The benefits of computers today are quite diverse, starting as tools to help write, draw, edit photos, play videos, play songs to analyze research data and operate programs to solve scientific, industrial and business problems.
We have long been familiar with gaming devices controlled by computer systems. In the industrial sector, computers have been used to control production machines with high precision (for example, CNC, a multi-purpose machine in the metal industry) so that we can find various metal industrial products that are varied, and we imagine it would be difficult if done manually.
The birth of CNC (Computer Numerically Controlled) machines dates back to 1952 when they were developed by John Pearseon from the Massachusetts Institute of Technology on behalf of the United States Air Force. Originally, the project was intended to make a special, complicated workpiece.
Initially, CNC machining devices required high costs and large control unit volumes. In 1973, CNC machines were still very expensive, so few companies had the courage to pioneer investment in this technology. From 1975, the production of CNC machines began to develop rapidly. This development was driven by the development of microprocessors so that the volume of the control unit could be more compact.
Nowadays, CNC machines are found in almost all fields. From the fields of education and research that use these tools, various useful research results are produced which are not widely used in the daily lives of many people.
The next development is known as the DNC (Direct Numerically Controlled) machine, which is more integrated for mass production in large industries. At the beginning of its development, CNC machines were relatively rare and very expensive, but currently, the use of CNC machines in the manufacturing industry has become more widespread. This is because :
● Production quality demands
● Productivity demands
● Machine prices are getting cheaper
In 1973, CNC machines were still very expensive, so few companies had the courage to pioneer investment in this technology. From 1975, the production of CNC machines began to develop rapidly. This development was driven by the development of microprocessors so that the volume of the control unit could be more compact.
In its use, CNC machines are found in almost all fields, both in education, the manufacturing industry and research. Using these tools produces various useful research results that are not widely used in everyday life among many people.
Compared to conventional machine tools, which are driven manually and semi-automatically, CNC machines have several advantages, including:
● Accurate
● Productive
● Flexibility
● Precise
There are several advantages of using CNC machine tools, namely: high productivity, high workmanship accuracy, uniform product quality and can be combined with additional software such as CAD/CAM software so that the use of CNC machines will be more effective, production time is shorter, production capacity is higher, costs manufacturing inferior products.
In this case, the computer function in the control system is emphasized on software. Software applications as part of the control system on machines that are widely used today are software with CAD/CAM systems.
This software has two main parts, namely CAD (Computer Aided Design) image design and CAM (Computer Aided Manufacturing) image design. CAD drawing design contains product drawings, which include geometric sizes and shapes, while CAM drawing design is in the form of designs regarding the feed process, toolpath, machine setup and other things related to the process or method to produce a product that matches what is drawn in the CAD process.
Combining a CNC machine with CAD/CAM will be more effective because with a CAD/CAM machine, the operator only needs to draw the workpiece, and then the results are saved on a computer or diskette.
After a drawing of the workpiece is created, the operator can look at the drawing again and execute it in simulation form so that if there are errors in the drawing, it can be identified first before executing it on the actual machine. This aims to prevent errors in product manufacturing. Apart from that, programs that have been created (saved) can be used repeatedly (for mass production).
In medium and large industries, you will often find the use of CNC machines to support the production process. Broadly speaking, CNC machines are divided into 2 (two) types, namely
● CNC lathe
● CNC milling machine
CNC lathes are broadly classified into two:
● TU CNC lathe (Training Unit)
● PU CNC Lathe Machine (Production Unit)
Both machines have the same working principle, but what differentiates the two types of machines is their use in the field. CNC TU is used for basic training in programming and operating a CNC equipped with an EPS (External Programing System).
Training Unit type CNC machines can only be used for light work with relatively soft materials. Meanwhile, CNC PU machines are used for mass production, so this machine is equipped with additional accessories such as an automatic opening system that applies hydraulic working principles, chip removal, and so on.
CNC Milling Machines are also broadly classified into two:
● TU CNC Milling Machine
● PU CNC Milling Machine
CNC is a machine used for automatic control in the industrial world. This machine functions to control the performance of other machines used. NC/CNC (Numerical Control/Computer Numerical Control) is a term used to indicate that a piece of manufacturing equipment; for example lathe, milling, etc.; computer-based numerical control that is capable of reading code instructions N, G, F, T, etc., where these codes will instruct the CNC machine to work according to the program of the workpiece to be made and operate it. With CNC machines, the accuracy of a product can be guaranteed to be more than 1/1000 mm, mass product processing with exactly the same results and fast machining times.
In this case, the CNC function replaces the operator's work in conventional machine tools. For example, tool setting work or adjusting the chisel movement until it is ready to cut, cutting movements and movements back to the initial position, etc.
Likewise with setting cutting conditions (cutting speed, feed speed and cutting depth) as well as other setting functions such as changing the tool, changing the power transmission (number of rotations of the main shaft), and direction of rotation of the main shaft, clamping, setting the coolant and so on.
CNC machine tools are equipped with various cutting tools that can create workpieces precisely and can perform numerically directed interpolation (based on numbers). CNC operating system parameters can be changed via the appropriate software program (software load program). CNC has been widely used in the metal industry.
In this condition, CNC is used to control the mechanical system of machine tools and metal cutting. So how thick and long the metal pieces produced by a metal cutting machine can be regulated by a CNC machine. Currently, it is not only the metal industry that uses CNC machine technology as an automation process.
Recently, CNC machines have developed so amazingly that they have changed the factory industry which previously used human labor into automatic machines. With the development of CNC machines, even complex workpieces can be made easily in large quantities. So far, making components/spare parts for a precision machine using manual machine tools is not easy, even if it is done by a skilled machine tool operator.
The solution takes a long time. If there is consumer demand to make components in large quantities in a short time, with the same good quality, of course it will be difficult to fulfil using manual tools. Moreover, if the shape of the workpiece ordered is more complicated, it cannot be completed in a short time.
Economically, the cost of the product will be expensive, making it difficult to compete with market prices.
The demands of consumers who want precise, equally good quality workpieces, in a short time and in large quantities, will be easier to work with CNC (Computer Numerically Controlled) machine tools, namely machines that can work through programming carried out and controlled via computer.
CNC machines can work automatically or semi-automatically after being programmed first via an existing computer. The program in question is a program for making work objects that have been previously planned or designed. Before the workpiece is executed or machined by a CNC machine, it is best to check the program repeatedly so that the program really matches the desired shape of the workpiece, and can actually be done by the CNC machine.
This checking can be done via the monitor screen on the machine or if there is no checking facility via the monitor, it can also be done via a plotter installed on the milling chisel/fake holder. After the program has actually run as planned, it is then carried out/executed by the CNC machine.
In general, the way to operate a CNC machine is by entering numerical commands via the buttons available on the instrument panel on each machine. Each type of CNC machine has its own characteristics according to the factory that makes the machine. However, in general, the characteristics of how to operate a CNC machine can be done in two ways, namely:
In this system, the starting point for placing the cutting tool used as a reference is to set a reference point that remains in effect throughout the machine operation process. For a lathe, the reference point is placed on the axis (center) of the workpiece to be machined at the end.
Meanwhile, on a milling machine, the reference point is placed at the meeting point between the two sides of the workpiece to be worked on.
In this system, the initial placement point used as a reference always moves according to the actual point stated last. For lathes and milling machines, the same method applies. Every time a movement in the workpiece processing process ends, the endpoint of the cutting tool movement is considered the starting point of the cutting tool movement at the next stage.
In line with the growing need for various industrial products with varying levels of difficulty, various variations of CNC machines have been developed. This is intended to meet the needs of types of work with a high level of difficulty. The following shows various variations of CNC machines.
A programming language is a command format in one block using letters, numbers and symbols. Inside the CNC machine tool there is a computer device called the Machine Control Unit (MCU). This MCU functions to translate code language into forms of axis movement according to the shape of the work object.
The language codes in CNC machine tools are known as G and M codes, where these codes have been standardized by ISO or other international bodies. The application of code letters, numbers and symbols on CNC machine tools varies depending on the control system and type of machine used, but the principle is the same.
So for the operation of CNC machine tools of different types there will be no significant differences. For example: CNC machine tools with an EMCO control system, the codes are entered into the DIN standard.
This code language can function as a communication medium between machines and operators, namely to provide data operations for the machine to understand. Entering program data into the machine's memory can be done with a keyboard or other device (diskette, cassette, and via RS-232 cable).
With the development of information technology, in the future it will be possible for CNC machine input to come from manual work drawings which are read via scan and then interpreted by a PC connected to the CNC machine.
The results of the scan reading will be processed by software on the PC into a simulation program in the form of CAD/CAM. Next, the simulation results will be executed into a CNC machine program that is ready to be executed to make the workpiece.
The history of CNC Machine evolution is indeed fascinating. Now, the machines have been an integral part of many industries and fields due to their efficiency and capability. If your business has the goal to increase productivity, there’s nothing better than to invest in good quality CNC Machines.
Yangsen can help you out with quality CNC machines. Get the best of your production cycle with our CNC, drilling, engraving, and milling machines. With more than 20 years of experience in the industry, we want to offer nothing but the best for all our clients.
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