1. Overview
With the continuous progress of society and the economy, product packaging has become a primary choice for product shipments. Among these, bubble wrap packaging is gaining increasing importance, mainly due to its functionality. Because the middle layer of a bubble wrap bag is filled with air, it is lightweight, elastic, and possesses sound insulation, shock absorption, and wear resistance. It is also waterproof, moisture-proof, and pressure-resistant. It is widely used for shock-absorbing packaging of electronic appliances, instruments, glass and ceramics, artwork, hardware machinery, furniture, and other products. It can be made into bubble bags, bubble kraft paper envelopes, car sunshades, heat-insulating cushions, and thermal insulation materials. By adding different additives to the plastic raw materials, various specialized bubble wraps, such as anti-static ones, can be produced.
In this context, bubble wrap machines have been widely adopted. The AC300 inverter launched by Weichuang Company has excellent torque control function, which can effectively control three-phase asynchronous motors and replace the previous torque winding or magnetic powder winding.
2. Introduction to Bubble Wrap Machine
The main body of the bubble wrap machine consists of a bottom unwinding mechanism, an extruder, a vacuum forming mechanism, a cooling mechanism, a transmission and traction mechanism, and a winding mechanism.
Figure 1. Schematic diagram of a bubble wrap machine
3. Application of AC300 frequency converter in bubble wrap machine winding
Solution Description:
The frequency converter adopts torque control in PG-free vector mode. The initial torque, i.e. the initial tension of the bubble film, is given by the PLC analog signal and set by the host computer. During the winding process, as the roll diameter increases, the PLC calculates the number of winding turns through the proximity switch installed in the winding mechanism, thereby calculating the current roll diameter and controlling the torque given at the current roll diameter. This control method has better flexibility than simply relying on the frequency converter to calculate the roll diameter and accumulate torque.
parameter:
F05.01: Number of motor poles
F05.02: Rated power of the motor
F05.03: Rated frequency of the motor
F05.04: Rated speed of the motor
F05.05: Rated voltage of the motor
F05.06: Rated current of the motor
F05.20:2 (Static Self-Learning)
After confirmation, the inverter will display L-00. Then press the "FWD" key, and the motor will enter static self-learning mode, which takes approximately 1 to 2 minutes. Once learning is complete, the frequency will be displayed. After learning is complete, continue setting the following parameters:
Important notes regarding the plan:
After each roll of material is changed, the current roll diameter must be zeroed to the roll diameter in the PLC; otherwise, the torque will be too large, causing the material to break.
4. Conclusion
Because using a frequency converter to control the rewinding of a bubble wrap machine is simple and straightforward, and greatly improves the reliability of the equipment, more and more customers are starting to use frequency converters to control the rewinding of bubble wrap machines.
