Table of Contents
What is CNC?
CNC (Numerical Control) machining is a material sampling technology. This means parts create by removing material from a solid block called a work piece using various cutting tools.
This is a fundamentally different manufacturing method compared to additive 3D printing or casting technology. The material sampling mechanism has both design limitations and its advantages.
Digital CNC technology
CNC machining is primarily a digital technology. With its help, you can produce high-precision parts with excellent physical properties directly from the CAD file. Thanks to the high level of automation, CNC machining is cost-competitive, both for single-piece production and for small batch production.
Almost any material can process on a CNC machine. The most common examples are metals (aluminum and steel alloys, brass, etc.), plastics such as ABS or nylon. Composite materials and wood can also process.
The basic CNC machining process can divide into three stages. First, the engineer designs the CAD model of the part. The machine operator then converts the CAD file into G-code and sets up the machine. Finally, the CNC system carries out all the machining operations. Of course, this requires some kind of control over the actions performed by the machine.
5-axis CNC machining
Multi-axis CNC machines come in three varieties: 5-axis indexed milling machines, 5-axis milling machines with continuous machining, and turning / milling machines with a working tool.
These systems are essentially machines with additional degrees of freedom. For example, 5-axis CNC milling machines allow you to rotate the machine bed or tool head (possibly all at once), in addition to three linear axes of movement.
The vast possibilities of these machines entail their increased cost. They require both specialized equipment and operators with expert knowledge. For highly complex or topology-optimized metal parts, 3D printing will take precedence.
Index able 5-axis CNC milling
- During machining, the cutting tool can only move along three linear axes.
- The platform and tool head can rotate between operations, giving access to the work piece at a different angle.
The 5-axis CNC milling system is also called 3 + 2 milling machines. They use only two additional freedoms between machining operations to rotate the working piece.
The main advantage of these systems is that they eliminate the need to manually move the work piece.
So parts with more complex geometries can be produced faster and with greater precision than on a 3-axis CNC machine. However, they lack the capacity for continuous operations.
Pros
- Eliminates the need for manual handling
- Produces complex geometries faster and with greater precision than a 3-axis machine
Cons
- Higher cost than 3-axis CNC machining
- It is impossible to recreate small details on the work piece
Main advantages of CNC machining
- Advanced automation related to numerical power without a computer. This means that the person’s intervention in each step can be reduced or even eliminated. However, there is always manual operation for specific tasks such as repair and prototyping. This allows for more outstanding production simultaneously as CNC machines are competent to run 24 hours a day.
- Higher accuracy and consistency of the pieces acquired. Today’s CNC machines have fantastic precision and repeatability specifications.
- Greater flexibility, being machine tools controlled by a computer program, carrying out new machining that only contains a few minor changes. It concerning a previous job requires loading a saved project, making specific changes, and keeping it separately, as in any other software. This allows quick changes and adaptation to any type of part and eliminates most prototypes.
- Excellent safety because in most movements, the operator has minimal interaction with the machine. Previously, when intervening in actions such as changing heads, loading material, stopping an activity, etc., there were more chances of having accidents.
