Quality Innovations: Scan Shiny Surfaces
If one trend in contact measurement is clear, it is that the start gun has been fired in the race to capture thousands of points per second at greater accuracy and speed for heightened inspection and reverse engineering performance. Among those in the lead is a new laser scanner that uniquely offers shiny surface scanning capabilities down to 8 micro inches lapped finishes. According to Giles Gaskell, director of new business development for NVision Inc. (Southlake, TX), this new technology outpaces conventional laser scanners when it comes to savings in accuracy, time and money.
"Conventional laser scanners have difficulty scanning shiny machined surfaces because the surface scatters the laser beam, confusing the sensor that records the position of the surface," Gaskell says. By contrast, the NVision ModelMaker Z overcomes this challenge through its ability to change the laser intensity and camera sensitivity based on operating conditions.
"As a result, recent tests have shown that this new laser provides excellent scanning performance on a wide range of machined surfaces and difficult-to-scan parts such as those with shiny or dark surfaces," he says.
Increasing accuracy and speed
Laser scanners improve on the capabilities of coordinate measuring machines (CMMs) and other contact measuring devices through their ability to capture tens of thousands of points per second, greatly increasing the accuracy and speed with which surfaces can be inspected or reverse-engineered. "But the nature of the scanning process always has created difficulties when scanning shiny surfaces," Gaskell explains.
"This problem can be avoided by spraying the scanned surface with a light non-reflective coating, but spraying is not allowed in many situations, either, because of health and safety restrictions or strict quality assurance procedures," he adds. This concern has caused many companies to fall back on less accurate and more costly conventional contact measurement methods.
The ModelMaker Z provides for greatly improved performance in hard-to-scan surfaces. The scanner recently was evaluated in a series of tests by scanning a comparator gage that provides a wide range of machined surfaces ranging from 500 microinches machined to 2 microinches lapped. The technology accurately scanned every surface on the comparator gage except for the two smoothest, 4 microinches lapped and 2 microinches lapped.
"Since its introduction a few months ago, our customers have seen how well the ModelMaker Z is able to scan shiny machined surfaces," Gaskell says. "Its powerful laser and sensor technologies make it possible to reduce cost and increase accuracy in a wide range of reverse engineering and quality control applications where laser scanners have not be useful until now."
The portable laser scanner captures complex 3-D geometry with a high degree of accuracy. The system is comprised of a portable CMM to which a 3-D laser sensor is attached, a PC and dedicated ModelMaker software that extracts, displays, manipulates and exports the data. The three sensors that make up the scanner capture more than 23,000 points per second and the available stripe widths of 35 millimeters, 70 millimeters and 140 millimeters ensure that a sensor is available for every application.
Systems can be supplied with one, two or three sensors to allow for enhanced sensitivity and real-time feedback. The side-mounted design makes the scanner unobtrusive and allows for easy control and ergonomic handling. ModelMaker software allows data capture with the laser or hard probe without the need to remove the sensor.
A new generation
A new camera design in this 6th-generation ModelMaker allows for higher accuracy by resolving details down to half that captured by the previous model. The new scanner, which incorporates the strengths of its predecessors, is capable of handling a broad range of applications-from small parts to full-size cars-and is anticipated to be used by many automobile manufacturers, as well as aerospace, injection molding and product design companies.
The ModelMaker Z also can be powered by a battery for up to two hours of remote operation and can be controlled by a laptop computer for a fully portable system.
General characteristics of the ModelMaker Z:
4Enhanced sensor performance allows the sensor to finely tune its sensitivity based on real-time feedback that reduces erroneous data.
4Adaptive Laser Power changes laser intensity based on real-time feedback of the color and reflectivity of the part, improving scanner performance.
4The scanner can be powered by a battery for up to two hours of remote operation and can be controlled by a laptop computer for a fully portable system.
TECHNOLOGY CONTACTFor more information on
the ModelMaker Z, contact:
112 Welford Ln.
Southlake, TX 76092