Dossier Parts cleaning – Hype or hysteria
Hot topic cleanliness – or maybe not? Companies across industry are now facing new challenges.9 Sep 2019
There are many reasons for this: new manufacturing technologies, new fastening and coating processes and/or materials, the realignment of whole industrial sectors, shorter product life cycles and smaller production batches, or even one-offs, regulatory changes, the digital transformation, more stringent standards for energy efficiency and climate protection, and not least the evolution in markets. All of this presents new challenges for today’s companies. In order to meet these challenges, existing technologies will have to be updated, while many sectors face the prospect of a disruptive process of restructuring. It is often difficult to predict the effects. But one thing is clear: companies, whether trading in global or national markets, will have to work harder in future to stand out from their competitors by tailoring their products and services to the specific needs of individual markets and sectors, as well as by offering consistently high quality and value for money.
It may not be obvious at first sight, but production processes such as parts cleaning have a key role to play here. Properly cleaned surfaces are vital for the success of follow-up processes such as coating, adhesive bonding, welding and assembly, and in order to guarantee the long-term, trouble-free functioning of systems and products.
A meteoric rise
This becomes clear when we look at the rapid development of industrial parts cleaning, which is a comparatively young discipline. Up until some 20 years ago, parts cleanliness was a minority issue, of interest to only a handful of manufacturing sectors, such as the semiconductor industry. The driving force behind its rise to wider prominence was, and remains, the car industry.
In the late 1990s, innovations such as common rail technology and unit injector systems, which made it possible to increase engine output while lowering consumption and emissions, meant that a large number of drive train components now had to meet defined standards of cleanliness. Also affected were a host of safety-related components, typically used in brake assist systems such as ABS or ESR, in airbags, and in steering systems.
What began as a problem for a few companies became an issue for many as from around 2000: particle deposits in components that can cause malfunctions, or the failure of complete assemblies or systems, in automobiles. These limiting values for cleanliness, often referred to as “residual soiling”, became an integral part of quality control, which in turn led to the development of the first automated microscope systems for particle analysis.
In order to create a uniform standard to facilitate comparison of results, the German Car Industry Association published a manual in 2005, Volume 19, Part 1, which, together with its international counterpart, ISO 16232, laid down guidelines for conducting analyses of component cleanliness. A second, revised edition appeared in 2015. This standard work has established itself as the basis for communication between customer and supplier on the subject of particulate cleanliness – and no longer just in the car-making and automotive component sector, but in many other industries as well.
The rapidly growing importance, in all branches of industry, of component cleanliness, and the consequent need for technical information and practical solutions, led to the establishment of parts2clean as the only international trade fair – to date – for industrial parts and surface cleaning.
Component cleanliness – a universal measure of performance and quality
Companies from across the industry spectrum are increasingly seeing component cleanliness as a key stage in the manufacturing process, creating value and directly impacting on the quality of the finished product. As a result, component cleanliness is now firmly established as a universal measure of performance and quality. Cleanliness testing and analysis, whether carried out in-house or outsourced, is now a standard procedure.
Where it is a matter of achieving specified limiting values for particulate cleanliness, the following principle generally applies: the individual component which is most sensitive to particulate contamination within a closed system determines the degree of cleanliness specified for the complete part or assembly.
This is not always the case, however, and a distinction has to be drawn between metallic workpieces produced by forming or machining, and electronic components. The latter often have to meet much higher standards of cleanliness, which are impossible to achieve following mechanical machining processes – or are only achievable with a great deal of effort and expense. As these components are normally produced at separate locations, and the function-critical areas of the components in question are fully enclosed, and therefore protected, problems with quality do not generally arise.
Markets and industries in transition are creating uncertainty
The car industry, which is still the world’s principal driver and consumer of industrial cleaning technology, is going through a protracted period of steadily accelerating change. The industry’s key markets – Europe, Asia and North America – are evolving in different directions. Europe, and Germany in particular, are facing a number of problems. These include the debate about fine particulates and nitrogen, the uncertainty and lack of direction regarding the power delivery system of the future, a gradual move away from the strategy of remaining open to different technologies, and the consequent abandonment of one of the core areas of expertise, namely a highly evolved combustion engine technology.
Added to this is the decline in personal mobility, particularly noticeable among the younger generation, and not least the question of how to respond to global trends such as autonomous driving and new manufacturing technologies. In China, the car and component supply industry is currently undergoing a technological shift, which is being driven and supported by the Chinese state. The main focus there is on electromobility, while research is going on in parallel into possible new power delivery technologies.
Factors such as environmental and climate protection are also playing an increasingly important role, along with energy conservation and resource efficiency. In the USA, the car market is proving relatively stable. European and Asian car makers have set up their own production plants here.
For these manufacturers, component cleanliness is a much greater priority than it is for US car makers, who dominate this market.
In the so-called emerging markets, component cleanliness is now a growing focus of attention, with the result that standards are not far behind those in Europe. Trade conflicts are adding to the uncertainty already generated by the technology shift that is taking place in various markets. These and other geopolitical events are having a disruptive impact on some established supply chains. What will happen here further down the line, and how markets are going to develop in the future, nobody can say with certainty.
Change as opportunity
Sectors that continue to show healthy growth include medical technology, the semiconductor and electronics industries, the optical industry, sensors and microtechnology, and the coatings industry. All these sectors offer new opportunities for manufacturers – but these also come with new and different challenges when it comes to parts cleaning. The requirements are largely the same as those that manufacturers of precision components have had to meet for some time past. But the general principle that the component which is most sensitive to particulate contamination determines the overall degree of cleanliness required can no longer be applied here. Mechatronic systems are a case in point: these often consist of a machined workpiece, plus electronic components and sensors. The degree of cleanliness required for the electronic components and sensors is frequently higher, or defined differently, than that specified for the mechanical part of the assembly.
Greater focus on surface film contaminants
The requirement for particulate contaminants typically specifies a maximum particle size of a micrometer or less, while specifications for chemical contaminants in the form of surface films are extremely stringent. And depending on the sector and the type of component, cleanliness may also be measured by the gas emissions from volatile, organic and inorganic contaminants, where the maximum permissible values are in the atomic percentage range. In the car industry, higher standards of cleanliness than ever before are now required for certain components, such as those used in the electrification of the drive train and driver assistance solutions, including autonomous driving systems. Here too, surface film contaminants and their removal are an issue of growing importance.
New fastening techniques are also focusing attention on the sometimes ultra-thin coatings left behind by manufacturing and processing operations. Lightweight alloy components, for example, are much more likely to be adhesive-bonded or laser-welded than fastened with screws or bolts, and that necessitates a suitably prepared substrate, at least at the contact face. The same applies to the growing number of plastic components now in use, putting further pressure on manufacturers to achieve higher standards of surface film cleanliness.
Seeing the bigger picture
These developments make it clear that parts cleaning can no longer be viewed in isolation. In order to ensure that detailed and demanding specifications for component cleanliness can be consistently met, irrespective of the workpiece and its intended application, the components must start out in good condition. This means, amongst other things, that previous processing stages, surface finish and deburring must be executed to a high standard of cleanliness. During machining, forming and surface treatment processes, organic matter can be deposited in internal radii, while sandblasting or similar processes can introduce foreign inorganic matter into the supposedly “cleaned” component. In addition, specific environmental and handling conditions can also make a big difference.
If any one of these areas is neglected, the requisite quality standard cannot be ensured. The question we have to ask is as follows: can companies allow themselves to adopt the experience-based processes and solutions of the past, and apply them to the future? There is a considerable risk of becoming uncompetitive in the medium to long term as a result of quality shortfalls or due to the need for costly additional work. So it is essential to look at the process chain and the value-adding chain in their entirety.
However, this necessitates a rethinking not only of the solutions for parts cleaning, but also of all stages in the value-adding chain. Thinking in terms of cost centres – a familiar corporate mindset – no longer works in this situation. Cleanliness becomes a quality factor that affects not only the individual component, but the entire process chain – from source material and manufacturing or processing to the finished product, including the means of production.
Ensuring process reliability
Wet chemical processes remain the most common cleaning technology used, particularly in the metalworking industry, optics, medical technology and other sectors, and this is unlikely to change in the future. So industry is continuing to develop new cleaning and drying processes, and optimizes existing processes. There is also a notable trend towards a combination of processes, such as deburring, cleaning, and drying.
A basic requirement for ensuring the quality, and therefore the successful outcome, of wet chemical processes is to tailor all aspects of the cleaning operation – chemistry, plant and process engineering, process flow – to the particular cleaning task in hand. It is also important to establish clear target values and tolerances in advance, and to check results against these. Continuous process monitoring and process control likewise play an important role. Automating these tasks contributes significantly to process reliability. Another consideration is the need to avoid recontamination of parts once they have been cleaned.
Digitization of wet chemical cleaning processes
Apps and cloud solutions are available for the control and monitoring of wet chemical cleaning plants, as well as for effective production planning and coordination, and these are being constantly developed and refined. The data collected by the control unit are stored, analyzed and intelligently linked. This allows various operations, such as management of cleaning media and exhaust fumes and control of the drying stage, to be controlled automatically. At the same time these solutions make it possible to predict the remaining service life of plant components. In addition, so-called key performance indicators (KPI) such as overall equipment effectiveness (OEE) are also made available by the control unit.
This information is of great value in determining, for example, whether the plant will be able to cope with an anticipated increase in cleaning load. And when combined with augmented reality (AR) technology, it can provide rapid, remote support for maintenance and repair work.
Automated dry parts cleaning
Dry cleaning processes such as air cleaning, CO2 snow blasting, laser cleaning and plasma cleaning are gaining ground in many sectors of industry, whether on the assembly line, to prepare contact surfaces for the application of adhesives or sealants, or prior to packaging. Integration into production and assembly lines is an important requirement here, which in turn makes it essential that the whole cleaning process is automated. In order to achieve high-quality results and cost-effective performance, a cleaning and automation concept precisely tailored to the individual production conditions is required. The digitization of plant and processes is possible to some extent with these dry cleaning technologies too.
Preparing for future challenges
In the present climate of change, forward-looking enterprises will need to engage even more with the specific needs and expectations of their buyer sectors. This will enable them to develop new or upgraded products and technologies. The specification for particulate and surface film cleanliness should be regarded as a product feature like any other, which must be maintained and protected throughout the production cycle. This in turn calls for solutions in industrial parts cleaning that are both future-proof and tailored to the specific spectrum of products and cleaning requirements.
Information direct from the source
But making the right decisions is only possible with a knowledge of the available technologies, processes and suppliers. And parts2clean is the perfect place to survey the market and discover what is available. Because the show covers all areas of industrial cleaning technology, with all the relevant suppliers on hand, it provides ideal opportunities for potential buyers to discuss their specific problems and learn about possible solutions. Furthermore, the various suppliers possess a wealth of experience across the industry spectrum. So they know how things are developing in specific sectors, what customers expect, and what points to look out for. As a result, manufacturers become a benchmark partner and their expertise a crucial factor in the development of processes and process flows.
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