Surface comparison
During surface comparison, two models are superimposed and the distance, that is the difference between the models, depicted using coloured areas. The findings obtained in this manner aid the analysis of production defects and permit adjustments to the production process to ensure compliance with quality standards.
Table of contents
- What is surface comparison?
- Surface comparison at Quality Analysis
- Surface comparison: the measurement method
- How are surface comparison, nominal-actual comparison and actual-actual comparison linked?
- Why are surface comparisons so important and for what are they utilised?
- Applications
- In summary: surface comparison
What is surface comparison?
Surface comparison is a method using which the geometry of a physical object is compared with a digital model or an actual component. Measurement techniques such as optical metrology with 3D scanning or 3D computed tomography are used for this purpose to prepare precise three-dimensional depictions of the object surface. The data obtained in this manner are then compared with the CAD models or other reference data. In this way the dimensional accuracy can be checked and it can be ensured that the parts produced are within the stipulated tolerances.
Surface comparison
at Quality Analysis
At Quality Analysis, we analyse your workpieces for deviations based on the nominal geometry of the CAD model or the actual geometry of a component. By using optical instruments and software, surface comparison permits a quick, accurate measurement that is of crucial importance for product development and quality assurance.
- Preparation of a 3D model of the component surface
- Highly precise analysis by means of computed tomography, optical metrology and analysis software such as ZEISS Inspect and Calypso
- Preparation of nominal-actual comparisons and actual-actual comparisons against CAD data with any alignment and colour-coded depiction of deviations
- Flexible measuring volume for different component sizes and accuracies
- Measurement in your production: our 3D scanners are suitable for mobile use
- Reliable results for radii, chamfers, contours, roughness, ripple, angles, recesses and length tolerances
Surface comparison: the measurement method
The measurement methods for surface comparison are aimed at undertaking precise, detailed comparisons between the geometrical characteristics of a physical object and its digital CAD model. The most important techniques include 3D scanning and industrial computed tomography. These methods permit the generation of high-resolution three-dimensional images, which depict comprehensively the surface of the object.
Actual-actual comparison: measurement method for direct component comparison
Surface comparisons are not only made using a CAD model, they are also undertaken using data from physical objects. Here the term actual-actual comparison is used. This method permits the comparison of two components, for instance to check for changes due to a process. Using the actual-actual comparison, it can be detected whether and how a component has changed during production, which is important for process optimisation and quality assurance.
Software-aided comparison of data
After acquisition, the real geometric data are analysed using specialised software such as ZEISS Inspect or Calypso and compared directly with the CAD data. This process identifies deviations and irregularities with high accuracy. Such measurement methods are essential for checking prototypes during the development phase and undertaking damage analyses by making it possible to monitor and exactly document compliance with design requirements.
Component optimisation by means of actual-actual comparison
Actual-actual comparison permits the precise determination of component deviations, for instance for re-qualification, and represents a cost-effective, resource-saving alternative to conventional inspection methods. Without any previous measurement or programming, it is possible to make statements about the relationship between two components quickly and undertake optimisation at an early stage. The subsequent evaluation of product quality and a clear false-colour image make irregularities clearly identifiable for employees.
How are surface comparison, nominal-actual comparison and actual-actual comparison linked?
Surface comparison is the generic term for the methods that compare the geometry of surfaces. This generic term covers specific methods such as the nominal-actual comparison and the actual-actual comparison. The nominal-actual comparison concentrates on the comparison of the geometry of a physical object with the nominal data from a digital CAD model to check whether the parts manufactured comply with the design requirements and are within the tolerances.
The actual-actual comparison, on the other hand, permits the comparison of two physical parts. This comparison is particularly useful for detecting differences that could be caused by the production process. Process deviations and changes during production can be acquired and analysed precisely by means of this comparison.
Why are surface comparisons so important and for what are they utilised?
Surface comparisons are an indispensable tool in many technical and industrial sectors, because they make it possible to measure and analyse the physical reality precisely. The exact evaluation of the conformity of manufactured objects with their digital designs is essential for ensuring the integrity and functionality of products. These comparisons contribute significantly to improving accuracy in production, reducing sources of defects and increasing product safety. Surface comparison is of relevance for the following applications:
Quality control
In production, surface comparison is used for checking the dimensional accuracy and surface quality of workpieces and the identification of production defects.
Damage analysis
Surface comparison can be used to identify and measure damage on components or tools.
Process optimisation
Process deviations and changes during production can be detected by means of surface comparison. This detection of deviations permits the fine tuning and improvement of production processes to increase efficiency and reduce scrap.
Applications
Medical technology
In medical technology, surface comparison is of vital importance for ensuring the safety and effectiveness of medical implants and instruments. The precise conformity of manufactured parts with CAD models ensures that products meet the strict statutory requirements and clinical needs.
Automotive
In the automotive sector, surface comparison is crucial for the development and production of precise vehicle components. The detailed check on the geometric characteristics of parts such as bodywork panels or engine components helps to ensure high quality standards and optimise aerodynamic performance. This comparison also makes it possible to identify production defects at an early stage, which results in cost savings and more efficient production processes.
Plastics industry
In the plastics industry, surface comparison has an important role during the quality assurance of injection moulded parts and other plastic products. By checking whether the parts comply with the design requirements, manufacturers can ensure that their products are of consistent form and function. This aspect is particularly important for components used in highly precise applications such as electronics or in the consumer goods sector.
In summary: surface comparison
Surface comparison is a central method in optical metrology and industrial computed tomography. During a nominal-actual comparison, the geometry of physical objects is compared with digital CAD models, during an actual-actual comparison, two physical objects are compared to detect deviations. In this way, compliance with quality standards can be ensured. These methods are in widespread use in sectors such as the automotive industry, medical technology and the plastics industry, where they are used for quality assurance and damage analysis.
