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Benefits of laser scanning | Introduction to laser scanning

This is the first in a series of articles about the benefits of laser scanning. In this article, you can learn about how laser scanning introduces highly effective inspection and helps to keep manufacturing costs down.

nikon metrology benefits laser scanning introduction laser scanning l100 discussionBeing first to introduce a new product onto the market gives a manufacturer a competitive edge that may even determine the ultimate success or failure of the project. Concurrent engineering, rather than completing tasks in different departments sequentially, is essential to reduce lead-time and lower development costs.

A key enabling measuring technology in this endeavor is 3D laser scanning, which provides a wealth of dimensional information about a part in a fraction of the time needed for measurement using a touch probe. In this article, Nikon Metrology explains how laser scanning provides time and cost advantages in production engineering and how manufacturers can benefit.

Laser scanning provides highly effective inspection

Whatever the product, be it a car, hand drill or mobile phone, customers expect its tightly-toleranced parts to fit together and function perfectly and at the same time be of high quality and attractive design. But how do manufacturers ensure this level of precision without delaying the development and launch of the product? The answer is to digitise the 3D shape and features of the prototypes with a non-contact laser scanner mounted on a coordinate measuring machine (CMM) or articulated arm and compare the results to the original CAD designs.

nikon metrology benefits laser scanning introduction laser scanning l100 feature inspectionLaser scanner based inspection of features in sheet metal.It is much faster to inspect a part this way than to use a touch probe to take discrete measurements. With tens of thousands of points per second being captured by the laser and added to the point cloud, a complete inspection cycle is often between five and 10 times faster than tactile probing. Furthermore, with the latter technique it is impossible to know what is happening between two adjacent discrete points, so the data is very sensitive to imperfections in the geometry being inspected. Parts that have flatness and roundness errors, edge rollover or burrs are particularly problematic. Radius compensation error is a further difficulty with tactile probing. When a stylus makes contact with the edges of a hole, for example, radius compensation may result in unexpected measurement points if a neighbouring surface is touched first.

Keeping costs down

OEMs are keen to keep down costs at every stage of the production cycle. The problem is that even a limited number of touch probe measurement points involve considerable programming overhead and creating tactile scanning cycles is even more complicated, time consuming and expensive. On the aerofoil surface of a turbine blade, for instance, 5-axis analogue scanning requires elaborate CMM programming to ensure that the probe tip continuously follows the part surface without colliding with it or the machine structure. Furthermore, the component needs to be clamped in a costly fixture.

With non-contact laser scanning there are fewer restrictions, so costs are reduced. It is not even necessary to datum the component; it can be placed anywhere on the table in any orientation or held in a simple fixture. Programming laser scanning cycles is easier and faster, both online and off-line, requiring only simple parallel sweeps of the head with short motion paths and limited or no head indexing.

nikon metrology benefits laser scanning introduction laser scanning CAMIOScan paths are created offline and the resulting point cloud is simulated to verify coverage.Interactive, multi-sensor Nikon CAMIO software streamlines the creation of scan macros. The scanner moves along linear and polygonal paths generated automatically or manually from the CAD model to keep the surface of the component within the field-of-view of the laser scanner.

For surface areas falling outside the path, virtual point cloud simulation reveals where to generate additional scans. Lower operational costs and further increases in inspection productivity are the end result. Laser scanners are often used in combination with tactile probes for alignment of a part or for a mixed measuring routine that might include accessing difficult internal features. Nikon Metrology’s multi-sensor CAMIO software provides a rich programming environment, with intuitive software tools for both tactile and laser scanning applications. A variety of inspection tools is available including full part-to-CAD comparison and intelligent feature extraction with GD&T tolerancing and profile analysis.

Read the full series of articles here.