Astute investment in integrated vision system technology by bottle packaging plant SC Johnson delivers consistent guaranteed quality product packaging for major overseas client.
Winning new business is all about keeping your competitive technology edge – providing effective solutions, fast. When bottle packaging plant SC Johnson were approached by an overseas client to fill and package two new product lines they were confident that their current production process – with line speeds of up to 150 bottles per minute – could meet the client’s demand. Incorporating vision system technology into their existing operation, however, was the added competitive edge SC Johnson were looking for to satisfy the most stringent of quality controls. Superior to other defective bottle inspection processes, where human inspection simply can’t keep up with line speeds and reject bottles before they reach the packaging phase, an effective vision system was the answer. With a tight production start time, however, SC Johnson needed the solution, fast.
A high-tech solution for high-speed production
A bottle defect inspection system designed for detection and rejection of low fill levels, missing caps, non-existent Julian/batch codes and missing or misaligned labels on a high-speed bottling line requires a turnkey vision system integration solution. Faced with complex interfacing issues with existing equipment Machinery Automation & Robotics (MAR) elected to integrate the highly effective Cognex Insight camera system at the SC Johnson plant. The Cognex Insight 1000 range of cameras was selected for its speed and interface ability as well as its capacity to differentiate two bottle and fill fluid colour types (blue and green) and accommodate an infinitely variable product conveyor speed.
The vision system at work
Two inspection stations are installed at the SC Johnson plant: the first to inspect fill level, Julian/batch code and cap placement; the second to inspect label application and alignment. Positioned at a distance of 150mm from each inspection table are two rejection stations, interfaced for automated operation whenever a defective bottle is detected.
A PLC is used to provide signal interfacing between the two vision inspection station cameras and the reject stations as well as for tracking of defective bottles for delayed rejection, eliminating potential timing problems between bottle defect capture and rejection. A siren and flashing light are installed to alert the operator to a missing cap detected at the first visual inspection station. Bottles not removed manually are tracked by the PLC control system and rejected at the second reject bin, specially designed to handle liquid spills.
A Cognex industrial touch-screen PC is installed and connected to both vision inspection station cameras over the Ethernet. This allows for on-site program changes and monitoring of bottle image capture and defect decisions via an operator interface screen. And, for ease of use, both cameras are monitored on a single screen simultaneously using Cognex’s Insight Explorer software. Maximising the capacity of the Cognex industrial touch-screen PC MAR included a bottle defect image storage feature for improved efficiency during commissioning and future line performance tracking.
In addition, the PC allows operators to select a new Julian/batch code for every day of production; the Cognex vision system uses recognition tools to check that a code is present, which, in turn, verifies that the Julian code printer is working correctly and the code clear on the bottle after filling.
Adding up the benefits
Investing in technology can be a risk. Investing in the right technology for your business is an asset. For SC Johnson, a complete vision system integration solution gave them the competitive technology they were looking for to guarantee precision packaging for clients providing them with:
- A complete turnkey solution including design, programming, installation and commissioning
- An effective partnership of world-leading Cognex vision technology and MAR’s extensive automation and vision system integration experience
- Expertise in lens, lighting, camera selections and automation
- A robust and reliable vision system designed for high-speed lines
- Project completion within a tight time frame
- A cost effective solution
Technology at work for SC Johnson
- The control system features an Allen Bradley MicroLogix 1500 PLC and uses software shift registers and sensors to alleviate timing issues in tracking defective bottles from the vision inspection station to the reject station
- The interface between the two Cognex Insight 1000 cameras and the Allen Bradley MicroLogix 1500 PLC is via hardwired signals for pass/fail signals and camera image capture triggers
- A single Cognex Insight 1000 camera inspects multiple defects in one image capture and recognition process at the above line speed
- Multiple Cognex Insight 1000 cameras are connected to the Cognex industrial touch-screen PC via an Ethernet switch to provide fast communications for image monitoring and operator interfacing
- Recognition tools available with Cognex detect the 3mm Julian/batch code verification at typical line speeds
- High-level recognition tools available with Cognex allow for slight movement in bottle presentation at high speeds ensuring reliable and repeatable defect inspections
- Sensors, activated by passing bottles on the line, provide a trigger to initiate camera image captures and bottle tracking
- Custom selected specialised lighting provides adequate lighting for each inspection station and removes ambient light changes adversely affecting the visual inspection process