When it comes to technically sophisticated production processes, Angst+Pfister’s wealth of knowledge in the rubber-metal components sector allows the company to work hand in hand with the customer to come up with solutions that are ready for mass production. “In close cooperation with our partners, we can react swiftly to unexpected problems,” says Mario Eckel. The Product Application Engineer at Angst+Pfister Germany is able to rely on the many years of broad experience offered by his own development team. In this case, it was possible to support PWO in becoming the supplier of a complete unit with integrated antivibration dampeners, thus broadening its position in its markets.
Connecting two experts
PWO is a supplier to the automotive industry with its headquarters in Oberkirch, Germany. 3400 employees work in five production facilities and four assembly sites on three different continents – in Germany, Mexico, Canada and China. Among over 1,000 products for safety and comfort in automobiles are dashboard supports, for example for the new BMW 3 Series. These hold the centre console, steering wheel and displays in place, and ensure safety by intelligently supporting the complex crash structure of modern passenger cars. At the same time, they create comfort by absorbing vibrations and thus reducing noise – all while meeting the highest standards of precision and durability. Thanks to its expertise in cost-effective lightweight construction, PWO contributes to environmentally-friendly driving and a greater range.
These instrument panel supports are decoupled from the air conditioner housing with rubber-to-metal bolts.
«Working in partnership with customers allows us to respond to unexpected problems early on.»
Mario Eckel, Product Application Engineer, Angst+Pfister Deutschland
PWO receives requests to equip the dashboard supports with additional components. One request was for rubber-metal vibration dampeners to be used in this type of assembly. When BMW asked for a decoupler, ready mounted on the steel supports for the housing of the air conditioning system, PWO turned to the experts at Angst+Pfister. The rubber-metal dampener that was required needed to connect the housing of the air conditioning system to the supports in such a way that it prevented both vibration and noise.
Overcoming challenges together
BMW defined the technical requirements for the design. Because Angst+Pfister is proficient in the specific technical language, they are able to apply it to the respective requirements. “It was a matter of supporting PWO technically, in order to comply with BMW’s standards: how is vulcanisation carried out? How do you join rubber to metal?” Mario Eckel explains. The decoupler consists of two cold-pressed, threaded metal bolts, which are connected with rubber. Although the component resembles a standard buffer, the challenge lay in the design of the threaded bolts. It is not possible to change the 23 millimetre diameter. The problem: the large diameter of the bolt head in comparison to the threads makes it vulnerable to cracking when screwed in automatically. This task is carried out by robots on the production lines at PWO and BMW. The challenge was to define the right production process for the metal components and to find a qualified partner. Last but not least, the entire solution had to work for very high volume series production.
The manufacture of cold-pressed bolts of this type is highly demanding. To meet the challenge, Angst+Pfister activated its large Europe-wide network. At the same time, the branch in Turkey was searching in Asia. “Nothing but rejections!” stated Mario Eckel. No company wanted to touch this “hot potato” – it was too risky. Fortunately, the Angst+Pfister engineers finally found a qualified subcontractor who is not only able to manufacture complex connecting parts such as this, but also has experience in the automotive industry. But even these experts needed some time to design the individual steps of the production process in such a way that the hexagonal bolt ends were suitable for automatic assembly. At the same time, this partner had to be audited as quickly as possible and accepted into Angst+Pfister’s supplier base – the start of series production was approaching fast.
“The next challenge was vulcanisation”, Mario Eckel continues. The primer used to bond the rubber to the metal was incompatible with the surface coating defined in the BMW standard. Some of the substances in the coating prevented it bonding cleanly with the rubber. Because of this, the first components failed the tests. The Angst+Pfister-team had, therefore, to find another material that demonstrated the same properties as the standard specifications in tests, but was suitable for the vulcanisation process. In so doing, Angst+Pfister relied on a great deal of internal knowledge – thanks to their own coating systems and their extensive experience with bonding agents. It was possible to carry out the tests immediately in-house.
One of these tests is the salt spray test, which addresses corrosion caused by weathering: how quickly do the components rust? Another test checks the bonding points between the metal and rubber, and involves stressing the components until they fail completely. The torques to be applied are also tested: how does the decoupler behave when the two bolts are turned against each other? “We were able to exceed BMW’s requirements – the part only broke when subjected to extreme forces,” says Mario Eckel. So they took care of the final step in producing the finished component; stamping the part number into the rubber.
Completion with an A rating
After successful approval of the component in accordance with the “PPAP Level 3” automotive approval process, the PWO and Angst+Pfister teams met at the Turkish plant in Bursa. As this was PWO’s first order, an audit in accordance with VDA 6.3 was due. Angst+Pfister has IATF-16949 certification, and passed with an A rating. PWO now has a certified partner for the decouplers, can accept further orders for assemblies with rubber-metal components in the future, and has this to say in praise of Angst+Pfister: “One key to success was the customer focus demonstrated by Angst+Pfister. They responded to our needs fast and visited our site in person on a number of occasions. You can rely on Angst+Pfister.”
Learn more about APSOvib® Antivibration Technology
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published: Oct 22, 2020, 2:37:00 PM by: Angst+Pfister Group