3D printing systems are nothing without the components that make them and formnext powered by tct will offer an opportunity for manufacturers to see some of the latest and greatest components. Cambridge Technology one of the leading suppliers of galvonometers that help to drive metal additive manufacturing systems have pieced together why their technology is so important.
For the first time Cambridge Technology, part of the Novanta Photonics Group, a leading company with a long history in galvanometer based beam steering technology, will be exhibiting at formnext. Taking pride of place will be the Lightning II digital galvanometer scanning solution.
Lightning II represents the culmination of many decades’ experience in the beam steering industry. Built on a 24-bit digital architecture, offering class leading precision and accuracy, the system is extremely capable, flexible and has already been integrated into numerous application domains.
Lightning II complements the evolution in additive manufacturing (AM) with a solution based on the six core technologies shown in figure 1 and discussed below.
Lightning II Figure 1
Lightning II Figure 1
State Space Servo
Unlike traditional galvanometric based control schemes, Lightning II incorporates a predictive control scheme. As shown in figure 3 the system uses a mathematical model of the galvanometer to predict how it will perform over its entire operating range. This ensures Lightning II addresses the application requirements, rather than being restricted to a narrow band of control responses.
CAM fig 2
Pulse Width Modulation (PWM) Drive
Lightning II’s Servo Driver uses Pulse Width Modulation (PWM) to drive the Galvanometer. This makes the driver more than 90% efficient, significantly reducing heat dissipation from the electronic servo driver board. This is important where the electronics are likely to be installed in an enclosed environment to protect from powder ingress.
GSB Bus
GSB Bus is Cambridge Technology’s proprietary bi-directional 24 Bit bus serial bus. Operating at 24MHz, it updates all channels every 10.67us. Subject to appropriate agreements Cambridge Technology’s application engineering team can support customers interfacing the bus into their own machine architecture. Particularly important in the AM environment where melt pool sensing and control is a key requirement.
Scan Pack Control
Skywriting
Unlike other implementations of skywriting, the entire trajectory is planned ahead of execution, thus optimizing performance and accuracy. Users can define parameters such as maximal radial error and break angle between vectors to help influence performance as shown in figure 3, resulting in trajectories similar to that shown in Figure 4.
CAM Fig 4
CAM fig 3
Constant Energy Density
Maintaining even power density is another critical element that contributes to attaining a great additive manufacturing solution. Scanpack can modulate power, frequency and pulse width of a laser. This ensures constant energy density even as the galvanometer’s dynamics change. An example is shown in Figure 5 below.
CAM fig 5
Figure 6 demonstrates even distribution of laser pulses as the galvanometers move to execute a sharp turn.
CAM fig 6
Beryllium(Be) Mirrors
Lighting II solutions use mirrors fabricated from Beryllium, a material that is four times lighter than steel and seven times stiffer. The resultant low inertia ensures superlative dynamic performance.
CAM fig 8
The Lightning II product supports all mirror coatings that are commonly used in laser additive manufacturing machines including 10.6um (CO2) and 1064nm (YAG). These coatings can support powers of up to 4KW (YAG) and 2.5KW (CO2) depending on the type of system defined. Other coatings are available to serve other additive manufacturing techniques, for instance SLA.
Encoder Position Detector
The encoder utilizes a proprietary arrangement of optical detectors and advanced signal processing electronics, resulting in an accurate, high resolution encoder. With 24 bit digital command and position signals available directly from the galvonometer itself it is theoretically possible to command positions in steps of 0.02 micro radians.
Lightning II – “A Platform to Build On”
LightningTM II is available both in 2 or 3 axis configurations. A 2 axis system typically requires the addition of an F Theta Lens to provide field flattening, whereas 3 axis solutions are generally available as a modular designs and readily integrated into the Additive Manufacturing Machines.
The high power 50mm 3 Axis system represents the exception to the modular design, due to additional cooling requirements.
CAM FIg 10
CAM fig 11
CAM Fig 9
To discuss your application, find out more about Lightning II, and see the live demo visit Cambridge Technology at formnext (Stand C77).
