Understand the 5 Axis CNC Process
5-axis machining is, as the name suggests, a form of CNC machining in which the cutting tool can move along five axes instead of the usual three.
So how does that work? Well, with a 3-axis CNC machine, the spindle moves up and down, side to side, back and forth. 5-axis machines, in addition to this 3-axis movement, have two further axes in play: either the table rocks side to side on two different axes or the spindle itself swivels on two axes.
Either of these methods (more on their differences later) allow the cutting tool to approach the workpiece from an infinitely greater number of angles, and this makes it possible to create highly complex shapes.
It also reduces the number of setups needed: machinists don't have to manually turn the workpiece over, because the cutting tool can simply reach more places. And this makes the entire machining process much, much faster.
Simultaneous 5 Axis Machining or 3+2 Axis Machining
5-axis CNC machines can differ from one another in another important way. Some 5-axis machines use what is known as "simultaneous" 5-axis machining, while others employ a "3+2-axis" method.
Simultaneous 5-axis
Simultaneous (or continuous) 5-axis machining is a form of 5-axis machining in which the machine can continually adjust movement on all five axes without pause. Simultaneous 5-axis CNC can be very fast, since there are no breaks between passes of the cutting tool.
3+2-axis
Another form of 5-axis machining is 3+2-axis, in which the machine can only move on the 4th and 5th axes (adjusting the angle of the cutting tool) when the cutting tool isn't moving along theX, Y and Z axes. This form of 5-axis machining can be slower than simultaneous 5-axis CNC, but may result in more rigid parts and longer tool life.
Trunnion-Style or Swivel-Rotate-Style
5-axis CNC machines can have dfferent configurations. All have spindles that travel along the X, Y and z axes, but machines can add the two "extra" axes in dfferent ways.The most common types of 5-axis CNC machine are trunnion-style machines and swivel-rotate style machines. Some machines combine features of both.
Trunnion-style 5 axis machine
A trunnion-style CNC machine is a kind of CNC mill with a moving table. That means the angle of the workpiece attached to the table can be adjusted, allowing the cutting tool to hit the material from different angles.
Trunnion-style machines have an A-axis and C-axis, and their advantages include better undercut access, effective removal of heavy materials and a larger overall work volume.
Swivel-rotate-style 5 axis machine
A swivel-rotate-style CNC machine is a kind of CNC mill with a rotating spindle. Adding a B-axis and C-axis to the spindle alows the cutting tool to hit the material from different angles, but in a different manner to a trunnion machine.
Advantages of swivel-rotate-style 5-axis CNC machines include the ability to handle heavy parts, since the table remains stationary, and compatibility with much shorter cutting tools - effectively reducing chatter and increasing accuracy.