Abstract:
A process for production of thin-walled plastics mouldings is described, via injection of plastics melt into a mould which has at least one fixed and at least one movable mould half, where an aperture gap is formed between the two mould halves in the opened condition of the mould, and where the two mould halves form at least one cavity of variable size in the closed condition of the mould, and where the movable mould half is moved without interruption onto the fixed mould half and the mould is closed, and where the aperture gap between the mould halves is continuously reduced, and where the plastics melt is injected into the mould during the movement of the movable mould half onto the fixed mould half. A feature of the invention is that the injection of the plastics melt takes place in accordance with a prescribable screw advance velocity profile or in accordance with a prescribable pressure profile for the pressure in the space in front of the screw.
Abstract:
A system and method are provided in which the rate of material flow to a plurality of gates (909, 911, 946, 948) can be controlled by a single controller (903). According to one embodiment, material is provided to first (915) and second runners (945), the first runner (915) comprising a plurality of distribution nozzles (905, 907), and the flow to the first runner (915) being controllable independently of the flow to the second runner (945).
Abstract:
The present application describes an electro-mechanical equipment for valve gate hot runner systems application to be incorporated into polymer material injection moulding. The equipment now disclosed enables opening and closing control of a control valve, allowing precise and efficient management of the material flow into the moulding cavity. The equipment developed is comprised of at least a linear actuator (2) which is installed in the mould (1), and which enables the control of the valve responsible for injecting the polymer material, in accordance with operating instructions issued by a control unit comprised of an actuation module (3) and a processing module (4).
Abstract:
The invention relates to a method for controlled driving of the cast axle (8) of pressure die casting machines, comprising a drive piston (15), wherein the forward and return motion of the piston (15) is carried out in a controlled manner. The invention is characterized in that the oil flow or oil pressure on the piston rod side is controlled/regulated by a pump (30) and additionally by a throttle valve (103) working in parallel at least during the filling phase, especially during the fast forward motion part.
Abstract:
A method for the automated optimization of an injection molding machine set-up process comprising injection molding one or more parts, inspecting the parts for defects, adjusting the injection stroke and/or the injection velocity and repeating the process until the defects are reduced. There is also disclosed a method comprising injection molding one or more parts, determining a mean injection pressure profile by measuring the injection pressure with the machine configured with a constant, desired injection velocity. Then the velocity profile is adjusted to reduce differences between the measured pressure and the mean pressure profile. A further method is disclosed wherein the kickback is calculated and adjusted from screw displacement, packing/holding time and pressure. Also disclosed is a method comprising injection molding one or more parts then determining the gate freeze time by incrementing the holding time and measuring the screw displacement.
Abstract:
A method for compensating for variations in the operating efficiency of electric motors (124, 156) used in plastic processing machines is disclosed. The current to the motor (124, 156) is continually monitored during all periods of operation to identify variations in the motor's actual efficiency as it relates to measurable machine performance. Normal operation of the electric motor (124, 156) is monitored to establish baseline current usage for the various periods (200, 226) of the operating cycle under given conditions. With a baseline established, variations in motor efficiency can be detected by monitoring the current during closed loop control (200, 226) of specific parameters and comparing the results to the baseline. Since the parameter is held constant by virtue of the closed loop, a deviation in current from the baseline indicates a change in efficiency. Based on the identified variance, the current to the motor (124, 156) during other (open loop) operations (210, 244) can be adjusted accordingly.
Abstract:
Die Erfindung betrifft ein Verfahren zur Herstellung eines Formteils (50) im Schaumspritzguss, bei dem durch Schmelzen eines thermoplastischen Kunststoffs eine Kunststoffschmelze (18) bereitgestellt wird, bei dem die Kunststoffschmelze (18) mit einem Treibmittel (22) beladen wird und bei dem die mit dem Treibmittel (22) beladene Kunststoffschmelze (18) unter Druck in einen Hohlraum (26) eines Formwerkzeugs (28) eingespritzt wird, so dass die Kunststoffschmelze (18) den Hohlraum (26) hinter einer durch den Hohlraum (26) laufenden Schmelzfront (34) ausfüllt, wobei die Einspritzgeschwindigkeit, mit dem die Kunststoffschmelze (18) in den Hohlraum (26) des Formwerkzeugs (28) gespritzt wird, so eingestellt wird, dass der Innendruck der Kunststoffschmelze (18) im Hohlraum (26) in einem Bereich (40), der einem Abschnitt der Schmelzfront (34) mit einem zeitlichem Abstand von höchstens 0,15 s nachfolgt, zumindest zu einem Zeitpunkt während des Spritzvorgangs größer ist als der kritische Druck des Treibmittels (22). Die Erfindung betrifft weiterhin ein Formteil (50) aus einem aufgeschäumten thermoplastischen Kunststoff, wobei das Formteil (50) einen Oberflächenbereich mit einer durch den aufgeschäumten thermoplastischen Kunststoff gebildeten optischen Strukturierung aufweist, deren gemitteltes Verhältnis der Glanzgrade gemessen in Fließrichtung zu den Glanzgraden gemessen quer zur Fließrichtung unter 1,9, vorzugsweise unter 1,5, insbesondere unter 1,2 liegt. Weiterhin betrifft die Erfindung Verwendungen eines solchen Formteils.
Abstract:
Systems and methods for controlling the closing speed of valve gated nozzles are disclosed. In one embodiment, a hot runner have a valve gated nozzle including a valve stem movable between an open position and a closed position is provided. The valve stem is moved at a first speed for a first portion of valve stem closure and a second speed for a second end portion of the valve stem closure.