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What are the factors that affect the stability of force transducers?

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What are the factors that affect the stability of force transducers?

(Summary description)There are many factors affecting the stability of force measurement sensors, which are summarised as follows

What are the factors that affect the stability of force transducers?

(Summary description)There are many factors affecting the stability of force measurement sensors, which are summarised as follows

Information

There are many factors affecting the stability of force measurement sensors, which are summarised as follows

 

1. The structure of the force measurement sensor

 

Force sensor elastic element, shell, diaphragm and the upper pressure head, the design of the lower pressure pad, must ensure that after the load on the structure does not produce performance fluctuations, or performance fluctuations are very small, for this reason in the force sensor design, should try to make the strain zone is a single, uniform stress; patch parts for the plane; in the structure to ensure that there is a certain resistance to eccentric load and lateral load capacity; installation force away from the strain zone. The displacement of the load support point should be avoided during the measurement.

 

2. Metal material of the elastic element

 

The metal material of the elastic element plays a key role in the overall performance and long-term stability of the force measuring sensor. Should choose the strength limit and elastic limit of high, elastic modulus of time, temperature stability, elastic hysteresis is small, mechanical processing and heat treatment of residual stress generated by the small material.

 

3. Mechanical processing and heat treatment process

 

Force measuring sensor elastic element in the mechanical processing process, due to the uneven surface deformation produces a large residual stress, the greater the cutting amount, the greater the residual stress, grinding process produces a large residual stress.

 

A reasonable machining process should be developed and an appropriate cutting dosage should be specified. Weighing sensor elastic element in the heat treatment process, due to uneven cooling temperature and phase change of metal materials and other reasons, in the core and the surface layer of the residual stress in different directions, the core for the tensile stress, the surface for the compressive stress. It is necessary to reduce the effect of residual stresses by generating stresses in the opposite direction inside them through the tempering process, which counteracts the residual stresses with each other.

 

4. Resistance strain gauges and strain binders

 

The resistance strain gauge of the load cell should have good performance, requiring good stability of the sensitivity coefficient, small thermal output, small mechanical hysteresis and creep, fatigue life up to 108 when the strain is 1000 x 10-6, small deviation of the resistance value, good uniformity of the batch quality, etc. Strain binder should have a large bond strength, high shear strength; elastic modulus is large and stable; good electrical insulation properties; with the same or similar thermal expansion coefficient of elastic components; creep and hysteresis is small; small volume shrinkage of the adhesive layer when curing.

 

5. Manufacturing process

 

The working principle and overall structure of the strain gauge force transducer dictate that certain procedures must be operated manually during the manufacturing process, and human factors have a greater impact on the quality of the load cell. It is therefore necessary to develop scientific, rational and repeatable manufacturing processes and to add automated or semi-automated processes controlled by electronic computers in order to reduce the influence of human factors on product quality.

 

6. Circuit compensation and adjustment

 

Strain gauge force transducers are assembled and manufactured, and the product is formed after the patch group bridge. Due to unavoidable internal defects and external environmental conditions, certain performance indicators of the load cell cannot meet the design requirements, so various circuit compensations and adjustments must be made to improve the stability of the load cell itself and its stability to the outside.

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Previous： What are the causes of errors in force measurement sensors when measuring objects? What is the solution?
Next： Force sensors in electronic equipment
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