What is the production process of a bag in a box

I. Core Preparation Before Production: Material Selection and Equipment Matching

• Determine the bag-in-box structure design: use LDPE for the inner layer to ensure compatibility, and aluminum foil/metallized film for the outer layer to enhance barrier properties, complying with QB/T4635-2014 standard.
  
  
• Select equipment according to production scale: integrated bag-making, spout-adding and filling machines are suitable for mass production; small and medium batches can choose the combination of bag-making machine + independent spout-adding machine + filling machine.
  
  
• Confirm the bag type (flat bag/stand-up bag) and spout position (middle/upper part) in advance, and match films and spouts with consistent heat-sealing performance.

II. Core Production Process: Step-by-Step Breakdown and Key Technologies

• Basic processes: Film unwinding → Printing (gravure printing/transfer printing) → Bag forming (three-Side Sealing/stand-up structure heat-sealing), controlling film deviation.
  
  
• Key processes: Automatic spout feeding and welding (ensuring tightness) → Sterilization (steam/gamma ray method, mandatory for food products) → Precision filling (gravity/pumping type).
  
  
• Finishing processes: Bag heat-sealing/screw cap sealing → Outer carton assembly → Nozzle embedding into the box through a cut-out opening, completing modular combination.

III. Quality Control and Implementation Optimization: Standards + Pain Point Solutions

• Full-process quality inspection: Film thickness testing, welding strength test, airtightness sampling inspection, filling weight calibration to avoid leakage risks.
  
  
• Common pain point solutions: Provide equipment modification and parameter adjustment plans for problems such as low equipment compatibility, film deviation and weak welding.
  
  
• Compliance and efficiency improvement: Refer to industry process specifications, optimize production workflow, and balance automated efficiency with cost control.