The 3D Laser System uses the combination of a line laser and a custom video receiver. The sensor views the cup at an angle, and can determine the metal level in the cup by reading the position of the line.
Because the line laser and 3D sensor are on opposite sides of the iron stream, the 3D Laser System is insensitive to variations in the iron stream.
While a traditional vision system often requires additional equipment and mold features to locate the cup, the 3D Laser’s point laser uses a combination of an active light source and simple triangulation to locate the cup.
During the last 50 years, pouring processes have evolved from manual (hand) pouring, via semi-automated systems to completely automated systems. Although hand and semi-automatic pouring is still common, high-volume production facilities use bottom-pouring technology (featuring a stopper rod and nozzle) featuring closed-loop control, with metal-level feedback from the pour cup to control the pour.
In the 1980s, two technologies were introduced to provide this level feedback, vision cameras and laser systems. In 2004, KOINS Co. Ltd, introduced its pourTECH™ system and a new approach to pouring, the 3D Laser System. The 3D Laser uses a combination of laser and vision to provide the most reliable real-time level data in the industry.
The 3D Laser System uses the combination of a line laser and a custom video receiver. On one side of the pour cup is a line laser, projecting a green laser line across the cup. On the opposite side, the 3D sensor picks up the image of the line, as it reflects in the metal surface. The sensor views the cup at an angle, and can determine the metal level in the cup by reading the position of the line.
For vertically parted molding lines, traditional laser systems require a modification of the pour cup to provide an area for the laser to measure the metal level while still keeping the cup size down, but since the 3D Laser projects a line across the entire cup, the system is able to collect level data from both sides of the pour stream, so it can provide more accurate information to the pourTECH™, allowing it to optimize its pouring control decisions.
A traditional vision-based system depends on the illumination from the iron in the pour cup to make a level interpretation. The light contribution from the iron stream must however be discarded (since it doesn’t represent level), a sometimes difficult task as the iron stream can wander from side to side during the pour, or fan out if the nozzle condition deteriorates.
With its green light source, the 3D Laser System is completely insensitive to the light from the iron (thanks to the difference in wave length) and because the line laser and 3D sensor are on opposite sides of the iron stream, the sensor will see a break in the laser line where the stream enters the cup, making it possible for the sensor to ignore that part of the reading. This makes the 3D Laser System insensitive to variations in the iron stream (side-to-side movement and fanning of the stream). As long as the 3D sensor can see a small portion of the line, the system can continue to operate – even with severely fanning iron streams.
In addition to the 3D sensor, the device opposite the line laser houses a point laser to position the pouring vessel over the mold on vertical molding lines, or to perform a cup check on flask lines, verifying the flask has both sand and a cup before pouring starts. While a traditional vision system often requires additional equipment and mold features to locate the cup (lights and mold notches, as it is difficult to see a black hole in black sand), the 3D Laser’s point laser uses a combination of an active light source and simple triangulation to locate the cup.
The 3D-Laser’s camera features a specialized C-Mos detector. This detector is programmable, which allows the system to decide which part of the detector to read and only “view” the area of the pour cup. This allows for higher data rates (traditional CCD detectors must have every cell read before a new image can be collected) and higher precision.
The 3D Laser is designed for use with small pour cups and does not require any modifications of the cup. Initially designed for pouring furnaces, the 3D-Laser has been successfully adapted for use with heated and unheated pouring ladles – such as KOINS’ own pouring units. PourTECH™ systems with 3D Lasers can be used together in pairs, allowing for simultaneous pouring of two molds without any interference between the two systems.
The level data from the 3D Laser is further processed by the pourTECH™ system controller, which in turn controls the position of KOINS’ actuator – and the opening of the stopper rod. This unit features an electric servo drive unit that moves at speeds of more than 100mm/sec.
The pourTECH™s controller has been designed to handle a multitude of external sensors, such as run-out detectors, pyrometers and final level sensors, to provide the foundry with additional production data.
With its mold-mapping feature, pourTECH™ will track each mold as it moves down the cooling line and allows the operators to view key data, such as pouring status, iron temperature and final level on the operator’s panel. The data displayed on the screen can be augmented with batch numbers, lab analyses and other pattern and pour specific information. The collected data can be sent to an external database, where it can be kept as a quality record for each pour, fully accessible by the plant engineers. With mold mapping, it is possible to provide cooling time control (CTC), to ensure that each mold is sufficiently cooled before it leaves the cooling line, while optimizing the production rate for the highest possible mold rate, taking advantage of line stoppages due to breakdowns, pattern changes, etc., to keep the mold rate up.
Goran Lowback is the president of Viking Technologies. Visit www.viking-technologies.com.