Claus Schulz, General Sales Manager, Christian Koenen GmbH
Claus Schulz has been employed with KOENEN GmbH since 2010. Claus Schulz was born in 1976 in Munich. After completing his school education, he started an apprenticeship as draughtsman in civil engineering in 1996, which he completed in 1998. Subsequently, he attended the Higher Technical Vocational School and passed the advanced technical college entrance qualification (1998). In 2000, he completed the basic studies in food technology, and in the following year, he successfully qualified as a Certified Fitness Manager at the BSA Academy. Mr Schulz held senior sales positions at several companies in the consumer electronics industry: From 1999 to 2001, he worked as Account Manager at Siemens/MMS, from 2001 to 2006, he held the position of Key Account Manager at Sagem Communications, and from 2006 to 2010, he headed the Key Account Management and Product Management department at Sky Deutschland. In 2010, Mr Schulz joined KOENEN GmbH where he initially held the position of responsible Director of Sales, Marketing, Purchasing and IT. In addition, he was a member of the Management Team. In January 2015, following the takeover of KOENEN GmbH by Christian Koenen GmbH, he took over functions in the business development area of Christian Koenen GmbH and has since then held the position of Director of Sales of KOENEN GmbH. In December 2015, he was promoted to General Sales Manager of Christian Koenen GmbH. Claus Schulz’s areas of expertise include process optimization and traceability.
Tel.: +49 89 665618 – 165
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Stencil printing allows for the efficient production of any batch size provided the aperture layout has been adapted to the requirements of the product. For small and large product volumes, it is vital to choose aperture ranges that ensure a constantly high print quality from the first to the last substrate. The right stencil options help achieve this goal. The new Application Center with integrated printer line permits practical tests in the line cycle.
Miniaturization & complexity – requirements for manufacturing equipment
Economy despite small Volumes for a high Componentry Mix
When using a good aperture layout, stencil printing can adapt to the current requirements of different designs. Modern stencil options, such as the stepped stencil technology or surface coatings, make it possible to print complex products with a wide range of designs in only one squeegee pass. Cycle and set-up times in stencil printing are low and permit economic production of small and large volumes.
The minimum dimensions of dwarfs like the design 0201 (metric) – not to be confused with the 0201 inch variant that has been known since the late 1990s – place high demands on the stencil quality, the PCB evenness and the cleanness of the printing environment (including cleaning of stencil bottom side in the printer).
Depending on the selected pad dimensions, stencil thicknesses of approx. 40 µm are used for these dwarfs. In this context, it must be considered that, in the normal environment of surface-mounting technology, these sizes can already be reached as a result of unfavourable solder mask application, the population print or particles present on the substrate. This means that just one piece of lint on the PCB might potentially double the paste application at that spot.
In addition, the high paste requirement of large components, such as connector pins, arranged on the same componentry must be taken into account. With increasing functionality of the componentry, the number of pins of the connectors and thus the dimension of the component will also increase. This, in turn, may produce additional challenges in respect of coplanarity and contour accuracy. In this regard, an increase in paste volume helps to prevent faults.
The stepped stencil addresses these requirements by providing the right paste amount for every component. Combined with the right surface finish, such as for example an electro-polished stencil with PLASMA coating, it is possible to directly produce even small volumes without the need for extended proof runs.
Optimal preparation prior to production is crucial in this context. A stable printing process requires a layout that is adapted to the product-specific conditions, and a high stencil quality. Normally, the pad geometry is used as the basis for determining the aperture layout. Current designs without connecting pins or balls, on the other hand, produce solder connections that require a precisely defined solder volume. In these cases, it is no longer sufficient to reduce the circumference of the pad. Often, the right solder volume must be calculated to ensure a secure process. This process requires additional information exchange and an accurate calculation of the paste volume to be used for printing.
Relevant parameters in this regard include: Connection sizes on the component, pad sizes on the substrate, evenness of the substrate surface and additional requirements of the total process. These variables can be used as the basis for the calculation to work out a suggested layout, which will then be implemented in the concrete product. For example, vias in pads should not be printed, meaning that no paste is deposited in these to reduce any problems in the process to a minimum.
The 3D stencil represents the extreme application of the stepped stencil as it permits printing of solder paste on different levels with height differences in the millimetre range. These processes are used where components are countersunk in the substrate, or where PCBs of different thicknesses must be processed together, as these are interconnected by flexible connections.
With proper prior planning, stencil printing offers a stable and accurate solder paste application. It is independent of the volume of the manufactured products and guarantees minimum cycle times. While alternative contract manufacture processes, such as dispensing, offer a better flexibility than solder paste printing, they place high demands on the process knowledge of the system setter. Comparatively low order speeds decelerate the line cycle, high material cost prohibit production of large volumes, and the possible minimum dot sizes make its use for very small designs impossible.
Meticulous prior planning is required to fully exploit the advantages that stencil printing offers. Especially for substrates, it is advisable to analyse the evenness beforehand to ensure that the printing process can be completed without any restrictions. Solder resist, via pluggings or other elevations on the surface may significantly restrict the printing process. If the critical areas are known, these can be left blank in the substrate side in order to minimise, or even completely compensate any effects.
On the printer line of the new Application Center of Christian Koenen GmbH, production conditions can accurately be simulated, permitting precise assessment of the printability. Comparative studies can be carried out in order to assess the effects on the printability of layout changes directly.
Since late 2014, Christian Koenen GmbH and Koenen GmbH share one Managing Director: Christian Koenen. With the reconstruction in Otto-Hahn-Straße 24, the two companies have moved closer to each other under one roof. This has resulted in numerous synergy potentials for both companies. The main beneficiaries are the customers of both companies who can now rely on an even broader process know-how in the area of screen and stencil printing and a strengthened employee base. The Application Center, for instance, is used by the staff of both companies. The laboratory includes three screen and stencil printers. Two of these have been integrated inline with a paste inspection system so that tests can be carried out in production conditions. The process team comprised of customer service consultants and application experts offers assistance and advice in all questions concerning process and stencil.