Outline of Load Cell Production Processes

1. Strain Gauge Production Process

• Bonding backing materials
  A metallic foil is bonded to a backing material (base) using adhesive. There should be no trapped air bubbles or dust.
• Curing
  A jig is used to apply pressure to metallic foil and backing material. The jig is placed in a high temperature oven to cure the adhesive. 
  
• Pattern exposure
  The metallic foil is coated with a photosensitizing agent and shielded by a mask of the gauge pattern. When the foil is exposed to light, only the photosensitizing agent in the gauge pattern is cured. 
  
• Etching
  The metallic foil outside the gauge pattern is dissolved using an etching liquid
  
• Trimming
  The resistance of the gauge is measured and adjusted using a diluted etching liquid.
  Once the adjustment is complete, a neutralizing liquid is added to end the etching. 
  
• Visual inspection
  Visual inspection is performed to verify that there are no defects in the gauge pattern and the base. 
  
  
  

2. Load Cell Production Process

• Finishing the surface of the spring material
  To enhance its adhesive strength, the surface of the spring material is sandblasted to a suitable level of roughness.
  
• Bonding
  After the surface of the spring material is washed, the spring material and the gauge are coated with an adhesive. The gauge is then attached to the spring material.
  
• Curing
  A jig is used to apply pressure to the gauge and spring material. The jig is placed in a high temperature oven to cure the adhesive.
  
• Four-corner adjustment
  A pan is attached to the load cell. The spring material is grinded and adjusted until the output is the same when a weight is placed on any corner.
  
• Testing the temperature characteristics on zero balance
  The load cell is placed in a thermostatic chamber, and its output voltages are measured at a low temperature and a high temperature. If the temperature characteristic specifications are not satisfied, a resistor with a high temperature coefficient is incorporated into the bridge circuit for adjustment.
  
• Moisture-proof coating
  A moisture-proof agent such as silicone is applied to the gauge and the circuit. 
  
• Inspection
  A power supply and a multimeter are connected to the load cell, and input and output resistance, insulation resistance, etc are inspected.