Machining Metal Removal

Written by Jerry Ratzlaff on . Posted in Welding Engineering

Cutting Speed formula

\(\large{ v_c =  \pi \; d_o \; N  }\)  

Where:

\(\large{ v_c } \) = cutting speed

\(\large{ d_o } \) = origional diameter of workpiece

\(\large{ \pi } \) = Pi

\(\large{ N } \) = rotation speed of workpiece

 

Cutting Time formula

\(\large{ t_c =  \frac{ l }{ f \; N }  }\)  

Where:

\(\large{ t_c } \) = cutting time

\(\large{ f } \) = feed

\(\large{ l } \) = length of cut

\(\large{ N } \) = rotation speed of workpiece

 

Cubic Inch Per Minute Metal Removal Rate formula

\(\large{ CIP =  SFM \; 12 \;\; IPR \; d_o   }\)  

Where:

\(\large{ CIP } \) = cubic inch per minute metal removal rate

\(\large{ IPR } \) = inches per revolutions feed rate

\(\large{ d_o } \) = origional diameter of workpiece

\(\large{ SFM } \) = surface feet per minute

 

Feed formulas

\(\large{ f =  \frac{ l_m }{ v }  }\)  
\(\large{ f =  v \; f_t \; Z   }\)  

Where:

\(\large{ f } \) = feed

\(\large{ f_t } \) = feed per tooth

\(\large{ l_m } \) = machined length per minute

\(\large{ Z } \) = number of flutes

\(\large{ v } \) = spindle speed

 

Feed Rate formulas

\(\large{ fr =  \frac{ HP }{ MMF \; c_d \; c_w }  }\)  
\(\large{ fr = RPM \; N \; CL  }\)  

Where:

\(\large{ fr } \) = feed rate

\(\large{ CL } \) = clip load per tooth

\(\large{ c_d } \) = cut depth

\(\large{ c_w } \) = cut width

\(\large{ HP } \) = horsepower

\(\large{ MRR } \) = material removal rate

\(\large{ N } \) = number of teeth on the cutter

 

Horsepower formulas

\(\large{ HP = MRR \; MMF }\)  
\(\large{ HP =  MMF \; c_d \; c_w \; fr  }\)  

Where:

\(\large{ HP } \) = horsepower

\(\large{ c_d } \) = cut depth

\(\large{ c_w } \) = cut width

\(\large{ fr } \) = feed rate

\(\large{ MMF } \) = material machining factor

\(\large{ MRR } \) = material removal rate

 

Inches per Minute Feed Rate formula

\(\large{ IPM =  RPM \; IPR  }\)  

Where:

\(\large{ IPM } \) = inches per minute feed rate

\(\large{ IPR } \) = inches per revolutions feed rate

\(\large{ RPM } \) = revolutions per minute

 

Inches per revolutions Feed Rate formula

\(\large{ IPR =  \frac{ IPM }{ RPM }  }\)  

Where:

\(\large{ IPR } \) = inches per revolutions feed rate

\(\large{ IPM } \) = inches per minute feed rate

\(\large{ RPM } \) = revolutions per minute

 

Material Machining Factor Table

MaterialMMF
Aluminum 0.12
Brass 0.4
Low-carbon Steel 1.25
High-carbon & Low-alloy Steel 1.5 - 1.9
Stainless and Tool Steels 1.8 - 2.2
Super Alloys 2.5 - 5.0

 

Material Removial Rate formula

\(\large{ MRR =  c_d \; c_w \; fr }\)  

Where:

\(\large{ MRR } \) = material removal rate

\(\large{ c_d } \) = cut depth

\(\large{ c_w } \) = cut width

\(\large{ fr } \) = feed rate

 

revolutions Per Minute formula

\(\large{ RPM =  \frac{ SFM \; \frac{12}{ \pi }  }{ d_o }  }\)  

Where:

\(\large{ RPM } \) = revolutions per minute

\(\large{ d_o } \) = origional diameter of workpiece

\(\large{ \pi } \) = Pi

\(\large{ SFM } \) = surface feet per minute

 

Surface Feet Per Minute formula

\(\large{ SFM =  \frac{ RPM \; d_o \; \pi }{ 12 }  }\)  

Where:

\(\large{ SFM } \) = surface feet per minute

\(\large{ d_o } \) = origional diameter of workpiece

\(\large{ \pi } \) = Pi

\(\large{ RPM } \) = revolutions per minute

 

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