Cutting tool and a process for making such a cutting tool
A cutting tool having a monolithic construction includes an injection molded shank, and an extruded fluted portion extending forwardly from the shank, the shank and the fluted portion having a monolithic construction. The process for making the cutting tool includes forming a cutting tool green body by injection molding a shank of the green body and extruding a fluted portion of the green body such that the shank and the fluted portion have a monolithic construction; and then sintering the cutting tool green body.
1. A process for making a cutting tool having a shank ( 60 ) and a fluted portion ( 64 ), comprising:
forming a cutting tool green body by:
injection molding, into a cavity, a shank of the green body; and
extruding, through a die, a fluted portion of the green body while separating the die and the cavity, such that the shank and the fluted portion have a monolithic construction; and
sintering the cutting tool green body.
2. A process for making a cutting tool having a shank ( 60 ) and a fluted portion ( 64 ), comprising:
providing an injection and extrusion system ( 10 ) comprising:
a fixed portion ( 20 ); and
a movable portion ( 22 ) that contacts the fixed portion ( 20 ) and is capable of moving away from the fixed portion ( 20 ) along a bidirectional movement direction (M); wherein:
one of the fixed and movable portions comprises a die ( 30 ) having a die bore ( 34 ) with a longitudinal axis (A), the die bore facing along the movement direction (M); and
the other of the fixed and movable portions comprises a cavity insert ( 46 ) having a longitudinal axis (B) and an insert bore ( 52 ) that faces the die bore ( 34 );
forming a cutting tool green body by:
(i) injecting molten tool material ( 38 ) through the die bore and into the insert bore, thus forming a shank ( 60 ) of the cutting tool green body;
(ii) moving the movable portion away from the fixed portion, and, simultaneously, extruding molten tool material through the die bore, thus forming a desired length (L) of a fluted portion ( 64 ) of the cutting tool green body, such that the shank and the fluted portion have a monolithic construction; and
(iii) cutting the fluted portion; and
sintering the cutting tool green body.
3. The process according to claim 2 , further comprising the steps of:
prior to sintering the green body, ejecting the shank ( 60 ) from the insert bore ( 52 ).
4. The process according to claim 2 , wherein:
the insert bore ( 52 ) comprises a core ( 86 ) that extends rearwardly from an insert bore bottom ( 54 ).
5. The process according to claim 4 , wherein:
the core ( 86 ) has a core diameter (D 1 );
the insert bore ( 52 ) has a cavity diameter (D 2 ); and
a diameter ratio (E) between the core diameter (D 1 ) and the cavity diameter (D 2 ) is in the range of 0.6 to 0.9.
6. The process according to claim 2 , wherein:
the die bore ( 34 ) comprises die bore portions that are twisted along the die bore; and
the cavity insert ( 46 ) is rotatable around its longitudinal axis (B), with respect to whichever of the fixed portion ( 20 ) and the movable portion ( 22 ) it belongs.
7. The process according to claim 6 , wherein:
the cavity insert ( 46 ) is forcibly rotatable.
8. The process according to claim 2 , wherein:
the die bore ( 34 ) comprises at least one pin ( 80 ) that extends rearwardly from a forward portion ( 70 ) of the die bore.
9. The process according to claim 8 , wherein:
the at least one pin ( 80 ) is twisted at least along a front portion thereof.
10. The process according to claim 8 , wherein:
a cross-section of the at least one pin ( 80 ), taken in a plane perpendicular to the longitudinal axis (A) of the die bore ( 34 ), is not round.
11. The process according to claim 8 , wherein:
the die bore ( 34 ) comprises a die bore peripheral portion ( 96 ) associated with the at least one pin ( 80 );
the die bore peripheral portion merges with a first die bore convex portion ( 98 ) at a first bore edge ( 108 ) and with a second die bore convex portion at a second bore edge; and
the at least one pin is closer to the first bore edge than to the second bore edge.
12. The process according to claim 8 , wherein:
the die bore ( 34 ) comprises a die bore peripheral portion ( 96 ) associated with the at least one pin ( 80 );
the die bore peripheral portion merges with a first die bore convex portion ( 98 ) at a first bore edge ( 108 ) and with a second die bore convex portion at a second bore edge;
a first chamber ( 102 ) is defined between the die bore peripheral portion and a separation plate ( 100 ) that is connected to at least one die bore convex portion;
a second chamber ( 104 ) is defined between the separation plate and the longitudinal axis (A) of the die bore; and
the first chamber is connected to an intake of a first tool material ( 38 ) and the second chamber is connected to an intake of a second tool material.
13. The process according to claim 12 , wherein:
the first tool material ( 38 ) is different from the second tool material.
14. The process according to claim 13 , wherein:
the first tool material ( 38 ) is harder than the second tool material; and
the second tool material is tougher than the first tool material.
15. The process according to claim 13 , wherein:
at least a portion of a length of the fluted portion is made from the first tool material and a remaining portion of the length of the fluted portion is made from the second tool material.
16. The process according to claim 12 , wherein:
the separation plate ( 100 ) is connected to the at least one pin ( 80 ).
17. The process according to claim 12 , wherein:
the first chamber ( 102 ) comprises the first bore edge ( 108 ) and the second bore edge.
18. The process according to claim 12 , wherein:
the first chamber ( 102 ) comprises the first bore edge ( 108 ); and
the second chamber ( 104 ) comprises the second bore edge.
19. The process according to claim 12 , wherein:
the first chamber ( 102 ) comprises the at least one pin ( 80 ).
20. The process according to claim 12 , wherein:
the second chamber ( 104 ) comprises the at least one pin ( 80 ).
21. The process according to claim 2 , wherein:
the insert bore ( 52 ) has a cavity bore diameter (D 2 );
the die bore ( 34 ) has a die bore diameter (D 6 ); and
the cavity bore diameter (D 2 ) equals the die bore diameter (D 6 ).
22. The process according to claim 2 , wherein:
the insert bore ( 52 ) has a cavity bore diameter (D 2 );
the die bore ( 34 ) has a die bore diameter (D 6 ); and
the cavity bore diameter (D 2 ) differs from the die bore diameter (D 6 ).
23. A process according to claim 2 , wherein:
the fixed portion comprises the die; and
the movable portion comprises the cavity insert.
24. A process according to claim 2 , wherein:
the fixed portion comprises the cavity insert; and
the movable portion comprises the die.
25. A process for making a cutting tool green body having a shank and a fluted portion, comprising:
injection molding, into a cavity, a shank of the green body; and
extruding, through a die, a fluted portion of the green body while separating the die and the cavity, such that the shank and the fluted portion have a monolithic construction.