An adaptable, high-speed 3D vision system was developed to detect defective parts in existing systems, in the thermoforming industry. A client requested a way to check for dimensional defects in a thermoformed part on a dry offset printer, up to 600 parts per minute. Due to a variety of issues, traditional machine vision was found to be neither reliable nor effective because each inspection needed to be done in less than 250 microseconds. The Industrial Control Inc. developed the IC ThermoChecker using a 3D smart camera to reliably detect and reject the defective parts, resulting in a substantial increase in defect detection before parts left the client's facility.
In the configuration used, the system can measure up to 130 profiles per part over the course of 30 ms, resulting in approximately 75,000 profiles per minute with multiple tools and measurements for each profile. The camera is calibrated at the factory to real-world values, allowing the user to set limits based on a measurement rather than an arbitrary value, resulting in a system much more easily understood by operators and engineers alike.
A major yogurt supplier had a recall in September 2013, a time-consuming and expensive problem for all parties involved. The IC ThermoChecker finds "leakers" or dents in cups during the printing stage. The 3D vision system monitors the surface for small defects that can affect the seal, resulting in spoiled product.
A larger yogurt manufacturer discovered the solution and encouraged its cup suppliers to implement the system. Since fall 2013, 11 systems have been installed at 5 plants among 3 customers, in the United States and Canada.
The surface inspection of 600 cups per minute (every 3 degrees, within 30 milliseconds) translates into almost 4,000 inspections per cup and 800,000 cups per day on each machine.
The system is installed just past the curing light in the print machine and is unaffected by the intense light. The high-speed PLC and computer instruct the existing machine and reject station when to reject bad cups.
3D vision attributes
The system can:
- Reduce your risk of recalls to protect customers and your company
- Save money with fully automatic inspection of every cup, without costly manual inspectors
- See exactly how the machine is running and reduce setup time
- Calibrate the machine faster with real data from the system
- Show shift counts for rejects onscreen or e-mailed or texted to a phone
- Reduce regrind cost
- Provide remote Internet support from Industrial Control.
Because the system is flexible, new applications are common. The ThermoChecker kit includes a control panel, touchscreen computer, mounting hardware, stack light, integrated programmable logic controller (PLC), and Internet support appliance. The system does not require programming and can be used with any web browser on any device. The company offers a free analysis of part samples with defects to determine feasibility.
- Larry Hildenbrand is new business development manager at Industrial Control Inc. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering, firstname.lastname@example.org.