Method and apparatus for grinding end cutting tools

Claim 2

In a grinding machine for grinding the gash in a workpiece having helical fluting and to be formed, by cuttiNg the gash, into a tool having helical fluting and end cutting teeth formed by curving radial fluting merging with said helical fluting, said machine including a grinding wheel and means for holding said workpiece, the improvement comprising: a. means for rotatably mounting the workpiece about a first axis approximately perpendicular to the axis of the workpiece for movement of the workpiece into contact with said grinding wheel; b. means for rotatably mounting the workpiece for rotation about its own axis, c. means for mechanically transmitting arcuate movement of said workpiece about said first axis into smooth, accurate, predetermined arcuate movement of said workpiece about its own axis, and d. means for positioning said workpiece relative to said grinding wheel for automatically grinding the gash in said workpiece when said rotary table is arcuately moved, said gash curving from a fade out depth at a nose of said workpiece to a full flute depth blending with one of said helical flutes.

Claim 3

The apparatus according to claim 1 wherein said means for grinding the gash includes means for arcuately rotating said grinding wheel about an axis perpendicular to the axis of rotation of said grinding wheel, slide means for longitudinally moving said grinding wheel along the axis of rotation of said grinding wheel and means for tilting said workpiece in a vertical plane to plus or minus a predetermined number of degrees above and below horizontal.

Claim 4

The apparatus according to claim 2 wherein said workpiece is a ball nose end mill, and wherein said means for grinding the gash in said workpiece comprises means for generating a plurality of grinds for grinding the gash, each successive grind being deeper as it blends with a corresponding helical flute until full flute depth is reached.

Claim 5

The apparatus according to claim 3 including means for tiltably adjusting said grinding wheel to position its axis horizontal, means for tiltably adjusting said workpiece mounting means to position the axis of the workpiece horizontal, and means for vertically adjusting the position of the grinding wheel, whereby said machine can also grind the primary and secondary relief of the end cutting teeth of said ball nose end mill.

Claim 6

A grinding machine for grinding the gash in a workpiece having helical fluting and to be formed, by cutting the gash, into a tool having helical fluting and end cutting teeth formed by curving, radial fluting merging with said helical fluting, comprising: a. a rotary table mounted for arcuate movement about a first axis; b. a work holder fixedly connected to said table for arcuate movement therewith; c. a workpiece holding assembly for holding a workpiece, said assembly being mounted on said work holder for arcuate movement about a second axis, said second axis being the axis of a workpiece held by said assembly; d. means for mechanically transmitting arcuate movement of rotary table about said first axis to a predetermined amount of arcuate movement of said workpiece holding assembly about said second axis, e. a grinding wheel mounted for rotation adjacent to said workpiece, and f. means for positioning said workpiece relative to said grinding wheel for automatically grinding the gash in said workpiece when said rotary table is arcuately moved, said gash curving from a fade out depth at a nose of said workpiece to a full flute depth blending with one of said helical flutes.

Claim 7

A grinding machine for grinding the gash in a workpiece having helical fluting and to be formed, by cutting the gash, into a tool having helical fluting and end cutting teeth formed by curving, radial fluting merging with said helical fluting, comprising: a. a rotary table mounted for arcuate movement about a first axis; b. a work holder fixedly connected to said table for arcuate movement therewith; c. a workpiece holding assembly for holding a workpiece, said assembly being mounted on said work holder for arcuate movement about a second axis, said second axis being the axis of a workpiece held by said assembly; d. means for mechanically transmitting arcuate movement of rotary table about said first axis to a predetermined amount of arcuate movement of said workpiece holding assembly about said second axis, e. a grinding wheel mounted for rotation adjacent to said workpiece, and f. means for positioning said workpiece relative to said grinding wheel for automatically grinding the gash in said workpiece when said rotary table is arcuately moved, said gash curving from a fade out depth at a nose of said workpiece to a full flute depth blending with one of said helical flutes.

Claim 8

The apparatus according to claim 5 wherein the axis of rotation of said grinding wheel is located in a vertical plane, and wherein said grinding wheel includes an assembly mounted for arcuate rotation about a horizontal axis, and also includes movable slide means movable longitudinally of the axis of rotation of said grinding wheel, for orienting the periphery of said grinding wheel in a predetermined position relative to said workpiece for grinding said gash.

Claim 9

The apparatus according to claim 6 wherein said work holder includes means tiltaBly mounting said chuck assembly for positioning said second axis anywhere within the range of from about 20* above to 20* below the horizontal.

Claim 10

The apparatus according to claim 7 wherein said workpiece is a ball nose end mill, wherein said first axis is approximately vertical, said second axis makes an angle of approximately 15 degrees below the horizontal, and said third axis is approximately vertical, and wherein said transmitting means includes a cam connected to a vertical shaft connected to and rotating with said rotary table, and a cam follower in contact with said cam and connected to said workpiece for translating arcuate motion of said cam to arcuate motion of said workpiece.

Claim 11

A grinding machine for doing work on a workpiece comprising: a. a rotary table mounted for arcuate movement about a first axis; b. a work holder fixedly connected to said table for arcuate movement therewith; c. a workpiece holding assembly for holding a workpiece, said assembly being mounted on said work holder for arcuate movement about a second axis, said second axis being the axis of a workpiece held by said assembly; d. means for mechanically transmitting arcuate movement of rotary table about said first axis to a predetermined amount of arcuate movement of said assembly about said second axis, e. said rotary table including a shaft having said first axis as the axis of rotation of said shaft, said shaft being connected to said rotary table for rotation therewith, and wherein said transmitting means comprises: f. a cam mounted on said shaft; g. a cam follower positioned against said cam for following a rise and fall of said cam; h. a rack and pinion assembly mounted on said work holder, said pinion being connected to said chuck assembly for rotation therewith and said rack being in meshing engagement with said pinion; and i. a cable connected at one end to said cam follower and at the other end to said rack, whereby arcuate movement of said rotary table about said first axis is mechanically transmitted to said assembly causing a predetermined arcuate movement about said second axis of a workpiece held by said assembly.

Claim 12

A grinding machine for doing work on a workpiece comprising: a. a rotary table mounted for arcuate movement about a first axis; b. a work holder fixedly connected to said table for arcuate movement therewith; c. a workpiece holding assembly for holding a workpiece, said assembly being mounted on said work holder for arcuate movement about a second axis, said second axis being the axis of a workpiece held by said assembly; d. means for mechanically transmitting arcuate movement of rotary table about said first axis to a predetermined amount of arcuate movement of said assembly about said second axis, e. said rotary table including a shaft having said first axis as the axis of rotation of said shaft, said shaft being connected to said rotary table for rotation therewith, and wherein said transmitting means comprises: f. a cam mounted on said shaft; g. a cam follower positioned against said cam for following a rise and fall of said cam; h. a rack and pinion assembly mounted on said work holder, said pinion being connected to said chuck assembly for rotation therewith and said rack being in meshing engagement with said pinion; and i. a cable connected at one end to said cam follower and at the other end to said rack, whereby arcuate movement of said rotary table about said first axis is mechanically transmitted to said assembly causing a predetermined arcuate movement about said second axis of a workpiece held by said assembly.

Claim 13

The apparatus according to claim 9 including fluid control means for forcing said cam follower into contact with said cam.

Claim 14

The apparatus according to claim 10 wherein said fluid control means comprises an air pressure source, a cylinderpiston assembly including a piston rod associated with said cable such that it can force said cam follower against said cam, an air line connected from said source to said cylinder, a solenoid valve biased to its open condition positioned in said air line, for controlling the application of air pressure to said cylinder, a microswitch for energizing said solenoid valve to its closed condition, a handle for opening and closing said microswitch, said handle being biased to maintain said microswitch open and being movable to close said microswitch only when said handle is used to rotate said rotary table during a forWard (i.e. clockwise) stroke.

Claim 15

The apparatus according to claim 9 wherein said cam has three lobes corresponding to three standard helices used on ball nose end mills.

Claim 18

The method according to claim 13 wherein said simultaneous rotating step comprises mechanically transmitting arcuate movement about said first axis to arcuate movement of said workpiece about its own axis, said transmitting step including providing a generally circular cam on a shaft defining said first axis, said cam having a lead corresponding to the helix angle of said workpiece and positioning said cam in contact with a cam follower connected to said workpiece, whereby said gash will blend with a helical flute of said workpiece.

Claim 21

The method according to claim 15 wherein said grinding step includes positioning said first axis, the axis of the grinding wheel, the axis of the workpiece, and the relative positions of the grinding wheel and workpiece such that a curving radial grind is generated from a fade out depth at the nose of said workpiece to a full flute depth blending with one of said helical flutes.

Claim 22

The method according to claim 16 including reorienting the axes of said grinding wheel and workpiece, after said steps of grinding the gash, such that a grind is generated for grinding the O.D. relief of end cutting teeth of said workpiece, and grinding said O.D. relief.

Claim 23

The method according to claim 13 wherein said grinding step comprises making a series of passes of said workpiece toward said grinding wheel, and incrementally advancing said workpiece and said grinding wheel toward each other after each pass until said gash is completed.

Claim 24

The method according to claim 13 wherein said grinding step comprises grinding a gash with a positive rake.

Claim 25

The method according to claim 13 including adjusting the relative position of said grinding wheel and said workpiece to grind a gash with one of a positive, a negative, and a zero rake.

Claim 26

The method according to claim 15 wherein said grinding step includes repeating said moving step a plurality of times and advancing said workpiece and said grinding wheel toward each other after each of said moving steps until said gash is completed.

Claim 27

The apparatus according to claim 1 wherein said grinding means includes means for grinding a gash with any one of a positive rake, a negative rake, and a zero rake.

Claim 28

The apparatus according to claim 8 wherein said grinding means includes means for grinding a gash with a positive rake.