Main Applications of Compressed Air in Injection Molding Machines
In injection molding production, compressed air plays an indispensable role. It is primarily used to power robotic arms for part removal, blow‑out demolding, cylinder‑actuated motion control, material conveyance, and mold cleaning. Due to variations in automation levels and manufacturing processes across different workshops, the actual consumption of compressed air can differ significantly.
Core Factors Affecting Air Consumption in Injection Molding Machines
To accurately assess an injection molding machine’s compressed air consumption, it is necessary to comprehensively consider the following key factors:
- Equipment tonnage and specifications:Large injection molding machines are typically equipped with larger cylinders and a greater number of auxiliary pneumatic components, resulting in a naturally higher base air consumption compared to smaller equipment.
- Peripheral automatic configuration:If a robotic arm, an automatic feeder, or a centralized material‑feeding system is installed alongside the injection molding machine, the air consumption of these peripheral devices often exceeds that of the machine itself.
- Molding cycle and cycle frequency:The shorter the production cycle, the higher the operating frequency of pneumatic components, and both the peak air consumption and the average air consumption per unit time increase accordingly.
- Pneumatic Component Quality and Piping Design:Poorly sealed pneumatic components can lead to significant internal leakage, while excessively long pipelines or undersized pipe diameters also increase pressure losses, thereby indirectly increasing the air compressor’s load.
How to Scientifically Calculate and Assess Gas Consumption
Due to differences in pneumatic system design among injection molding machines of various brands and models, it is not possible to establish a fixed standard value. In practical workshop planning, the following approach is typically used for evaluation:
- Refer to the equipment nameplate or instruction manual:Reputable injection molding machine manufacturers provide the equipment’s rated air consumption, typically expressed in liters per minute or cubic meters per minute; this serves as the most fundamental reference data.
- Introduction of the simultaneous utilization factor:Within the workshop, none of the injection molding machines or peripheral equipment are likely to reach their peak air consumption simultaneously. When calculating the total air demand, the rated air consumption of all equipment should be summed and then multiplied by a reasonable simultaneous‑use factor.
- Calibration with Measured Data:For commissioned workshops, the accurate approach is to install flow meters on the main pipeline to measure the average and peak air consumption during actual operation, using these data as the basis for expanding compressor capacity or selecting the appropriate model.
Recommendations for Air Compressor Selection and Piping Network Optimization
After determining the compressed-air demand of the injection molding machine, selecting the appropriate air compressor also requires attention to pressure matching and energy‑efficient design. Typical injection‑molding processes operate at pressures between 0.6 and 0.8 MPa. Taking into account pressure losses in the plant’s piping network and potential future capacity expansions, the compressor’s rated discharge pressure should be specified with an adequate margin. Moreover, given the highly variable nature of the injection molding machine’s air consumption, it is advisable to prioritize variable‑frequency compressors and configure them based on the actual air‑demand profile to ensure efficient, energy‑saving system operation.