Smart Molding International 2-2020

31 www.smart-molding.com machinery able hydraulic booster on demand. This ensures that themachine operates with the best possible efficiency both during running production and during start-up after a production interruption. While the caps are not yet completely cooled and very easy to demould during ejec - tion in ongoing production, the ejec - tors have to apply more force in stop situations to remove caps that have al - ready cooled down in the mould. Since production interruptions are rare, it is more efficient to use servo-hydraulic drive amplification than to generally equip the machine with more powerful ejector drives. High forces only when they are actually needed – that is EN - GEL's motto. The new e-cap generation is offered with two different ejector drive tech - nologies. The machine works with hydraulic ejectors as standard. Servo- electric drives are available as an op - tion, which require around ten percent less energy. More powerful plasticising unit for poor-flowing HDPE The plasticising unit was completely redesigned in the course of the e-cap's further development, as the properties of the materials to be processed have also changed. The raw material manu - facturers have adapted the materials to the lower cap weights. For CSD (car - bonated soft drink) caps, the melt flow index (MFI) of today's HDPE grades is between 0.8 and 1.4 g/10 min. Very short cycle times require particularly high plasticising rates. ENGEL has in - creased the torque of the plasticising drive accordingly and developed both a new plasticising screw and a new highly wear-resistant sliding ring non-return valve specifically for cap manufacture. Both products are part of the standard scope of supply of the new e-cap ma - chines. With its new design, the barrier screw processes high viscosity HDPE in a particularly gentle way, even given high throughput levels, while ensuring a very good melting rate and homoge - neity of the melt. This further contrib - utes to the high process stability and repeatability of e-cap machines. Optimising energy consumption across the entire system Cleanliness and energy efficiency have been essential characteristics of the series right from the outset. With an encapsulated toggle lever and a very clean linear guide of the moving plat - en, the e-cap machines reliably meet the requirements of strictly regulated production in the food industry. The machines' all-electric drive tech - nology makes a major contribution to their outstanding energy efficiency. In addition, braking energy is recuperated, reliably preventing the need for expen - sive peak power. Thanks to the very high efficiency of the drives used, the e-cap machines also only require a minimum of coolant. The e-cap 380, for example, operates at high speed with a specific energy consumption of 0.37 kWh per kilogram of pellets processed. As a system supplier, ENGEL pre - cisely coordinates all the components of the production cell right from the start of the project. “This allows us to fully leverage the efficiency potential throughout the entire production cell,” as Mairhofer emphasises. The new e-cap is available in the sizes 220, 280, 380 and 420 with clamping forces from 2,200 to 4,200 kN. ENGEL www.engelglobal.com Caps are becoming lighter and lighter, causing increasingly tough challenges for the injection moulding machine technology. (Pictures: ENGEL) With extremely short cycle times of less than two seconds, the new e-cap ensures very high precision and repeatability. (Pictures: ENGEL)