Installing a frequency converter on the injection molding machine

Before frequency conversion transformation

Injection molding machines generally consist of parts such as feeding, melting, injection molding, cooling, and mold opening. After opening the mold, the plastic parts are taken out and then closed for the next cycle.

Firstly, the hydraulic pressure, flow rate, and pressure required for each process in injection molding are different. For the oil pump motor, the load during the injection molding process is in a changing state. The flow rate of the pump is designed according to the maximum required flow rate. The hydraulic flow rate provided by the oil pump at a constant speed during operation. When the required flow rate of the injection molding machine is less than the maximum flow rate, the excess hydraulic pressure will flow back through the relief valve, resulting in the loss of this part of energy.

Secondly, in the design process, commonality is generally considered, and the maximum capacity is used as the basis. Therefore, the designed capacity of the user's oil pump motor is much higher than the actual needs, resulting in a phenomenon of "a big horse pulling a small car" and causing a large amount of waste of electrical energy.

Once again, due to long-term full speed hydraulic circulation flow and severe mechanical friction of hydraulic components, adverse phenomena such as high oil temperature, excessive noise, and shortened mechanical life are caused.

Advantages after renovation:

1. Soft start extends the service life of the motor and reduces its impact on the power grid;
2. The function of stacking multiple speed, flow, and pressure commands facilitates the implementation of different process requirements for operating frequency, thereby improving the quality of plastic products;
3. Improve the efficiency of the motor, reduce energy loss, and achieve significant energy-saving effects in the system, generally reaching 20% to 50%;
4. Reduce noise and extend the service life of machinery such as oil pumps;
5. Reducing the vibration of mold opening and locking, prolonging the service life of the mold;
6. The heat generation of the system is significantly reduced, the oil temperature is stable, and the service life of the hydraulic system is extended.

Conclusion:

The load nature of injection molding machines is constant torque, with hard mechanical characteristics and high requirements for dynamic characteristics. ANYHZ FST-650L series or injection molding machine specific frequency converters can be selected. The dedicated frequency converter for injection molding machines adds a 0-1A signal conversion link on the basis of the universal frequency converter, improving its performance. Generally, the capacity of the frequency converter should be appropriately increased.

At present, most of the injection molding machines are permanent magnet synchronous motors, and only a portion of the old models are three-phase asynchronous motors. When equipped with a frequency converter, it is necessary to inform the sales team in advance to facilitate the selection of a suitable frequency converter. In addition, when replacing old frequency converters, different brands of frequency converters need to consider 485 communication.