Abstract: In a motor drive injection unit and a motor drive injection method, which can obtain an injection speed suitable for a molding material having fast solidifying speed as well as can securely carry out pressure keeping for a predetermined period of time while making a position of an injection piston unmovable after injection and filling are completed, a molding material in a cylinder is injected into a metal mold by converting a rotational motion of an electric servo motor into a reciprocating motion of an injection piston in the cylinder through a plunger with a ball screw, a surge pressure control means is provided for placing the injection piston in the cylinder in an unmovable state when at least a predetermined amount of a load is applied to the injection piston by the molding material in the cylinder, the surge pressure control means includes a combination of rotation control means of the electric servo motor and an upward movement suppression mechanism of the injection piston, and further, an injection s

Abstract: In a motor drive injection unit and a motor drive injection method, which can obtain an injection speed suitable for a molding material having fast solidifying speed as well as can securely carry out pressure keeping for a predetermined period of time while making a position of an injection piston unmovable after injection and filling are completed, a molding material in a cylinder is injected into a metal mold by converting a rotational motion of an electric servo motor into a reciprocating motion of an injection piston in the cylinder through a plunger with a ball screw, a surge pressure control means is provided for placing the injection piston in the cylinder in an unmovable state when at least a predetermined amount of a load is applied to the injection piston by the molding material in the cylinder, the surge pressure control means includes a combination of rotation control means of the electric servo motor and an upward movement suppression mechanism of the injection piston, and further, an injection s

Abstract: An injection molding machine having a simple structure and adapted to quickly operate for injection molding without taking in air bubbles is provided. The injection molding machine comprises a plunger and a nozzle for injecting the molten metal fed from the plunger into a metal mold. The plunger has a cylinder section with a through hole bored through an upper portion of its lateral wall for introducing the molten metal, and a piston for slidingly reciprocating within the cylinder section. A communication hole is bored through the piston and communicates with the through hole at a predetermined position. The communication hole runs from the lateral wall of the piston through the inside thereof and has a non-return valve arranged therein to allow only a flow from the lateral wall of the piston.

Abstract: An injection molding machine having a simple structure and adapted to quickly produce molded products without significant flaws on the surface is provided. It comprises a plunger being adapted to introduce the molten metal into the cylinder section, a nozzle for injecting the molten metal fed from the plunger into a metal mold and a piston arranged within a cylinder section of the plunger to slidingly reciprocate. It includes a piston drive unit for driving the piston to slidingly reciprocate, a stopper member for controlling the retracted position of the piston drive unit and a position selecting unit for defining a projected position and a retracted position for the stopper member.

Abstract: A method and apparatus for controlling the die-retaining force of an extruder is disclosed. In the operation of an extruder adapted to retain a die with a container actuated by a container cylinder and effect extrusion of a billet readied for use in the container by forcing the billet through the die, to keep the die-retaining force of the extruder constant, the control of the die-retaining force of the extruder is carried out by causing the container cylinder to impart to the container a force directed away from the die so as to be sequentially decreased during the first half period of the extrusion and causing the container cylinder to impart to the container a force directed toward the die so as to be sequentially increased during the last half period of the extrusion.

Abstract: A hydraulic cylinder mounted on a frame assembly is communicated with a hand operated pump for actuation thereby. A plurality of punch-die assemblies, to be selectively mounted in the frame assembly for perforating, notching clipping or like operations, each comprise a punch or punches carried by a punch holder constrained to up-and-down motion relative to a die. When placed in the frame assembly, any selected punch-die assembly has its punch holder disposed under a ram connected to the piston of the hydraulic cylinder, so that upon manual activation of the pump, the punch or punches can be forced down to perform a desired operation in cooperation with the die. The punch and die assembly has a presser which urges the workpiece against a lateral side of the punch, and the workpiece can be acted upon at two locations at the same time, one location being directly above the other.