Screw Air Compressor Selection is not just about horsepower – it’s about matching your application needs with the correct air quality, CFM capacity, and duty cycle. This guide will help you make the right decision whether you’re in PET packaging, pharma, automobile painting, CNC workshops, or general industrial production.

We’ll cover:

  • Oil-Injected vs Oil-Free Screw Compressors
  • CFM & HP sizing
  • Industry-specific compressor selection
  • Real-world examples with focus keywords for SEO

    1. Oil-Injected vs Oil-Free Screw Compressor – Which One to Choose?

Oil-Injected Screw Compressor

An oil-lubricated screw air compressor is ideal for general industrial use where ultra-clean air is not mandatory. These compressors are rugged, reliable, and cost-effective for continuous operation.

Used In:

  • Plastic molding air compressor systems
  • CNC machine air supply
  • Textile air compressor setups
  • General workshop compressed air

Oil-Free Screw Compressor

An oil-free screw compressor is used when air purity is critical. These systems are certified for ISO 8573-1 Class 0 air, meaning zero oil content – essential in industries where contamination can damage the product.

Used In:

  • Pharmaceutical packaging
  • Food processing
  • Electronics & cleanrooms
  • PET bottle blowing (in clean air zones)

    2. Sizing Screw Compressors – CFM, HP & Duty Cycle

Choosing the correct size is key to avoid overloading, low pressure, or energy wastage.

What is CFM?

CFM (Cubic Feet per Minute) tells you how much air your process needs. Don’t go by HP alone.

For example:

Always calculate the total CFM usage and add 20% buffer for safety.

What is Duty Cycle?

If your machines run 8–12 hours continuously, you need a 100% duty cycle screw compressor. For part-time use (2–3 hours/day), consider a reciprocating air compressor instead.

    3. Industry-Specific Compressor Selection

Let’s look at how to choose the right compressor for different applications with real-use examples

PET Bottle Blowing

Requirements:

Best Fit:

Automobile Painting & Body Shops

Requirements:

  • Clean, dry air for smooth paint finish
  • Constant pressure without moisture or oil

Best Fit:

  • Oil-Injected Screw Compressor
  • With coalescing filters and refrigerated dryer

 

Pharmaceutical Packaging / Cleanrooms

Requirements:

  • Class 0 air purity
  • Dry and sterile compressed air

Best Fit:

  • Certified Oil-Free Screw Compressor
  • Add desiccant air dryer, sterile filter, and stainless-steel tank

Textile, Molding, & General Manufacturing

Requirements:

  • Reliable and efficient compressed air
  • No need for oil-free unless specified

Best Fit:

  • Oil-Lubricated Screw Compressor
  • With automatic moisture drain, aftercooler, and receiver tank

Buyer’s Checklist

Choose compressor based on FAD (Free Air Delivery), not just HP
Always plan 20–30% more CFM than today’s demand
Go for VFD screw compressors if your load varies
Ensure you have service support in your region
Match compressor output with dryer and filters

Need Help Selecting the Right Screw Compressor?

At Comptech Compressors, we help industries find the perfect screw air solution with:

Free plant load study
Industry-specific compressor sizing
Energy-efficient VFD options
Installation & AMC service

Contact us today to get the best screw air compressor for your factory.