Even with the current state of the art scanners it is necessary to apply spray in some application cases; while spaying parts for reverse engineering and prototype parts has become an accepted practise spraying large volume of parts in production application is problematic due to the spray contamination. A new self vanishing, Aesub Blue, has been developed by scanning experts that disappears with hours leaving no clean-up of spayed objects.
Aesub Blue is claimed as perfect for use with ‘next-to-line’ automated scanning solutions.
Transparent and very Reflective Parts
Because we are dealing with optical technologies, light needs to be reflected off the surface back into the detector of the scanner. In case of a transparent surface it is clear that the light will go through the surface and the scanner won’t “see” anything. In the case of a very reflective part, a mirror for example, the light beams will be reflected in a very focused way instead of in a diffused way. This means that the chance of the beam hitting the reflector of the scanner is greatly reduced and the scanner won’t “see” the reflected beam of light.
In both cases, using spray will make the surface matt and white which is the perfect surface for scanning.
When the part has deep pockets, the scanner receives a reflection from the walls of the pocket onto the bottom for example. This causes some disturbance in the pattern of the light manifesting in the scan as “artefacts” or bad data.
Obtaining Best Quality and Accuracy
When quality and accuracy is important spray is commonly applied to remove as much as possible all the causes like color differences, differences in reflection, texture etc.
Below can be viewed the structured light pattern of an optical scanner on a small black plastic part. The first one is without spray and the second one is with a very thin coat of sprayed powder. For the software it is a lot easier to detect the black and white lines on the sprayed version and thus the scan is of a much higher quality.
The coat of spray delivered by Aesub Blue is very consistent and homogeneous. The sublimation time depends on temperature, air flow, material and layer thickness. In summer the spray will evaporate faster than in winter. Different materials will have different evaporation times. A thicker coat of spray or multiple layers will stay longer. Typically after one hour the coating starts disappearing and after several hours the spray coating completely disappears. The new spay has application for production scanning as well as in application with deep grooves and pockets that are difficult to clean after application of non-disappearing sprays. Aesub Blue has a thickness of 0,005 to 0,015mm depending on how many coats are applied delivering a very high quality spray.
For more information: www.tetravision.be