Compressed air consumption of CNC machine tools

In the application scenario of CNC machine tools, the amount of compressed air needs to be comprehensively calculated according to the specific process requirements, equipment configuration and production rhythm. The following from a professional point of view for you to analyze its core elements and quantitative methods:

1. baseline usage of a single piece of equipment

1. basic functional gas
   • spindle cooling: continuous air supply is required, and the typical dosage is 0.1-0.3m & sup3;/min (floating according to spindle power)
   • tool magazine change: single action consumes 0.5-1.5m & sup3;, frequency depends on processing beat
   • protective curtain purge: conventional configuration 0.05-0.1m & sup3;/min continuous gas supply
2. auxiliary process gas
   • scrap blowing of workpiece: when the air pressure is 0.5-0.7MPa, the gas consumption of a single air gun is 0.2-0.4m & sup3;/min
   • fixture cleaning: the automatic production line shall be equipped with pulse purging system, and the instantaneous flow rate can reach 1.2m & sup3;/min
   • precision positioning: pneumatic chuck/guide rail needs 0.3-0.6m & sup3;/min stable air supply

computational model of 2. multi-machine linkage

1. synchronous coefficient method
   • formula: Total Demand = & Sigma; Single Base Usage × Synchronization Coefficient
   • (Synchronization coefficient according to the degree of automation of the production line value, manual line to take 0.6-0.8, flexible line to take 0.8-1.0)
   • example: 5 machining centers (single datum 1.2m & sup3;/min) form FMS system, total demand = 5 × 1.2 × 0.9=5.4m & sup3;/min
2. peak superposition method
   • applicable scenarios: there are multiple devices performing high-pressure process conditions at the same time
   • calculation steps:
     • identify the maximum instantaneous gas consumption of each equipment (e. g. tool change + chip blowing superposition)
     • weighted by Concurrent Use Probability
     • add 20% Safety Margin

incremental demand for 3. special processes

1. high speed machining center
   • air seal of main shaft bearing: 0.15-0.25m & sup3;/min clean air (oil content <0.01 mg/m & sup3;)
   • linear motor cooling: additional 0.5-0.8m & sup3;/min dry air
2. five-axis machine tool
   • rotary shaft brake: 0.3-0.5m & sup3;/min emergency air supply is required
   • optical inspection: 0.2m & sup3;/min constant pressure air supply for air bearing

4. system optimization strategy

1. gas tank configuration
   • capacity selection: configure according to 15%-20% of the total demand, for example, 6m & sup3;/min system is recommended to configure 1.2m & sup3; gas storage tank
   • layout points: close to the peak gas equipment installation, shorten the pipeline response time
2. pressure belt optimization
   • graded gas supply: set the system pressure to 0.7MPa, and install a pressure reducing valve at the terminal to 0.5MPa (chip blowing station)
   • energy saving benefits: every 0.1MPa pressure reduction, energy consumption decreased by about 7%
3. leak Management
   • test standard: total leakage should be <5% of total air supply
   • rectification measures:
     • the annual leakage of 1mm diameter leakage point (at 0.6MPa) is 18000 m & sup3;
     • it is recommended to conduct ultrasonic leak detection every quarter, focusing on quick-plug connectors and solenoid valve groups.

5. selection decision tree

1. single machine operation scenario
   • basic configuration: select the model with 1.2 times the benchmark usage (for example, a single 1.2m & sup3;/min equipment, configure 1.5m & sup3;/min air compressor)
   • additional recommendations: equipped with 30L micro gas tank, buffer tool change instantaneous impact
2. flexible production line
   • core configuration: frequency conversion screw machine + modular pipeline
   • extended reservation: select 1.5 times according to current demand and reserve fast interface
3. clean workshop application
   • mandatory requirements: three-stage filtration system (precision filter + activated carbon adsorption + sterilization filter)
   • special certification: ISO 8573-1 Class 2 cleanliness certification (oil content <0.1 mg/m & sup3;)

6. economy assessment
take a production line consisting of 10 machining centers (single datum 1.2m & sup3;/min) as an example:

• basic configuration: 15kW screw machine (rated displacement 2.4m & sup3;/min)
• frequency conversion scheme: 18.5kW frequency conversion screw machine (adjustable range 0.8-2.8m & sup3;/min)
• investment comparison:
  • initial cost: frequency conversion scheme is about 15% higher
  • five-year TCO: The energy-saving benefit of the frequency conversion scheme can still save 80000 yuan after covering the cost difference.

It is recommended to quantitatively evaluate the economy and reliability of different configurations by simulating the gas curve through professional software in combination with the specific process beat. For multi-shift production scenarios, it is recommended to adopt the combination scheme of central cold dryer + regional adsorption dryer to ensure that the compressed air quality is stable at ISO 8573-1 Class 1 standard.