CNC is an abbreviation of Computer Numerically Controlled. It is a new feature widely available for machine tools like lathe, milling, drilling, etc. to enhance their working ability and efficiency with the aid of a computer. To date, the working of some of these machines is manually operated which gives no chance for operators to rest or concentrate on other tasks. CNC machines are considered as they offered high average precision and accuracy and also time efficiency.
Today we’ll be looking at the definition, parts, elements, working principle, types, specifications, and applications, as well as the advantages and disadvantages of CNC machines.
What is a CNC machine?
CNC machines can be defined as machine tools that are automatically controlled by means of a computer. CNC machine processes a piece of material like metal, plastic, wood, ceramic, or composite to meet the spec of a coded programmed instruction without a manual operator.
The working program is written by a person or generated by graphical computer-aided design (CAD) software. As for 3D printers, the part to be printed is sliced before the program will be generated on the computer. The second operation of CNC machines is known as Computer-aided manufacturing (CAM), the topic is similar to CAD but discusses the production areas.
Read more: Controls Codes for CNC machines
For some component that requires a number of different tools like drills, mills, saws, etc. modern machines comprise multiple tools into a single cell. However, a number of different machines use an external controller and the component is moved from machine to machine by human or robotic operators. In either case, the steps are applied to parts that require a very close match with the original CAD
How CNC machines work:
The working of a CNC machine is quite interesting due to the fact that it is a computer base. The machine works based on CAD and CAM programs as well as computer control. just as earlier mentioned, CAD is a drawing software of the item to be produced, which serves as a carbon copy of the product. That is, the computer automatically produces what the CAD display. It is also used to improve the productivity of the designer, improve communication through documentation, improve the quality of design, and create a backup file for the next production.
Whereas, CAM (Computer-Aided Manufacturing) features two different codes such as G-codes and M-codes on which all programs are written and fed to the machine to perform various operations i.e. the turning and grooving operation on a lathe.
Read more: Various types of CNC machines
The video below contains the working of the lathe CNC machine:
Below are codes used in CNC programming:
The M-codes represent the miscellaneous machine commands which do not command axis motion. The format is the latter ma followed by two to three digits. Below are five functions:
- [M02 End of Program]
- [M03 Start Spindle – Clockwise]
- [M04 Start Spindle – Counter Clockwise]
- [M05 Stop Spindle]
- [M06 Tool Change]
Read more: Working principles of CNC machines
G-codes are used for commanding specific movements of the machine, such as machine moves or milling functions. G-codes differ between lathe and mill applications. The format is later G followed by two to three digits. Below are some functions of G-codes:
- [G00 Rapid Motion Positioning]
- [G01 Linear Interpolation Motion]
- [G02 Circular Interpolation Motion-Clockwise]
- [G03 Circular Interpolation Motion-Counter Clockwise]
Parts of CNC Machine:
Machine tools that feature CNC comprise the following parts:
- Tailstock quill
- Footswitch or pedal
- Control panel
- Tool turret
Elements of the CNC Machine system:
The following stated below represent the elements of the CNC machining system:
- Tape Reader
- Servo system
- CNC machine tool
Types of CNC Machines:
CNC machines can be classified into the following types:
- CNC laser cutting machine
- 5-axis machine
- CNC Lathe Machine
- CNC Milling Machine
- 3-D Printer
- CNC router Machine
- CNC Plasma Cutting Machine
- Pick and Place Machine
Read more: Parts and elements of CNC machine systems
Specification of a CNC machine can be categorized into the following points:
- Centers height.
- Distance between centers.
- Swing diameter over the bed.
- Swing diameter over the cross slide.
- Transverse movement of the cross slide.
- Hole in the headstock spindle.
- Spindle end-use taper.
- Spindle diameter.
- Spindle end taper.
- Sleeve travel.
- Rapid transverse.
- Programmable feed rate.
Main Spindle specifications:
- Speed range.
- Output power.
Applications of CNC Machine:
These are some applications of CNC Machines:
- The main application of the CNC machine is to work with greater accuracy and automatically control the machine tool.
- This is also used in large fabrication industries.
- This machine is used for the automatic removal of metal from the workpiece.
Advantages and Disadvantages of CNC Machines:
The following stated below represent the advantages of CNC machines:
- mistakes in cutting conditions or in dimension can easily be edited Providing better precision and accuracy to the workpiece.
- Fewer workers are required which helps to save labor costs.
- A highly skilled operator is not required.
- Complex designs with high accuracy in the minimum possible time can be produced on CNC machines.
- It features an online editing program, which means any changes and modifications by the part data stored in the computer without sending the tape for re-processing.
- The conversion of the unit can easily be done by this machine (SI to British or from British to SI).
- It can diagnose its own fault easily, there is special software that enables easy troubleshooting if the CNC system fails to operate, and also have the capability to assist in maintaining and repairing the system automatically.
- It also helps with safety reasons.
- Low Maintenance required
- Reduce setup change over time.
- The CNC Machine has Higher Production and capability.
- It can run for 24 hours a day.
- It is Reliable.
Despite the great benefits of CNC machines some limitations still occur. Well, here are some disadvantages of CNC machines:
- The installation cost is high.
- Even the parts of the CNC machine are high.
- It requires highly skilled professionals to solve issues when a failure occurs.
- Computer knowledge is required.
- Program knowledge is required
That’s it for this article, “Everything you need to know about CNC machines”. I hope the knowledge is attained, you can freely ask a question via our comment section. Don’t forget to share with other students. Thanks!