Advances in Laser Micromachining and Microprocessing

Many challenges associated with integration of the HMI host application and the motion / CNC controller are also solved:

• Optimizing NC program download, compilation, and execution time
• Managing G/M Code modality in order to support ‘mid-program start’
• Displaying, handling, and logging machine fault and error conditions

The competitive advantages of a Laser Microprocessing and Micromachining system are often related to application specific functionality. As the name implies, a customizable CNC HMI development platform provides value to the machine developer by allowing application specific HMI customization with relatively little effort. Simple examples of such customizations may be custom tabs, buttons, or screens.

More sophisticated customizations may involve process visualization or integration of other devices in the machine such as cameras and laser displacement sensors.

The Integrated Graphical HMI

Laser Microprocessing and Micromachining systems used in applications such as flex PCB drilling and cutting, glass and polymer display processing, semiconductor processing, precision optics manufacturing, high precision additive manufacturing, and more, are often used in high-tech research and production facilities. In such as the system operator is not a CNC machinist. The Integrated Graphical HMI can directly take in a CAD file from which a laser path is defined and the corresponding machine code is then automatically generated and executed on the motion controller (figure 2). In such cases, a separate CAM or post-processing software is not required.

A customizable Integrated Graphical HMI development platform, with built in functions for specific processes such as laser marking, drilling, etching, cutting, additive manufacturing, etc. provides significant added value to the machine builder / integrator and end user by solving a number of development challenges out of the box:

• A wide range of CAD files are natively supported (DXF, DWG, Gerber, NC Drill, STL, etc.) and can easily be manipulated to easily create motion recipes (scaling, rotation, tiling, etc.)
• Parameters for all motion axes can be configured and monitored from a single window / location
• Real time monitoring and data collection of motion feedback, laser status
• Commonly used devices such as cameras and Galvo scanners are natively supported and configurable within the HMI. New devices can easily be integrated as well (no need to write new libraries from scratch)
• Full simulation capabilities allow the user to see the expected laser beam path and determine expected process duration

Similar to a CNC Style HMI development platform, an Integrated Graphical HMI development platform can be also customized for application specific functionality.

For many laser microprocessing and micromachining applications, the motion performance is critical in determining the achievable accuracy and repeatability of the process. Motion performance is affected both by the profile generation (commanded motion path) and the servo performance (how well the actuators / stages follow the commanded motion path). Today’s sophisticated motion / CNC controllers provide advanced profile generation and servo performance optimization features, such as:

• Minimal energy profile generation
• Motion segment blending and corner smoothing (figure 3)
• Adaptive servo control algorithms
• Autotuning and performance characterization tools
• Advanced PWM drive technologies

In addition to motion performance, position based output synchronization also has a significant impact on laser microprocessing and micromachining accuracy and repeatability. This task has traditionally been handled within the motion / CNC controller or drive that is physically connected to the machine actuators.

Recently however, dedicated laser control modules have become available, which provide additional flexibility and capabilities with respect to provides position based output synchronization for laser triggering (figure 4) and gating (figure 5). Once added on to a motion control network, the module can be configured (via software) to provide synchronized outputs based on motion of any combination of axes in the network. The laser control module can be configured to operate in various ‘laser control modes’, making it simple to implement a wide variety of applications:

For applications where the laser pulses are not triggered individually by an external control system, a gating mode can be used. In such applications, the gating signal is typically turned on / off precisely at the beginning or end of a motion segment or block, though it can also be done at arbitrary locations along a motion path.