Power blasting technology for dry CO2 blast cleaning

With the new QuattroClean power blasting technology for dry component cleaning, liquid carbon dioxide is compressed into granular cleaning pellets and blasted onto the surface with compressed air. The usual external pellet production required for dry ice blasting is no longer necessary.

Acp Systems has developed the new QuattroClean power blasting technology for production-integrated, dry component cleaning. In this innovative process, recycled, liquid carbon dioxide is compressed into granular cleaning pellets and accelerated with compressed air through a nozzle designed specifically for the application and blasted onto the surface to be cleaned. As there is no need for the external pellet production and the associated logistical effort involved in conventional dry ice blasting, a fully automated, uninterrupted cleaning or deburring process can be realized.

The goal of optimizing energy and resource efficiency is leading to the increased use of dry processes in industrial parts cleaning, which can be used to reliably remove contaminants. At the same time, more and more companies are looking to automate cleaning processes and integrate them into production lines. With the innovative QuattroClean power blasting technology from Acp Systems AG, both can be combined. The newly developed cleaning process makes it possible to efficiently and reproducibly remove stubborn particulate and filmic contaminants from practically all materials and material combinations used in industry, either over the entire surface or partially, using cleaning granulate made from recycled liquid carbon dioxide. The range of applications extends from surface treatment in so-called "cold" bodywork to the removal of welding beads and the fine deburring of medical instruments and high-quality watch components.

The medium is fed into the QuattroClean power jet system from bottles or tanks and therefore has an unlimited shelf life. A specially developed, integrated unit compresses the liquid CO2 into granular cleaning pellets. This represents a decisive difference to classic dry ice blasting, where pellets or dry ice blocks are produced externally and fed into the cleaning system. The continuous, automated media supply of the QuattroClean power blasting system is the essential prerequisite for fully automated, production-integrated cleaning processes.

The macro particles generated by the compressor unit are accelerated with compressed air and blasted through a nozzle onto the surface to be cleaned. Four effects occur when the jet of compressed air with a temperature of around minus 78° C hits the surface: The thermal effect leads to sudden local cooling, and the different expansion coefficients between the contamination and the substrate cause cracks in the contamination. The mechanical effect caused by the momentum transfer results in the detachment of contaminants. On impact, the granulate changes from the solid to the gaseous phase, whereby the volume increases abruptly by a factor of around 600. This sublimation effect creates micro-pressure waves that detach impurities. During the phase transition, the solvent effect also ensures that filmic/organic impurities are removed. The strength of these effects and therefore the intensity of the cleaning jet can be adapted to different cleaning applications and workpieces by adjusting the carbon dioxide flow rate, the compressed air pressure and the nozzle design.

This process flexibility makes the new QuattroClean power blasting technology extremely versatile. For example, the joint areas of car body parts can be partially cleaned and activated automatically for bonding. This is also the case when different materials, such as metal and plastic, metal and wood or different plastics, are to be permanently bonded together. The robust process and a large working window offer advantages compared to other dry cleaning processes such as atmospheric plasma and laser. When it comes to removing adhesive residue after joining, the new process also quickly ensures cleanliness in line with requirements. The preparation of bonding or welding areas and the removal of welding beads are also classic areas of application. For these tasks, lines in which the pre- and post-processing is carried out by a robot are also possible. In the automotive industry and electromobility, cleaning tasks in fuel cell and battery production, including solid-state batteries, are among the other areas of application. The process is also used to automate the cyclical cleaning of DLC coating tools, for example, in order to increase throughput.

The mechanical force of the granulate and the local embrittlement caused by the strong cooling also enables the inline removal of burrs on metallic components such as high-quality watch components and medical instruments. Burrs can also be removed from injection-moulded or machined plastic components, including those made of polyphenylene sulphide (PPS) and polyether ether ketone (PEEK) as well as fiber-reinforced plastics, during mould parting and machining.

Tests in Acp's technical center make it possible to determine the general suitability of QuattroClean power blasting technology for the respective task and to define the appropriate process parameters. Decisive factors here are the cleanliness and/or deburring requirements as well as cycle time specifications. Based on these specifications, Acp Systems implements corresponding system concepts that can be operated as standalone solutions or integrated into production or integrated into interlinked production environments. The recording and documentation of all process parameters ensures complete traceability. (OM-11/23)