Fast shuttering and accurate firing of laser pulses is essential to ensure consistent, high quality processing. One option is to link laser power to pulse rate and modulation; if the power is fixed, then the motion system will need to run at a constant speed to ensure that the correct level is delivered across the surface. This suits operations such as raster scans, where the laser is fired following the motion in one direction, or during the constant velocity phase between acceleration and deceleration phases. However, cutting and welding applications may also need the laser pulses to overlap at a consistent ratio, even when the motion path speed is not constant, and laser pulses occur at a fixed frequency; non-uniform pulse delivery could create heat-affected zones, weak regions or breaks in the cut or weld path.
One of the simplest methods of controlling laser power is to link it to the velocity of the motion path, by connecting the analogue output in the controller to the power input of the laser. Most controllers will allow you to do this, but jerky motion may result in bad processing, and poor placement accuracy can lead to low quality parts. Another approach is to precisely control the laser by pulse placement along the motion path, regardless of the vector velocity. It is also possible to combine these two methods to control scaling of the power output, which overcomes undesired features of the laser electronics or optic path.
Physik Instrumente’s ACS Laser Control Module (LCM) offers a reliable, modular way to construct motion systems. Based on EtherCAT industrial network technology, it does not rely on encoder data, and allows drives to select specified axis requirements. The simple architecture of this add-on module is ideal for laser control: there is no need to change the drive types, which greatly simplifies the cabinet design; there are no changes to the existing hardware, which reduces stock requirements for spare parts; and there is no additional wiring except a simple Ethernet cable. Combined with graphical script creation in SPiiPlusSPC – which automatically generates the code necessary to overcome language issues – this makes it really quick, easy and extremely cost effective to construct a universal drive offering high performance laser control for virtually any application.
For more information about the LCM, visit https://acsmotioncontrol.com/products/laser-control/lcm
