Case Studies

Automotive & E-Mobility

Ecoclean’s high-efficiency EcoCdry vacuum drier reduces robot cell workload

Improved cleaning for less investment cost

Meeting stricter cleanliness standards within the same cycle time – to meet this requirement repeatably in cleaning diesel engine crankcases, a German automotive manufacturer fitted its robot cells with EcoCdry high-efficiency vacuum driers made by Ecoclean. The units eliminate the need for pre-drying inside the cell, thus freeing valuable cycle time for the actual cleaning and high-pressure deburring treatment.

In the automotive industry, engine and transmission parts are often subjected to high-pressure deburring and cleaning. These operations are carried out in cells affording a high degree of flexibility to process workpieces such as cylinder heads, engine blocks and crankcases to high cleanliness standards within short cycle times. If the requirements on residual contamination are raised, e.g., for a new engine generation, the robot will need more time to clean and debur the part in the cell. Accordingly, additional robot cells will become necessary in most cases since the assembly line timing is set to a given throughput. Such was the situation faced by a major German automotive manufacturer, but the company found a more efficient solution in cooperation with Ecoclean of Monschau.

Cleaning and deburring instead of pre-drying

The crankcases are cleaned and deburred in EcoCflex Classic robot cells. Before each workpiece leaves the cell, it is pre-dried to remove most of the water adhering to its surfaces. To this end, the robot positions the crankcase in front of a blowing device within the cell. This step takes up to 10 seconds off the overall cycle time.

In order to make more meaningful use of this interval “wasted” on pre-drying, an EcoCdry unit was assigned to each robot cell. Ecoclean had developed this highly efficient vacuum drier roughly 1 year ago, along with the new EcoCflex 3 system. This robot cell – successor to the EocCflex Classic – was designed from the start for a drying process performed entirely outside the cleaning machine. The EcoCdry is part of the standard equipment package. However, thanks to its modular design, the vacuum drier can also be retrofitted to existing robot cells.

Dependable drying via effective vacuum technology

Apart from the commonly used vacuum pump, the EcoCdry possesses an additional accumulator vessel in which a vacuum is perpetually generated by the pump. Since the pump runs continuously anyway due to the rapid cycle times used in automotive manufacturing, this feature involves no additional energy consumption but merely makes more efficient use of the power input.

The crankcase is placed in the vacuum chamber by a gantry loader. Next, the chamber is closed and then evacuated abruptly. This creates a vacuum of around 500 mbar within one second. A very strong airflow will form as a result. The water adhering to the part is literally “sucked” off the surface and piped into a tank. For reliable drying of the part, the existing vacuum is then raised to 30 mbar.

Reduced investment

Since the EcoCdry unit easily copes with any residual water adhering to the product, pre-drying in the robot cell is no longer necessary. The German OEM thus gained an additional 10 seconds of cleaning time. These are used to increase the cleaning time of critical crankshaft areas and to focus on the removal of any stuck chips. It is thus possible to achieve more stringent cleanliness standards efficiently without investing in additional cleaning machines. Needless to say, the high-efficiency vacuum driers come at an additional expenditure, too. However, this expenditure falls far short of the cost of an extra robot cell that would otherwise be needed.

*Source: SBS Ecoclean Group.

Non-metallic Components

Use of modified alcohol instead of perchloroethylene for cleaning deep-drawn and extruded parts

Innovative machine technology doubles throughput and boosts cost-efficiency

At SFS intec AG’s plant in Flawil/Switzerland, a need to expand capacity as well as environmental considerations called for the replacement of an existing cleaning system using perchloroethylene. The company opted for an EcoCcore unit tailored to its specific requirements. The new cleaning system supplied by Ecoclean relies on modified alcohol. Thanks to innovative cleaning technology, it doubles the throughput at reduced per-unit costs while further enhancing cleaning quality.

The history of SFS began in 1928 with the Stadler hardware store in the town of Altstätten. Today, SFS Group AG of Switzerland is the global leader in mechanical fastener systems and precision formed components. These items find their uses, e.g., in the automotive, construction, mechanical fastening, electrical, electronics, aeronautical and medical equipment industries.

Cleanliness for safety-relevant automotive parts

Serving the automotive industry and its tiered suppliers, SFS intec AG manufactures cold-formed and deep-drawn components as well as plastic injection mouldings and assemblies, e.g., for airbags, restraint systems, brakes, and active and passive safety devices. The production of these safety-relevant parts takes place at the company’s European headquarters site, as well as in Asia and North America. The plant at Flawil in the Swiss canton of St. Gallen makes deep-drawn and extruded items of various metals, e.g., steel, nickel-plated steel strip, copper, brass, and aluminium. Each of these parts is cleaned after leaving the press. “In the cleaning process, it is necessary to meet the specific customer’s demands regarding particulate cleanliness. And needless to say, the parts must also be free of grease”, explains Markus Stäheli, head of Surface Technology at SFS intec in Flawil. Since the application involves the removal not just of particles, abrasion residue, emulsions and pressing or drawing fluids but also of chlorinated cutting oils, the company used to run a solvent-based cleaning system relying on the use of perchloroethylene (PCE).

Focusing on throughput and eco-friendliness

As the existing system had reached its capacity limit, investment in a new one was needed. Naturally, the new plant was to provide a certain capacity reserve for the future. In addition, SFS intec at Flawil wanted to do away with perchloroethylene in order to improve its environmental performance as well. With this set of specifications in mind, the company contacted three equipment manufacturers of which Ecoclean GmbH finally won the contract. The SFS Group was already using around 25 cleaning machines – including six EcoCcore systems – worldwide from this manufacturer. This innovative solvent-based system with its transparent glass design supports the use of both hydrocarbons and modified alcohols. Operating under a full vacuum, it comes with an extensive standard equipment list which comprises, e.g., two flooding tanks, heat recovery, full-flow and bypass filtration, and various additional features to improve its cleaning performance and quality while cutting per-unit costs at the same time.

Changeover from PCE to modified alcohol

“Ecoclean informed us in great detail about the capabilities of this new system and the use of modified alcohol. We were thus able to attain our objective of improving the site’s environmental performance”, says Markus Stäheli. Nevertheless, removing the chlorinated oils from the product proved a challenge. This was resolved jointly with Solvadis, the chemical supplier, who conducted extensive oil compatibility tests and solvent analyses that yielded a suitably stabilized modified alcohol. At SFS intec, solvent quality is tested regularly using the chemical supplier’s test kit. If necessary, the solvent can be perfectly adjusted again with the aid of a matching stabilizer to maximize its service life. The results were validated through cleaning trials conducted with an EcoCcore at one of the equipment manufacturer’s test centers. „Ecoclean really gave us good support in connection with our switch from PCE to the partially polar solvent”, Markus Stäheli notes.

Superior throughput in volume production

As for the second objective, i.e., boosting capacity to accommodate future growth, the EcoCcore is perfectly equipped for this purpose by design. With a work chamber designed for part containers measuring up to 670 x 480 x 400 mm as standard, it can handle a batch volume exceeding that of its predecessor by about one-third. Accordingly, SFS intec can now combine four (instead of two) of its commonly employed 480 x 320 x 200 mm cleaning baskets to form one batch, thereby doubling throughput. The maximum batch weight amounts to around 200 kg. As for the 670 x 480 x 300 mm part containers also used by the company, a special adapter allows these to be used in the new machine as well.

Tailor-made machine concept

“Apart from increased machine capacity, a slightly shortened cleaning cycle contributes further to the system’s enhanced throughput”, Markus Stäheli adds. This is owing to an EcoCcore engineering concept aimed at delivering high cleaning performance and quality. It includes features such as, e.g., an innovative preliminary steam degreasing step. With this technology, the oil-carrying distillate is not passed into the flood tank, contrary to common practice, but is directed straight into a distillation unit of nearly double capacity. This design minimizes oil deposits in the flood tank while counteracting an oil enrichment of the solvent.

In order to meet SFS intec’s high cleanliness standards, the machine concept was suitably customized. Thus, the unit is equipped with an ultrasonic system in addition to its standard injection flood-wash functionality. As an innovative feature, the ultrasound can be used simultaneously with the filtration function, with the volumetric flow rate being frequency controlled. Particles are thus discharged concurrently as they are removed and cannot settle in the work chamber. Filtration is performed by a bag filter with integrated magnetic separation plus a downstream cartridge filter in the case of flooding tank No.1, while flooding tank No. 2 is served by two cartridge filters.

A further option ordered by SFS is an add-on module comprising a third flood tank for a preservation step. All stainless steel tanks are designed without internal heater fittings, which does away with chip and dirt traps.

Given the floorspace situation at SFS intec, the maintenance hatches are configured as roll-up doors of matching design.

Fully-automatic process

The machine is loaded via a twin-track roller conveyor on which the loads are placed. The operator removes the routing documents for the job and scans their bar code with a reading device. The plant control system automatically selects the part-specific cleaning program and starts it once the door of the work chamber has closed. Due to the great diversity of parts, SFS intec uses around 50 cleaning programs. The various process parameters, such as the times and intervals for the injection flood wash and steam degreasing cycles, the ultrasound power and duration, and the drying operation can thus be adapted accurately to the parts being cleaned. “With cleaning times of between 6 and 9 minutes, we achieve an outstanding cleaning quality with the EcoCcore. Moreover, the cleaning process has definitely become more cost-efficient”, Markus Stäheli delightedly reports.

*Source: SBS Ecoclean Group.

Medical Technology

A comprehensive cleaning solution for „critical“ dental and medical products

Cleanliness adds value in medical equipment manufacturing

Products for use in dentistry and human medicine must meet the most exacting cleanliness standards – e.g., instruments classified as “critical” have to be sterile whenever they are used. In order to supply such items in an already sterilized state as an additional customer benefit, Gebr. Brasseler GmbH invested in a new cleaning and packaging facility that even includes a cleanroom. Around 12,000 different parts undergo in-process and final cleaning in an array of Ecoclean solvent-based cleaning systems and aqueous-type ultrasonic ultra-fine cleaning systems made by UCM AG.

The Komet trademark has its origin in 1923, when the Brasseler brothers founded the factory for dental drills bearing their name. Through innovation, precision and high quality, the company has evolved into a globally active manufacturer of medical instruments and equipment. Apart from instruments and systems for use in dentistry and dental technology, Brasseler GmbH & Co. KG’s product portfolio also comprises rotary instruments for ENT and neurosurgery, arthroscopic shaver blades, and orthopedic surgery items such as saw blades, guide pins, cannulated screws and wires. Moreover, as a contract manufacturer, Komet makes customer-specific products for use in dental implantology as well as high-precision parts for diverse other branches of industry.

Reliable compliance with strictest cleanliness standards

Although its products are marketed in around 100 countries, the company conducts all development and manufacturing at its Lemgo site, relying on over 1,000 employees and around 1,000 production units. „In order to further improve our customer service, we invested in a new packaging concept and a cleanroom of around 250 sq.m. last year. This will enable us to produce up to 10 million instruments in sterile packaging for dental and medical uses each year. Our part cleaning operations had to be fully revamped as well in this context“, reports Helge Neitzel, Head of Abrasive Instrument Manufacturing at Gebr. Brasseler.

Accordingly, high demands were placed on the new in-process and pre-packaging cleaning equipment. Apart from cleanliness, the specification called for high throughput and availability rates as well as for a flawless  technical documentation. Given the diversity of parts and materials – the company produces around 12,000 different items made of carbide metal alloys, stainless-grade and other steels, ceramics and titanium – it was necessary to provide several solvent-based cleaning systems to perform cleaning between the individual process steps. „This allows us to segregate the material flows and hence, to prevent cross-contaminations“, explains Marcus Becker, Cleaning Technology Group Leader at Gebr. Brasseler. Final product cleaning and the cleaning cycle ahead of product packaging in the cleanroom are performed with ultrasonic ultra-fine cleaning equipment using aqueous media. The company also thought it important to source both system types from the same manufacturer.

Cleaning trials and equipment technology tipped the scales

In quest of information relating to eligible equipment manufacturers, the project managers looked around at the parts2clean trade fair. Gebr. Brasseler then performed cleaning tests with six manufacturers. In the end the company opted for Ecoclean GmbH’s solvent-based EcoCbase P2 and Compact 70P cleaning systems. Both models use modified alcohol which removes both polar and non-polar contaminants from the product. Cleaning and drying operations are performed under vacuum, so no additional explosion protection is necessary. When it came to the multi-chamber systems for ultra-fine cleaning, the customer chose the solution proposed by the Swiss UCM AG, a Ecoclean group company. „What mattered to us was the overall package – the advice received, the cleaning test results, equipment design and technology, the service network, and the price/performance ratio. Their offering matched our expectations exactly”, Helge Neitzel justifies his company’s decision.

Reproducible, fast and efficient solvent-based cleaning

Following diverse processing steps such as machining, grinding and coating, approx. 950,000 parts pass the solvent-based cleaning processes in two shifts every day. The control units can store eight cleaning programs each, selectable via a bar code depending on the cleaning step.

For reliable removal of the various contaminants – e.g., machining oil, grease or abrasive residue, chips, particles and chemicals from the galvanizing process – the systems possess two flooding tanks each for the pre-cleaning and main cleaning/degreasing operations. Additional steam degreasing features and ultrasound units ensure that the level of cleanliness required for the next downstream operation will be achieved reproducibly and efficiently. „And all this is performed in short treatment cycles. This is due, on the one hand, to the high vacuum power. On the other hand, the work chamber is filled very quickly thanks to the powerful pumps and large-diameter piping. Indeed, this is a point on which the Ecoclean systems distinguished themselves from competition”, Marcus Becker adds.

Effective reconditioning of the solvent through continuous distillation plus full-flow and bypass filtration likewise contribute to the high cleaning quality. Some filters are equipped with magnetic inserts which improve the retention of metal chips.

Final cleaning with direct transfer into the cleanroom

Among ultrasound-based multichamber systems for ultra-fine cleaning, Brasseler was particularly impressed by the four-sided overflow feature developed by UCM, which is used on all tanks. In every tank, the cleaning or rinsing fluid is introduced from below, moves upwards, and then flows out over the rim on all sides. Foreign matter and particles are thus discharged from the tank without delay. This ensures an intense cleaning treatment of the product while also preventing re-contamination when the parts are lifted out of the bath.

We found this feature on no other manufacturer’s product. A further detail we liked about UCM’s system are the so-called medicinal trays. Due to their special design, they prevent disease agents from accumulating and settling in the trays from where they might then contaminate the parts to be cleaned,” Marcus Becker explains. The quality of the cleaning and rinsing baths is permanently monitored by sensors, even on ultra-fine cleaning processes.

In order to ensure that the segregation of materials achieved at the in-process cleaning level via the use of multiple cleaning lines will be maintained in final cleaning as well, the first cleaning stage comprises three tanks. These are followed by a rinse process, another cleaning step, and three rinsing steps of which the last two are carried out with de-mineralized water. To prevent any re-contamination of the parts in the hot-air drying process, the dryers are equipped with HEPA filters.

The ‘pre-packaging cleaning’ system is virtually identical. Here, the first cleaning step is carried out in a tray, irrespective of product material. In addition to the HEPA filters, laminar flow boxes are fitted above the last rinsing stage and the dryers. Moreover, the cleaning system and its conveyor unit are fully enclosed to ensure the cleanliness of all products entering the cleanroom.

For their intermediate and final cleaning processes, Gebr. Brasseler work with 16 cleaning programs in each case. Programs are selected via a bar code on the product routing documents, which is read by a scanner. „We can combine up to twelve orders in one batch. The control software checks automatically if all parts are to be cleaned by the same program. If this is not the case, an alarm signal is issued and the process cannot be started”, Marcus Becker explains.

Equipment qualification, process development and validation

Except for one solvent-based system, all new cleaning equipment was qualified in compliance with EU and FDA (U.S. Food and Drug Administration) rules and the cleaning processes were validated accordingly. „Ecoclean and UCM cooperated with us in carrying out the necessary DQ, IQ and OQ qualification steps and in preparing the requisite documentation. They also helped us develop the diverse cleaning processes. Actually, the new equipment provides us with cleaning capabilities which exceed our current needs. We consider this an investment in the future, just like the new packaging solution and the cleanroom. It all helps us to further expand our market position,” Helge Neitzel concludes.

*Source: SBS Ecoclean Group.

Precision Optics

Highly versatile ultrasonic system for dependable final cleaning of microstructures

No particle larger than 1 µm

Technological advances in the field of microstructures and the need to process larger substrates called for the installation of a new final cleaning system at POG Präzisionsoptik Gera. The equipment solution proposed by UCM AG won the customer’s approval. It makes it possible to clean both untreated wafers as well as structured and coated substrates. The cleanliness specification stipulating “no particle larger than 1 µm” is reliably fulfilled.

When the Zeiss Works in Gera/Germany were closed down in 1991, a group of former high-level executives led a management buyout to preserve and develop the long tradition of optical manufacturing at Gera, thus marking the birth of POG Präzisionsoptik Gera GmbH. Today, the company has 140 employees. It develops and produces, on the one hand, custom optical precision parts, components and devices for the entire optical range of the spectrum. These items are used by customers all over the world in the fields of mechanical engineering, measuring technology, industrial image processing, medical equipment, laser technology, and the semiconductors and aerospace industries. On the other hand, the company has gained international renown as a manufacturer of both standardized and custom optical microstructures, e.g., net grid and scale graticules, USAF resolution targets, pinhole apertures and calibration targets. In this segment, POG can handle all development and production process in-house. “We recently expanded our fabrication of microstructures in terms of both the range of technological options and the size of substrates we are capable of handling. Consequently, a new final cleaning system was needed”, reports Jan Schubach, one of POG’s managing directors.

Maximum cleanliness is required

POG’s optical microstructures are made chiefly from B 270 glass and quartz glass, as well as from ceramic and glass-ceramic substrates. A final cleaning step designed to remove dust, ultra-fine residue of polishing products and fingerprints is mandatory both with untreated substrates and after adding the structure and coating. Since the structures applied to the substrates measure only 2 µm in some cases, the cleanliness specification requires that no particle should be larger than 1 µm. POG developed a solution for these very exacting cleaning tasks jointly with an external consultant while discussing its technology with various equipment makers.

One versatile cleaning system instead of multiple special types

“We were looking at different cleaning concepts for special uses such as cleaning masks or a specific substrate configuration for the semiconductor industry. In all likelihood, we would have needed three different systems to meet our needs. This prompted us to get in touch with UCM. We already possessed one cleaning system from this equipment maker, and our consultant, too, had gathered good experience with the company in another project”, Jan Schubach explains. Swiss UCM AG, a member of the Ecoclean Group, revised and adapted the equipment concept together with POG and the consultant. “UCM addressed our proposals very flexibly, drawing on their own extensive experience in the manufacture of cleaning systems for optical products”, the managing director remembers.

The new ultrasonic cleaning line comprises a total of eleven stations, including seven immersion tanks. These are designed for the following process steps: wet loading, cleaning with multi-frequency ultrasound (40 and 80 kHz), megasonic cleaning, rinsing, fine-rinsing, infrared drying over an indexing belt conveyor, and unloading.

The wet loading operation and all cleaning and rinsing processes are performed with demin. (fully demineralized) water. Depending on the cleaning program, the rinse water is used in a cascade loop, discarded, or passed to a separate drain. This method contributes to the high cleaning quality, as does the four-sided overflow feature developed by UCM which is used on all tanks. The cleaning or rinsing fluid enters the tanks from below, moves upwards and then exits by overflow on all sides. As a result, foreign matter removed from the product will be discharged from the tanks straight away. This avoids re-contamination during unloading of parts while also preventing the formation of dirt pockets in the tanks. In addition, the substrates are treated very thoroughly and uniformly.

The rinse tanks come with another special design feature. Water is pumped into these tanks at high pressure so as to cause turbulence. This suffices, in conjunction with the product movement, to rinse the substrates without ultrasonic assistance at present. However, the mechanical equipment and control system are both prepared to support a future integration of ultrasound so that the user will be able to respond quickly and flexibly should more exacting demands arise.

Fully automatic cleaning in a cleanroom

The cleaning system is integrated into a cleanroom. The substrates to be treated, measuring up to 10 inches in size, are placed manually in the system’s handling racks in special cassettes. The operator then selects the appropriate part-specific cleaning program. This is stored in the system’s controller and determines which stations will be used in each case and which treatment parameters – e.g., ultrasonic power and frequency, dwell time – should be set for each tank. In order to ensure accurate compliance with the defined treatment duration at each station, the flexible control system supports an input of „priority times“. „We are currently working with 10 programs for the diverse substrates and have been achieving excellent results with all cleaning tasks from the very start. The cleaning system has been operating smoothly since its handover in March 2015. Indeed, we haven’t seen any of the teething troubles usually encountered with such complex equipment”, Jan Schubach notes with satisfaction.

*Source: SBS Ecoclean Group.

Metalworking

Supplier optimizes part cleaning to match changed requirements

Combining the right cleaning system and tank type is key to success

When handling a portfolio of around 1,000 different parts it is no easy task to fulfill growing demands on technical surface cleanliness reliably. In order to meet this challenge, the precision part supplier Allweier not only invested in two new custom-equipped cleaning systems but also acquired a set of versatile cleaning tanks built to match the needs of the cleaning process. Thanks to this combination, the machining contractor meets all cleanliness specifications in a forward-looking and tangibly more cost-effective manner.

In the field of transmission engineering, Allweier Systeme GmbH has been a major player for close to 10 years. Allweier Präzisionsteile GmbH was established more than four decades ago as a vendor and system / development partner for machining solutions. The core competencies of this family-owned enterprise headquartered at Überlingen/Germany, on the shores of Lake Constance, lie in CNC turning, milling and grinding services as well as in module and component assembly. The company owns an extensive pool of highly advanced equipment for machining aluminium parts (including castings) in addition to steels, cast iron, cast steel, titanium, and special materials. Its portfolio currently comprises around 1,000 different items for diverse applications in mechanical engineering, plant construction, automotive manufacturing, conveyor technology and robotics, marine and offshore systems, optical and medical equipment, railways and other sectors. In all, Allweier processes around 20 million parts each year.

Cleaning the machined parts poses quite a challenge, on the one hand, because of the sheer diversity of materials, part geometries and dimensions. On the other hand, demands on the technical cleanliness of surfaces have grown significantly over the last few years. Requirements such as ‘zero particles larger than 600 µm’ are common today, and steel parts need to be perfectly protected against corrosion as well, explains Thomas Schmidt, Technology Planner for Rotary Machining Processes at Allweier Präzisionsteile GmbH. In order to reach the specified levels of cleanliness with due process reliability while boosting the efficiency of the cleaning step in the manufacturing chain, the company invested in two Universal 81W cleaning systems from Ecoclean GmbH plus a set of custom-designed cleaning tanks designed and manufactured by Metallform Wächter GmbH.

Tailor-made equipment for superior efficiency

“We talked to four equipment manufacturers and conducted cleaning trials. Ecoclean not merely gave us excellent advice but also offered the equipment solution best suited to our task”, Thomas Schmidt reports. The Universal 81W has a vacuum-tight working chamber in which its cleaning, rinsing and drying operations take place. Both systems ordered are designed for a basket size of 670 x 480 x 300 mm (LxWxH) and a maximum charge weight of 150 kg. In order to ensure a reliable removal of adhering particles and chips as well as of machining fluid residue, the work chamber is equipped with a high-performance injection flood washing function plus an ultrasonic cleaning system with a power rating of 10 watts per liter of bath volume. The parts are dried by combined hot-air and vacuum treatment. “We also have parts with cavities which often were still moist upon leaving our old continuous cleaning line. Thanks to vacuum drying, these products now come out 100% dry as well”, Thomas Schmidt adds.

The different requirements on cleaning aluminium and steel parts are addressed by tailor-made configuration of the new cleaning systems. Thus, the system for steel parts and steel castings has four flood tanks. This makes it possible to adapt the fluid used in the cleaning step to the given part (i.e., steel or casting). The third and fourth flood tanks hold the rinsing and preservation fluids, respectively. The Universal 81W on the aluminium cleaning line is equipped with three flood tanks. It comprises an additional treatment system for the demineralized rinsing water. The quality of this water is monitored continuously. “With aluminium parts, it is very important to rinse with demineralized water and to ensure quick and complete drying. This ensures that the parts will remain free of stains and discolorations”, the Technology Planner explains.

Around 80 per cent of all parts are cleaned in defined position. Parts are supplied by an automatic feeding system comprising buffer sections at the entry and exit. Appropriate cleaning programs are stored in the system controllers. The part-specific program for each load is selected either by a basket identification system using sensors, or manually by the operator. After the cleaning process the parts pass through a cooling zone from which they emerge ready for immediate packaging.

The fluids from all flood tanks are subjected to full-flow filtration in the supply and return lines alike. While the cleaning fluids are run through bag filters, cartridge filters are used for the rinsing and anti-corrosion fluids. This system yields a highly effective removal of particulate contaminants. Film-type contaminants such as emulsions are removed first by the oil separator and then, for additional cleanliness, by the Aquaclean system. The latter evaporates the fluid from the flood tanks and returns the condensed liquid into the process circuit while collecting the dirt residue in the Aquaclean tank. This fluid treatment method increases bath life while also reducing the equipment outage times necessitated by bath changes.

Versatile tanks, purpose-designed for the cleaning process

In order to realize the full potential of their new systems, Allweier invested in a set of new cleaning tanks at the same time. These allow all parts to be variously arranged inside for maximum cleaning and drying performance. The requirement spelled out by the company to its four candidate suppliers was that all parts had to be protected as effectively as possible in the tank, apart from being arranged and secured so as to withstand rotation. After all, the baskets are swung and turned through up to 360 degrees in the cleaning cycle. Moreover, each tank needed to hold a maximum number of parts without restricting fluid or ultrasound access to the product and hence, impairing the system’s cleaning action. Ease of handling was likewise high on the priority list. „In the first phase we were looking at tanks for ten different parts. With that objective in mind, all companies received the same documentation from us. Metallform stood out among the other vendors as early as in this bidding phase. For instance, they supplied 3D design drawings of the tanks with product arranged inside, so I was able to imagine at once how the part would be placed and fixed in the basket. Their consulting service, too, was and continues to be excellent. All this is backed by plenty of competence and in-depth analysis”, Thomas Schmidt explains his company’s decision in favour of Metallform Wächter GmbH.

In addition to a range of rigid, part-specific product carriers for fast-selling parts, a variety of different semi-flexible and fully flexible solutions were implemented. These are designed to be used for different components or component families at the same time and to be quickly and easily adaptable to another part by the operator while production continues. „Metallform is showing us optimum support in reducing the necessary number of part carriers by providing flexible technology. We derive benefit from this not merely by saving investment cost but also through reduced space demand on the shop floor“, the Technology Planner explains. For instance, the range comprises a part carrier for aluminium annular housings measuring between 240 and 320 mm in diameter and between 20 and 100 mm in length. Relocatable prism-type rake supports inserted into the basic carrier allow different parts to be reliably accommodated and secured. At the same time, the part fixtures can be arranged such as to be in contact with the parts at uncritical points only. For disc-shaped parts of diverse diameters, Metallform developed a fully variable system. It consists of two different inserts of which one defines the number of shelf rows while the other defines their depth. It is thus possible to create a part-holding structure in no time, whether in a MEFO box or in the basic rack. Locking is by means of spring-loaded snap engagement bolts.

All part carriers and cleaning baskets are made of round stainless steel wire with an electropolished surface finish. The round wire makes for good all-round fluid and ultrasound access to the parts. In addition, optimum draining properties are ensured while dirt and fluid carryover is minimized. Moreover, the round wire provides a reduced contact surface area. Local sheathing in clip-on Teflon tube sections for additional part protection is an option.

Superior quality and higher cost-efficiency

This combination of new cleaning systems and tanks enables Allweier to not only reach, but in fact outperform technical cleanliness standards for all parts in a reliable manner. „We carry out periodic laboratory analyses, and these have shown that we are achieving a much better cleaning result. Unlike our previous continuous cleaning line the system requires no compressed air for drying. Moreover, the cleaning process is so effective now that the parts made in three shifts can be cleaned in just around two. So it goes without saying that we are working more efficiently as well“, Thomas Schmidt concludes.

*Source: SBS Ecoclean Group.

Surface Processing

Optimizing pre- and intermediate cleaning of powertrain parts in machining lines

Steam, instead of compressed air, is also efficient with MQL processes

In automotive engine and transmission manufacturing lines, cleaning parts between machining steps is now state-of-the-art practice. Often this is done with compressed air, which needs to be generated at a high expense of energy. One favourable alternative from the perspective of operating costs consists in steam cleaning using Ecoclean’s EcoCsteam system. This solution can also be integrated into production lines for pre-cleaning parts machined by the minimum quantity lubrication (MQL) method. The result will be a tangibly increased bath life in downstream aqueous cleaning.

Minimum quantity lubrication (MQL) stands for a trend that is rapidly gaining ground in the manufacture of aluminium and steel automotive powertrain components. This is hardly surprising, since the ultra-sparing application of a mix of fine oil droplets and compressed air in machining, e.g., crankcases and crankshafts, cylinder heads and connecting rods provides substantial energy savings. It also eliminates the costly and complex functions associated with the supply, disposal, reconditioning and storage of coolants. A further advantage of MQL is that it improves work convenience by avoiding personnel exposure to heavily oil-laden air. In all, the technique provides many benefits underpinning the automotive industry’s advance towards sustainability.

But where there is light, there is also shadow. In MQL processes, the downside lies in part cleaning. The lubricant residue on the workpiece, although minimal in quantity, sticks extremely to the surface, gluing chips and particles in place, as it were. This effect calls for a significant extra effort in the subsequent aqueous cleaning cycle, resulting in a greatly reduced bath life. Instead of lasting four weeks, as is common with machining processes based on standard coolants, the bath fluids must be changed after as little as one week in the case of a MQL process.

This translates not just into higher cleaning costs but also into reduced plant availability. It this therefore only logical that OEM and powertrain part manufacturers should be aiming for a solution to minimize contaminant carryover into the cleaning system so as to prolong the service life of the cleaning bath again.

Efficient pre-cleaning using wet steam

The compressed air systems commonly used for in-process cleaning are virtually ineffective against such slight but highly adhesive contamination. An efficient alternative is to pre-clean the workpieces with Ecoclean’s steam-cleaning system EcoCsteam. It relies on the use of hot wet steam in conjunction with a high-velocity airflow. Since the steam-cleaning operation is easy to automate, the technology can be integrated directly into the manufacturing line as a compact modular system, providing pre-cleaning within the specified cycle time.

Unlike conventional boiler-type systems, the EcoCsteam operates on the principle of flow-through water heating. Water is passed through a pipe system equipped with heating coils which heat it to the optimum temperature for dislodging the MQL process residue. The steam’s moisture content is likewise adapted to the contamination. This special steam generating method not only minimizes water demand to a mere 250 – 300 milliliters per hour; it also provides steam of unchanging quantity and quality, and with constant properties in the cleaning operation. For enhanced cleaning performance, a cleaning agent may be added. The high-velocity airflow serving as a carrier and accelerating medium is produced by a turbo-fan. This causes significantly less operating cost than a compressed air system.
The water and steam throughput, heat input and air flow rates can be precisely adjusted by the EcoCsteam system’s controller and are continuously monitored and adapted by the PLC.

Doubled bath life

In the EcoCsteam process, the transformation of water to steam occurs only at the nozzle outlet. Shrouded all around by the high-velocity airflow, the steam jet is then focused onto the contaminated surface. Upon impact, the wet steam modifies the viscosity of the MQL residue. The latter is atomized into ultra-fine droplets and dislodged from the workpiece surface by the airflow, along with particles and chips. The substances thus removed is fed to an integrated filtration and disposal unit. Here, chips are filtered out and collected in a separate container while the water can be reconditioned or discharged. Alternatively, the steam cleaning module may be connected to the user’s own disposal system.

Tests have shown that, depending on the complexity of the given surface, at least 50% of the adhesive MQL residue can be removed by the steam cleaning process. The carryover of foreign matter into the cleaning system is thus cut by half. As a result, the service life of the cleaning bath is doubled. This leads to a tangible reduction in costs per part: Assuming that 50 per cent of the cleaning costs are expended on the disposal of used fluid as well as on chemicals, water and energy for new baths, the doubled fluid lifetime translates into savings of around 25 per cent per cleaned part.

Advantageous also in intermediate cleaning of coolant-contaminated parts

Optimum intermediate cleaning is also achieved between machining cycles using conventional coolants. Compared to solutions relying on costly compressed air, the EcoCsteam system saves operating costs. In addition, the steam cleaning technology requires less floorspace than a belt cleaning system and distinguishes itself by exceptionally short cycle times. Moreover, the cleaning process is carried out without chemicals, using only water with or without the addition of an optional corrosion inhibitor.
As an invariably clean medium, steam also opens up a number of further application options in the production of power train components. One example is the spotless cleaning of polished surfaces, e.g., of crankshafts or camshafts, prior to their visual inspection by an automatic optical image recognition system.

*Source: SBS Ecoclean Group.