Cleanliness in the submicrometer and atomic percent range

For integration into a cleanroom, the ultrasonic precision cleaning systems are equipped according to the cleanroom class. (Image source: UCM / Gebr. Brasseler)

By combining wet chemical and low-pressure plasma cleaning for fine degreasing in a system, the surface values required for subsequent coating or bonding can be achieved efficiently. (Image source: Ecoclean)

The various treatment stations of the application-specific ultrasound precision cleaning systems can be accessed flexibly, and defined processes can be prioritized. (Image source: Philips Medical Systems)

In the specially developed immersion spray rinses for fine cleaning, the parts are sprayed when pulled out, which improves the rinsing effect. (Image source: Zeiss)

New and further developed products lead to very high cleanliness specifications in many industrial sectors. Similarly, changes in manufacturing, assembly, and coating technologies, as well as stricter regulatory requirements, result in more demanding requirements for particulate and film cleanliness of components. To reliably and efficiently meet these values in series production, not only need demand-oriented cleaning and drying processes as well as suitable plant technology be implemented, but also the software implementation and the cleaning environment must be appropriately adapted.

Whether production equipment for the semiconductor industry, biotechnology, laser and sensor technology, devices for measurement and analysis technology, components for batteries and fuel cells, optical systems, or machine tools, the requirements for performance and reliability of the products are extremely high. This results not only in high demands on the manufacturing precision of the components but also on their cleanliness. For medical technology products such as implants, instruments, cannulas, and endoscopes, particulate and film contamination from manufacturing processes are a key criterion due to stricter regulatory requirements. Additionally, there is a trend toward miniaturization and functional integration with ever smaller and more complex components. These developments lead to particulate cleanliness specifications in the micro- and nanometer range, as well as very strict requirements regarding residual film contamination in increasingly many industrial sectors. Application-specific limits are also set for outgassing rates of organic substances and residual moisture, as well as for surface analyses for residues of prohibited substances, down to the atomic percentage range. Furthermore, in the production of these miniaturized parts, there is a trend toward larger, integrated manufacturing modules. This also presents new challenges for cleaning processes and the necessary plant technology.

This results in very demanding tasks for component cleaning, which extend across the entire manufacturing chain. As a complete provider of future-oriented solutions, the companies of the SBS Ecoclean Group cover the entire spectrum of precision and fine cleaning. This enables the adaptation of cleaning processes, their software control, equipment, and environmental conditions to the respective requirements and applications.

The right plant concept

When selecting the appropriate cleaning system for the specific task, the first consideration is whether a pre-, intermediate, or final cleaning should be performed. Depending on the application and the cleanliness requirements to be achieved, the solution can be a chamber or inline immersion cleaning system, a flexible ultrasonic inline immersion system based on standardized modules, or a custom-designed ultrasonic fine cleaning system. Cleaning chemistry as well as the optimal process technologies, such as spray, high-pressure, immersion, ultrasonic or megasonic cleaning, plasma cleaning, injection flood washing, Pulsated Pressure Cleaning (PPC), and, if necessary, passivation/conservation, are also matched to the application and the contaminants to be removed.

Cleaning processes and systems for the highest purity

The core competence of the Swiss company UCM AG lies in the design of individually configured ultrasonic multi-chamber systems and processes for fine cleaning. Key factors include the material and geometry of the parts to be cleaned, the type and amount of contaminants, the particulate and film cleanliness specifications to be achieved, as well as permissible outgassing rates and maximum residuals of prohibited substances in the atomic percentage range, if applicable. Particular attention is also paid to selecting suitable cleaning chemistry and media supply, such as the use of osmosis or fully demineralized water. The materials and manufacturing processes used for constructing the cleaning system and transport automation are chosen with regard to avoiding dirt formation and re- and cross-contamination. Cleanroom-compatible equipment and integration into a cleanroom environment are also feasible.

Standard features of systems for precision and fine cleaning include multi-frequency ultrasonic systems, which allow flexible adjustment of the frequency and intensity of ultrasound to meet the requirements of different parts. For complex components, capillary structures, or porous surfaces, such as those produced by sintering or additive manufacturing technologies, the PPC process is additionally employed. Features such as multi-sided overflow in all cleaning and rinsing chambers, as well as specially developed immersion-spray nozzles for fine cleaning, help ensure very high cleanliness specifications are reliably met.

The determination of which cleaning and rinsing systems to use with which parts, as well as the process parameters specific to the component such as temperatures, ultrasound power and frequency, PPC intensity, dwell time in various cleaning and rinsing chambers, is carried out during process development. Drying is usually implemented as infrared and/or vacuum drying, depending on the complexity of the component and its heat absorption capacity. The resulting part-specific cleaning programs are stored in the system control. An important role is also played by the software implementation of the cleaning process. It ensures, among other things, that the specified dwell times in the cleaning and rinsing tanks are precisely maintained and that prioritized procedures, for example for very sensitive components, can be carried out.

The choice of plant and process solution that offers the best balance of cleanliness and cost-effectiveness can be determined through cleaning trials in the precision technology centers of Ecoclean and UCM using original parts.