An overview of metrology using LVDT transducers

Tactile measurement technology plays a crucial role in dimensional metrology solutions, primarily utilizing linear transducers based on the LVDT (Linear Variable Differential Transformer) principle.

Introduction to touch probe technology

Linear transducers come in various types, distinguished by their measuring range, tip force, ability to push/retract the probe automatically, and dimensions.

The measuring range is chosen based on the dimensional tolerances of the part, while the tip force is selected according to the sensitivity of the part’s material.

The capacity to push or retract the probe is determined by the requirements of the automation system, and the dimensions are chosen based on the accessibility of the part’s surface for measurement.

Principle of LVDT transducers in metrology

This approach transforms the linear motion of the transducer’s probe into a measurable electric signal. The tactile transducer’s probe is pushed until it makes contact with the surface of the part to be measured, and the resulting electrical signal corresponds to the distance traveled by the probe, reflecting the dimension of the part.
 
The point or area of contact between the probe and the part is critical for accurate measurements. Different probe tips are available, differing in shape, size, and material. The shape and size of the tips vary, with options such as knife, blade, pin, roller, point, flat, and more. The material of the tips, such as tungsten carbide, ruby, nylon, and silicon nitride, is chosen based on criteria like cost, hardness, and compatibility.
 
The selection of probe tips is crucial for achieving accurate and reliable measurements.

Benefits of measuring dimensions with touch probes

Tactile sensors offer high reliability with accuracies better than 1 micron and precisions below 0.1µm. More benefits include their small dimensions and their measurement versatility.
 
They can be easily networked to measure multiple dimensions and control geometries, making them cost-effective tools for integration into automated machines.
 
Setsmart focuses on selecting and assembling commercially available technologies that best fit the customers’ requirements in terms of cost and performance.

  • Simple and fast

    Measurements performed in seconds, independent of the user’s skills

  • Accurate and repeatable

    Excellent metrological performance

  • Versatile

    Numerous simultaneous measurements on the same part

  • Stand-alone operation

    For unattended use

Related products

  • For the automated control of outer diameters of shafts, tubes, and other cylindrical objects.

    METRIX-OD-card

  • For controlling the geometry of parts with well-specified shapes : straightness, perpendicularity, parallelism, roundness, coaxiality, etc.

    METRIX GEO