Multi-Axis CNC Mills are the most common type of Multi-Axis CNC machine used in industry today, as their familiarity to 3-Axis mills
The two most common kinds of Multi-Axis CNC Mills are:
4-Axis HMC's are often the "bread and butter" machine for many machine shops, as they typically offer just the right amount of capacity, capability, and automation for most machined parts
Most often these machines have 3 linear axes (X+Y+Z) and one rotational axis (A), allowing cutting tools to machine all the way around a part along one axis
The benefit here is that for a rectangular part with perpendicular features (ex: Dice), you can access 4 or more sides of the part in a single setup. A part like a 6-sided Die would take a maximum of 2 setups on a 4-Axis HMC, compared to 6 setups on a 3-Axis VMC/HMC
4-Axis HMC's often utilize integrated pallet systems to decrease setup time between operations, with many having pallet pools, with multiple pallets
5-Axis VMC's are the quickest-growing type of CNC Machine on the market today - most shops had zero or maybe a single 5-Axis CNC machine in their inventory less than 10 years ago, and now most shops have multiple 5-Axis VMC's
There are several reasons for this:
Lack of machines; few 5-Axis machine designs existed 10 years ago
Lack/inability of CAM toolpaths to efficiently utilize all 5 axes
Lack of CNC Programmers that know how to safely & efficiently program 5-Axis CNC Machines
Most often these machines have 3 linear axes (X+Y+Z) and t wo rotational axes (A & B), allowing cutting tools to machine at complex angles all the way around a part
Mill-turns combine the functionality of CNC lathes and CNC mills, and come in a variety of shapes, sizes, & axis configurations
Mill-Turns can be generally divided into two categories:
Multi-Axis Lathes have milling capabilities typically one of two ways:
Live-Tooling, of which there are generally two kinds:
Axial Live-Tools, which are fixed parallel with the turning spindle axis (Z), and can mill features on the face of parts or side profiles, similar to 3-Axis milling
Radial Live-Tools, which are fixed perpendicular to the turning spindle axis (Z), and can mill features on the sides of a part, similar to 4-Axis milling
Milling Spindles
A separate, often adjustable-angle milling spindle can achieve part features comparable to that of 5-Axis CNC Mills, with the added speed and efficiency of CNC Lathes
Multi-Axis Mills that have turning capabilities typically do so using the following two things in combination with one another:
High-RPM Rotational Axis (A/B)
By being able to rotate an axis at high enough RPM's, Mills can adequately/efficiently utilize non-rotating cutting tools to achieve turning
Indexable Turning Tools/Spindle
By indexing/clocking (fixing in place) a non-rotating, single-point turning tool in a milling spindle, the tool can be moved against a rotating workpiece to achieve turning
Robots are flexible automation tools, meaning they can be used for a wide variety of applications, including subtractive manufacturing (machining)
Learning to programming a robot to execute subtractive toolpaths is similar and sometimes identical to programming a robot to execute additive toolpaths, pick-and-place operations, and other commonly-utilized applications of industrial and collaborative robot arms
The most common type of Robots used for subtractive manufacturing are 6-axis industrial robot arms
These types of Robots are also often used in conjunction with additional axes (rotary/linear) to increase the functional work envelope of the robot arm and/or allow the arm to machine much larger parts
Contact your instructor to do an in-person Multi-Axis CNC Identification Walkthrough in the Lab
During this walkthrough, you will look for, identify, and (where possible) jog all the axes of the following:
4-Axis CNC Mill
5-Axis CNC Mill
6-Axis Robot
After correctly identifying the multi-axis machines, determine whether or not the machines are "Dedicated" or "Plus" machines
Also determine the capabilities and limitations of the machines based on their construction, axis limits, and other external factors
Just for fun, see if you can identify what the following multi-axis machine pictured to the right is (type, number of axes, etc.):