WHY 3-AXIS SCANNING?
As the number of large area, web feed and remote applications that use laser processing continue to grow exponentially, Cambridge Technology’s 3-Axis Systems are gaining more and more popularity in the marketplace due to its: 1) large field of view, 2) small spot size, 3) ability to scan pre-defined 3D surfaces and 4) ability to use high power lasers. Compared to mechanical processes, laser processing using 3-Axis Scanning provides improved flexibility, quality, setup time and throughput. The advantages of a 3-Axis Scanning System is particularly apparent in converting applications such as cutting, marking, welding, perforating, slitting, trepanning, drilling, and surface treatments. The diversity of commercially available lasers enable processing of a variety of materials such as paper, cardboard, plastic, glass, metal, textile, foil etc.
1) 3-Axis Scanning Systems are primarily used for scanning large field two-dimensional surfaces where field flattening lenses are no longer practical. By placing the focusing lenses before the scan head, the sizes of the optical elements become independent of the field size (Figure 1). This flexible design allows Cambridge Technology 3-Axis Systems to be readily configured for a wide range of field sizes with a single, economical lens set enabling large area laser scanning for converting applications.
Figure 1. Beam delivery of a 3-Axis Scanning System
2) The dynamic focus module is used as the standard third axis in Cambridge Technology 3-axis scanning configurations in order to create beam waists to be imaged by the objective optics. This imaging mechanism combined with relatively large aperture of the scanning mirrors provide smaller spot sizes compared to F-Theta based 2-Axis Scanning Systems.
3) Another unique application for 3-axis systems is scanning three-dimensional surfaces. Orchestrated by the Cambridge Technology’s EC1000 controller, the X and Y axes will direct the laser to a point on a two-dimensional work field while the 3rd axis will focus the laser beam to the corresponding Z position dynamically, providing the capability of scanning predefined three-dimensional surfaces. Relatively small movements of the DFM will correspond to large focal shifts at the target plane due to optical leverage of the imaging system. Using this leverage, 3-axis Systems can perform 3-dimensional scanning and field flattening for each work plane simultaneously.
Figure 2. CTI's Enclosed high-power 3-Axis Scanning System
4) The number of processes utilizing High Power Lasers is growing rapidly. Cambridge Technology 3-Axis Scanning Systems utilizes pre-scanning objective method which completely eliminates the need for F-theta lenses. Pre-scanning objectives remove the low power handling limits of scanning systems which are usually set by F-Theta lenses. Also, 3-Axis Systems use relatively large mirrors which allow the delivery of higher laser powers. These two unique attributes make 3-Axis Scanning Systems the most suitable product for high power material processing applications (Figure 2).
This cutting edge technology allows Cambridge Technology’s 3-Axis Scanning System to offer unique advantages when it come to accuracy and speed.
ACCURACY: Cambridge Technology 3-Axis Systems have many unique advantages when it comes to accuracy. These include but not limited to: CTI Position Detector (PD) Technology, Small spot size on the work surface and CTI Calibration Technology.
CTI 3-Axis Systems utilize two different scanning technologies: ProSeries-2 Analog and Lightning-2 Digital. Scanners for the Analog System have CTI patented optical PDs which provides accurate and repeatable positioning of the laser beam for most applications. Lightning Digital technology, on the other hand, offers a solution for the highest accuracy demanding applications. These digital scanners use encoder-based position detectors which provide high-resolution feedback signals to be analyzed by the controller. The result is revolutionary! Even at sharpest corners and at high speeds, these galvos will stay within the given error envelope eliminating the need to choose between accuracy and speed.
Another unique advantage of a 3-Axis System is its comparatively small spot size. As mentioned before, as opposed to F-theta based scanning systems, the post objective scanning technology allows larger mirror apertures to be used. In this case, larger aperture means smaller spot size. This feature significantly increases the accuracy to pin point the target during laser processing. Cambridge Technology offers the largest variety of aperture sizes for 3-Axis Systems ranging from 20mm to 100mm.
Last but not least, Cambridge Technology 3-Axis Systems enables the customer to fully calibrate the scanners to their overall system for improved accuracy. Any tip, tilt and surface variations between the scanner mounting block and the work piece can be compensated by the dynamic 3rd axis since each X-Y coordinate has its own unique z-height. Cambridge Technology offers a variety of proprietary methods for 3-Axis calibration as well as enabling the customer to use their own calibration methods when they are needed. Although these tools are there to improve the accuracy of the system, the overall system will be as accurate as the measurement technique used in order to calibrate the system. CTI applications engineers can help you choose the right calibration and measurement tools for your application.
SPEED: For the Cambridge Technology 3-Axis Systems, the question is not “How fast can the system scan?” but “How fast would you like your system to scan?” Cambridge Technology 3-Axis Systems, utilizing the post-objective scanning technology, have variable working distances. Although the maximum angular speed is constant, varying the working distance allows the user to choose the linear speed that they would like to scan at. Scanning speeds up to 60m/s are achievable with the new Lightning-II 3-Axis Systems.
Another important advantage of a 3-Axis System is throughput. The post objective scanning technology allows larger mirror apertures to be used. As we have previously learned, larger aperture means smaller spot size and smaller spot size means higher energy density at the work surface. Thus, if the process is laser power limited, the system throughput can be increased by simply using a larger aperture 3-Axis System. Cambridge Technology has the largest variety of aperture sizes for 3-Axis Systems ranging from 20mm to 100mm.
With improved throughput, the variable field size can now handle materials up to 1200mm x 1200mm. And they can be ganged together to expand the width much larger. When added to a roll to roll processing system, throughputs of over 720 M²/Min can be achieved.
From the day they invented galvanometer scanning over 40 years ago to the present times, Cambridge Technology has been perfecting the state-of-the-art in scanning technology, always staying one generation ahead of market requirements. Whether your primary need is speed, stability, cost, reliability, size, precision, quality, or performance, Cambridge Technology can provide a scanning solution optimized to your specific application.