New automation options in production metrology

Automatic placement, measurement and sorting with an optical coordinate measuring machine

At EMO 2019 (Hall 6 stand E39) 3D metrology supplier Bruker Alicona will be presenting how an optical coordinate measuring machine can be used to automatically load, measure and sort in OK/not OK parts. The core of this automation solution is the extension of their CMM machine with collaborative robotics. 

The combination of high-resolution optical 3D metrology and collaborative robotics is already familiar for Bruker Alicona. Their “Cobots”, consisting of a collaborative 6-axis robot and a high-resolution optical 3D measuring sensor, are well established in the industry and used for automated measurement of smallest component features in all sectors of metalworking. New is the connection of their optical coordinate measuring system µCMM with a collaborative robot arm, which will be presented live at the EMO show as a “Pick & Place” solution. Show visitors will be offered a real-life application: The component measured is a proven customer application from industrial quality assurance. Together with German high-performance stamping supplier Stepper, the automated measurement of 3-fold stamping inserts will be presented. The measurement is applied to verify position, shape and roughness with only one optical sensor.

Reduced measuring times

The stamping insert is a part of punching tools which are used, among other things, for the manufacturing of automotive contact parts. Stepper produces up to 2550 contacts per minute, within a few years 3 billion parts have already been manufactured. “In terms of measuring, most important are shape deviation, surface quality and the position of the tool relative to the outer contour,” explains Marcel Heisler, Head of Laser Ablation and High-Speed Cutting at Stepper. And he adds: “With Bruker Alicona I cover all this with just one optical sensor.” For the stamping supplier, the µCMM coordinate measuring system is the ideal solution. On the one hand, the system delivers high accuracy even for components with tolerances in the single-digit µm range. On the other hand, users benefit from the efficient usability, which is designed for the usage of several operators. For Stepper, who apply various optical metrology solutions in their quality assurance, the use of an optical coordinate measuring system is a milestone. One of the most beneficial features is the significant reduction in measurement time when measuring optically. The decisive factor is that users don´t need to scan the entire component in order to check the relevant component geometries. “We only measure those parts of the outer contour that we really need,” Heisler says. “This reduces measurement time by more than 2/3.”

Measure components with more than 90°.

A further advantage in regard to increased efficiency is the functionality of lateral probing. This enables to optically measure vertical surfaces without re-clamping the component and is realized by the technology “Vertical Focus Probing”. With this, Bruker Alicona has expanded its core technology Focus Variation in spring 2019, providing a range of new applications in industrial measurement technology. Stamping supplier Stepper also sees new fields of use: “The possibility of measuring flanks with more than 90° opens up a completely new spectrum of measurable parts for us. So far, we have mainly measured embossed and bent parts. Now we can also measure cylindrical, continuous contours such as cutting punches and cutting inserts.”

Ensuring shape accuracy and surface quality

In addition to the position of the tool, dimensional accuracy as well as surface quality of the stamping insert are measured. Since Stepper produces 3 parts simultaneously with each stroke, they not only check the compliance with tolerances in comparison to CAD data. Moreover, by shape measurement it is ensured that all 3 molds match exactly.

The surface quality is verified by measuring the surface roughness. Depending on requirements, users can choose between profile-based and areal-based measurement. In many cases, tool specialist Stepper uses area-based surface measurement because the roughness parameters Sa/Sq/Sz obtained in this way enable more detailed information about the components´ surface state.

Automation with “Pick & Place

The Bruker Alicona µCMM is a purely optical micro coordinate measuring system, with which users combine advantages from tactile coordinate measuring technology and optical surface metrology. With just one sensor, dimension, position, shape and roughness of components are measured in high accuracy. The spectrum of measurable surfaces includes common industrial materials and composites such as plastics, PCD, CFRP, ceramics, chrome, etc. Matt to highly polished components are measured in high accuracy, traceability and repeatability.

The fact that their optical CMM machine can also be used in production is based on various hardware and software extensions. Each system is equipped with air-bearing linear drive axes which enable wear-free operation and accurate, fast measurements. In combination with a special “Automation Manager” software interface, measurement series for testing GD&T and roughness parameters can also be automated. This automation interface also offers applications such as digital measurement planning, extended order management or connection to QM and ERP systems. A new option is to combine the CMM as a “Pick & Place” solution with a collaborative robotic arm, allowing automatic loading, measuring and sorting into OK/not OK parts within a measuring process. This extension is based on the interaction between an administrator, who pre-defines measurement series (teach-in), a robot for manipulation and assembly of components and the optical 3D measurement sensor. The teach-in of measurement series takes place in three steps and requires no programming knowledge. The robot takes over the loading of the pallet with the components to be measured, the positioning on the measuring system and the further sorting in OK/not OK pallets.

www.alicona.com