Motorcycles Present Unique Finishing Challenge for Robotic System

by Rachel Whitton
ABB Inc. Posted 04/21/2008

Problem:
When motorcycle manufacturers seek to upgrade base coat finishing lines at their plants, ABB Paint Automation was there to help.  The finish requirements, materials used, and curved shapes of motorcycle gas tanks and fenders presented a unique finishing challenge requiring precise program repeatability and fluid controls.

Solution:
One solution for a major motorcycle manufacturer was to divide their production into three independent base coat lines called Base Coat #1, Base Coat #2, and Candy Coat.  Each line is furnished with two enclosed, opposing paint spray booths with an ABB IRB 5002 hollow-wrist electric painting robot in each.  The gas tanks and fenders are mounted on fixtures that are conveyed through the finishing stations by a continuously moving floor conveyor. Mounting the robot manipulator on a riser allows the IRB 5002 to effectively reach over and across the parts thus optimizing its large work envelope.  The highly articulated hollow-wrist design allows the robot to spray back toward itself when necessary to allow the electrostatic spray gun to follow the flowing contours of the parts.

A programmable controller is used to hold the program and color numbers that are eventually downloaded to the individual robot controllers.  As the part fixture moves into the robot stations, an encoder delivers pulses that are used to synchronize conveyor movement to the robot controllers.  Once in a robot station, the fixture actuates a switch that loads the proper program to the robot controller and starts the program.

During the spray program, the robot controllers manage not only the manipulator movements but the electrostatic spray gun functions as well.  Each robot is equipped with Analog Paint Regulation (APR) consisting of electro-pneumatic transducers in the vertical robot arm that control the spray gun atomization, fan, remote fluid regulator pilot air and high voltage.  During the robot program, signals are sent to the transducers that enable the gun functions to be changed to suit the surface of the part being painted.  Response time is quick due to the proximity of the transducers to the spray gun.  The result is quick gun response and increased transfer efficiency because the atomization, fan, fluid flow, and high voltage can be tailored for the application area.  In addition to APR, the robots are furnished with Integrated Process Systems (IPS) which provide closed loop fluid control by using feedback from an in-line gear meter to control the transducer that, in turn, controls the fluid flow.  IPS enables the material flow rate to remain precisely as set and compensates for changes in material viscosity.  By maintaining precise fluid flow control with the closed loop system, material transfer efficiency is further increased.

Color change sequencing is also controlled entirely by the robot controllers.  When a color change is required, the programmable controller releases a color change program number to the robot controllers at the appropriate time.  The program start signal initiates the color change program and the robot controllers send signals to solenoid panels that, in turn, operate color valves to purge, flush, and re-load the material lines with the desired color.

Since this major motorcycle paint system installation in 1996, ABB has installed similar systems in many plants in various locations in the U.S.  ABB is proud of its association with these motorcycle manufacturers in helping to maintain a tradition of quality, and keeping the dreams alive for motorcycle enthusiasts.