Types of Broaching Tools Optimal Cutting Equations

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Types of Broaching Tools Optimization Cutting Equations

Typical types of broach tooling are illustrated below. Before the broaching process, a broach access hole or feature is created at a desired and optimal size to facilitate access for the broach tool and minimal material removal requirements.

 Description Broach Illustration Gear Broach- Internal Rectangular Broach Double Keyway Broach Single Keyway Broach Internal Helical Groove Broach Round / Diametric Broach Round / Diametric Broach Square Broach

Optimal Cutting Equations

Broach Tool Teeth Pitch:

The optimal broach tool pitch teeth should be specified by the depth and length of the tool cut, as well as the force required to operate the broaching tool by the machine tool.

Broach Tool Pitch Formulas Equation:

Where:

L = Length of cut by broaching tool (inches)

d = For External broaching, depth of cut per tooth as given by Table A
d = For Internal broaching, depth of cut per tooth per side or one-half difference in diameters of successive teeth for round broach tools.

F = Constant
Brittle material, F = 3 - 4 roughing operations, use 6 for finishing operations.
Ductile material, F = 4 - 7 roughing operations, use 8 for finishing operations.

b = Width of cut removed by broaching tool (inches)

P = Pressure (tons/in2), depth of cut X width of cut ( inches) see Table B

T = Rated capacity of broaching machine (tons)

Design Data Surface Broach Tools
Table A

 Material to be Broached Depth of Cut per Tooth, Inch Face Angle or Rake, Degrees Clearance Angle, Degrees Roughing a Finishing Roughing Finishing Steel, High Tensile Strength 0.0015–0.002 0.0005 10–12 1.5–3 0.5–1 Steel, Medium Tensile Strength 0.0025–0.005 0.0005 14–18 1.5–3 0.5–1 Cast Steel 0.0025–0.005 0.0005 10 1.53 0.5 Malleable Iron 0.0025–0.005 0.0005 7 1.5–3 0.5 Cast Iron, Soft 0.006 –0.010 0.0005 10–15 1.5–3 0.5 Cast Iron, Hard 0.003 –0.005 0.0005 5 1.5–3 0.5 Zinc Die Castings 0.005 –0.010 0.0010 12 5 2 Cast Bronze 0.010 –0.025 0.0005 8 0 0 Wrought Aluminum Alloys 0.005 –0.010 0.0010 15 3 1 Cast Aluminum Alloys 0.005 –0.010 0.0010 12 3 1 Magnesium Die Castings 0.010 –0.015 0.0010 20 3 1

Broaching Pressure P
Table B

 Material to be Broached Depth d of Cut per Tooth, Inch Pressure P, Side-cutting Broaches 0.024 0.010 0.004 0.002 0.001 Pressure P in Tons per Square Inch Steel, High Ten. Strength … … … 250 312 200-.004″cut Steel, Med. Ten. Strength … … 158 185 243 143-.006″cut Cast Steel … … 128 158 … 115-.006″ cut Malleable Iron … … 108 128 … 100-.006″ cut Cast Iron … 115 115 143 … 115-.020″ cut Cast Brass … 50 50 … … ............ Brass, Hot Pressed … 85 85 … … ............ Zinc Die Castings … 70 70 … … ............ Cast Bronze 35 35 … … … ............ Wrought Aluminum … 70 70 … … ............ Cast Aluminum … 85 85 … … ............ Magnesium Alloy 35 35 … … … ............