The O-INSPECT multi-sensor coordinate measuring machine from Carl Zeiss Pty Ltd is being employed by Schwan Cosmetics to check cosmetic pens reliably and accurately.
Schwan Cosmetics Kunststofftechnik GmbH & Co. KG specialises in the manufacture of high-quality, plastic packaging solutions. Schwan-STABILO Cosmetics produces cosmetic pens on behalf of many well known international cosmetic companies.
The company set up a new production hall for plastic injection moulding in early 2009 at their Weissenburg facility. The Plastics Technology Division, operating as an independent GmbH & Co. KG is a competency centre for injection moulding technology and colour composition/ colorimetry for plastics.
Schwan Cosmetics simultaneously wanted to reorganise quality assurance and introduce state-of-the-art machinery. The optical measuring machine used for initial sampling and the ECLIPSE contact coordinate measuring machine from Carl Zeiss used for tool-making were only capable of performing the required measurements either optically or by contact.
Günter Lurz, the new President and his QA employee, Markus Meier quickly realised that only a multisensory coordinate measuring machine would be able to meet their current and future needs.
The finished parts required the combined optical and contact measurement of the characteristics, with the results of the inspection to be made quickly available in an informative measurement log. Additionally, the prevalent part geometries also necessitated a rotary table to completely inspect the round plastic parts with minimal movement of the measuring axes of the CMM.
The number of parts manufactured during each injection procedure has increased considerably, particularly through the use of multiple-cavity tools, which are an ideal solution when high production volume has to be achieved with low item prices.
At Schwan Cosmetics Kunststofftechnik, this method is used to mould up to 32 parts in one run, resulting in more than 380 million plastic parts leaving the production facility annually.
The demands on the precision and homogeneity of multiple-cavity tools are even higher than those placed on standard injection moulding tools. With such high throughput, the proper alignment and insertion of the tools is vital.
During initial sampling, Schwan Cosmetics Kunststofftechnik inspects the parts manufactured by the tools, with the tools being approved for serial production once process reliability has been achieved. Quality assurance therefore, requires measuring equipment that can flexibly and quickly deliver informative results.
With customers demanding a wide range of colours and surfaces, the utilisation of different colours is a particular challenge during the manufacture of the plastic components. While plastics such as ABS and PP are used for the coloured plastic components, functional parts are made of polyoxymethylene (POM).
To ensure the functionality of a cosmetic pen, the single plastic components must adhere to very exact dimensional tolerances of 0.02mm. Compliance with the tolerances of all these parts is essential since their functionality must be guaranteed at all times under different conditions. For example, if the end-user wants to apply lipstick, the cap on the lip liner must open and the colour core must extend without a problem every time.
Coordinate measuring machines must not only deliver the results quickly but also be easy to use and be suitable for different measuring requirements.
Schwan Cosmetics decided to purchase an O-INSPECT coordinate measuring machine from Carl Zeiss, as it met all their requirements. The comprehensive approach of CALYPSO measuring software that unites the user-friendly optical and contact measurements in one interface also played a key role in the final decision.