During the course of manufacturing, spare car wheels require labelling with safety instructions which must remain intact for the product’s lifespan. Previously, labels had been attached manually, composed of up to six stickers, and this led to issues with bubbles and crooked stickers. A fully automated labelling solution was therefore required.
TAMPONCOLOR supplied a fully automated printing system with a TS 420 E/P-RT printing machine to print the labels onto the wheels. The painted wheels are fed into the print station horizontally. A handling system using NC-axes loads and fastens them in workpiece holders on an electromechanical rotary table with up to 12 stations before conveying them into the printing station.
The yellow areas with cut-out sections for the labels are printed onto the black-painted wheels so that the black labelling appears in negative. The diameter of the printed image is a maximum of 360 mm, the size of the cliché is a maximum of 420 mm x 420 mm. The printing pad moves exclusively in a vertical direction, by means of a freely programmable hollow shaft servo motor with linear axis and a maximum compressive force of 15,000 N. The servo-motor-driven speed variations during absorption from the cliché and transfer onto the wheel allow for optimum ink transmission. Horizontal movement of the cliché and the ink tray is pneumatically-driven. After printing, the inscription is dried with hot air, then removed and transferred to the conveyor belt via a further handling system with special grippers. The labelling system has a cycle time of 6s in a 24h three-shift operation. Alternatively, for the same task, TAMPONCOLOR offers a system solution with a linear conveyor system for the same output quantity, according to customer-specific production conditions.
The costs of labelling can be considerably reduced using the pad printing station. Quality issues caused by incorrectly attached labels are no longer a problem. Pad printing ensures that product labels are resistant, reliable and last the duration of the product’s lifespan.
