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It was the eighth time ENGEL recognised applications that make excellent use of the advantages of ENGEL's injection moulding machines with tie-bar-less clamping units. For the first time, the prizes were awarded in three categories: "Efficient use of the mould area", "Innovative process integration" and "Economical automation concept".
27 plastics processing firms from 14 countries applied for the internationally coveted distinction this year. All the applications submitted were scrutinised closely by the jury, who then discussed the respective advantages and compared them to the use of conventional machines with tie-bars. The jury traditionally consists of three representatives from the areas of university research, industry and the trade press. The 2015 panel included Prof. Dr Frank Ehrig, director of the Institute for Material Engineering and Plastics Processing (IWK) at the University of Applied Sciences Rapperswil in Switzerland, Gunnar Hack, managing director of Hack Formenbau in Kirchheim unter Teck, Germany, and Harald Wollstadt, editor-in-chief of the trade magazine Plastverarbeiter, which is published by Hüthig in Heidelberg.
The replacement of metals with plastics is progressing rapidly, and this also includes components under car bonnets. Hengst SE & Co. KG, which is headquartered in Münster, Germany, has developed a thermoplastic solution made from polyamide reinforced with glass fibre for fabricating oil filter module bases that are used in various Audi and Volkswagen four-cylinder diesel engines. The filter bases are among the most sophisticated components that the automotive supplier manufactures at its production plant in Nordwalde, Germany. The single-cavity mould has altogether eight core pulls, which account for its considerable size. The bases are made on an ENGEL victory 3550/450 tech injection moulding machine with a clamping force of 4,500 kN.
Before the tie-bar-less solution was chosen, alternative offers based on injection moulding machines with tie bars were requested. These began at a clamping force of 8000 kN. A machine of this size would have been needed so that the bulky mould could be mounted and set up through the tie bars, even though the injection moulding process itself requires significantly less clamping force. The tie-bar-less 4,500-kN machine enabled Hengst to reduce the investment and operating costs for the application considerably, keep the production cell compact and also drastically shorten the time spent for mounting and setting up the mould. The integrated ENGEL viper 40 robot can reach from the side directly into the mould area without having to circumvent any obstacles. This lowers the working height and ensures that the robot remains well clear of the heavy-duty crane in the relatively low-ceilinged production hall.
The excellent use of the tie-bar-less mould area in this application helps in various ways to make the application very efficient overall. It has won Hengst the 2015 ENGEL HL Award in the category "Efficient use of the mould area".
At 20 million units per year, connectors for garden hoses are the components with the highest production volume at Gardena Manufacturing GmbH in the southern German municipality of Gerstetten, a company of the Husqvarna Group. Since January of this year, an ENGEL victory 740H/310W/400 WP combi injection moulding machine has been used for them. Only the tie-bar-less clamping unit makes it possible to combine maximum precision with very short cycle times in the newly developed two-component process.
The integrated ENGEL easix multi-axis robot removes 16 hose connectors from the machine every 16 seconds. In order to be able to process the thermoplastic housing material and the elastomer for the grip surfaces simultaneously, the rotary mould has two sets of 16 cavities and four sets of 16 cores. The process has an ingenious twist: after the thermoplastic components have been injection moulded, the mould then turns the cores so that they are in a cooling position before overmoulding the soft components in a third step. This prevents the cooling from extending the cycle time. When turned to the fourth position, the connectors can finally be removed from the mould.
The four sets of 16 cores are each arranged in linear fashion. The heart of the tie-bar-less clamping unit, the force divider, plays an especially important role in ensuring the connectors produced in the cavities at the top and the bottom have exactly the same wall thickness as those produced in the middle cavities. Two of these central flexible elements are located behind the moving mould mounting platen and distribute the clamping force evenly across the entire mould cross section. In so doing, they guarantee very high reproducibility levels and excellent mould protection and have thus made a crucial contribution to the fact that the production cell hasn't produced any quality-related rejects since it was commissioned.
Although the mould completely fills out the 4000-kN machine's mould area with its many cooling connections, there is still enough room for movement. If the mould were to be used on an injection moulding machine with tie bars, the machine would have to be considerably larger. That would also make the cycle time longer, because bigger machines need more time than smaller ones to open and close the mould.
Last but not least, the efficient automation of this application is only made possible by the tie-bar-less technology. Despite its very long gripper, the robot arm can reach the mould cores directly from the side. The jury was won over by the high precision and process consistency levels, which were achieved despite the unconventional arrangement of the cavities only due to the even distribution of the clamping force through the force divider. Gardena also fully exploits the potential of the ENGEL tie-bar-less technology with its hose connector manufacturing process. The 2015 ENGEL HL Award in the "Innovative process integration" category has therefore been given to Gardena.
Space is very limited under a car bonnet. Like a big 3D puzzle, the various components needed to make the car run all have to fit together neatly. The best example of this is the oil level measurement modules. So that they fit into the space provided in the best possible way, they are no longer made of steel but completely of plastic. In addition to more design freedom, the plastic reduces the weight of the modules and also means they can be produced using a very economical manufacturing process. Schneegans Freudenberg Silicon GmbH uses projectile injection technology (PIT) to produce more than 3 million modules every year for BMW, Daimler, Volkswagen, Seat, Audi and Skoda in Losenstein, Austria. Every 45 to 50 seconds, two completely assembled units are ejected from a fully automated production cell, the core of which is a tie-bar-less ENGEL victory 400 tech injection moulding machine. Four integrated multi-axis robots share the tasks of inserting the projectiles, removing the moulded parts from the mould, detaching the overflow cavities, printing on the front of the funnels, fitting O-rings, assembling oil sleeves and dipsticks, leak testing and packaging the finished modules.
As space is not just of particular importance under the bonnet, but also in Schneegans's production hall, a tie-bar-less solution was always going to have to be used for producing the modules. It allows the multi-axis robot supporting the injection moulding process to work especially close to the clamping unit and access the cavities without losing any time. Using a machine with tie bars would have meant having to employ significantly more complex removal processes, and a larger machine with at least 6000 kN of clamping force would also have been necessary. This would have increased the production cell's footprint and lengthened the cycle time.
ENGEL's tie-bar-less technology makes a crucial contribution to the high efficiency of the fully automated production in this application at Schneegans, and the jury has honoured this by selecting as the winner of the "Economical automation concept" category of the 2015 ENGEL HL Awards.
In addition to the winners, ENGEL has announced the names of the other applications that made the shortlists for each category. Gustav Hensel (Lennestadt, Germany) and UAMT (Oradea, Romania) completed the "Efficient use of the mould area" list with the manufacture of covers for cable junction boxes and the production of handbrake handles, respectively.
In the "Innovative process integration" category, the remaining shortlist places were taken by Valeo Autoklimatizace (Rakovnik, Czech Republic), which submitted its fabrication of ventilation flaps for cars, and Tente-Rollen (Wermelskirchen, Germany), whose application was the manufacture of double castors for hospital equipment.
In the "Economical automation concept" category, Mora (Mora, Sweden) and Weidplas (Rapperswil, Switzerland) were the best-placed candidates behind the winner with the fabrication of outdoor knives and the production of air ducts and bonnet scoops, respectively.