Dear Readers,
With growing interest and expansion in Asia, our quarterly DELO-Newsletter for Asia informs you about the latest trends around bonding technology. If you wish to receive our Newsletter regularly, please send a short e-mail to newsletter@delo.de or just click on "reply". Please contact our DELO Representative Office in Singapore at +65 6562-8013, singapore@DELO.de, for any queries.
Meet us! DELO at trade shows worldwide You can find all exhibition dates at http://www.DELO.de/en |
|
Reliable bonding of automotive cameras
New mCD adhesives for temperature-sensitive materials
Car with front camera Camera-based driver assistance systems in cars are experiencing an upswing. The electronic eyes help drivers of many limousines, such as the E-class or the BMW 7 series, park, keep the car within the lane, and maintain a safe distance from other vehicles. 360° cameras will continue being in particular demand. They can reliably detect pedestrians and warn the driver in time. New technical innovations in the field of automotive cameras also create increased requirements on the individual components used for a camera. The utmost quality and reliability in terms of lens quality and pixel density are demanded. At the same time, the suppliers depend on producing as cost-effectively as possible for the automotive market as competition is tough. This is where high-tech adhesives come into play. Even if it is often only a very tiny drop, adhesives are already used in millions of cameras. They ensure that certain components of the automotive camera are reliably bonded and therefore working properly. Adhesives are required for a great variety of components. They bond housings, sensors to printed circuit boards, or lenses.
Adhesives for sensitive materials
The materials used in automotive cameras are mostly sensitive to elevated temperatures. "The previously used adhesives often required elevated temperatures to cure reliably", explains Marc Schwarz, Process Manager at DELO Industrial Adhesives. "But high temperatures may be a problem for temperature-sensitive components. With our newly developed mCD adhesives, we close an important gap." The advantage of these adhesives is that they are low-temperature curing at +80 °C. Therefore, they lend themselves for temperature-sensitive materials and are ideal for fast processes with high output as they cure within a very short period of time. The adhesive range developed in DELO's labs meets numerous requirements. They give high adhesion to disparate substrate materials, such plastics as PC, PA, PBT, ABS/PC, LCP, PPS, and also glass, ceramic and FR4. This method is used to bond, for example, compact camera modules such as image sensor chips to PCBs, or housings.
Use of DELO-DUALBOND for active alignment
In particular, the low-temperature-curing adhesives like the dual-curing DELO-DUALBOND are used in the "active alignment" process. The issue here is to balance tolerances of optical assemblies and sensors in production with the help of multi-axis active alignment. Optical components like mirrors, lenses, or prisms are aligned on the substrate during fixing by means of the adhesive. The adhesive must remain liquid during alignment. As soon as the component has obtained the correct position for optimal image quality, the adhesive is quickly lightcured within a few seconds. Afterwards, the adhesives have achieved sufficient initial strength to keep the components fixed in the desired position for subsequent final curing by heat at only 80 °C. This ensures that adhesive in shadowed areas is also reliably cured. In contrast, purely UV-curing products can often not be completely cured. In addition, uncured adhesive would lead to reduced reliability and increased waste rates in the production process. In particular, as long as the adhesive is liquid this results in outgassing. Fast preliminary fixing with UV lights eliminates long curing times. That means that the customer benefits from short cycle times, high output, and low-temperature curing when using temperature-sensitive components. It is important that the adhesive shows only low shrinkage so that the correct position of the component is maintained. The new DELO-DUALBOND adhesives are characterized by low water absorption and low shrinkage. "At the same time, no decomposition products may condensate on the optical elements. Furthermore, no corrosion may occur on surrounding electronic components", adds Marc Schwarz.
Comprehensive testing
The adhesives were thoroughly tested. The tests performed include durability tests and aging tests, like the special 85 °C / 85 % r. h. test over a period of 1000 h, as well as various shrinkage tests. The results prove that the adhesive completely meets all requirements. DELO has developed a specifically tailored LED lamp range that is ideal to cure the mCD adhesives. In the field of compact camera modules, DELO Industrial Adhesives works together with machine manufacturers all over the world in order to jointly develop trendsetting solutions.
Advantages
|
|
Order further information on the adhesives: marcom@delo.de |
|
The active alignment processFast processes in switch production
Sealing of soldered contacts of push buttons Automotive microswitches are sealed by DELO adhesives. The challenge is to bond the housing to the bottom while sealing the connector pins. Automotive applications with high production volumes and high quality demands require fast and in-line capable bonding processes, that combine short cycle times with reliable process control. Radiation-curing adhesives meet all these requirements, with their simple dispensing and fast curing.
"Process reliability is especially important in customer applications", explains Bernd Ebenslander, Sales Engineer at DELO Industrial Adhesives. "The microswitches are used in safety-related assemblies, such as airbag deactivation switches or control systems for belt buckles." At the same time, the process must be suitable for very high production volumes and must enable short cycle times.
This challenge was met by the use of the low-viscous and fluorescent DELOKATIOBOND KB554 adhesive. It is filled into the cavity of the component from two sides in just one cycle. The adhesive's constant viscosity and unchanging flow behavior ensure complete wetting and sealing without capillating into the housing gap. In the next machine cycle, the adhesive is cured within one second by a microwave area lamp. The adhesive contains a fluorescing agent for fully automatic adhesive coverage monitoring by a camera system.
Using this technique, missing adhesive or contaminations at the connector pins of the component can be reliably detected. Irregularities, such as may be caused by dispensing problems, are automatically detected a few seconds after curing, and remedial steps can be taken immediately. This contrasts favorably with heat-curing adhesives, were such failures can often be detected only after oven curing, by which time many rejects have already been produced.
Pin casting for short-stroke keys
Another application example is pin casting for the short-stroke keys used in membrane keypads and operator panels. The connector pins of these keys must be bonded into the PBT housing and sealed against ambient influences at the same time. The hardness of the adhesive has a major influence on the haptics, in other words, the switching behavior of the key. In the past, a one-component heat-curing epoxy resin was used. This required a long oven line for adhesive curing, with accordingly high space requirements and energy costs. By eliminating the tunnel oven, the use of DELO-KATIOBOND 4571 adhesive permits cost-neutral integration of light-curing bonding technology into the existing production line. In addition, cycle times are substantially reduced by this radiationcuring epoxy, since irradiation time to initial strength is just 5 seconds. Narrow adhesive viscosity limits enable constant flow behavior. At the same time, the yellowbrown color of the adhesive allows easy and fast application control. Tests show that the adhesive is also suitable for subsequent lead-free high-temperature soldering processes.
DELO increases sales by nearly 40 percent
DELO Managing Partners Dr. Wolf-Dietrich Herold and Sabine Herold
DELO Industrial Adhesives recorded total sales revenues of EUR 41 M at the end of the fiscal year on March 31, 2011. This represents a disproportionally high increase in sales by 37 percent over the previous year. DELO remains committed to further expansion of business to drive future growth. The company is currently building a pilot plant for the synthesis of raw materials, and a new laboratory building.
"We experienced tremendous growth in the past fiscal year", says Dr. Wolf-Dietrich Herold, Managing Partner at DELO. With total sales of EUR 41 M, DELO recorded an enormous increase in sales over the previous year (fiscal year 09/10 sales: EUR 30 M). "In view of the company's very positive development, we invest in our future by building a pilot plant and another laboratory building", adds Dr. Herold.
International growth
"The increase in sales by 35 percent in our home market in Germany is very encouraging", says Dr. Wolf-Dietrich Herold. Sales abroad could be increased by 38 percent and now represent 57 percent of total sales revenues. Growth was mainly achieved in Asia. Sales increased by 38 percent. Sales growth in China amounted to 40 percent, and in South East Asia to 38 percent. "Innovation industries such as display technology, photovoltaics and the RFID sector experienced strong growth," says Dr. Herold. Business also went well in the USA. "We grew our sales by 290 percent," adds Dr. Herold. Already in 2008 DELO founded its own US subsidiary, DELO Industrial Adhesives LLC. This was further expanded in the past fiscal year, and additional sales staff from Germany was added.
More staff
The company's growth is also reflected by the number of employees. Today, DELO employs a total of 260 people (FY 09/10: 230 employees). Most new people were employed in the divisions of Engineering and Sales. DELO is planning to hire about 60 further employees in Germany and abroad in the coming 11/12 fiscal year.
Focus on Germany as a location
DELO is still committed to Germany as a business location. The company located in Windach near Munich is currently building a pilot plant on which they will synthesize own raw materials in the future. On top of that, the construction of a new laboratory building already started. Completion is scheduled for 2012. Production and development of the high-tech adhesives for a wide range of industries, including automotive supply, microelectronics as well as card and display industry will remain in Windach. Furthermore, DELO employs sales engineers all over the world and cooperates with a wide network of sales partners.
Black Dam&Fill encapsulants
Black encapsulants for smart cards
Ideal for the smart card industry
DELO has recently developed new Dam&Fill chip encapsulation compounds. These heat-curing adhesives are optically intransparent, give very high mechanical protection, and can easily be processed on already existing encapsulation systems. They are used for encapsulating smart cards. The requirements prevailing in the smart card industry are enormous. The reason is that the module's functioning must be safeguarded from production to mail dispatch to its use by the end user as a chip card (ID card, bank card, health insurance card, pay-TV card, phone card) or as a SIM card in the cell phone. The chip and the contact must be reliably mechanically protected from pressure, bending and torsion. It is also necessary to protect the sensitive silicon chips and gold wires from physical influences and environmental conditions, such as humidity, cold or heat.
Innovative encapsulation technology
The new Dam&Fill adhesives give major advantages for these special requirements, especially in the security field. Their new chemical composition makes possible very fast curing. In addition, a very high degree of mechanical protection can be reached. What is brand-new is the possibility to encapsulate the chips in such a way that opacity is given without molding them in an expensive process. This is especially important for light-sensitive chips, or if the chips are to be hidden for security reasons. Unlike UV-curing encapsulants, the new adhesives can achieve complete intransparency in the range of UV light and visible light and in the near IR range. It is possible to process and cure the new products on existing chip encapsulation systems. Therefore, it is not necessary to invest in new special equipment. The only precondition is that the systems are retrofitted with modern heating bars. Furthermore, the minimum curing temperature of 110 °C and curing times of a few minutes open up further application opportunities.
Interested in learning more about our black chip encapsulation compounds? Order data sheets and product information: marcom@DELO.de
Adhesive-friendly design
Testing in our lab: density meter
How is adhesive-friendly design made possible? Gudrun Weigel, Director of Applications and Process Engineering at DELO, gives design engineers advice on how to make the most out of the strong points of bonding technology.
The general trend is more and more towards bonding technology. Is bonding increasingly replacing other joining methods like welding, soldering or riveting?
Bonding is a very effi cient joining method being used in various industries and applications with ever-growing success. One example: Miniaturization is one of the decisive trends pushing the development of bonding technology. Chips in smart labels or sensors used for example in the automotive industry are becoming smaller and smaller. Adhesives help to protect the sensitive electronic parts, while saving weight and energy. What's more, adhesives aren't just used for joining and sealing components to protect them from environmental influences, but also for electrical connections, insulation, and heat dissipation. Furthermore, highperformance materials are becoming more and more specialized. In many cases, these dissimilar materials cannot be joined by welding. Although I must add that the choice of the joining method always depends on the specific application task and its requirements.
Is there an adhesive that can bond everything?
Definitely not! Just like there is no single material that can do everything! Each adhesive has certain properties and is only suitable for certain applications and materials. For example, hinges made of aluminum or stainless steel are bonded to the panes of glass partition walls. This application presents high requirements on the design. Therefore, the adhesive doesn't just have to be long-term resistant. It must also be transparent and mustn't change its color! The adhesives used in the engine compartment of a car are subject to extremely high temperatures and chemicals such as oil, fuel and brine. In this case, the adhesive must withstand these harsh conditions.
What do I have to consider in order to select the right adhesive?
Solving bonding problems is very complex. It is our task to support our customer in finding the appropriate adhesive so that it fulfills the requirement profile and can be integrated into the customer's production process. The adhesive selection involves, for example, translating the stresses on the connection into an adhesive property profile and assessing the fundamental properties of the materials to be bonded. Some adhesives stick well to glass, others ideally adhere to certain plastics. Further factors are adhesivefriendly design of the components to be bonded, the stresses the connection is subject to in practice, integration into the production process and training of the adhesive users.
What do you understand by "adhesivefriendly design"?
It's not only the whole package of requirements to be fulfilled by the composite that must be considered. Adhesive-friendly design also includes sufficiently large bonding surfaces, correctly dimensioned bonding gaps, even distribution of tensions and prevention of peel and bending stress. A uniform adhesive layer thickness can be ensured by a defined supporting surface, for example. For this purpose, spacers integrated into the component or an appropriate tongue and groove connection are conceivable. A tongue and groove connection can also prevent the penetration of humidity or other substances.
Which role do the respective material surfaces play?
The surface finish and the type of material are some of the decisive factors for excellent composite strength and long-term resistance of the connection. The reason for this is that the adhesive must wet the surface well in order to establish suffi cient bond strength. Plastics like PTFE (Tefl on) and POM (polyoxymethylene) are more difficult to bond than polyamide, polycarbonate or others. Also contaminants like separating agents or oily surfaces can impair or prevent the establishment of bonding forces. Therefore, surface pretreatment methods should always be considered in order to achieve perfect and reproducible bonding results.
How can I increase the bond strength in such cases?
Surface pretreatment methods like degreasing, plasma treatment or flaming are designed to clean the surfaces from substances that impair wetting or reduce adhesion, and to increase the surface tension. In addition, the surface can be roughened by grinding or blasting, which further improves adhesion. The goal is to get a reproducible, long-term resistant connection.
And how do you and your team select the appropriate adhesive?
We conduct various tests in our Engineering lab to narrow down the choice. This helps the customer select the ideal product for his application task and production conditions. For example, we measure the strengths before and after aging even under the influence of heat to determine if and how the composite and the adhesive have changed. The properties we test include cohesive properties such as Young's modulus, elongation at tear and tensile strength. We continue developing numerous tests in cooperation with our customers. We store components under high air humidity and heat in our climatic or shock test chambers to simulate environmental conditions in time lapse. These preliminary tests allow us to make a promising initial selection and, thus, to make the customer's job easier. Furthermore, integrating the adhesive into the manufacturer's specific production process is important. In this regard, the curing time is an essential factor as processes with short cycle times require adhesives that cure very fast and reliably!
Mrs. Weigel, thank you very much for the interview!
Product imitation
When using DELO adhesives, it is essential to ensure that they are original. Recently, the first product imitations have emerged in China. A new DELO customer ordered DELOPHOTOBOND adhesive online, but received something completely different under the name. On his website, this supplier claims to be an authorized dealer of DELO, which of course is not the case.
Using counterfeit products can lead to substantial consequential damage as a consequence of deviations from the properties required. In addition, the business model based on extensive consulting and development is undermined. DELO advises its customers to gather detailed information on authorized partners before purchasing DELO products. If there are any uncertainties or questions concerning originality and quality, customers are asked to directly contact DELO. This is of special importance to the customer, as DELO does not accept liability for damage resulting from the use of imitations.
Trade fairs and events
DELO will be present for you at various trade fairs and events in 2011:
- European Photovoltaic Conference and Exhibition - EU PVSEC
September 5 – 8, Hamburg / Germany - Assembly & Automation Technology Expo
September 20 – 22, Chicago / USA - Cluster Conference "Organic Photovoltaics"
September 21, Würzburg / Germany - Bondexpo
October 10 – 13, Stuttgart / Germany - Solar Power International
October 17 – 20, Dallas / USA
You can find more details at www.DELO.de/en