Form milling cutter for the machining of titanium alloys etc
A method of manufacturing a multi-tooth fir-tree or bulbous form milling cutter, by the grinding of a blank with a grinding wheel, wherein, a flat clearance angle Θ of between 0° and 20° is generated on each tooth ( 13 ) by the path ( 14 ) of the grinding wheel ( 10 ), with each tooth ( 13 ) having a width (X) from tip to point of maximum clearance (see FIG. 5 ), calculated as follows: —X={[(R tan Θ)cos Θ] cos Θ}±0.25% (being calculation (A)) where R=radius of cutter, and where Θ=clearance angle measured from a tangent to the tooth tip, and furthermore, wherein, each tooth ( 13 ) has a variable depth (Y) around the cutter, calculated as follows: —Y={[πD]/[180/Θ]}0.5±0.2. (being calculation (B)) where D=maximum diameter of the form at any given point along the form. The invention also includes fir tree and bulbous milling cutters produced by the above defined method.
1. A method of manufacturing a multi-tooth fir-tree, or bulbous form milling cutter, by the grinding of a blank with a grinding wheel, wherein,
(i) a flat clearance angle Θ of between 0° and 20° is generated on each tooth, by the path of the grinding wheel, with each tooth having a width (X) from tip to point of maximum clearance, calculated as follows: —
X ={[( R tan Θ)cos Θ] cos Θ}±0.25%
where R=radius of cutter, and
where Θ=clearance angle measured from a tangent to the tooth tip,
and furthermore, wherein
(ii) each tooth has a variable depth (Y) around the cutter, calculated as follows:
Y={[πD]/[ 180/Θ]}0.5±0.2,
where D=maximum diameter of the form at any given point along the form.
2. A method as claimed in claim 1 , wherein Θ is about 12°.
3. A method as claimed in claim 1 , wherein Θ is 6-12°.
4. A method as claimed in claim 1 , wherein the grinding wheel is a form grinding wheel.
5. A method as claimed in claim 1 , wherein the grinding wheel is an angled wheel to contour grind the form.
6. A multi-tooth fir-tree or bulbous form milling cutter produced by the method defined in claim 1 in high speed steel.
7. A multi-tooth fir-tree or a bulbous form milling cutter produced by the method defined in claim 1 in carbide.