Abstract: A method for producing a polytetrafluoroethylene particle, which includes subjecting tetrafluoroethylene to suspension polymerization in an aqueous medium to prepare a suspension-polymerized particle of polytetrafluoroethylene, washing and then crushing the suspension-polymerized particle or crushing the suspension-polymerized particle with washing to prepare a crushed particle, dehydrating the crushed particle to prepare a crushed particle having a water content of 40% by mass or less, and subjecting the dehydrated crushed particle to heat treatment to produce a polytetrafluoroethylene particle.

Abstract: A method for producing a polytetrafluoroethylene powder, which includes subjecting tetrafluoroethylene to suspension polymerization in an aqueous medium to prepare a suspension-polymerized particle of non melt-processible polytetrafluoroethylene, drying the suspension-polymerized particle to prepare a dry particle, subjecting the dry particle to fluorine radical treatment to prepare a fluorine radical-treated particle, and crushing the fluorine radical-treated particle to produce a polytetrafluoroethylene powder. Also disclosed is a polytetrafluoroethylene formed article obtained by forming the polytetrafluoroethylene powder, as well as a polytetrafluoroethylene compression-molded article obtained by compression molding the polytetrafluoroethylene powder.

Abstract: When first and fourth output transistors (15) and (18) are turned on, the voltage at the connecting point between the first and second driving transistors (19) and (20) drops. When second and third output transistors (16) and (17) are turned on, the voltage at the connecting point between third and fourth driving transistors (21) and (22) drops. As a result, voltage differences between the collectors and emitters of the first and second input transistors (2), (3) and the first and second current source transistors (13) and (14) increase so that saturation of the first and second current source transistors (13) and (14) can be prevented. Since a resistor is connected between a connecting point between upper and lower output transistors and a connecting point between upper and lower driving transistors having inverted phases from the former two transistors, current is limited and oscillation can be prevented.

Abstract: In a power amplifier apparatus comprising four amplifiers, each amplifier is adapted to amplify the half-wave output signal of a first differential amplifier by means of second and third output amplifiers (2, 3) to drive load (4) by their output amplifying signals and add the output amplifying signals by means of a non-linear circuit (5) in order to control the output DC voltage with the output signal of a second differential amplifier (6) according to the difference between the signal obtained by the non-linear addition and reference value Vref. Feedback signals X and Y of the left front first differential amplifier (1LF) and feedback signals X' and Y' of the right rear first differential amplifier (1RR) are applied to a single clip detection circuit 9 so that any clip in the output signal of the first and second output amplifiers can be detected by means of the feedback signals X, Y, X' and Y'.

Abstract: A powder molding machine capable of providing a uniform density of molding powders filled in a molding cavity of a die for improving the strength of molded products includes a die, upper and lower punches and a feeder, and is further provided with a feeder driving unit, which reciprocates a feed shoe between an advanced position at which molding powder is supplied to the die and a retracted position at which no interference occurs during a pressing operation by the punches. The feed driving unit includes a mechanism for enabling the feeder shoe to pass over the die and also to be swung in left and right directions while retracting and while still over the die.

Abstract: A positioning correction method for a motor-operated injection molding machine, intended to eliminate waste of power supply to or overheat of servomotors by locking up in an ideal state the motor-operated injection molding machine, which uses a toggle mechanism or crank for mold clamping and other operations. During the lockup period, a load RA acting on a mold clamping servomotor 7 is detected (S8), and a position command value PM for the servomotor 7 is increased or decreased in the next cycle in a direction such that the value of the load RA is reduced, if the value of the load RA is greater than a preset reference value V0 (S12, S13). As a result, a rotation center Q1 of a crank 2 and two opposite ends Q2 of a link 3 are locked up in a straight line, so that a moment of rotation produced by a mold clamping reaction force is removed from the rotation center Q1 of the crank 2.

Abstract: An injection molding condition setting method capable of setting optimum molding conditions quickly and easily. A processor (12) of a control device furnished with an expert system, which includes a state table containing a plurality of states each composed of a combination of mold information, resin data, molding conditions, molding defect data, and molding monitor data, and a weight table listing weighted countermeasures against defect molding set for every state, retrieves a state nearest to a trial injection state, which is discriminated in accordance with the mold information, resin data, and molding conditions set before the start of trial injection, the molding monitor data detected during the execution of the trial injection and the molding defect data inputted after the end of the trial injection, from the state table, and determines a molding defect countermeasure corresponding to the retrieved state and having the maximum weight with reference to a weight table.

Abstract: An injection molding machine of an automatic core change type includes a mold clamping section including stationary and movable platens fitted with first and second matrixes of a mold, respectively, a mold changing robot and a mold stocker severally attached to the mold clamping section and separately controlled by way of a control section, and a temperature controller for controlling the respective temperatures of the first and second matrixes and the mold stocker. As an arm and a chuck move and rotate, respectively, a first cavity unit, attached to the first matrix, is taken out from the first matrix, transported toward the mold stocker, and stored in its corresponding storage hole of the mold stocker. Then, another first cavity unit is taken out from the mold stocker, transported toward the mold clamping section, and attached to the first matrix, whereupon the replacement of the first cavity unit is completed. A second cavity unit is replaced in like manner, whereupon the mold replacement is completed.

Abstract: A method for taking countermeasures against faulty molding in which, with the aid of an expert system, restoration to a nondefective molding condition when faulty molding takes place during the mass production of molded products. When threshold values of a plurality of molding parameters, and information indicative of countermeasure processes, respectively corresponding to combinations of evaluations on these parameters and determined on the basis of the knowledge and experiences of skilled persons, are manually entered through a data input device (119), they are stored in tables of a memory (110) beforehand under the control of a processor (114). Upon start of the mass production, the injection time, metering time and cushion amount which are measured or calculated during a molding cycle, and the resin pressures corresponding to the manually set screw positions at the time of passing the gate and filling are set in the tables as reference values of the parameters.

Abstract: An injection control method for an electrically-operated injection molding machine is provided, which is capable of sharply increasing the injection speed of a low-priced electric injection molding machine. A command pulse train is supplied to a servo circuit for an injection servomotor whereby substantial rotary motion of the injection servomotor is initially prevented, as a result of the fact that the torque limit value (Ts) is set at a value sufficient to establish equilibrium between the output torque of the injection servomotor and the resin pressure acting on the injection screw. The error between the target rotational position of the injection servomotor and an actual rotational position thereof then is allowed to increase until it reaches a feed stop positional error (Fs).