safer for generating vacuum.