If you want to fabricate better parts, retain your customers, and grow your business, it pays to prioritize system accuracy and precision. Delivering a superior product (while minimizing scrap and rework) is impossible without equipment that delivers superior performance. This applies to virtually all systems and fabrication methods but is especially important when considering your next laser system.
What Are Accuracy & Precision, Exactly?
Simply stated, precision allows fabrication of parts that are highly consistent. Accuracy, on the other hand, compares a finished part to the ideal dimensions. With these two conditions there are four possible outcomes:
Low Precision & Low Accuracy: the worst possible outcome. The part features are neither repeatable nor sufficiently close to their measurements as defined by the part specifications. The process must be changed or improved dramatically to produce high quality parts and maintain throughput.
High Precision & Low Accuracy: in this case, part dimensions differ consistently and predictably from specifications. Sometimes rework can make up the difference but this process impacts throughput and efficiency.
Low Precision & High Accuracy: in this case, part dimensions often match specifications but a lack of consistency results in many out of tolerance parts. Some parts make it into the next manufacturing step while others must be reworked or scrapped.
High Precision & High-Accuracy: the best of both worlds. Part to part repeatability ensures consistent output and results that can be steadily passed onto the next manufacturing step. High accuracy means that parts are sufficiently close to their ideal dimensions. High consistancy and quality enables smoother operations and better products for the end user.
Accuracy & Precision Start with a High-Performance Tool
Lasers have earned a reputation as high-accuracy and high-precision tools for everything from cutting, drilling, welding, and marking to advanced microprocessing. Fiber lasers in particular have seen widespread adoption due to their ease of integration, reliability, and energy efficiency. Fiber lasers offer the flexibility to be optimized for a wide variety of materials and applications by tuning laser parameters like power, wavelength, and spot size.
As a remote, non-contact process, the stability of fiber laser processing enables extremely high repeatability. Under the correct conditions, lasers produce virtually identical features operation after operation. The inherent accuracy and precision of laser processing may be diminished, however, when paired with an inaccurate and imprecise system. To take full advantage of the power of laser processing, a sufficiently high-performance laser system is necessary.
Building a High-Accuracy, High-Precision Laser System
Designing and building a highly accurate and precise laser system means combining qualities and functionalities to create something that is more than the sum of its parts. Take, for instance, the LaserCube Laser Cutting System — the most accurate and precise laser cutting system on the market today. LaserCube was built from the ground up to meet the demands of cutting applications that demand repeatable, high-quality results. A few key features help LaserCube stand above alternative laser cutting systems.
Natural Granite Base
Accuracy and precision start with a stable foundation. The gantry system in LaserCube is built around natural granite. Natural granite offers a number of superior material properties, primarily high strength and stiffness that enable excellent absorption of vibrations caused by machine motion. Natural granite also has a low coefficient of thermal expansion — approximately half as much as that of steel and cast iron. When compared to alternatives, natural granite is the material of choice for high-performance machine tools.
Linear Motors / Linear Encoders
The system motion of LaserCube is driven by non-contact brushless linear motors and high-precision linear encoders. Linear motors and encoders are a critical element for high-performance cartesian systems. LaserCube uses a gantry configuration with two motors and encoders powering the Y axis with a single motor driving the X axis. This design enables high accelerations due to the lightweight design of the cross axis. Minimization of moving mass dramatically reduces following error at high speeds and accelerations to allow for rapid traverse and contouring velocities.
Alternative motion systems like ball screw and rack and pinion systems require periodic maintenance and eventually wear, compromising system performance. Systems that utilize rotary encoders often suffer accuracy issues due to manufacturing variations in the pitch of the leadscrew or rack. In the longer term, wear of the recirculating ball bearings in the ballnut will reduce repeatability.
Precision Assembly
High-performance components mean less if they are they are not assembled with care and precision. The assembly of each LaserCube is performed using precision metrology tools and assembly techiques to measure critical features like straightness, flatness, squareness, and parallelism of the guideways. This provides an extremely accurate map of the straightness and flatness of the motion systems. The result is unmatched cutting accuracy and precision.
Vision Registration
Even with the maximum achievable accuracy and precision, a variety of factors can result in parts and features that are out of spec. Poor part fixturing or tolerance issues caused by previous non-laser steps can result in a non-ideal target for a laser system.
With this in mind, LaserCube can be equipped with a vision system that positions cuts where they belong even when part and feature placement vary. The vision system scans parts prior to firing the laser to automatically account for the effects of dimensional deviations or operator error, reducing process requirements prior to laser cutting. For complex and pre-processed materials such as screen-printed plates, punched parts, or chemical etched components, vision registration minimizes rework and scrap.
Learn more about the LaserCube Laser Cutting System here.
