Abstract:
Eine Nadelverschlussdüse (10) für ein Spritzgiesswerkzeug hat einen Düsenkörper (20), in dem wenigstens ein Schmelzekanal (30) ausgebildet ist, der an oder in einem Düsenmundstück (40) endet und mit einer von wenigstens einem Formeinsatz (50) gebildeten Formkavität des Spritzgiesswerkzeugs strömungsverbunden ist. Eine Verschlussnadel (60) durchsetzt den Schmelzekanal (30) und das Düsenmundstück (40) längsverschieblich und ist dabei von einer Öffnungs- in eine Schliessstellung bringbar. Zur Zentrierung der Verschlussnadel (60), die an Ihrem unteren Ende einen Verschlussteil (70) bildet, ist vor einem Dichtsitz (D) wenigstens ein Einlaufkonus (46) vorgesehen. Um eine dauerhaft präzise Nadelführung und -abdichtung zu gewährleisten und um gleichzeitig eine Beeinträchtigung der Temperaturverteilung im Bereich der Düsenspitze zu vermeiden, besteht das Düsenmundstück (40) aus einem hoch wärmeleitfähigen Material, während der bzw. jeder Einlaufkonus (46) für die Verschlussnadel (60) in einem konzentrisch zur Längsachse (L) der Nadelverschlussdüse (10) ausgebildeten Zentrierkörper (80) aus verschleißfestem Material ausgebildet ist. Letzterer ist an und/oder in dem Düsenmundstück (40) formschlüssig gehaltert und mit einem eine Austrittsöffnung (44) für die Schmelze bildenden Endabschnitt (84) mit dem Formeinsatz (50) in Eingriff bringbar.
Abstract:
The present invention relates to a sprue bar assembly (38) for use with a number of different injection molding machines. The sprue bar assembly (38) comprises a fixed sprue bar section (46) having a first channel (76) through which molten material, such as a plastic resin, flows. The first channel (76) communicates with the outlet of a source of the molten material. The sprue bar assembly (38) further comprises an adjustable sprue bar section (48) having a second channel (78) through which molten material flows and a powered unit (64) for holding the adjustable sprue bar section (48) in contact with the fixed sprue bar section (46) so that molten material can flow from the first channel (76) to the second channel (78) without leaking and for changing the length of the sprue bar assembly (38) as needed to accommodate molds of different shutheights. In a preferred embodiment of the present invention, the fixed sprue bar section (46) and the adjustable sprue bar section (48) are each provided with a valve gate for preventing drooling or leakage of the molten material when the two sections are separated.
Abstract:
An injection molding apparatus (19) comprising: a manifold (30), a nozzle (50), a distal tip of the nozzle being comprised of a highly heat conductive insert (55) and an insulation cap (64) that is substantially less heat conductive than the insert, the downstream end portion of the insulation cap being disposed between the gate and the downstream end portion of the highly heat conductive insert forming a fluid seal (S) around the gate (85), a valve pin (90), wherein when the valve pin is in a gate closed position (P4), an axially interior surface (76s) of a fluid exit aperture of the insulation cap surrounds a gap enabling circumferential surface (92) of the valve pin forming a spatial gap immediately upstream of the gate between the interior surface (64s) of the fluid exit aperture (64) of the insulation cap (60) and the gap enabling circumferential surface (92) of the valve pin (90)
Abstract:
An injection molding system having an improved valve gate arrangement that provides molded articles with improved vestige and or surface quality.
Abstract:
A nozzle-tip apparatus (100), comprising: a nozzle-tip body (102) configured to connect with a molding-nozzle assembly (200). The nozzle-tip body (102) has a front end (104) defining an exit orifice (106). The exit orifice (106) is configured to slidably receive a valve stem (202) of the molding-nozzle assembly (200). The nozzle-tip body (102) has a pressure-relief feature (108).
Abstract:
An improved injection molding apparatus having a valve-gated injection nozzle for regulating a flow of molten material through a connecting passageway to a mold cavity. An end portion of the valve stem is configured to cooperate with a complementary sealing portion of the connecting passageway, when the valve stem is configured in a closed position. The mold cavity further includes a vestige forming portion that is located adjacent the sealing portion that is partially defined by a bottom portion of the valve stem when it is configured in the closed position. The apparatus is characterized in that the vestige forming portion extends radially outwardly from the sealing portion such that a first cross-sectional area of the sealing portion is smaller than a second cross-sectional area of the vestige forming portion. Accordingly, tearing along the vestige of the part is substantially avoided.