Not a single fingerprint remains

If subsequent processes or product functions require it, component cleaning is shifted to the cleanroom. Developing a suitable system for this requires all sorts of design tricks and finesse. One mechanical engineering company has chosen dry snow blasting technology for these applications.

In industries such as medical technology, pharmaceuticals and optics, sensor, laser and measurement technology, or the semiconductor supply industry, as well as electronics and microtechnology, parts and components must meet increasingly stringent specifications for component cleanliness. As a result, there is a growing need to relocate cleaning processes to clean and pure environments. This is because even particulate contamination in the submicrometer range can severely impair process and product quality, as can very small filmic chemical residues, stains and fingerprints. In order to solve these cleaning tasks reliably, scalably, stably and economically, appropriately adapted equipment is indispensable. Such a cleaning solution is offered by acp systems AG, a technology provider for advanced clean production including process automation and system integration based in Ditzingen, Germany.

The new JetCell-HP is a cleaning cell designed for cleanrooms with dry quattroClean snow jet technology. The compact and digitally controllable solution enables a wide variety of cleaning tasks to be performed automatically in standalone mode or inline. Cleaning is performed dry with climate-neutral carbon dioxide.

The compact cell for flexible automated production is made entirely of stainless steel with smooth, homogeneous surfaces without external screw connections. The cell can be easily integrated into a linked production line or operated as a stand-alone system. All equipment components and materials are designed for cleanroom applications. For example, removed impurities and sublimated carbon dioxide are continuously discharged by the integrated exhaust system. The flow-optimized design of the process chamber ensures that this is done in a targeted and rapid manner. Recontamination of cleaned parts can thus be prevented just as effectively as the formation of dirt nests.

To ensure consistently good cleaning results, the JetCell-HP is equipped as standard with a sensor system that continuously measures the snow jet density. The digitally controllable cleaning system can be easily integrated into and controlled by higher-level host computers via standardized interfaces. For complete documentation and traceability, all process parameters, such as CO2 and compressed air supply as well as blasting time, are automatically recorded and transferred to the host computer.

Decisive for the good cleaning effect of the quattroClean system from acp systems is the design of the wear-free two-substance ring nozzle through which the liquid carbon dioxide is passed. When leaving the nozzle it expands to fine particles. They are focused by a separate compressed air jacket jet and accelerated to supersonic speed. When the easily focusable cleaning jet impinges on the surface to be cleaned, the four mechanisms of action (thermal, mechanical, solvent and sublimation effect) ensure that particulate and filmic chemical contaminants are reliably removed.

The crystalline carbon dioxide sublimates completely during cleaning. The surfaces/parts are therefore dry and can be fed directly to the next production step. Cleaning is gentle on the material, so that even sensitive and finely structured surfaces can be treated.

The scalable quattroClean process can be easily adapted to different component geometries and enables both partial and full-surface cleaning. The process validation and design are carried out customer and application specific by tests in the technical center of acp systems AG in Ditzingen. The process parameters determined in this way can be stored in the JetCell-HP controller as part-specific cleaning programs.

In addition to the control system, the complete technology for the snow blasting process and the media preparation are integrated in the system housing. For commissioning, therefore, only electricity, compressed air and carbon dioxide from bottles or a tank need to be connected.

acp systems AG www.acp-systems.com