Apparatus and method for thermoplastic extrusion
AssigneeStratasys, Inc.
InventorsJohn Samuel Batchelder, Robert L. Zinniel
Life of this patent
Estimating the term…
Abstract
An apparatus and method for controlling the extrusion of thermoplastic through one or more discharge orifices is described. An apparatus comprises one or more thermally conductive flow tubes defining flow channels in a heated thermally conductive body and terminating in discharge orifices. Each flow channel may be independently valved on and off, by selectively supplying a flow of coolant. An array of flow channels can be independently opened and closed in a predetermined pattern, so as to vary the extrudate configuration of thermoplastic emerging from the discharge orifices. By extruding thermoplastic layer-by-layer onto a base in this manner, a three-dimensional object may be formed.
Claims43
A freeze valve apparatus for thermoplastic, comprising:
- a thermally conductive body heated to a temperature at which a thermoplastic is flowable and having a cavity which contains a thermal insulator;
- a thermally conductive hollow flow tube defining a flow channel for a flow of the thermoplastic and having an inlet region, an outlet region terminating in an exit orifice and a mid-section between the inlet and outlet regions, the flow tube extending through the thermally conductive body such that its inlet and outlet regions are captured within the thermally conductive body and its mid-section passes through the cavity;
- and
- means for directing a flow of coolant having a temperature lower than a lowest flowable temperature of the thermoplastic through the insulator in the cavity and around a portion of the flow tube mid-section, such that heat transfer to the coolant causes solidification of thermoplastic in the flow channel in a region of the flow tube mid-section.
A freeze valve apparatus for thermoplastic, comprising:
- a thermally conductive body heated to a temperature at which a thermoplastic is flowable and having a cavity which contains a thermal insulator;
- a thermally conductive hollow flow tube extending through the thermally conductive body such that a mid-section thereof passes through the cavity, the flow tube having an inlet above its mid-section for receiving a flow of the thermoplastic and an exit orifice below its mid-section for discharging the thermoplastic;
- and
- means for causing solidification of the thermoplastic in a region of the flow tube mid-section to valve-off the flow channel.
A multi-orifice freeze valve apparatus for thermoplastic, comprising:
- a thermally conductive body heated to a temperature at which a thermoplastic is flowable and having a cavity which contains a thermal insulator;
- a plurality of thermally conductive hollow flow tubes defining a plurality of flow channels for a flow of the thermoplastic, each flow tube having an inlet region, an outlet region terminating in an exit orifice through which thermoplastic is extruded and a mid-section between the inlet and outlet regions, and each flow tube extending through the thermally conductive body such that its inlet and outlet regions are captured within the thermally conductive body and its mid-section passes through the cavity;
- and
- means for independently causing solidification of the thermoplastic in a region of each flow tube mid-section to selectively valve-off the flow channels.
Dependencies are inferred from the claim text.