Selecting Right Type & Size of Air Compressor for Injection Molding
Choosing the right compressor model and correctly sizing it are essential steps for any plastic manufacturer aiming to optimize operations and minimize costs. This guide provides a comprehensive overview to help you select and size the ideal air compressor, maximizing the efficiency and reliability of your injection molding processes.
Understanding the Role of Air Compressors in Injection Molding
Why Air Compressors Matter in Injection Molding
Air compressors in injection molding support critical operations, including powering hydraulic actuators, maintaining consistent pressure for mold filling, and ensuring product integrity. The correct air compressor can lead to improved cycle times, higher product quality, and better overall operational efficiency.
A well-suited compressor provides consistent airflow, maintains optimal pressure, and supports precise material injection—all crucial factors for high-quality output.
In addition to this ensuring the compressor operates in the most efficient way according to your factory demand patterns with minimal maintenance and wasted energy.
Unique Demands of the Plastic Industry
Injection molding in the plastic industry demands high-volume production, precision, and strict quality control. The right compressor needs to support these requirements while withstanding continuous use in demanding environments. Misalignment in compressor choice can lead to performance issues, such as pressure fluctuations or unexpected downtime, affecting production costs and product consistency.
Key Criteria for Selecting an Air Compressor for Injection Molding
Compressor Type and Technology
Selecting the right type of compressor is the foundation of an efficient injection molding process. Depending on the type of raw material for mold, for injection molding, rotary screw compressors are often preferred for discharge pressures up to 15barg due to their reliability, which are critical for high-cycle applications. Oil-free compressors are ideal in cases where air purity is essential, as they prevent oil contamination that can affect product quality guaranteeing 100% Class 0 Oil-free air quality, especially in sensitive applications like medical or food-grade plastics.
For certain other raw materials, higher discharge pressure is needed during injection molding process and oil-free three stage reciprocating compressors are the choice to make.
Energy Efficiency and Cost-Effectiveness
Energy-efficient compressors can lead to significant long-term savings, as energy costs can make up to 70% of the total cost of owning and operating an air compressor. Models with Variable Speed Drive (VSD) technology automatically adjust to fluctuations in production demands, reducing energy consumption by up to 35%. Evaluating compressors based on total cost of ownership – that includes energy efficiency and maintenance, adds to potential cost savings over time making a notable impact, particularly in high-volume production environments.
Reliability and Durability
In injection molding, compressor reliability is essential to avoid costly downtime. Opt for robust, low-maintenance compressors designed for heavy-duty use. Features like advance oil-cooled motors with IP66 protection and IE5 efficiency are maintenance free components, adding to your reduced service intervals.
Air Compressor Sizing – Essential Considerations for Plastic Manufacturers
Importance of Proper Sizing in Injection Molding
Selecting the correct compressor size is as crucial as choosing the right type. An undersized compressor may lead to pressure drops, affecting mold filling consistency and cycle times affecting your final product. Conversely, an oversized compressor can lead to excessive unload energy, operational inefficiency, and unnecessary wear and tear. Proper sizing ensures that the compressor can meet the peak demand of your production line without compromising efficiency or longevity.
Key Sizing Factors
1. Required Air Pressure (PSI): Injection molding depending on the type material will either need medium pressure between 5-10barg or high pressure above 15barg varying based on mold complexity and product requirements.
2. Airflow (CFM): The air compressor must provide enough minimum volume or airflow, measured in Cubic Feet per Minute (CFM) or liters/sec or m3min etc., to meet the peak demands of the injection molding machine.
3. Fixed or Variable: For continuous or flat load, consider compressor with a 100% duty cycle. For variable load as a typical factory would always have, add one variable speed compressor to your centralized compressor room for fluctuations in air demand.
Calculating the Right Size for Your Production Needs
To determine the correct compressor size, start with your machine’s peak demand for airflow and pressure. Here’s a simplified method:
1. Calculate Total CFM Needs: Sum up the CFM requirements of all machines using compressed air simultaneously.
2. Add a Buffer for Peak Demand: Multiply the total CFM by 1.1 -1.2 to account for peak usage periods.
3. Select Compressor Capacity: Choose a compressor with a CFM output that meets or exceeds this peak demand, ensuring continuous operation without overloading.
Example: If your injection molding line requires a steady airflow of 100 CFM, you would choose a compressor rated for at least 110-150 CFM to maintain efficient operations during high-demand cycles.
Combining Selection and Sizing – Making the Best Choice
Matching Compressor Type and Size for Optimal Performance
The ideal air compressor for injection molding aligns both type and size with your production requirements. For instance, a rotary screw compressor with VSD technology is optimal for plastic manufacturers who need both flexibility and energy efficiency. Matching the compressor size to your specific injection molding needs ensures that production remains uninterrupted, minimizes energy costs, and reduces wear on the compressor over time.
Atlas Copco’s Solutions for Injection Molding
Atlas Copco provides a range of air compressors specifically designed to meet the rigorous demands of injection molding. Our GA VSD+ rotary screw compressors offer advanced energy savings with adaptable airflow, while our ZT oil-free compressors ensure air purity for applications with stringent quality requirements. Atlas Copco also provides expert consultation services to help you determine the best compressor size for your production needs, ensuring an optimal balance of performance and cost-effectiveness.
Selecting and sizing the right air compressor is vital to achieving consistent quality and efficiency in plastic injection molding. From the compressor type to precise sizing based on your facility’s unique needs, these factors play a critical role in optimizing production and minimizing costs. By partnering with experts and choosing reliable, efficient air compressor solutions, plastic manufacturers can enhance productivity and maintain high-quality standards.