Automatic Dimensioning, Weighing and Scanning (DWS) technology is allowing plant operators to think outside the box.
Traditional volume measurement technology has only allowed volume measurement of cubic objects and boxes; however, laser technology allows legal-for-trade volumetric measurement of a range of different object shapes and sizes.
“Volume measurement technology in the past included light curtains, a basic array of photocells mounted on a production line to monitor the size and width of boxes,” SICK automatic identification division product specialist Daniel Perez-Bello told FEN.
“Light-curtain technology can only give operators very basic measurements for cubic objects and boxes,” he said.
According to Perez-Bello, customers are now demanding high-accuracy and high-speed volumetric readings of a range of different shaped objects.
“Light-curtain technology only senses the shadow of the object, so if you put a pyramid through this device it would only measure the pyramid’s height and width,” Perez-Bello said.
“This technology would not calculate the volume of a pyramid-shaped item, but laser scanning volumetric devices allow users to measure the volume of irregular objects.”
TNT Express has recently equipped a depot in Germany with a fully-automatic DWS system to increase productivity during package processing.
A SICK calibrated volume measurement system and omni-portal reading system were integrated as a package solution for the plant.
The system allows users to charge customers for the number and volume of packages transported.
The system improves sorting, preparation, and distribution processes, as each package has a unique identity due to its bar code, weight, and dimensions.
“The sensors can be used in legal-for-trade applications in Australia, where customers can be charged on the volume reading given by the equipment,” Perez-Bello said.
“Suppliers could previously only charge by the weight of packaging as there was no accurate way to measure the volume of boxes.”
“Big boxes that are very light can take up a lot of space, but the cost for those items was small.”
SICK’s laser volumetric equipment has been approved by the National Measurement Institute of Australia (NMI).
DWS system components have been certified by the Federal Institute of Physics and Technology in Braunschweig, Germany, on the basis of testing parameters in the OIML R129 standard.
The scale value and calibration error limit are 0.5 cm with a maximum transport speed of 3 m/s, and objects with an edge-length more than 50 mm can be measured with calibrated accuracy.
The system can be used in combination with approved-for-trade scales and bar code scanners for a complete DWS system.
Laser volumetric sensors can be mounted above any point in the packaging process.
“The bottom receiver of light-curtains had to be mounted at a gap in the conveyor, which limits the placement of the volumetric device,” Perez-Bello said.
“This system has two heads placed over the conveyor, and can be mounted onto an existing system at any point.”
The laser volumetric system uses time-of-flight technology to calculate the volume irregular-shaped products.
“The time-of-flight technology has been integrated with a cubic algorithm to be suitable for volumetric equipment,” Perez-Bello said.
The NMI requires that technology is placed over a straight conveyor and not located between conveyors working at different speeds.
Sensors can not be used with roller conveyors because the freight tends to shake, and sensors must be used on conveyors with very little incline.
“The technology has a great return on investment,” Perez-Bello said.
“A large airline freight company was transferring boxes of flowers to Australia from Japan, but they were only charging as per the weight of the huge boxes, which were very light.”
“The introduction of the volumetric device allowed the company to increase their profit by 20%.”
TNT Express in Germany integrated a bar code reading portal into the DWS system to identify packages and control their destination at the sorting plant.
In addition to an evaluation unit the system consists of several standard scanners with integrated real-time autofocus.
The scanners generate a wide reading field and at least one scanner can always read the bar code label.
The system’s evaluation unit controls the individual scanner’s reading activities, processes the reading gate and path information, and assigns the bar code information to the particular object.
All relevant information for sorting and revenue recovery is available through an Ethernet system.
Key contact:
SICK
www.sick.com.au
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