New competitively priced small hydraulic presses.

Two new small hydraulic-clamp injection machines from Battenfeld of America, West Warwick, RI., are said to combine "a new level" of proportional controls with numerical entry and many mechanical advantages at a competitive price. Battenfeld has re-entered the under-50-ton market segment with newly designed Plus 250 (27.5 U.S. tons) and Plus 350 (38.5 tons), which were first introduced at the K'92 exhibition in Dusseldorf, Germany, last October (see PT, Jan. '93, p. 67). Battenfeld's last offering of this size was in 1985 with its BA 230 series machine.

NEW |FRIENDLY' CONTROLLER

The Plus series is equipped with a new Unilog 1020 digital process controller, which is said to combine the easily learned operator interface of the Unilog 2040 with a number of components of the Unilog 4000. Data entry for all parameters is via keypad that is aided by a pictorial format. Principal parameters, such as opening and closing speeds and pressures for clamp and injection, are digitally entered. Preset and actual values of parameters may be easily compared by looking at two adjacent LED displays on the console, which helps to eliminate variations between operators from shift to shift. Cursor keys on the control are used to change the numerical value of each process function. An option on the controller is data storage for up to 20 mold setups.

The complete sequence of process functions is displayed as a series of LEDs that signal a problem if a fault occurs and then provides an error code for quick location of the problem and its solution.

A large number of control features are offered as standard. Linear positioning transducers are placed on both the clamp and injection cylinder, and proximity switches are supplied on the ejector and injection carriage. There are two closing speeds on the clamp, two holding pressures, two opening speeds, and two injection speeds. On the ejector, forward and return speed and pressure are digitally adjustable. Screw decompression is provided both before and after metering. Cycle and fill-time monitoring can be performed with or without automatic switch off functions. Other standard features include oil preheating, plug-in heater bands, and digital temperature, and stroke displays.

CLAMP AND INJECTION FEATURES

The hydraulic clamp on these machines has only two tiebars, although generous specs are said to permit the use of a wide range of molds. Distance between tiebars is 10.63 in., and total mold-mounting area is 10.63 x 9.84 in. Minimum mold height is 5.91 in., and max. daylight is 17.72 in., while maintaining a max. clamp stroke of 7.87 in. The hydraulic ejector of the new units has a force of 2.89 tons and a stroke of 3.94 in., both of which are said to exceed those of other machines in this class.

Design of the cast platens has been optimized through finite-element modeling in order to make them torsionally rigid enough to support larger molds, according to Battenfeld. Clamp seals are set back from the mold, which is said to increase their life and to help make the new machines suitable for clean-room molding applications. The dead space on the clamp is equal to the stroke, so that the exposed tiebar cannot reach the sealing point. The feature is said to protect the machine during mold installation. An added benefit here is that the seals are located so that the oil cannot penetrate the mold area if a seal fails. Also, a slot in the frame for mold hoses prevents them from being pinched or crimped. Platen bolting pattern complies with Euromap standards.

A completely new injection unit features hydrostatic bearings on the injection plunger and offers a choice of three screw diameters with shot sizes of 0.8-1.6 oz on the Plus 250 and four screws with 0.8-2.3 oz on the Plus 350. Maximum injection pressures range up to 35,250 psi on the Plus 250 and 44,000 psi on the Plus 350. The Plus 250 has a standard plasticating capacity range of 52-95 lb/hr; the Plus 350 ranges from 52 to 103 lb/hr. Dry-cycle rate for these machines is 1.33 sec.

Other features include an energysaving variable-volume pump with proportional valves for pressure and speed. The heat exchanger has a water-saver valve that comes on when needed.

The machine's footprint is small, occupying floor space of 86.61 x 33.5 in. Price, also, is described as modest: $23,500 for the Plus 250 and $26,700 for the Plus 350, including Unilog 1020 controller. (CIRCLE 26)