With the rapid development of the household industry, China has become the leader in the total amount of wood processing. At the same time, a large number of artificial boards are used in building decoration, panel furniture and other industries, and China has made great progress in the field of board cutting machinery. For many carpentry workshops or carpentry enthusiasts, table saw is the most important and frequently used woodworking tool. Its basic function is to cut a large piece of wood to achieve the size you need. Direct sawing with a table saw can only cut parallel to the saw blade, but it can make a regular round shape, a square tenon, a round wooden stick, a tapered wooden square and so on when combined with the auxiliary tools.
The use of table saw not only brings convenience to human production and life but also brings some harm to people. For example, when cutting wood, the noise pollution of table saw is very serious, which is harmful to people’s health. Noise is a kind of sound that causes people’s irritability or is too loud to endanger human health. Noise is the sensory hair cells that damage the auditory organ (cochlea) of the ear. Once the sensory hair cells are damaged, they will never recover. The sound of electric sawing wood is about 90 dB. Studies have shown that when the noise is 90 dB, the sensitivity of rod cells in people’s retina to distinguish brightness begins to decline, and the reaction time to identify weak light is prolonged; When it reaches 95 decibels, the pupil will dilate.
Table saws can be divided into push table saws, precision table saws and desktop table saws, among which push table saws are the most widely used sawing equipment in the woodworking industry. The following analysis takes the push table saw as an example.
Why is it so loud when using a table saw?
Summarize the characteristics that push bench saw is easy to produce noise, such as high rotating speed (spindle speed 4000r/min, pre-cutting spindle speed 8000r/min), different rotating speeds, simple transmission system (multi-wedge belt and flat belt transmission), simple working structure (mainly movement components, pre-cutting components and motors are cantilever-mounted, which increases vibration to produce noise), and relatively thin installation is easy to produce noise when working. All these characteristics determine that the push table saw will produce unique noise in the working process. According to the sources of noise, the push bench saw mainly produces two kinds of noise. The first one is the noise caused by vibration due to its own structure and working characteristics, which is usually called structural vibration noise; Secondly, the noise caused by its working characteristic noise and its rheology is called airflow noise.
According to the above classification, taking the push table saw studied in this paper as an example, the causes of noise are analyzed as follows:
structural vibration and noise. First, in the process of cutting board, the noise produced by cutting artificial board is lower than that of cutting solid board. Because the man-made board has been artificially processed, the density of the board is basically unchanged, while the solid wood board is affected by its uneven density, which causes the saw blade to vibrate and produce greater noise. This reason can be summarized as the vibration of the saw blade caused by the workpiece or the noise caused by the vibration of the workpiece itself; Secondly, when cutting the same plate, the noise produced by using saw blades produced by different manufacturers is different. The reason is that the saw blades produced by different manufacturers have different standards, which can be summarized as noise caused by vibration of parts themselves; Thirdly, when the prototype is idling without the saw blade, there are two possible reasons.
- The reason for high-speed rotating shaft, because the two rotating shafts of the push bench saw produce vibration and noise due to uneven material, heat treatment deformation, machining error and assembly error.
- The push bench saw adopts belt drive to transmit torque. Noise caused by friction, rolling and impact in torque transmission. Fourthly, the push bench saw uses the motor as the power source, and it is installed in a cantilever manner, which will produce vibration and noise when the motor runs. In addition, the cantilever installation structure amplifies the noise.
Airflow noise. Airflow noise is due to the fact that a high-speed rotating saw blade will form an airflow field within a certain range. Under the influence of external factors, when the flow speed of the airflow field changes, turbulence and eddy current phenomena will occur around the saw blade, which will lead to vibration of gas and noise.
How do make table saw quieter?
In the prior art, the noise of saw blade sawing is inevitable, but some measures can be taken to improve it. For the noise reduction measures of saw blades, it is generally used to cut noise lines on the base of saw blades, so as to reduce the noise level of saw blades when working. Meanwhile, the stability of the saw blade itself is improved.
Faced with the noise problem of push bench saw, many researchers gave noise reduction measures. Through reading a large number of documents and combining with practice, aiming at the above reasons of noise, noise reduction can be carried out in the following ways:
- R&D and design noise reduction: Many manufacturers of push-table saws, especially those with R&D and design capabilities, should run through the idea of noise reduction in all stages of R&D of push-table saws, so as to reduce the noise of push-table saws at work from the source. Considering the factors of reducing the running noise of the machine, square pipe stiffeners are added on the inner surface of the side plate of the machine body to increase the rigidity of the machine body, thus reducing the noise caused by the vibration of the machine body in the working process. It can also put forward higher requirements for parts processing in the research and development stage to avoid vibration and noise caused by parts processing errors or assembly errors in advance.
- Manufacturing noise reduction. For push-table saw manufacturers, in production and manufacturing, the qualified rate of parts prone to vibration and noise should be guaranteed, and the production process should be innovated to avoid brutal installation and other factors to ensure the quality of push-table saw and control the generation of vibration and noise. For enterprises using push bench saw, it is also a way to reduce vibration and noise by paying attention to the maintenance of the machine in the production process, reducing overload operation and ensuring its smooth operation.
- Do a good job of cooling and lubricating the saw blade. In order to ensure that the noise of the saw blade will not be high due to deflection, the current mature solution is to do a good job of cooling and lubricating the saw blade. Among them, the scheme of adding special cutting oil to a micro-lubricating device is the best solution for cooling and lubricating saw blades. When the cooling oil is sprayed on the saw blade in atomized form by the micro lubricating device, the heat accumulated on the saw blade can be effectively led out, thus ensuring the stability of the saw blade when working. Its own oil consumption is only 0.05 ml per second, which greatly reduces the oil burden of enterprises.
- Passive protection. In the process of using the push bench saw, the harm of vibration and noise to the operator can be avoided by wearing protective equipment, such as wearing earplugs and earmuffs, which can effectively avoid the harm of noise to the ears.
Generally speaking, the noise problem of saw blade is a problem that every enterprise engaged in profile processing has to face and solve. Whether this problem can be properly handled indirectly determines the production and processing level of the enterprise itself and the safety level of the working environment.
Bohrt Company has rich experience in noise control. Welcome to inquire.