Metals are the raw material for a huge variety of products. In other words, we can make nothing without metals. Almost every product we use consists of metals. There are various metal machining technologies used in the manufacturing industry.
Have you ever thought about how the metals formed into various shapes or products? There are several techniques for that, such as chemical & mechanical processes. When it comes to mechanical techniques, There are a lot of conventional techniques used for shape metals. Some of them are as follows,
Turning (Lathe machine)
We can form the metal parts having a circular profile by turning. A cylindrical chuck holds the workpiece. The chuck rotates with the workpiece (concentric motion). Cutting tools remain stationary near the chuck. They are often movable along 2 axes i.e. Parallel to the workpiece & perpendicular to the workpiece. So we can feed the tip of the cutting too onto the workpiece & cut the metal. Click here to find out more.
Machinists use milling machines to make flat surfaces, chamfers, notches, profiles, drilled holes on workpieces. We can mount our workpiece on the bed of the machine by means of a vice. The cutting tool moves along the X, Y, Z directions. Endmills, drilling tools, boring tools are the most used types of cutting tools. We can penetrate the cutting tools into the workpiece according to the required operation. Click here to find out more.
If a very smooth, fine finished & precise flat surface is required, surface grinding is a suitable technique. the grinder is a spinning wheel made with an abrasive material. The machine consists of the grinding wheel, bed & a clamping chuck. Magnetic chucks used to clamp the ferromagnetic metal pieces. For nonferromagnetic metals, we can use a mechanical vice. The bed is moving in back & forth lateral directions beneath the grinding wheel. So the spinning wheel grinds the surface of the workpiece while it moves linearly. Click here to find out more.
The above mentioned are very few techniques used in the conventional metalworking industry. Apart from that, there are many techniques such as cylindrical grinding, slotting, shaping, tapping, drilling &, etc.
Limitations & challenges of conventional technologies
Some of the limitations of the conventional metal machining technologies are as follows,
Precision & accuracy
Operating a conventional machine is not an easy job. The biggest challenge is precision. Most of the milling & lathe machines have a precision of 0.01mm, but the machine operator should carefully operate the machine until the process ends. If the operator makes a small mistake, the entire workpiece may be discarded. That is, It all depends on the experience & the knowledge of the operator. Since this involves human error, most of the time, it’s difficult to achieve maximum precision.
All these machines consist of tooth wheels. Because of the wearing effect, these wheels get damaged, that is, clearances form between the adjacent wheels ( Play or lash). So there will be a loose motion between the wheels, resulting in accurate movement of machine parts. For example, if you feed the cutting tool for 4 mm depth, the actual movement of the tool may be less than 4 mm. So if there is any wheel play, the operator must consider that.
occupational Safety is another concern. Some of these machines associated with serious hazards. For instant, Lath machines. The spindle is usually a cylindrical chuck. It rotates with high torque. In most lathe machines, there is no guard in order to prevent contact between the chuck & the operator.
Also, some machines have a self-action moving system. That is the machine tool or bed moves automatically. Sometimes the manual handles of the machine are rotating very fast along with the self-action. So these are serious machine hazards.
Development of conventional machining technologies into high technological machines
Today, The industry uses these techniques, not as conventional ones. Now all these operations come as highly automated machines. They have very high accuracy & precision. They are called ‘CNC Machines‘. CNC stands for Computer Numerical Control.
How a CNC machine works ?
Unlike conventional metal machining technologies, CNC machines do their job by itself. The machine operator must program the machine according to the operation. He should specify every single step of the machining process along with all the parameters ( tool data, cutter paths, cutting depths, heights, offsets &, etc). Then he clamps the workpiece on the machine bed. After the program initiation, the machine does the entire job for the workpiece.
So this is a brief explanation of the development of metal machining technology. Our next article will be about CNC machines.
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