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New "ONSERT" joining method saves energy
Industrial applications use a great variety of techniques to attach elements to sheets. Welding of threaded studs is extremely rational and enables a high degree of automation as expensive drilling and screwing or riveting can be avoided with this method. However, stud welding reaches its limits where the thickness of the sheets to be connected is below 0.5 mm or welding is impossible for other reasons. At this point, stud bonding comes into play as an alternative joining method. This method was jointly developed by the adhesive manufacturer DELO together with Böllhoff, a group specializing in fastening and assembly technology.
Application areas of threaded studs
Welded studs are used where fastening elements are irremovably joined to a metal carrier. The areas of use are versatile. Welded studs can be found in many objects of everyday life, begun by car body panels over housings of household appliances such as washing machines or cookers up to shipbuilding or aircraft construction. For stud welding, an arc is ignited between the face of the stud and the component. Both surfaces are locally melted and then joined under low pressure (see fig. 1). Depending on the welding technique, studs are welded to sheets with a thickness down to 0.5 mm. The component must be accessible from one side only. A great variety of stud shapes is conceivable, such as threaded studs, pins, tapped sockets, hooks, loops and special welding elements adapted to the specific fastening task. Advantages of this technology include high loading capacity as the complete area is welded, high productivity thanks to short welding times and high potential for automation.
Especially in the automotive industry, more and more sheets made of high-alloyed steel are used for reasons of weight reduction. As these steels give high strength, sheet thicknesses can be reduced to a great extent. Even capacitor discharge stud welding reaches its limits at a wall thickness of 0.5 mm. Sheets with this thickness and below cannot be welded anymore. Furthermore, the spot weld emerging on the opposite of the sheet impairs the appearance, especially when joining components with visible faces. Therefore, welding is often not possible for appearance reasons. In addition, the use of this welding technique is restricted to non-lacquered metal components.
Setup of bonded studs as an alternative joining technology
If it is not possible to weld the studs for the reasons stated earlier, they can be replaced by special connection elements that are bonded to the substrate. The adhesive manufacturer DELO, together with Böllhoff, has developed a new technology in the form of the special ONSERT method. The fastening elements are initially molded with a transparent plastic so that the bonding area is accessible to light. The reason is that the adhesives can be light-cured through the fastening element within a few seconds if short cycle times are predetermined in production. The bonded studs combine the advantages of weld studs, such as a high degree of automation, short cycle times and high loading capacities with the possibility to bond sheets with a thickness below 0.5 mm and non-metal light-weight materials. In addition, the components do not emerge at the visible faces unlike elements welded to the sheets. Therefore, this joining method is also suitable for components that have to give an attractive appearance.
Energy consumption in comparison
Another plus is that bonded studs require significantly less energy as no material must be melted. For adhesive curing, light with a wavelength of 400 nm, provided for example by LED lamps, is sufficient. In order to weld a stud with a thickness of 6 mm and a circular projection to a zinc-plated sheet with a wall thickness of 1 mm, an effective welding current of approx. 18 kA is required at a resulting voltage of 2 V and a welding time of 100 ms. 3.6 kJ are effectively implemented. For resistance welding, a typical efficiency of a factor of 0.53 kJ is indicated. This results in an energy demand of 6.8 kJ per stud. For comparison, the total power consumption was measured for the use of bonded studs and the DELOLUX 80 curing lamp including cooling system. The power consumed amounts to only 117 W at an amplitude of 100 %. The energy required for a normal irradiation time of 5 seconds is therefore only 0.6 kJ per element.
The technology of bonded connection elements is used where welding technology is impossible for reasons of thin sheets, requirements on the appearance, or the material combinations used. When using light-curing adhesives, it is possible to bond a connection element in just seconds. Therefore, this technology is particularly suitable for automated processes with short cycle times. On top of that, the ONSERT technology has the upper hand as to the significantly more efficient energy balance. Welding an element requires elevent times more energy than bonding it with a lightcuring adhesive.
DELO builds new pilot plant and expands laboratory building
High construction cranes are shaping the Windach landscape. They show that something is going on at DELO. At the moment, the laboratory building is being expanded. A U-shaped complex is developing that matches the existing buildings in terms of architecture. DELO is steadily growing as shown by the sales volumes achieved in the past years. Therefore, more capacity is required for personnel. Another 60 people or more are yet to be employed this year. These are supposed to be accommodated in the new laboratory building in addition to R&D and Engineering staff. Unlike the existing building, the new complex has a full cellar and an extra floor. Offices for a total of approx. 130 work stations are to be provided on three floors.
Already in August, the building of the new pilot plant for chemical synthesis was completed. All in all, building took nearly one year including interior fitting. In the new chemical production plan, own raw materials and primary products will be developed and produced in the future. The Chemical Foreman for R&D explains that a closed mixer with a usable volume of 300 liters is used for production in the pilot plant. This mixer is fully automatically controlled via a process control system. In addition, it would be possible to expand to five mixers with a total volume up to 2,000 liters when necessary. The ceremonial opening of both, laboratory building and pilot plant, will probably take place in spring 2012.
DELO adhesives in electric motors
Company HANNING ELEKTRO-WERKE produces electric motors individually adapted to the customer's needs. HANNING uses DELO-ML adhesives to bond the ball bearings in the motor housings.
HANNING ELEK TRO-WERKE in Oerlinghausen, Germany, looks back on six successful decades in electric motor manufacture. Application areas of the motors include centrifuges, industrial door drives, vacuum pumps, drain pumps for washing machines and dishwashers, and adjustment drives in hospital beds and treatment tables.
Meanwhile, bonding is prevailing over screwing, riveting and welding as an essential constructional element in mechanical engineering, especially in the field of electric motors. To join the materials used in this field, DELO has developed special adhesives. These have properties that are adapted to miscellaneous applications and requirements.
HANNING also uses DELO-ML adhesives to bond ball bearings in dissimilar bearing shields of special motors. These onecomponent adhesives are anaerobic and cure under exclusion of oxygen within a short period of time. They are well resistant to elevated temperatures and chemicals, and give high strength after having completely cured.
The adhesive is applied by rotor spray. In this method, the adhesive is sprayed onto the component through rotation. Thanks to this controlled application, the components to be bonded inside the motor are only thinly wetted with DELO-ML. The DELO-ML product family offers special adhesives with matching properties for any motor design.
Company HANNING ELEKTRO-WERKE in Oerlinghausen, Germany, has been establishing itself on the global market as a drive specialist for customer-specific drive components and systems. About 1,500 employees develop, produce and sell individual drive components at five locations in Germany, Lithuania, China and India. Great importance is attached to a wide but nevertheless specific product range that finds use in a great variety of industrial fields. Therefore, the company is subdivided into three business areas: drive technology, equipment technology and adjustment technology. HANNING ELEKTRO-WERKE does not only have technical know-how. The advantage is that comprehensive knowledge of the industries, in other words detailed knowledge of the needs and conditions of the user industries, is made available to the customers.
Three market divisions
Disparate motors with outputs up to 7.5 kW with associated electronic systems and software, as well as frequency converters are the core products of the drive technology division. Drain and circulation pumps for industrial dishwashers and washing machines, synchronous drain pumps for the household appliance industry, and motors or fans for heating, ventilating or drying are the focus in equipment technology. The adjustment technology division develops and produces adjusting devices and spindle drives that are mainly used in dental chairs, operating or x-ray tables but also in industrial applications. Each division works like a company within the company, with own development, production and process control departments and an own, specialized sales department.
DELO develops new LED area lampsDELO strengthens its lamp portfolio by DELOLUX 804 and DELOLUX 806.
The DELOLUX 804 and DELOLUX 806 curing lamps allow fast and even curing of the photoinitiated-curing DELO-KATIOBOND, DELO-PHOTOBOND and DELO-DUALBOND adhesives. Thanks to their optimized radiation profile in longitudinal and transverse direction, DELOLUX 804 and DELOLUX 806, or a combination of both, are suitable for casting smart card modules and can also be used in lamination processes. These curing lamps are offered in two dissimilar lengths (DELOLUX 804 in 460 mm and DELOLUX 806 in 690 mm), and in dissimilar wavelengths (365 nm and 400 nm).
DELOLUX 804 and DELOLUX 806 can be perfectly combined as a result of the new lamp geometry. By arraying several lamps, it is either possible to reduce the cycle time of the production process, or to vary the width of the laminated fi lms. Advantages of both area lamps include that they are easy to integrate into production processes.
DELOLUX 804 and DELOLUX 806 are based on the mature technology of DELOLUX 80 that has already proven to be highly effective. At the same time, the lamp design is genuinely innovative. As in DELOLUX 80, the lamp heads are liquid-cooled. In general, LED curing lamps have clear advantages over classic discharge lamps. They can be switched on and off as often as required, have a long lifetime of more than 20,000 hours under normal operating conditions, and deliver consistent process parameters.
REACH and GHSThe fundamental reform of the European chemicals legislation – the special REACH Regulation – has already been in force for a few years. Now it is time to implement the "globally harmonized system", or GHS for short, which is a method created by the UN to classify and label chemicals. We talked to DELO's expert for chemicals legislation about the development, the current status and the future of REACH and GHS:
What is understood by REACH and GHS?
REACH stands for 'Registration, Evaluation and Authorization of Chemicals'. Apart from a few exceptions, all substances must be registered within the framework of REACH. In addition, comprehensive physical and toxicological data must be provided. GHS and the European interpretation, the special CLP Regulation, strive for a globally uniform or harmonized classification and labeling of chemicals. It is expected that such a harmonization will involve facilitation for the continuously globalizing economy.
What is the current situation?
The first REACH registration period for large-volume and substances of particularly high concern already expired at the end of 2010. The next periods for substances down to more than 1 ton per year will expire in 2013 and 2018. GHS is currently being implemented in many countries. We are already receiving the first raw materials labeled as being compliant with GHS.
How does global implementation work?
REACH as well as GHS are very complex and are being implemented at the moment. GHS is some kind of modular "buildingblock system". Each country can pick out the individual parts to be implemented. This doesn't make global harmonization easier, of course. This difficulty is compounded by the fact that the countries determine the point of introduction themselves. For mixtures, some countries such as China demand GHS-compliant labeling already this year. This is of particular interest to DELO, being a formulator of adhesives. In Europe this regulation will be binding as late as 2015.
What experience have you at DELO had with REACH and GHS so far?
No problems occurred during the preliminary registration phase of REACH. Furthermore, the first registration deadline was met without any difficulties. At the moment, special focus is on exposition scenarios as supplements to material safety data sheets. These scenarios are supposed to summarize comprehensive information on the entire lifecycle of substances. Standardized "descriptors" specify who (user) uses what (product) in what way (process), and where the product remains (for example, environment). Our suppliers already provided us with the first extended material safety data sheets with exposition scenarios. Some of them are substantially comprehensive and may comprise 100 pages or more. For DELO as a formulator the question is how to deal with it as the authorities haven't made available any practicable guidelines yet.
What is positive about the introduction of REACH and GHS?
In general, enhancing the knowledge of chemicals (by REACH) and global harmonization (by GHS) are of course positive. Apart from the major issues and uncertainties that are associated with both regulations, there are reasonable improvements. For example, thanks to REACH important information on the hazard potential can now be found on the first page of the material safety data sheets. Nevertheless, it must be said that, regardless of how promising and reasonable the concept behind REACH may be and how good "globally harmonized" in GHS may sound, there is still a long way ahead to implement the regulations. Much too often, theory and practice are two completely different animals.
What does the future hold?
DELO watches the developments with great interest. It is of the utmost importance to be always well informed. This is how we can make sure that you we prepared for possible surprises, that is to say amendments. In connection with REACH, a watchful eye is kept on the further amendments in the field of exposition scenarios and the list of SVHC candidates. This list is currently including 53 substances and we fulfill all requirements. The next two registration periods are also interesting. It remains to be seen whether DELO will be faced with major changes. As in the past, we will still be able to ensure the availability of raw materials, and therefore the security of supply of our DELO products.
Top 100 – 100 companies on the road to success. DELO is one of them!
DELO obtained a top rank in the "Top 100" innovation awards. The Vienna University of Economy observed the innovation behavior of a total of 272 German SMEs over a period of several months. The 100 best of them, including DELO Industrial Adhesives, will bear the seal of quality for one year.
Sabine Herold commented the award: "For us, creative ideas and fresh thinking are not only a means of sales increase. We are also passionate about this subject and want to make things happen. This award makes us proud and shows that it is worthwhile pulling together."
DELO is Germany's Customer Champion 2011
In a customer survey conducted by the independent forum! market research institute, DELO could clearly stand out from its competitors in the fields of reliability, professionalism and flexibility. Therefore, DELO can now call itself "Best Medium- Sized Industrial Business".
The award was given to Christian Walther, Sales Director at DELO, in the scope of a ceremony held in the Electoral Palace Mainz on May 10, 2011. Sabine Herold, Managing Partner, together with the entire company highly appreciated this honor and recognition.