Metal toll processors use special equipment to refine the surface of flat rolled metals and prepare them for forming into final products such as appliances, vehicles, and architectural products. Services can include leveling and polishing the surface of the metal, slitting it to exact widths, and cutting it to exact lengths.
Each batch of metal is marked for the customer as it is being processed. Marks can include the customer name, material grade and specifications, and the original heat number from the mill. This enables the metal to be properly identified when it is shipped to the customer for processing, preventing product mixups. Ink jet marking is typically used since the marks are very visible, they do not affect the surface of the metal, and they can be easily removed or covered with paint once the metal is formed into finished products.
A typical ink jet system utilizes several printheads mounted across the processing line. Marks can be applied at specific locations across the width of the metal by moving the printheads laterally and/or by turning individual heads on or off for different widths.
After processing, the metal is covered with a paper or plastic layer to protect the finish. Since the markings are then covered by paper, an additional printhead is used to print markings on the underside of the metal for additional identification at the customer site.