Applications Quality
Applications Quality pens with improved sustainability 4 00 million parts per year in a wide variety of colours and materials are the basis for the high-quality ballpoint pens by Senator from Groß-Bieberau. The company from Germany is increasingly producing with a view to greater sustainability. In addition to using almost exclusively tie-bar-less ENGEL injection moulding machines, which are not only precise but also flexible and energy-efficient, Senator is also increasingly using bioplastics. The advertising material manufacturer became known for its high-quality writing instruments. The company has been back in the family’s hands since the end of 2018. The owners focus on developing sustainable products, efficient processes, flexible, energy-efficient Engel injection moulding machines and now more intensively on bioplastics. Sustainability is more than bio Bioplastics are increasingly in demand from the advertising materials market. Up to 2017, Senator processed approximately 50 to 60 tonnes of biobased plastics. Two years later, the amount is almost four times higher. However, the company developed writing instruments made from polylactides (PLA) ten years ago for good reason. “Approximately one kilogram of CO 2 is released to produce one kilogram of PLA. That is only about a quarter of what is generated for the same volume of a (comparable) conventional plastic,” says Michael Monitzer, head of production and member of the management board, quantifying the benefits for the environment. Even the dyes used to colour the organic pens are organic. However, since ballpoint pens – even those made of bioplastics – often end up in the residual waste due to a lack of a collection system, Senator is taking things a step further and currently testing the processing of recycled PLA that was previously used for other products. “For reasons of sustainability, we are not only focusing on organically based materials, but also on recycled materials,” said Monitzer. However, these pose a very special challenge for the company. Writing instruments are high-tech parts Precision is of the utmost importance when injection moulding the individual parts of a ball-point pen. Even with the usual plastics, the narrow tolerances can only be maintained with a great deal of experience. With recycled, organic or other newly developed, organically based materials, injection moulding of high-quality ballpoint pen parts requires specific know-how. In order to achieve dimensional accuracy, the residence times in the injection unit, the injection duration, moulds and cooling systems must be precisely devised. For example, the moulds for each shaft are filled at three injection points as the plastic has to follow long flow paths. “We use a 24-cavity mould with a sprue system that is balanced to allow the parts fill evenly,” says Alfred Kopp, head of the injection moulding department, giving a brief insight into the specific requirements for ballpoint pen production. With organic materials, on the other hand, the correct residence time in the screw is one of the secrets for parts that meet all optical and geometric requirements. Injection moulding machines are another of the writing instrument manufacturer’s secrets. On both production floors, Senator produces almost exclusively on tie-bar-less Engel victory machines with different clamping forces. “The injection moulding machine plays a major role here”, explains Alfred Kopp. “For example, we inject parts for different orders one after the other from different plastic materials. We only use one mould on the machine for this, as the shape does not change, just the colour and raw material. This means that the screw geometry must be suitable for all materials used, but the parameterisation on the machine differs. If we also take into consideration that we process all kinds of materials, from recycled material to bioplastics and conventional plastics – and with different colour additives, then it is easy to imagine that not a single batch is like any other. Minimum setup time, efficient parts handling Despite the wide variety of materials and colours, Senator assures its customers that it is able to deliver advertising material of exactly the same quality and colour within a few days. In order to make this work, the company uses the software authentig by TIG (Technische Informationssysteme GmbH, Rankweil, Austria). When an order is released, the MES (Manufacturing Execution System) transmits the basic data of the injection moulding process from the host computer to the selected machine, where the order is then produced after fine adjustment by the machine operator. Energy efficiency as part of the sustainability strategy Sustainability clearly means a great deal to the company: “The durability of our writing instruments clearly benefits the environment, because the useful life is an important, but unfortunately often little-noticed factor for more sustainability”, says Erik Würkner. “Because if you look at the entire life cycle of a product, the climate-influencing 44 bioplastics MAGAZINE [05/20] Vol. 15
Applications By: Susanne Zinckgraf Manager Public Relations ENGEL AUSTRIA GmbH component attributable to production decreases the longer the product is in use.” In order to further reduce this share, the intent is to significantly reduce energy consumption in production in the coming years. This year, the company, which is already certified to ISO 14001 and exclusively relies on green electricity, is also planning certification to ISO 50001. From left to right: Thorsten Habich, ENGEL Deutschland; Erik Würkner, Senator; Alfred Kopp, Sena-tor; Michael Monitzer, Senator; Franz Pressl, ENGEL AUSTRIA. The ENGEL victory machines make an important contribution towards high energy efficiency. The ecodrive servo-hydraulic system cuts the energy losses that are usually dissipated via the cooling water. As a result, cooling water consumption is also an indicator of the injection moulding machine’s energy efficiency. “At Senator, the servoelectric victory machines achieve the low consumption level of all-electric machines in many applications,” as Franz Pressl explains. “Optimising the cycle times is another tweak”, as Erik Würkner reveals, “This is why we are currently testing the possibility of connecting additively manufactured cooling systems in the moulds. They shorten the cooling time.” Other starting points for greater energy efficiency include minimising energy peaks at start-up time; and switching to a smaller machine, which is made possible by tie-barless technology, also saves energy. In addition, the use of a smaller machine has further advantages, particularly for thermosensitive bioplastics, such as the shorter residence time of the melt in the smaller injection unit. Perfectly geared for the future at 100 This year, Senator is celebrating its 100 th anniversary. No reason to rest on the laurels of past achievements – on the contrary: “What I can imagine is having a highly automated RFID-based injection moulding production system that makes it possible to trace individual injection-moulded articles back to the machine and the batch,” says Monitzer. These considerations also include material supply system on the production floor so that, ultimately, the entire process chain can be automated on a per order basis in line with the Industry 4.0 standard, from the material supply to the injection moulding machine, through part removal and assembly to dispatch or storage of the products. “In order to remain competitive in Germany, we have to learn a lot from other industries and do a lot of homework here ourselves,” Monitzer is certain. Tie-bar-less Engel victory injection moulding machine Writing instruments are high-tech parts. The switching mechanism of the ballpoint pens is very filigree, but it must be durable and can only have tolerances in the hundredth of a millimetre range for auto-mated assembly. www.engelglobal.com | www.senator.com Beautiful colour range of ball-point pens bioplastics MAGAZINE [05/20] Vol. 15 45
