Tire Inspection & DOT Code Laser Engraving
Pioneering system enables black-on-black character reading.
Newly manufactured tires must be marked with information related to the construction method and day of production. The marks that need to be applied to the tire did not lend themselves to mechanization. The challenge to Newton was to create a new, automated method of tire marking and validation across the manufacturer's entire line of approximately 2,000 different tire sizes and tread patterns.
Newton engineers developed pioneering technology for this project by creating the software and modifying the camera and illuminators to enable the machine vision system to read black figures on a black tire surface. This had always caused significant challenges.
The custom tire inspection machine measures the sidewall profile and adjusts a robotic device which carries a camera array and high powered laser. The end effector adjusts to the sidewall allowing a constant perpendicular view and standoff distance from the tire. The tire conveyor moves at 120 to150 ft. (36.6 m - 45.7 m) per minute, with a minimum 4 in. (10 cm) gap between tires.
The machine vision system initially locates and identifies the first seven, raised DOT alpha-numerics on the tire sidewall. The vision system is able to read the three different font styles used in the DOT code by the manufacturer. Next, the system finds the appropriate framed marking location, engraves the necessary data with the laser and finally validates that the mark is correct.