Reduced material manufacturing is different from additive manufacturing technology in that it involves removing materials to produce parts of the required size. They are now deployed in many industries, such as aviation, automotive, metallurgy, etc. The article in this issue of the Antarctic bear carefully discusses the differences between reduced and additive manufacturing, as well as their complementary effects on each other. Firstly, there are various types of reduced material manufacturing methods, just like additive manufacturing involves multiple processes. For example, you may have heard of the term "CNC machining". It is the acronym for computer numerical control, covering material removal techniques based on numerical programs for controlling machine tools, such as drilling, turning, milling, or boring, which we often discuss. CNC machining can now be compatible with a wide range of materials, from plastics to metals. That is to say, not all reduction manufacturing technologies use digital programs. Next, we will also introduce some popular cutting methods.
What is CNC machining?
CNC machining includes several processes, introducing turning and drilling techniques, and the machining process is specific to moving parts on a rotating axis. The energy required for machining parts is provided by the motion of the parts themselves. These methods make it possible to manufacture any part modeled after rotation. Specifically, it is a two-dimensional drawing infinitely replicated along the axis of rotation, forming a three-dimensional model. Although the names are different, turning and boring are very similar because they both use the same principles. The main difference is that boring works inside the part, while turning works outside, allowing for the processing of wood, metal, and certain plastic materials. Turning and boring machines are now appearing in many industries, such as the automotive, aerospace, medical, and even decoration sectors.
Let's continue to discuss another technology, namely milling. Milling has extremely high accuracy, the ability to create parts with internal cavities, and the ability to process parts, making it an extremely important manufacturing method. This technology uses milling cutters to cut materials horizontally. This means that when the milling cutter is in the material, it can move vertically and remove the material along its path. Due to its suitability for various tasks and material processing, milling is compatible with many materials. However, this method also has some drawbacks, which can reduce its processing convenience. For example, the processing of a part is usually divided into several steps/operations, which require regular tool replacement.
The tools used for drilling and milling are very similar, but should not be confused. Drilling is only used to round holes with a drill bit. Although milling provides greater manufacturing freedom, especially allowing for the production of holes or shapes with diameters larger than oneself, drilling allows you to drill holes with diameters equal to the drill bit diameter. Although there are many advantages, milling is much slower than drilling when drilling, which is why drilling is more suitable for continuously performing several identical cuts. Although CNC machining includes many technologies, reduced material manufacturing is not limited to these. Other methods, such as cutting, are also adopted by many industries.

Different cutting techniques
Some people use laser cutting, such as in the automotive manufacturing industry using lasers to produce precision parts such as brake pads, while others choose EDM. EDM, also known as discharge machining, comes in three forms: wire cutting, sinker cutting, and fast drilling. Unlike traditional drilling, it can use electrodes to drill thinner and deeper holes. Although these different methods are relatively slow, their difference from other methods lies in their accuracy. Electrical discharge machining can be applied to the production of parts made of concrete, stone, metal, and many other materials.
In addition to discharge machining, laser cutting is also a commonly used cutting technique. This technology can quickly and accurately cut several materials through lasers with a power of several hundred watts. For example, for parts with a cutting area of 1 square millimeter, the tolerance is plus or minus 20 micrometers. In addition to cutting, laser machines can also perform carving. There are two forms of laser cutting machines. Carbon dioxide lasers and fiber lasers are used for cutting and carving metals. Although laser cutting machines have many advantages, they also have some drawbacks: when operating such machines, harmful gases may be released. In addition, due to the fact that lasers cut materials through heat, the laser itself may overheat. Therefore, it is necessary to cool it, which often requires additional auxiliary equipment.
Among several major reduction manufacturing processes and more specific cutting techniques, we have found that water jet cutting. This process is based on the use of a water jet, accompanied by abrasive, to impact the surface of the material at high speed. This leads to material shrinkage and separation, forming the desired shape. A high-pressure compressor is needed to generate this water jet. The nature of the jet and related materials will affect the depth and speed of cutting. This technology is very popular in the aerospace, automotive, and mechanical industries. It has high precision, is compatible with many materials, and unlike various reduction processes, it is not harmful. When other processes generate chips, dust, or smoke, water jet cutting eliminates all of this waste because the water jet carries it away along its path.