Linde Material Handling (LMH) in Aschaffenburg, Germany, have used the GageMax coordinate measuring machine (CMM) and GEAR PRO software to measure gears close to production. This measuring technology from Carl Zeiss ensures reliable quality assurance.
Originally, Linde Material Handling measured gears with special gear measuring machines. Since they had already purchased a CMM from Carl Zeiss to measure standard geometric workpieces, they also wanted to use it for the measurement of gears. While measurements in the past were made between two peaks, coordinate metrology is based on the functional surfaces. Comparative measurements have shown that the same results can be achieved when the conditions are the same.
Errors resulting from clamping on the plug gage are eliminated. Therefore, the workpieces can be completely measured on one CMM which contributes to increased efficiency and a reduction of costs and sources of error.
LMH Material Handling had PRISMO CMMs in their measuring labs for several years. Now, they intend to perform measurements near the production machines to optimise processes. A GageMax from Carl Zeiss makes it possible. This coordinate measuring machine is a production measuring centre designed for use directly in production. GageMax offer speed, insensitivity to rough environmental conditions such as dirt and temperature fluctuations, and a higher degree of user friendliness and safety.
Externally and internally geared spur and spiral gearing in the module range of 0.75mm up to 12mm is produced in a wide range of manufacturing steps from pre-machining to hardening and finishing. The diameters of the gears range from several centimetres to a half metre. The quality fluctuates between class 6 and 8. In addition to the PRISMO measuring machines in the measuring labs, there are also GageMax measuring machines with GEAR PRO software in the single batch production areas.
As a result, operators perform the measurement on the shopfloor. They need only to clamp the workpiece to the rotary table and start the measurement plan. Production runs in three shifts. This means that the measuring equipment must work around the clock. This places special requirements on the CMMs and the software. Production demands that disruptions are documented. These documents show that measuring equipment from Carl Zeiss is reliable and has not caused any failures in production up to now.
Quality management at Linde Material Handling employs the latest methods. For this, the measurement results must be stored on a centralised server. Employees at the factory in Kahl am Main are responsible for the global quality assurance of the gears. They know that the requirements of gear measurement are high. They define all measures needed to ensure production. This applies to the specification of parameters stored as qs-STAT data. Furthermore, the test records and graphics are stored as PDF files. The measurement and evaluation data of a gear must be defined before a gear can be measured.
Linde Material Handling have established an offline station for this, so that the coordinate measuring machines are not unnecessarily occupied during the programming.
GEAR PRO involute software is used to transfer the data, which is usually available as figures, from the measuring sheet to the gear dataset. It is stored by user-friendly GEAR PRO gear software. Everything is arranged logically and can be quickly accessed. After the figures are entered, the values are shown in a 3D display and as a CAD model, enabling the user to inspect the plausibility of the values. There are no standard gears. The specifics are deviating basic gear data, corrections or special evaluations. Everything can be defined with GEAR PRO standard software and easily entered.
Even if the current quality assurance system has reached a high level, Linde Material Handling still see room for improvement. This refers to an automatic feeder for GageMax, the inspection of gear hobbers following regrinding and the use of the CALYPSO automation interface. The automation interface enables the operator to select the measurement plan for a workpiece based on an image, clearly improving process reliability.