System and Method For Extruding Parts Having Microstructures
A manufacturing apparatus for manufacturing extruded parts having microstructures comprising: a support structure; a hopper carried by the support structure for receiving feedstock; an extrusion chamber operatively associated with the hopper for receiving the feedstock from the hopper and melting the feedstock above a feedstock melting temperature; a die carried by the support structure having die microstructures disposed on an inner surface of the die, the die microstructures having a plurality of microfeatures each having an upper surface and a lower surface, the melted feedstock being forced through the die to produce an extrudate having extrudate microstructures; and, a cooling assembly wherein the extrudate microstructures of the pre-cooled extrudate have larger physical dimensions than that of the extrudate microstructures of the cooled extrudate.
1 . A method of manufacturing an extruded item by an extrusion manufacturing process comprising the steps of:
providing an extrusion feedstock;
providing an extrusion die having microstructures disposed on an interior surface of said die, said die having a plurality of microfeatures having a depth between about 0.1 and 500 μm wherein each of said microfeatures includes an upper surface and a lower surface;
creating an extrudate having pre-cooled extrudate microfeatures by forcing said feedstock through said extrusion die so that said extrudate includes physical properties selected from the group consisting of: hydrophobicity, hydrophilicity, self-cleaning, decreased or increased hydro-dynamic drag coefficients, decreased or increased aerodynamic drag coefficients, increased friction, reduced friction, optical effects, increased adhesion, decreased adhesion, oleophobicity, oleophillicity, tactile effects, anti-blocking and any combination of these; and,
cooling said extrudate so that said pre-cooled extrudate microstructures have a larger physical dimension than that of said extrudate microstructures of said cooled extrudate.
2 . The method of claim 1 wherein said extrudate microstructures of said cooled extrudate have a height in the range of 70 to 90 μm, a width in the range of 120 to 160 μm and a general slope shape.
3 . The method of claim 1 including gathering said extrudate so that said extrudate microstructures of said extrudate have a larger physical dimension than that of said extrudate microstructures after said extrudate has been gathered.
4 . The method of claim 1 including:
processing said extrudate in a manner taken from the group consisting of:
drawing down, flattening, stretching, embossing, coating, stamping, rolling, spiraling, heating, freezing and any combination of these; and,
wherein said extrudate microstructures of said extrudate have larger physical dimensions than that of said extrudate microstructures of said extrudate after said extrudate passes through said post extrusion assembly.
5 . The method of claim 1 including:
providing a mandrel having microstructures disposed on an outer surface of said mandrel; and,
creating an inner cavity in said extrudate having an inner surface having microstructures.
6 . The method of claim 1 including cooling said extrudate so that said area of said microstructure on said extrudate prior cooling said extrudate compared to an area of said microstructure post said extrudate is 0 . 5 to 25 times smaller.
7 . The method of claim 1 including drawing said extrudate so that said area of said microstructure on said extrudate prior said drawing is 0 . 5 to 25 times smaller than a surface area of said microstructure on said extrudate post said drawing.
8 . A method of manufacturing extruded parts having microstructures comprising:
melting feedstock above the feedstock's melting temperature;
forcing the melted feedstock through a die, the die having a lower surface having an arc defined in the lower surface and an upper surface having an upper channel, the upper surface having a concave potion;
producing pre-cooled extrudate having pre-cooled extrudate microstructures;
cooling the pre-cooled extrudate;
producing a post-cooled extrudate wherein the microstructures have a height in the range of 70 μm to 90 μm, a width in the range of 120 μm to 160 μm and a general slope.
9 . The method of claim 8 wherein the step of producing pre-cooled extrudate having include the step of producing pre-cooled extrudate having a physical shape taken from the group consisting of a film, a square column, rectangular column, trapezoidal column, asymmetrical column, circular column, oval column, triangular column and any combination of these.
10 . The method of claim 8 including the step of gathering the post-cooled extrudate.
11 . The method of claim 10 including the step of producing post-gathered extrudate microstructures that have physical dimensions smaller than that of the pre-gathered extrudate microstructures.
12 . The method of claim 8 including processing the post-cooled extrudate in a manner taken from the group consisting of: drawing down, flattening, stretching, embossing, coating, stamping, rolling, spiraling, heating, freezing and any combination of these.
13 . A method of manufacturing extruded parts having microstructures comprising:
melting feedstock above the feedstock's melting temperature;
forcing the melted feedstock through a die having a plurality of microstructures disposed in the an inner surface;
producing pre-cooled extrudate having pre-cooled extrudate microstructures;
cooling the pre-cooled extrudate;
producing a post-cooled extrudate wherein the post-cooled extrudate microstructures have a height in the range of 70 μm to 90 μm, a width in the range of 120 μm to 160 μm and a general slope.
14 . The method of claim 13 wherein the step of producing a post-cooled extrudate includes producing microstructures on the pre-cooled extrudate arranged in an alternating pattern so that the post-cooled extrudate includes physical properties taken from the group consisting of: hydrophobicity, self-cleaning, increased hydro-dynamic drag coefficients, decreased or increased aerodynamic drag coefficients, increased friction, reduced friction, optical effects, increased adhesion, decreased adhesion, oleophobicity, oleophillicity, tactile effects, and anti-blocking.
15 . The method of claim 13 include the step of providing a die having microstructures disposed on an inner surface of the dye, a lower channel included in the die having walls having an interior angles of incident in relation to an upper surface less than 90°, a width having a range of between 0.25 to 1.25 mm and a height having a range of 0.25 to 1.25.
16 . The method of claim 13 including the step of forming a post-cooled extrudate microstructure having a wall angle of at least 90°.
17 . The method of claim 13 including the step of forming a post-cooled extrudate microstructure having a general pillar shaped cross-section.
18 . The method of claim 13 including the step of forming a post-cooled extrudate microstructure having dimensions in the rage of 0 . 1 μm to 500 μm.
19 . The method of claim 13 including forming an interior cavity in the pre-cooled extrudate having microstructures on an inner surface of the interior cavity.
20 . The method of claim 13 including:
forming post-cooled extrudate microstructures disposed on an external wall of the pre-cooled extrudate;
forming an interior cavity in the pre-cooled extrudate; and,
forming microstructures on an inner surface of the interior cavity.