Perfect Plastics

O-INSPECT inspects cosmetic pencils at Schwan Cosmetics

Cosmetic articles have been beloved items since the days of the ancient Egyptians. The often valuable substances must be packaged as securely and aesthetically pleasing as possible. Schwan Cosmetics Kunststofftechnik GmbH & Co. KG specializes in the manufacture of high-quality, plastic packaging solutions. The O-INSPECT multi-sensor coordinate measuring machine from Carl Zeiss inspects these parts reliably and accurately.

The Schwan-STABILO group is known by many as a manufacturer of writing utensils. Far less known is the fact that Schwan-STABILO Cosmetics produces various cosmetic pens on behalf of many well-known international cosmetic companies. A new production hall for plastic injection molding went into service at the beginning of 2009 for Schwan-STABILO Cosmetics at the company’s Weissenburg facility.

Requirement: multi-sensors

During the construction of a production and administration building in Weissenburg, the company also wanted to reorganize 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 realized that only a multi-sensor coordinate measuring machine would be able to meet their current and future needs.

Injection-molding process

The number of parts manufactured during each injection procedure has increased considerably, particularly through the use of multiple cavities. Multiple-cavity tools are often the ideal solution when high production volume has to be achieved with low item prices. Multiple-cavity means that the form delivers many identical products per cycle. At Schwan Cosmetics Kunststofftechnik this method is used to mold up to 32 parts  in one run, resulting in more than 380 million plastic parts leaving the production facility annually.

Different materials

Customers now also demand a wide range of colors and surfaces. The utilization of different colors is a particular challenge during the manufacture of the plastic components. For the colored plastic components, the company primarily uses typical plastics such as acrylonitrile-butadiene-styrene copolymer (ABS) and polypropylene (PP). 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 0.02 mm. Compliance with the tolerances of all these parts is essential. Their functionality must be guaranteed at all times under different conditions. For example, if a customer wants to apply lipstick, the cap on the lip liner must open and the color core must extend without a problem every time. The quality feature of reliable operation is defined by the required removal force or torque.

The right solution

The demands on a measuring machine are also far reaching. It must deliver the results quickly, be easy to use and be suitable for different measuring requirements. In the end, the company decided to purchase an O-INSPECT from Carl Zeiss. This is also due in no small part to the measuring machine manufacturer’s flexible reaction to the demand for a rotary table. During a pilot contract, a rotary table was delivered for O-INSPECT for the first time. 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.

About the company

Founded in 1855, Schwan-STABILO is now run by its fifth generation. With the first eyebrow pencil in 1927, the company’s expertise in writing utensils was applied to a completely new sector – cosmetics. The company addressed the growing requirements on plastic technology with the founding of Schwan Cosmetics Kunststofftechnik GmbH & Co. KG in 2009 in Weissenburg, Germany. With around 90 employees, the company manufactures elaborate plastic containers for cosmetic articles and develops know-how.