Non contact measurement plays an important role for manufacturers in today’s engineering world.

Unlike non contact inspection, many traditional contact measurement devices such as, micrometers and vernier callipers touch the surface in order to determine the dimensions of a component.  When a measurement device has to physically touch a part it is measuring, a number of drawbacks are introduced:  Firstly, the part could be damaged or marked. Secondly, if a part is unfixed, hinged, or designed to move, contact is likely to introduce an inherently unstable measurement result which is unlikely to be repeatable or produce consistent results when further measurements are collected. 

In addition, contact measurement devices often have little capability to output measurement data meaning that operators have to write down results or manually input them into a computer.  This is very laborious and prone to errors, both in terms of interpretation and input.

 

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How non contact measurement has evolved over time

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For many years, optical non contact measurement was found in engineering workshops in the form of a shadowgraph or profile projector. These systems worked by showing a magnified image against a scale. Components were either taken to the machine to cast, prepare and then measure, or they were cut up to provide samples and placed upon a light table. This would show a projection of its shape in much greater detail so surface conditions could be visually inspected. 

Early designs were simply visual checking devices, although later versions also had some digitaisation capabilities with additional electronic measurement capability.  Nonetheless, the process was slow and not suited to an inline inspection environment.  Today, with modern developments,  non contact measurement has developed to include far more advanced imaging and inspection methods, including handheld optical measurement tools such as GapGun.   This means that accurate and repeatable dimensional data is achievable faster and more simply than ever before.

Why do manufacturers need to carry out non contact inspection?

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Manufacturing is becoming a more complex process every day:  Products become more complex and with tighter tolerances.  The variety of materials that products are manufactured with continues to develop and products have to be made in a cost effective and reliable way. Non contact measurement offers the ability to assess the dimensional integrity or profile of a part quickly without touching the surface.  If the surface distorts with pressure, non contact inspection offers a method for surfaces to be measured and assessed to ensure the continued quality inspection at every point in the production process. 

 

Market leading non contact inspection with GapGun

Third Dimension’s non contact measurement system, GapGun, is a leading optical measurement system that is both portable and intuitive. Using GapGun, true non contact measurement of geometric surface conditions and edge profiles can be carried out by operators, simply, portably and with minimal training. The GapGun carries out non contact inspection using cutting edge technology that helps ensure that operators are able to use the system as simply as possible. This includes an onscreen compass to help angular orientation. A large colour touch screen displays the profile being inspected and also indicates acceptable measurement condition by the screen colour. This works in conjunction with green LED indicator lights on the sensor head. Together, these signal to the operator when the system is in the correct position relative to its surface in order for a measurement to be taken, reliably and repeatably.

Examples of surfaces that GapGun measures non contact quickly and easily  include, metallic and plastic surfaces and even liquids prior to curing such as, glue beads and composite structures. In addition, soft surfaces that may move or distort are easily assessed. For example a headliner, glove box or dashboard in a car made from nylon, plastic, wood or leather.  

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