Automation penetration

Robots are paired with an automated shuttle system at the Pepperidge Farm plant in Bloomfield, Conn., to deliver pans. "They have 13 different pan types at different storage locations delivering to three production lines at the plant," says Jeremy Kopicz, project engineer for Genesys Controls, a Lancaster, Pa., manufacturer of industrial control systems. "The plant has five robots operating over three lines. Pan changeovers can be done on the fly."

Previously, bread line workers pulled pans off and put them back on the lines. Today, the robots pick and stack pans. A tracking vehicle unit slides into the shuttle interface conveyor. Another car moves into the racking area where pans are dropped off or picked up. "The system reduces human labor by a tremendous amount," sums Kopicz.

An eye on vision systems

“As machine vision technology has become more rigorous it has become more successful in addressing applications in the food industry,” says Nello Zuech, a consultant to the vision industry and contributor to www.machinevisiononline.org.

“While there are many applications of machine vision in the packaging side of the food industry [newer] applications include sorting and grading,” he continues. “With advances in color cameras and the underlying ability of microprocessors to handle the additional data derived from color-based processing, more applications are being addressed. In some cases multispectral processing is now possible at the speeds required to keep up with processing tons of a product per hour.”

Inspection is a key job for vision systems in the food industry. A Cognex vision system inspects bottle caps at Original Juice Co.

Original Juice Co., Northgate, Australia, wanted assurance that every cap on its bottles was applied fully, straight and not skewed, and that the tamper-band is not broken. The company wanted a vision system that could inspect a variety of imperfections not tolerated on high-speed lines and filling equipment.

In addition to being reliable and repetitive, the vision system would need to inspect at speeds of up to 300 bottles per minute. The In-Sight 5100 from Cognex (www.cognex.com), Natick, Mass., incorporates a die-cast aluminum housing and sealed industrial M12 connectors to achieve an IP-67 rating for dust and wash-down protection on the factory floor. These environmental attributes would prove to be crucial in withstanding the wet, citric-acid environment of the inspection site.

The overall system consists of a touch-screen industrial PC incorporated into a stainless steel enclosure. The enclosure also houses the Ethernet hub, the digital power supply of the lights, a PLC and various power distribution components. After bottles have been filled and capped they travel down the conveyor line, where two cameras sequentially inspect the bottles.

The first camera looks directly at one side of the bottle and inspects the bottle cap at this side only. A red LED backlight provides the camera with a silhouette image of the bottle. Back lighting provides maximum contrast between the product outline and its background and is ideal for measuring external part edges. This results in images that work extremely well for the vision sensor's measurement and inspection tools.

When the bottle comes within the camera's field of view, a sensor is triggered and an image is taken. Cognex In-Sight vision software tools then analyze the image for defects and determine whether a bottle is flawed or not. In the event of a failure being detected, a fail signal is sent via one of the camera's outputs to the PLC. The PLC then triggers a reject mechanism, which removes the bottle from the line. After passing the first camera, the bottle will travel a little further before the second camera acquires another image of it, performing the same inspection on the other side of the bottle cap.

Labor vs. machine: the payback drama continues

The high capital outlay required for highly automated systems poses a perpetual challenge of cost justification, particularly when important issues like job displacement are drawn to the fore. The makers of automation equipment claim that, in general, European companies are quicker to recognize the return on investment than American processors.

"We make a continuing effort to lower the cost of the equipment we bring to the market," says ABB's Smith, pointing to the improved costs of drives and lowered cost of manufacturing. "Look at a robot in the 1980s. The cost today is half what it was then. A $110,000 robot in the 1980s costs about $55,000 to $60,000 today. We have had to reduce our costs to stay competitive and to be available to all companies."

Improved software has greatly simplified robotics usage, she adds. "Now we have structured packages that make it much easier to develop a program." A software package called "Robot Studio" enables processors to develop production programs completely off-line. Changeover is often simple and quick, even when it involves significantly different products. "Often it is just a matter of changing software, or changing software and a gripper (flexible hand)," she says.