Cleaning Solutions for the Automotive Industry
In the automobile industry, component cleanliness is considered quality criteria. The requirements are getting stricter, and the cost pressure is increasing with every new vehicle generation. The automotive industry, as well as its suppliers, are increasingly interested in maximizing the potential of the parts cleaning process.
The automotive industry is putting a lot of emphasis on reducing emissions and fuel consumption as well as improving safety and comfort. Engines that run more efficiently and produce high power are sought after, as well as components with tight tolerances. This is only possible with components that are highly precise, and they also have a higher sensitivity to contamination. Even particles as small as 500, 200, or 100 um, if they land in the wrong spot, can cause failure and damage in the field. In the meantime, automotive manufacturers have started to define particle size distributions in certain functional modules, such as power trains, steering, and brakes. For example, no more than 1,00 particles between 100-200 um, or 500 particles between 200-400 um. To meet and document these requirements in some cases, it is necessary to make large investments in industrial part cleaning technology. Calculations show that the costs of cleaning systems which meet a specific requirement “no particle larger than 1,000um” are up to three times more expensive than those which are used for parts contaminated by larger particles.
Minimising Contamination
In some cases, the question of the potential for economic optimization in the parts-cleaning process is pursued in spite of or even because of the high investment amounts involved. The component design is one approach since the geometry of the part and the steps of manufacturing, such as turning, milling, assembly, and cleanability, are all determined at the design stage. It is the latter that usually has no influence, and it is this which causes problems in subsequent production: parts with corners, edges, or drill holes where particles or processing residues are difficult to remove or impossible.
Contamination is inevitable because the material is removed in the process of chip-forming machining. The amount of particles, chips, and burrs on workpieces is affected by the quality of the cooling fluid and the machining fluid. Suitable purification/filtration prevents previously washed-away contamination from being returned to the component once again.
This can be done by rinsing the tool with a more purified fluid in a separate tank. This may seem like an extra expense at first. It pays off in the long run, thanks to the shorter cleaning time and/or longer bath service life, as well as improved component quality. The residues that are removed by mechanical pre-cleaning, such as vibration, shaking, or spinning the surface of the component, do not put any extra load on the cleaning agent.
When multi-stage metal forming or machining processes are used, intermediate cleaning steps can prevent contamination and the mixing of media.
Cleansing Processes That Are Ideally Laid Out
Modern cleaning systems can meet even the highest demands of component cleanliness, provided the cleaning process is matched perfectly to the contamination, geometry, material, and cleanliness specification.
Only a specific cleaning procedure for each part can adhere to the limit value of “less than 1,000 um”. In order to achieve this, the current state of the art uses a multi-stage process. In the first stage, the workpieces undergo mechanical cleaning to remove some of the machining fluid adhering. In the second step, water is injected under pressure into the cleaning bath below the surface. The whirlpooling effect washes out chips and contamination from hollow spaces, such as threaded holes. The use of water jets that are directed at the openings and lances that advance into holes allows for optimal results in a short period of time. The same applies to high-pressure cleaning and deburring. The drying process is then followed by the rinsing.
The need for flexibility is a result of the many engine and gearbox variations, along with ever-shorter product life cycles. This applies to cleaning individual parts as well. Robotic cleaning systems integrated into production lines are able to achieve this. These robots offer a level of flexibility comparable to machining centers, thanks to the options for easy reprogramming.
Batch cleaning is used to clean large quantities of parts, either as bulk or individually positioned products. These cleaning tasks can also be performed with single- and multi-chamber systems that can be integrated into the production line. Modular design and interlinking options ensure adaptability to individual requirements as well as expansion in line with actual needs.
The container has a significant impact on the final results and economic efficiency of cleaning processes. In this regard, there are two main questions: Are all parts of the container easily accessible for the medium or the washing mechanism from every angle? Can the part be positioned in the container so that the critical areas are treated in a targeted manner?
A requirement for effective cleaning is to remove loosening contamination from the bath so it doesn’t get redeposited onto the parts. To ensure continuous particle removal, a gentle, constant bath movement is needed on one hand, and effective filtration that is matched to actual particle sizes is needed on the other.