Model SB1027 | O P E R A T I O N | For Machines Mfg. Since 8/09 |
Setting Spindle Speed
Using the correct spindle speed is important for safe and satisfactory results, as well as maximizing tool life.
To set the spindle speed for your operation, you will need to: (1) Determine the best spindle speed for the cutting task, and (2) configure the mill controls to produce the required spindle speed.
Determining Spindle Speed
Many variables affect the optimum spindle speed to use for any given operation, but the two most important are the recommended cutting speed for the workpiece material and the diameter of the cutting tool, as noted in Figure 33:
To avoid damage to the spindle, gears, or cutting tools:
• Spindle rotation must be turned OFF and |
the spindle must be at a complete stop |
BEFORE you change the spindle speed |
range. |
• The mill is designed to ONLY operate with |
the spindle speed range selector in either |
the high or low position. To avoid damaging |
the moving parts inside the headstock, |
never start spindle rotation without the |
range selector detent pin firmly seated in |
either the high or low position. |
• When changing the spindle speed range |
*Recommended
Cutting Speed (FPM) x 12
Tool Dia. (in inches) x 3.14
= SpindleSpeed (RPM)
and the direction of spindle rotation |
reverses, you will need to either change |
the cutting tool for the direction of spindle |
*Double if using carbide cutting tool
Figure 33. Spindle speed formula for milling.
Cutting speed, typically defined in feet per minute (FPM), is the speed at which the edge of a tool moves across the material surface.
A recommended cutting speed is an ideal speed for cutting a type of material in order to produce the desired finish and optimize tool life.
The books Machinery’s Handbook or Machine Shop Practice, and some internet sites, provide excellent recommendations for which cutting speeds to use when calculating the spindle speed. These sources also provide a wealth of additional information about the variables that affect cutting speed and they are a good educational resource.
Also, there are a large number of
rotation or use the spindle direction switch |
to compensate for the change. |
Setting Spindle Speed Range
Setting the spindle speed range involves using a lever to engage/disengage the spindle spline with the bull gear.
To set the spindle speed range:
1.DISCONNECT MILL FROM POWER!
2.Use the chart below to find the spindle speed range that includes the required spindle speed for your operation.
Spindle Speed Ranges
Low Range |
|
High Range |
|
When the spindle speed range is changed, the direction of spindle rotation will reverse. ALWAYS know which way the spindle
is rotating before beginning the cutting operation.
