1: Linear cutting speed:
V=πDN/1000
N=rpm (number of spindle revolutions)
D=￠mm(cutting diameter)
V = M/min
= 3.14
2: Cutting power:
KW=(Ks×V×d×f)÷(6000×λ)
W=Kw (cutting power)
f=advance amount (mm/rev)
d=cutting depth (mm)
λ=0.7～0.85 (mechanical efficiency)
Three: Cut resistance:
P = Ks×q
P=KG
Ks=kg/mm square
q=f×d[Zone de coupe[mm carré]]
Four: Cutting torque:
T=P×(D/2)
T=kg-m
D=￠mm(cutting diameter)
Five: Feed speed and feed quantity:
Vf=N×f
Vf=feed speed (mm/min)
N=rpm (number of spindle revolutions)
f=advance amount (mm/rev)
Six: Drilling time:
T=L/Nf=πDL/1000Vf
T=drilling time (min)
D=￠mm(drill diameter)
L = drilling depth (mm)
V = M/min
f=advance amount (mm/rev)
Seven: Tool tip arc radius compensation:
Z=r(1-tanθ/2)
X=Ztanθ
Z=Z direction correction value
X = X direction correction value
r = radius of the arc of the tool tip
θ = angle between oblique lines
8: Workbench power supply:
Vf=fz×Z×n
Vf = bench feed (mm/min)
fz=feed per tooth (mm/t)
Z=Number of cutter teeth
n=number of cutter turns
CNC Lathe Roughness Calculation Formula and Usage
1: Feed – the greater the feed, the greater the roughness. The larger the feed, the higher the processing efficiency and the lower the tool wear. Therefore, the feed is usually determined last and the feed is determined based on the required roughness.
2: R tool tip – The larger the R tool tip, the lower the roughness, but the cutting force will continue to increase, which requires greater machine tool rigidity and greater rigidity of the material itself. It is recommended that general lathes cutting steel parts below 6150 should not use tool tips higher than R0.8, and hard aluminum alloys should not use tool tips higher than R0 ,4, otherwise shape and position tolerances such as true roundness, straightness, etc. of the machine will be compromised. There is no way to guarantee it, even if the roughness can be reduced, it will be in vain!
3: Calculate the power of the equipment when cutting As for how to calculate the power required for cutting (taking 80% of the motor’s KW as a limit), we will talk about it in the next post. It should be noted that most CNC lathes now use variable frequency motors. The characteristic of variable frequency motors is that the higher the speed, the higher the torque, and the lower the speed, the lower the torque. Therefore, when calculating power, please. Divide the KW of the variable frequency motor by 2 for comparison.
The level of rotational speed is closely related to the linear speed during cutting. Traditional ordinary lathes use a motor with constant rotation speed/torque and rely on mechanical speed changes to achieve the rotation speed change effect, so it is “100% maximum”. Torque output “at any time., which is better than a variable frequency motor. But of course, if your spindle is driven by an expensive constant torque servo motor, it’s perfect.
The main reason for the minimum roughness a lathe can achieve is spindle accuracy. According to the maximum roughness calculation method, if the runout accuracy of your lathe spindle is 0.002mm, which corresponds to a runout of 2 microns, then it is theoretically impossible to do this. machine roughness. Parts with roughness less than 0.002 mm (RY2.0), but this is the maximum possible value. Generally speaking, it is calculated as if 50% of parts with a roughness of 1.0 could be processed. Combined with the RA algorithm, the result will generally not exceed 50% of the RY value, which becomes RA0.5, and then calculate that the wiper blade effect is reduced by 50%. Then the final limit of the lathe with a spindle runout of 0.002 can be processed down to approximately RA0.2 of artifacts.
Daguang focuses on providing solutions such as precision CNC machining services (3-axis, 4-axis, 5-axis machining), CNC milling, 3D printing and rapid prototyping services.
