Model Change for Mainstay All-Electric Injection Molding Machine NEX Series
Nissei Plastic Industrial recently implemented a model change for its mainstay all-electric injection molding machine NEX series that boosted precision stability and machine speed with the objective of expanding demand for the machines. The taking of overseas orders commenced in January. The current model change incorporates 1) clamping force feedback control for automatic correction of clamping force, 2) faster injection speed and response, and 3) a new version of the dedicated TACT controller. The function for automatic correction of clamping force was developed in order to realize a "direct-pressure-type toggle mechanism." Through utilization of expertise regarding direct-pressure clamping mechanisms, which Nissei has been particular about, accumulated over many years, the function enables use of a toggle clamping mechanism with a similar sensation to direct clamping. Almost all injection machine manufacturers including Nissei adopt toggle-clamping mechanisms for clamping in all-electric injection machines in order to effectively utilize the characteristics of servomotors. However, with a toggle mechanism, 1) the clamping force initially set changes with the passage of time due to thermal expansion of the mold and tie bars whose temperatures rise, 2) the actual clamping force is unknown, and 3), clamping force adjustment cannot be carried out during automated operation, among other problems. The new Nissei function allows automatic correction of clamping force in the toggle clamping mechanism that has changed as a result of temperature rises in the mold, etc., during automated or continuous operation of the molding machine and in addition, the clamping force can be changed during automated operation. The characteristics of the function are 1) clamping force can be varied during molding or setting of the molding parameters with a similar sensation to direct clamping, 2) volume production can be shifted to before the tie bar shaft temperature becomes constant and product yields are improved, 3) the initial precision of the mold can be maintained as excess clamping force setting is not required, and 4) performance of the mold clamping mechanism "Flat Clamp" of the injection molding machine series has been further improved in terms of mold protection and low pressure clamping, for example, making the series suitable for fast cycle precision molding. Low inertia servo motors have been employed as the driving sources (initially for clamping forces of 30-110 tons) in order to enable higher speed, faster response injection, fast molding cycles, and precision reproducible molding, as well as molding of thin-wall products, and faster injection speed and injection start-up time have been realized. Injection speed of the 50-ton injection machine is 500 mm/s, which is about 1.5-times as fast as the previous machine (330 mm/s) and accompanying this, injection start-up time has been improved by about 2.7-fold in terms of response. Through this, reproducible molding if high-quality thin-wall molded products becomes possible. Upgrading of the dedicated TACT Controller has entailed addition of software for such tasks as injection filling control operation and precision metering control, and simplified setting of the high-sensitivity mold protection function. The NEX Series comprises 10 machines starting with the 147-kN (15-ton) clamping force NEX15 and ranging up to the 4460-kN (460-ton) NEX460.
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NEX80-9E
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