What is SPINDLE OVERRIDE?

What is SPINDLE OVERRIDE?

SPINDLE OVERRIDE is a function on the Operation Panel of CNC machines used to adjust Spindle's rotational speed to "percent" while the machine is running.

On the control panel, it is often found as a knob or switch that says:

SPINDLE OVERRIDE

Around the knob are percentage numbers such as 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120% to 150%. The percentage range of each machine may vary by model and manufacturer.

What does the number on the knob mean?

Under 100%

= Spindle rotates slower from the reference speed.

100%

= Use the speed according to the reference level.

Above 100%

= Spindle spins faster from the reference speed.

The important point is that the number on the knob is "percent," not directly rpm.

50% doesn't mean 50 rpm.

100% doesn't mean 100 rpm.

120% doesn't mean 120 rpm.

These are the proportions used to adjust the Spindle speed from the reference speed at the time.

Example of calculation

Suppose the reference speed while running is 1,000 rpm.

50%

1,000 × 50% = 500 rpm

80%

1,000 × 80% = 800 rpm

100%

1,000 × 100% = 1,000 rpm

120%

1,000 × 120% = 1,200 rpm

The principles are:

Reference Speed × SPINDLE OVERRIDE (%) = Adjustable Rear Speed

So when the percentage changes, the Spindle speed changes according to the proportion.

Percentage is equal. Why is rpm not equal?

Because the result depends on the reference speed that is calculated.

Case 1

Reference speed of 1,000 rpm

SPINDLE OVERRIDE 50%

1,000 × 50% = 500 rpm

Case 2

Reference speed 2,000 rpm

SPINDLE OVERRIDE 50%

2,000 × 50% = 1,000 rpm

Both cases set SPINDLE OVERRIDE at 50% the same, but the rear speed is not adjusted because the reference speed is different.

So 50% is "proportion," not fixed cycle speed.

When is SPINDLE OVERRIDE used?

1. Conditioning cutting during work

When sound, vibration, debris, or cutting conditions are found to be inappropriate, percentages can be added or reduced to observe the resulting effect.

2. Reduce speed when high heat occurs

If abnormal heat is found, Spindle speed can be temporarily reduced to observe working conditions.

3. Vibration reduction

In some situations, the Spindle speed adjustment may help to observe and find the right range of speeds to cut.

4. Trial adjustment during operation

It can increase or decrease the percentage gradually to see the effect on sound, vibration, debris and skin.

Caution

Increasing beyond 100% means the Spindle rotates faster from the reference speed, so the limits of the tool, workpiece and fixture must be considered.

Improper speed can cause oscillation, affecting work skin, tool life, and cutting conditions.

On the other hand, reducing a large percentage does not always mean that it is more appropriate or safer, because too low a speed can also cause cutting conditions to change.

Therefore, it should be adjusted gradually and the actual effect observed during work.

Summary

SPINDLE OVERRIDE is a function on the Operation Panel for adjusting Spindle speed as a percentage from the reference speed.

Under 100% = Slow Down

100% = Reference level

Above 100% = Faster

The percentage on the knob is not a direct rpm value, and the same percentage may get different rpm if the reference speed is different.

Easy to remember:

SPINDLE OVERRIDE = Spindle Speed Percentage Adjustable Knob

# SpindleOverride # SpindleSpeed # CNCProgramming # CNCLathe # CNCMachining