Safety of vacuum suction cup feeding

Nowadays, most laser cut thin plates are mainly loaded by manual lifting, with at least three people required to lift plates that are 3m long, 1.5m wide, and 3mm thick. In recent years, manual assisted feeding mechanisms have been promoted, generally using a lifting mechanism+electric hoist+vacuum suction cup system to achieve feeding.Here, briefly analyze the principle and precautions of vacuum suction cups, hoping that more sheet metal users can understand this knowledge.

The pressure principle of vacuum suction cups
Vacuum suction cups rely on vacuum pressure to suck and grasp the sheet metal. The surface of the board is relatively flat, and the lip edge of the suction cup is relatively soft and thin, which can be adhered to the board. When a vacuum pump is used to vacuum, a vacuum is generated in the inner cavity of the suction cup, forming a negative vacuum pressure. The suction force of a vacuum suction cup is proportional to the pressure (vacuum degree, pressure difference between inside and outside the suction cup) and the area of the suction cup, that is, the higher the vacuum degree, the greater the suction force; The larger the suction cup size, the greater the suction force.

Dynamic suction safety
According to data tested by foreign professional vacuum companies, the safety factor for vacuum pressure generated by conventional electric hoists is required to be twice. To ensure safety, our company calculates the theoretical suction force of the suction cup and sets the safe vacuum pressure under the condition of 60% vacuum, and then divides it by 2 to obtain the required safe suction force.

The influence of suction cup and sheet condition on actual suction force
1. It is necessary to regularly clean the lip surface of the suction cup (the side that fits the plate), and regularly inspect the suction cup for scratches, cracks, and aging. If necessary, immediately replace the suction cup with a new one. In fact, many companies are using suction cups that are unsafe and pose safety risks.
2. When the surface of the board is severely rusted and uneven, the safety factor should be increased, otherwise it may not be firmly absorbed. In response to this situation, our company has innovatively applied a fast hook system, with 4 sets symmetrically integrated at both ends of the crossbeam. The system is applied in two situations: ① sudden power outage during the feeding process, the use of a diamond hook, and the plate will not fall off. The material will be loaded again when the power is on; ② When the board is rusted or the thickness exceeds 10mm, first use a suction cup to lift it a bit, and then attach a diamond hook to ensure safety and safety.  

The influence of vacuum power source on vacuum pressure
Vacuum suction cup feeding is a manually assisted method of feeding, which needs to ensure personnel safety. The vacuum degree of a vacuum generator is lower than that of a vacuum pump, so a vacuum pump is usually used as a vacuum pressure source, which is safer. Professional feeding system companies do not use vacuum generators, and another factor is due to the requirement for high-pressure gas. 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 is using three/two phase electricity, which needs to be connected from the workshop electrical box to the control electrical box of the vacuum suction system. If the customer's on-site driving is too high and it is not convenient to connect the battery, they can use a diaphragm pump and use a 12V battery to power up, and charge the battery regularly.