Hot runners to the fore in production of writing instruments
Reduced cycle times, optimised energy input
Using Günther hot runner technology Blue Flow nozzles meant that the cycle time could be reduced by a further 4 seconds. These nozzles have special thick-film heating elements with 55% of the energy in the area of the tip. This reduces the required temperature input into the melt.
Environment-friendly production with savings in energy and resources is a strategic goal for Schneider. This has been proven by repeated EMAS certification since 1998. The use of hot-runner systems is an important element in reducing the amount of plastics required in the process. In addition, the Blue Flow nozzles in combination with the two-part shaft need significantly less energy and help meet the requirements of EMAS certification.
The production of ink cartridges is just one part of the product manufacture at Schneider; other business units comprise the production of high-quality pens and text highlighters. Multi-component injection moulding is increasingly used in the production of these parts. In the multi-component injection moulding various materials are combined together in the injection mould.
As a rule, a lot of new articles have a softer, ergonomic gripping area made of an elastomer such as TPE or TPU and a harder basic body made of PE, PP or ABS plastics. Up to 16 different colour combinations are produced for individual writing instrument series. The range of colours makes it necessary for the hot runner system to have good colour changing properties to allow a very rapid change from one colour to another during production. Likewise, as the colour batches are temperature-sensitive during processing they require a homogeneous development of temperature over the entire melt channel in the hot runner system without temperature peaks.
The company’s marketing and sales departments place an increasing focus on surfaces, contours and the visibility of the products. This requires more use of valve-gate hot-runner systems. For the new Schneider “One“ series of ink pens both Blue Flow nozzle types - 6NHF100LA-1.0S and 5NHF100VA-0.8S - are used in the 2-C injection moulding process. To ensure that the needles open and close the injection points precisely and evenly, the pneumatic version of a lifting plate is used as a drive. These lifting plates are moved by the corresponding quantity of cylinders and equipped with special guide elements to allow operation with process reliability.
To guide the coated needles in the valve-gate nozzles, needle guides made of powder metallurgical steel are used close to the gate. This ensures a long service life. The valve-gate hot-runner system was delivered as a hot half completely assembled and wired by Günther.