How does the cutting force changes with rake

How does the cutting force changes with rake - eliminate...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
How does the cutting force changes with rake angle? Applications: Machining Grinding Friction Wear Prof. Christopher Brown WPI
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Machining forces and Friction α sin cos c t F F F + = sin cos t c F F N - = φ sin cos t c s F F F - = cos sin t c n F F F + = Rake face Frictional force and normal force Shear plane forces F t F n F c F s N F = = τ μ tan tan tan t c c t F F F F - + = Tool workpiece friction coefficient µ 90-(τ-α+φ)
Background image of page 2
Fc=Fs cos φ + Fn cos (90- φ) Use Trig identity Fc=Fs cos φ + Fn sin (φ) 1. Write Fc in terms of Fs and Fn
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Eliminate Fn From the geometry of Merchant’s circle Fn=Fs/tan(90- (τ-α+φ)) =Fs tan(τ-α+φ) Fc=Fs cos φ + Fs tan(τ-α+φ)sin (φ) Fc=Fs (cos φ + tan(τ-α+φ)sin (φ))
Background image of page 4
Fs=S w doc/sin φ (shear stress * area) Fc=Sw doc/sin φ (cos φ + tan(τ-α+φ)sin (φ)) Fc=S w doc (cot φ + tan(τ-α+φ)) Write Fs in terms of shear stress and cutting geometry
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
φ = 45-τ/2+α/2 (Merchant) Fc=S w doc (cot (45-τ/2+α/2) + tan(τ-α+ 45- τ/2+α/2)) Fc=S w doc (cot (45-τ/2+α/2) + tan(45+τ/2-α/2) Use Merchant’s equation to
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: eliminate the shear angle Normalize and simplify Fc/Swdoc = (cot (45-/2+/2) + tan(45+/2-/2) Use trig identity Fc/Swdoc = 2tan(45+/2-/2) Fc=Fs cos + Fn cos (90- ) 1. Fc=Fs cos + Fn sin () 2. Fn=Fs/tan(90- (-+))=Fs tan(-+) Fc=Fs cos + Fs tan(-+)sin () 3. Fc=Fs (cos + tan(-+)sin ()) 4. Fs=S w doc/sin (shear stress * area) Fc=Sw doc/sin (cos + tan(-+)sin ()) 5. Fc=S w doc (cot + tan(-+)) 6. = 45-/2+/2 (Merchant) Fc=S w doc (cot (45-/2+/2) + tan(-+ 45-/2+/2)) 7. Fc=S w doc (cot (45-/2+/2) + tan(45+/2-/2) Fc/Swdoc = (cot (45-/2+/2) + tan(45+/2-/2) 8. Fc/Swdoc = 2tan(45+/2-/2) Normalized cutting force versus rake angle 2 4 6 8 10 12 14 16 18 20-60-40-20 20 40 60 rake angle degrees normalized cutting force =0.8 =0.6 =0.4...
View Full Document

This note was uploaded on 04/29/2008 for the course ME 1800 taught by Professor Brown during the Winter '08 term at WPI.

Page1 / 9

How does the cutting force changes with rake - eliminate...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online