Manufacturing PET (polyethylene terephthalate) plastics requires specialized air compressors—PET piston compressors. These piston compressors are widely used by plastic bottle producers to produce plastic bottles and packaging for industries such as beverages, food, and personal care.

Applications of air compressors in PET bottle manufacturing

Air compressors for PET bottle injection molding

Injection molding involves injecting molten thermoplastic or thermosetting plastic into a closed mold cavity using compressed air generated by screw compressor or piston compressors. After solidification, the final product is formed.
In injection molding, piston air compressors are used for tasks such as equipment cleaning, mold ejection, air-assisted part forming, tube inflation, vacuum/pressure molding, and cylinder operation. Compressed air technology is compatible with most thermoplastics and engineering materials (e.g., PS, HIPS, PP, ABS).
The success of blow molding depends on stable and clean airflow at predefined pressures. PET piston compressors that deliver consistent high-pressure air ensure the one-time production of complex, dimensionally precise, or metal-inserted plastic parts.

(Air compressors for PET bottle injection molding)

Air compressors for PET bottle blow molding

The PET bottle blow molding process involves heating preforms, mold clamping, stretch-blow forming, post-blow shaping, mold opening, and demolding. Compressed air is injected into heated preforms to expand them into the desired PET bottle shape.
PET blow molding piston compressors serve as critical auxiliary equipment in PET packaging production, widely applied in beverage, edible oil, condiment, dairy, liquor, beer, pharmaceutical, and daily chemical industries.

(Piston Air Compressor)

Understanding core requirements

Selecting the right piston compressor model requires evaluating multiple factors to meet specific operational needs.

Determine air demand

Flow rate: Required air volume per minute (m³/min or L/min).

Pressure: Varies by application.

Common applications and requirements:

Application	Pressure Range	Flow Rate (Typical)
Preform injection molding	6–8 bar	Low to medium
Blow molding	30–50 bar	High
Pneumatic actuators/robots	6 - 10 bar	Low
Air cooling	6–10 bar	Medium

For simultaneous injection molding and blow molding, consider a dual-pressure system or integrated air compressor units for low- and high-pressure needs.

Calculating required flow rate

Total flow demand (m³/min) = Σ (Single equipment consumption × Quantity) × Simultaneity factor × (1 + Leakage factor) × (1 + Future expansion factor).

Parameters:
Single equipment consumption: Refer to equipment manuals or industry standards (e.g., 0.5–5 m³/min for injection machines).
Simultaneity factor: 0.6–0.9 (lower for more equipment).
Leakage factor: 10%–20%.
Future expansion factor: 10%–30%.

Selecting air compressor types

Type of air compressor	Features
Single-stage piston compressor	Max pressure ~10 bar; suitable for injection molding only.
Two/three-stage piston compressor	Pressure up to 30–50 bar; ideal for PET blow molding.
Lubricated air compressor	Durable and efficient; requires air treatment (filters/dryers).
Oil free air compressor	Suitable for food-grade production.

Matching post treatment systems

High-quality air is critical for bottle clarity, strength, and food safety, it’s essential to configure post treatment equipment for your PET piston compressor to ensure pure and clean compressed air.
Aftercooler: Reduces outlet air temperature.
Dryer: Removes moisture (desiccant or refrigerated).
Filters: Eliminate oil (coalescing), dust (particulate), and odors.
Air quality standards (ISO 8573-1):
Particles: Class 1.
Water: Class 4 (dew point ≤ +3°C).
Oil: Class 1 (≤0.01 mg/m³).

Energy efficiency considerations

Air compressors account for 30%–50% of a plastic bottle plant's energy consumption.
VSD (Variable Speed Drive): Adjusts output to demand.
High-efficiency motors (IE3/IE4).
Heat recovery systems: Reuse waste heat for process water.

Scalability and redundancy planning

Make sure your PET piston compressors can handle:
Peak demand: During maximum production.
Future expansion: Include 10%–20% surplus capacity.
Backup/redundancy: Maintain
production during main unit downtime.
Best practice: Use multiple smaller compressors with smart controls (instead of one oversized unit).