Motion Control Software Reduces Complexity in Seam Welding

Overview

This video demonstrates the resulting motion profile created by five line program. The ability to use motion control software to append additional rotation matrices to compensate for angular alignment errors is also demonstrated.

Implantable medical devices that rely on electronic assemblies to regulate heart functions or control chronic pain are typically packaged in titanium “clam shell” enclosures. These enclosures must be hermetically sealed to ensure that the recipient of the device is protected from infection and to prevent the premature failure of the electronics. The hermetic seal is created through a laser welding process where the part is rotated and translated on a 4-axis motion platform. The creation of the laser weld path has historically been created with CAD/CAM software where the weld path is broken down into a series of small linear moves. Part geometries that consist of six linear/circular features in 2D space result in a program that contains hundreds of small linear moves. The relationship between initial part geometry and the resulting program is lost in the translation. 

Aerotech’s Automation 3200 motion platform reduces the complexity of implementing hermetic seam welding processes by allowing direct programming in part coordinates. The part coordinates are transformed in real-time into motion commands for the axes. Part hermetic seam weld geometry can be changed on the machine because there is a one-to-one correspondence between features on the device and the motion program. With the laser weld path expressed in a base Cartesian X/Y/Z coordinate system, additional path modifiers can be easily applied. For example, rotation matrices can be used to compensate for part alignment errors and surface speed can be regulated to minimize accelerations that occur as a result of small radii features on the part.