Food Engineering

Keeping an eye on the wafer

April 1, 2008
Inspection system reduces rejects, increases productivity by 5%.

The simple installation of the Cognex In-Sight 5400 vision sensor at Mannerschnitt allows the checking station to be kept compact. Fisheye view from directly overhead shows the vision sensor (center) taking a picture of a package in transit. Source: Cognex.

With an annual capacity of 8,800 tons of flat wafers and biscuits, the world’s largest wafer oven is located at Mannerschnitt’s plant in Perg, near Linz, Germany. The plant has been producing chocolate wafer treats known as Mannerschnitte or Neapolitaner for 100 years. Enormous quantities of product are processed by 100 employees, who ensure the portions are packaged correctly and kept airtight.

Mannerschnitt decided a vision system-based checking station could help with packaging quality. Besides being easy to operate and program, the vision system would have to perform reliable inspection of up to 400 packages per minute, check many product variants and make the production process smoother. In addition, the vision system would have to cope with 25 packaging color variants, handle 100 texts in different languages printed on the packaging, inspect label positioning, prevent dents and defects in the packaging and verify the presence of picture and text.

Schmachtl Gmbh from Linz, a Cognex partner system integrator, impressed Mannerschnitt with the results of a feasibility study done for the Perg plant. The solution employed Cognex’s In-Sight 5400 vision sensor to keep the design of the inspection station simple, allowing the mechanical set-up and installation to be done internally by Mannerschnitt’s own engineering/maintenance team. The inspection station checks whether the label is equally positioned from the left and right edges of the packaging, whether there are dents or defects in the packaging, which picture and text are on the packaging and much more.

To ensure operator and production efficiency, Schmachtl programmed customer-specific vision tasks for a wide range of packaging variants. It was important for operators to be able to easily manipulate the inspection station. The high-performance vision sensor combined with the capabilities of PatMax vision software allows many characteristics to be checked simultaneously and quickly. Individual packages flow through the inspection station on the conveyor without needing to be in a particular position. The vision system also detects any faults in the packaging supplied by external vendors.

Mannerschnitt employees are able to easily train various characteristics on the vision system for the entire range of packaging. This enables the staff to react quickly to various types of faults. For example, if a package is dented, it may become jammed further down the line, resulting in additional unnecessary product rejects. Now these incidents are at a minimum, and the processor is able to guarantee the packaging is airtight and flawless in appearance. By keeping interruptions in the production flow to a minimum, productivity has increased by around 5%.

“If the conveyor belt is operating at a speed of, for example, 270 packages per minute, then just a few seconds of defective production means several dozen rejected packages,” says Reinhard Gassner, Perg plant manager. “This is not just a question of cost; it also has a negative effect on the production flow. Problems like this are now in the past.”

For more information:

John Lewis, 508-650-3140, john.lewis@cognex.com.