Infinite FocusG5 with Advanced Real 3D Rotation Unit
The shift away from subtractive engineering to additive manufacturing techniques means that designers need to reconsider how products are designed to allow effective use of the AM technology.
The layer-wise nature of AM enables the manufacture of highly complex shapes with very few geometric limitations compared to traditional manufacturing processes. This freedom-of-design has led to the technology being used to manufacture topologically optimised shapes with improved strength to weight ratios, particularly in aerospace and automotive sectors.
As a result of this heightened adoption, design consideration needs to be given as to how these parts can be measured. The measurement requirements are not only geometric, there also needs to be an understanding of the functional parameters of a machined AM surface which cannot be assessed with conventional surface finish measures.
The market is rapidly evolving with a growing range of products that can be produced by AM techniques therefore the demand for measurement and verification of these products is also increasing.
In XY geometric terms some features on the products produced can be readily measured with conventional measuring methods. However in terms of surface texture and micro geometry conventional measuring methods are not suitable. The unsuitability can be due to restricted access of, for example, a touch probe for dimensional measurement, or, in the case of a tactile profilometer stylus tip size and tip radius. These restrictions open the door to optical measurement which is only limited by the wavelength of light.
Metrology specialist, Alicona, hosts a range of optical metrology products that fulfil the demands placed on the measurement solutions based on the principle of FocusVariation. This optical technology produces 3D data models that are presented to the user as a full natural colour image. The 3D data is used to perform the required measurements and can also be used to compare against CAD.
The focus variation metrology technique has some unique properties in comparison with other interferometry and conventional microscopy techniques;
- Steep Slope Measurement: Most optical measurement techniques have limitations on the angle of slopes that can be measured. This restriction is not caused by individual manufacturers but by the technique employed that restricts this to 60 degrees. The focus variation technique allows angles >85 degrees to be measured. This is important when trying to characterise surfaces, particularly in the Y Z plane in ebeam techniques.
- Surface Finish Measurement: The Alicona metrology systems allow the measurement of both roughness and surface texture (functional parameters). Whereas Roughness is commonly used surface texture measurements provide an increased level of information about surface function and improved robustness.
- True Colour 3D models, Anaglyph Viewing and CAD comparison: 3D data models are presented in natural colour with the colour registered to the 3D data. The 3D data models can be presented in wire frame or point cloud format; this allows the comparison of data against a CAD model or allows reverse engineering against another scanned product. Unlike other optical techniques that present a pseudo height map, the data can be viewed as an Anaglyph view and a height map can be added to display features according to their height position. As the colour is registered to the 3D data accurate positional assessments can be made.
- Measurement of finish on form: Tactile measurement systems are generally unable to measure finish on a form or on a very rough surface. The Alicona systems have built in form removal allowing measurement of finish on very complex forms.
The range of measurement solutions offered by Alicona provide fully traceable measurements on most surfaces and can be used in laboratories, production or measurement environments to provide a high-accuracy measurement solution.