Faster adjustment of machining parameters with optical 3D measurement
As geometries of precision molds grow in complexity, measurement systems for quality assurance are subject to ever increasing requirements. The Focus-Variation technology makes it possible to verify the geometry and surface finish of electrodes and EDM molds. It also allows users to demonstrate the high precision of their machine tools, as illustrated by the cooperation of companies Alicona and Makino.
The complex geometries of injection micromolds and precision molds demand measurement systems that make it possible to verify geometrical tolerances of molds and rapidly adjust machining parameters. The robust, areal-based technology of Focus-Variation by Alicona, a leading provider of optical 3D measurement systems, allows molding companies to optimize their manufacturing processes in several ways. First, it can be checked whether electrodes and EDM molds correspond to their geometrical specifications. Second, the surface structure and finish of EDM molds can be determined using roughness measurement. Combined, geometry and roughness measurements allow molding companies to identify optimum electrode operation parameters.
Rapid adjustment and optimization of sinker EDM parameters
Along with milling, grinding, and punching, sinker EDM is one of the most common processes used in die and mold making. In mold making, this method is mainly used to manufacture injection molds for precision plastic parts with complex geometries. A range of parameters influence process reliability and quality of the finished forms. For instance, voltage and frequency greatly affect material removal and, consequently, how fast the electrode wears out. The faster material is removed, the higher the roughness of the resulting mold and the less wear on the electrode. Conversely, the slower material is removed, the smoother the resulting mold and the greater the wear on the electrode. Knowing which surface structure results on the mold from particular machining parameters makes it possible to optimize electrode operation. Practical long-time tests have shown that manufacturers save over 10 % on electrode usage when relying on Alicona measurement systems. Alicona also provides 3D measurement systems for quality assurance in production. The measurement systems of Alicona are based on the Focus-Variation technology. Alicona systems are known for fusing the functionality of 3D surface measurement systems with the properties of micro-coordinate measurement systems. This combined technology allows users to carry out dense, repeatable high-resolution measurements of the geometry and roughness of surfaces with just one measurement system. Geometrical tolerances are verified through an automatic comparison to a CAD dataset. This comparison of targeted and actual values is relevant for measuring the electrode’s geometry in mold making and plays an important role in product development as well. One example for this is the monitoring of shrinking processes. In this context, it is necessary to verify whether the geometry of the workpiece after demolding and the resulting decrease in volume correspond to the required specifications. At the same time, it must be ensured that the shrinking process is precise, repeatable, and linear, so as to guarantee a uniform surface of the formed workpiece. This is where Focus-Variation allows a precise analysis of a formed/molded workpiece’s density ratio by measuring the void volume (Vvc). The void volume is one of the so-called “functional parameters” that can only be determined using areal-based measurement systems. Die and mold making companies also use Alicona systems to demonstrate their machines’ high precision to potential customers. 3D measurements of finished workpieces make it possible to show that geometrical tolerances in the micro- and nanometer range are maintained. This applies not only to providers of sinker EDMs, but to companies in milling, grinding, and punching in general.
Makino uses Alicona systems to verify surface quality and contour accuracy
For Makino, a leading provider of machine tools for die and mold making, it is important to demonstrate the high precision of their machines used for machining hardened steel. “Molds produced by our systems are already perfect when they come out of the machine,” says Andreas Walbert, Head of Marketing & Product Planning at MAKINO Europe. “Alicona provides us with the perfect technology to demonstrate the high surface quality and contour accuracy of our machines to our customers.” Makino uses Alicona’s high-resolution optical 3D measurement systems to measure the geometry and the roughness of milled workpieces with microgeometries. This allows the company to verify the high precision of its milling and EDM machines. The high working distance and large measurement area of Alicona systems make it possible for Makino to measure a range of different component shapes and sizes, ensuring high flexibility. 3D visualization of workpieces at high contrast and depth of focus provides additional support in demonstrating manufacturing precision.
