How to Increade Linear Feed Rate Milling

This page introduces formulas for calculating basic parameters necessary for face milling. The figures obtained from the calculation are for reference only. The conditions for machining depend on the machine tool you are using. Use the optimal conditions according to your actual machining circumstances.

• Cutting Speed (vc)
• Feed per Tooth (f)
• Table Feed (Vf)
• Machining Time (Tc)
• Net Power (Pc)
• Kc Values

• π (3.14): Circular constant
• DC (mm): Cutter diameter
• n (min^-1): Spindle speed

memo

This formula is used to calculate the cutting speed from the spindle speed and the outer diameter of the cutter.
Example:
Cutter diameter (DC) = 100 mm
Spindle speed (n) = 400 min^-1
In this case, the cutting speed (vc) is approximately 125.6 m/min.

• vf (mm/min): Table feed per minute
• z: Number of teeth
• n (min^-1): Spindle speed (Feed rate fr = zxfz)

memo

This formula is used to calculate the feed per tooth from the table feed per minute (feed rate), the number of teeth, and the spindle speed.
Example:
Table feed per minute (vf) = 450 mm/min
Number of teeth (z) = 10
Spindle speed (n) = 600 min^-1
In this case, the feed per tooth (f) is 0.075 mm/t.

• fz (mm/tooth): Feed per tooth
• z: Number of teeth
• n (min^-1): Spindle speed (Feed rate fr = zxfz)

memo

This formula is used to calculate the table feed per minute (feed rate) from the feed per tooth, the number of teeth, and the spindle speed.
Example:
Feed per tooth (fz) = 0.2 mm/tooth
Number of teeth (z) = 8
Spindle speed (n) = 600 min^-1
In this case, the table feed rate is 960 mm/min.

• L (mm): Total table feed length (Length of material (l) + Face mill diameter (DC))
• vf (mm/min): Table feed per minute

memo

This formula is used to calculate the machining time from the total table feed length and the table feed per minute (feed rate).
Example of finishing a block of FC200 cast iron to have a flat surface of:
Width = 150 m
Length = 250 mm
Face milling conditions used:
Feed per tooth (fz) = 0.35 mm
Number of teeth (z) = 12
Spindle speed (n) = 200 min^-1
Cutting speed (vc) = 120 m/min
Face mill diameter (D1) = 220 mm
In this case,
the table feed per minute (vf) and the total table feed length (L) are:
vf = 0.35 × 12 × 200 = 840 mm/min
L = 350 + 220 = 570 mm
Substitute these values into the formula:
Tc = L ÷ vf
= 570 ÷ 1120
= 0.679 (min) × 60
= 40.74 (sec)
The machining time (Tc) is approximately 40.74 seconds.

• ap (mm): Depth of cut
• ae (mm): Width of cut
• vf (mm/min): Table feed per minute
• Kc (MPa): Specific cutting force
• η: Machine efficiency

memo

This formula is used to calculate the net power required for face milling based on the depth and width of cut, the table feed per minute, the specific cutting force, and the machine efficiency. Example of calculating the net power required to cut tool steel with:
Depth of cut (ap) = 5 mm
Width of cut (ae) = 70 mm
Table feed per minute (vf) = 300 mm/min
Other conditions:
Specific cutting force (Kc) = 1800 MPa
Machine efficiency (η) = 80% (0.8)
Cutting speed (vc) = 80 m/min
Cutter diameter (DC) = 250 mm
Number of teeth (z) = 16
In this case, first you calculate the spindle speed (n) and then the feed per tooth of the cutter (fz).
Spindle speed (n) = 1000・vc ÷ π・D
= (1000 × 80) ÷ (3.14 × 250)
= 101.91 min^-1
Feed per tooth (fz) = vf ÷ (Z × n)
= 300 ÷ (16 × 101.91)
= 0.184 mm/tooth
Substitute the above into the formula:
Pc = (5 × 70 × 300 × 1800) ÷ (60 × 10⁶× 0.8)
= 3.937 kw
The net power required for face milling (Pc) is approximately 3.94 kW.

Workpiece material	Tensile strength (MPa) and stiffness	Specific cutting force Kc (MPa) for each feed
		0.1 (mm/tooth)	0.2 (mm/tooth)	0.3 (mm/tooth)	0.4 (mm/tooth)	0.6 (mm/tooth)
Mild steel (SS400, S10C, etc.)	520	2200	1950	1820	1700	1580
Medium steel (S45C, S50C, etc.)	620	1980	1800	1730	1600	1570
Hard steel (S55C, S58C, etc.)	720	2520	2200	2040	1850	1740
Tool steel (Carbon tool steel (SK), etc.)	670	1980	1800	1730	1700	1600
Tool steel (Alloy tool steel (SKS), etc.)	770	2030	1800	1750	1700	1580
Chrome-manganese steel (Manganese carbide (MnC), etc.)	770	2300	2000	1880	1750	1660
Chrome-manganese steel (Manganese carbide (MnC), etc.)	630	2750	2300	2060	1800	1780
Chrome molybdenum steel (SCM grades, etc.)	730	2540	2250	2140	2000	1800
Chrome molybdenum steel (SCM grades, etc.)	600	2180	2000	1860	1800	1670
Nickel chrome molybdenum steel (SNCM415, etc.)	940	2000	1800	1680	1600	1500
Nickel chrome molybdenum steel (SNCM439, etc.)	352HB	2100	1900	1760	1700	1530
Austenitic stainless steel (SUS304, etc.)	155HB	2030	1970	1900	1770	1710
Cast steel (SCC, etc.)	520	2800	2500	2320	2200	2040
Hard cast iron	46HRC	3000	2700	2500	2400	2200
Meehanite cast iron (FC350, etc.)	360	2180	2000	1750	1600	1470
Gray cast iron (FC250, etc.)	200HB	1750	1400	1240	1050	970
Brass (C3710, etc.)	500	1150	950	800	700	630
Light alloy (Al-Mg, A5005, etc.)	160	580	480	400	350	320
Light alloy (Al-Si, A4032, etc.)	200	700	600	490	450	390
Light alloy (Al-Zn-Mg-Cu, A7075, etc.)	570	880	840	840	810	720

INDEX

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Source: https://www.keyence.com/ss/products/measure-sys/machining/formula/milling.jsp

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