Cleaning paint fixtures is an important but often time-consuming aspect of the vehicle manufacturing process. KMT Robotic Solutions has launched a robotic cleaning system to remove excess paint on trolleys that transport parts to and from the paint shop, with the goal of reducing the possibility of fire when trolleys are in paint ovens.
Removal of excess paint is usually a manual operation, but the robotic cleaning system is fully automated and operates in a low-noise and safe enclosed cell. The robot creates a high level of repeatability and accuracy in the process, according to KMT. With movement available along seven axes, the robot facilitates cleaning of fixtures that have complex geometries. Pure tap water is used as the cleaning medium. A cold process, it does not damage the part. The only residual material is wastewater and the substance removed (e.g., paint, grease, oil). KMT says only a limited amount of preventive maintenance is required.
The system incorporates an inverted ABB IRB 2400 foundry robot using the latest-generation IRC 5 controller. It is normally mounted onto a true seven-axis track-motion for maximum reach and attack-angle flexibility. The robot and track-motion are assembled within an enclosed cell to provide safe operation and low noise levels, and to contain and collect residual water from the process. The enclosure for the system has what KMT says is a compact footprint.
In a typical KMT setup, trolley-carriers are sent by rail to the enclosed robotic cleaning system cell. An automated rolling door opens to allow the trolley to be brought inside. Once the door closes, an operator initiates a start sequence to let the robot conduct cleaning/paint removal on the trolley. When the cycle ends, the trolley leaves the cell through a second rolling door on the opposite side. If the cleaned trolley passes a manual inspection, it is returned to the paint line. If it fails the inspection, it is returned for a second cleaning cycle.
A standard KMT 50P intensifier generates high-pressure water at up to 3200 bar (46.5 ksi), with a water flow of 3.8 L/min (1 gal/min). Through hard and soft piping, the water is directed to a uniquely designed unit called the Rotojet nozzle mounted on the sixth axis of the robot. High-pressure flexible hosing ensures maximum movement for the robot and a very high level of flexibility for the cleaning process. The Rotojet nozzle has a pneumatically driven spindle with a swivel joint, allowing the high-pressure water to exit four 0.18-mm (0.007-in) orifices in a rotating pattern. This produces a cone-shaped spray. For cleaning of complex 3-D fixtures, the jet moves around the trolley at an offset distance of 50 to 100 mm (2.0 to 4.0 in). The robot travels over the trolley at a rate of between 30 and 50 mm/s (1.2 and 2.0 in/s).
Other versions of the system can perform additional functions, including removal of excess polyurethane and other plastics from injection moldings. Also offered is the option of abrasive blasting using a mixture of water and sand within the same cell. It is designed to be economical and easily run by a single operator.