Types of Broaching Tools Optimal Cutting Equations

Manufacturing Processes

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

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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:

Minimum Pitch =
Allowable Pitch =

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	…	…	…	............