Does laser scanning measure up?

Converging technologies in precision measurement systems have opened up a realm of possibilities for Australian manufacturers but how is the industry adopting the changing technology?

Precision measurement technology is now more precise than ever and manufacturers can expect improved productivity levels on both the production line and in the field.

The convergence of existing technology such as touch-probing with newer laser scanning and optical sensor technology is the culmination of a 60 year industry history and, according to industry experts, will take precision measurement and CMMs in an exciting new direction.

While fixed, bridge style CMMs have experienced little change in the past few years, the trend towards multi-sensored and non-contact measurement machines is growing, particularly when it comes to portability.

David Eldridge, GM at Hi-Tech Metrology says he has observed a definite hike in customer interest in portable products which he believes reflects the changing nature of Australian manufacturing.

“We are finding manufacturers want to measure on site and they want the ability to move the measuring machine to the project they are working on,” Eldridge said.

“Portable machines tend to work well with a smaller batch run which is probably the reason for their growing popularity.

“More and more, Australian manufacturing is moving to a lower volume of manufacturing. The high volume manufacturing we used to have in the past, ideal for CMMs, is becoming less and less common.”

Eldridge also believes portable systems are less susceptible to temperature fluctuation. Portable arms are often made of carbon fibre and many technologies have temperature compensation built into the software, including probing systems that are able to sense the temperature of the material being measured.

“Optical tracker systems are completely wireless and they use LEDs and CCD cameras to measure parts, meaning they are completely independent of temperature,” he said.

“Some technologies are getting to the stage now where there is no mechanical movement; they are completely light-based or camera-based systems and therefore have no need for a controlled environmental temperature.”

According to Morrie Wyatt, Technical Advisor at MTI Qualos, an articulated arm style machine is ideal for portability. He argues articulated arms are generally used in ad hoc style projects in the field or workshop, whereas a fixed CNC machine would be more useful in higher volume production environments, where the repeated measurement of identical components is better suited to CNC machines than manual arms.

“Laser scanning using an articulated arm is a very effective way of reverse engineering shapes as the high accuracy requirement isn’t there. However when measuring components where a high accuracy level is required, a fixed machine is preferable,” Wyatt told Manufacturers’ Monthly.

Non-contact measurement

As the desire for portability grows, so too does the popularity of non-contact measurement systems.

While optical and laser scanning sensors have been around for nearly a decade, the accuracy and resolution quality they are now producing is enabling them to gain ground as basic control elements in precision measurement.

Wyatt believes hardware has finally caught up with the abilities of laser technology, allowing it to now reach its full potential.

“Hardware constraints are now gone,” Wyatt said.

Eldridge adds that the quality of laser scanning systems and the amount of data they are now able to collect is where laser scanning technology is at its most exciting.

“For example, the FARO Laser ScanArm V5 laser scanning systems can scan almost 500,000 points per second of data. It’s just mind-blowing in terms of the amount of information.

“It moves about 3-4 inches above the part it’s scanning, in a line that is about 120mm wide and collects 500,000 points of XYZ data each second as it’s scanning,” he said.

“Manufacturers can expect improvements in the quality of data due to the resolution and the definition of the information, as well as the accuracy.

“Laser scanners are now actually able to scan bright, shiny parts which you couldn’t previously do due to the reflection from the laser beam,” Eldridge said.

Many optical and laser sensored portable measuring systems still connect to a computer via a cable or wire due to the large volume of data they are collecting. However, there is steady movement toward completely wireless scanning equipment via Bluetooth, despite the smaller amount of data these particular machines are able to collect.

Both men agree that when comparing the local industry to expanding manufacturing in China, Australia is slow in the uptake of laser technology.

“But it is growing incrementally,” Eldridge said.

“Laser scanning sheet metal parts in the automotive area is becoming more and more the global norm.

“We’re beginning to see it adopted here in Australia as the automotive industry demands it in order to remain competitive internationally.”