Many people know the meaning of the idiom "sharpening a knife does not make you cut wood", but few people can really apply it to practical work.
The idiom "sharpening a knife does not delay firewood cutting" means that although sharpening a knife will take some time, it does not delay firewood cutting. The knife is sharp, and the firewood cutting is faster and more efficient. The deeper level of "sharpening the knife does not make mistakes in cutting firewood" is a metaphor for fully preparing in advance, which can speed up work and improve the quality of work.
In the production and processing of stone materials, the saw blade of the bridge cutting machine should not only be sharpened, but also sharpened during use.
After using the saw blade for a period of time, with the wear of the saw blade, the sharpness of the saw blade decreases, the efficiency of cutting plate decreases significantly, the quality of cutting plate is poor, and it emits a sharp sound.
The new saw blade can cut more than 100 square plates a day. After a period of use, the saw blade can only cut more than 80 square plates. Sometimes the output is lower, and the saw blade cannot cut some hard stones. If it is forced to cut, the saw blade will emit sparks, make more sharp noises, and even lift the materials on the workbench sometimes; As the sharpness of the saw blade decreases, the cut board is also terrible. The front side of the board is chipped and corner is dropped, and the edges are serrated; The bottom side is as ugly as a dog.
When the cutting occurs, people who understand the cause of the problem will find refractory bricks to "sharpen" the blade of the saw blade, improve the sharpness of the saw blade, and eliminate the passivation of the saw blade. However, those who do not understand this truth will let this phenomenon continue, and slowly cut the material. The production efficiency is low, and the quality of the cut board products is poor until the saw blade can not be cut. When the height of the blade head is still high, the saw blade can be replaced, which leads to the waste of the saw blade.
I have experienced such a thing before. The factory order cutting task was urgent. I invited several outsourced employees of the bridge cutting machine to the factory to cut the boards of Huangjin Ma and Yabaiyu. When I checked the progress of the board cutting from the night to the next day, I saw a large number of missing edges and corners, as well as jagged edges on the surface. Why is the board cut by outsourcing personnel so bad?
Their reason is that these two kinds of materials, Yabai Jade, have high hardness and many surface cracks. Brittle jade is easy to crack edges and corners. Although Huangjinma is a granite material, it is loose, granular and litchi surface. Therefore, it is easy to cut boards and corners will fall, and jagged surface edges are inevitable. Ask the outsourcing personnel if they have sharpened the knife after cutting the board overnight? They were silent.
Outsourcing personnel only emphasized the causes of edge collapse and corner fall from the objective situation of materials, and did not find responsibility subjectively. They did not sharpen the blade when the blade was not sharp during the cutting process. They only focused on cutting the blade at a high speed and cutting more output (because outsourcing employees are purely piecemeal and earn more money). How can they cut boards of good quality? This is the real reason why there are many edge chippings, corner drops and serrated edges when outsourcing personnel cut boards. Figure 1 shows the edge collapse on the bottom of the plate caused by the sharp blade.
No matter which saw blade factory produces, with the increase of the use time and wear of the saw blade, the saw blade will become sharper and does not need to be sharpened. Especially when cutting marble, granite, quartz stone and rock plate with high hardness, the sharpness will decline faster. Some hard stones even need to be sharpened when cutting one or two large plates to improve the sharpness of the saw blade. The sharpness of the saw blade decreases during use due to internal factors:
No matter what kind of diamond circular saw blade is, whether imported or domestic, it will be subjected to the action of centrifugal force, sawing force, sawing heat and other alternating loads during the stone cutting process without exception. The action of these forces makes the saw blade wear and sharpness continuously decline. The harder the stone is, the more obvious the sharpness is. Due to the force effect and temperature effect, the diamond circular saw blade is worn and destroyed.
According to temperature effect, the influence of temperature on saw blade process is mainly shown in two aspects:
First, lead to graphitization of diamond in the agglomeration;
The other is to cause the thermal stress between the diamond and the matrix, which leads to the premature falling off of the diamond particles.
The new research results show that:
The heat generated in the cutting process is mainly transmitted to the cutter head, and the temperature in the center of the cutter head is not high, generally between 40~120 ℃. However, the temperature of abrasive grinding point is relatively high, generally between 250 ℃ and 700 ℃. However, the coolant only reduces the average temperature of the cutter head and has little effect on cooling the abrasive particles. Such a temperature will not lead to the carbonization of diamond graphite, but will change the friction performance between the abrasive grains and the machined parts, and cause the thermal stress between the diamond and the binder, leading to a fundamental change in the failure mechanism of the diamond.
Temperature effect is the biggest factor affecting the damage of the saw blade. Effective cooling is the precondition to avoid temperature effect. At the same time, appropriate linear speed, cutting depth and feed speed of the saw blade should be adjusted according to the nature of the stone.
Abrasion damage: due to the force effect and temperature effect, the saw blade will often be worn after a period of use. There are five forms of abrasion damage, including abrasive wear, local crushing, large area crushing, falling off, and mechanical abrasion of the bond along the sawing direction.
Abrasive wear: the diamond particles constantly rub with the workpiece, the edges are passivated into a plane, the cutting performance is lost, the friction force is increased, and the sawing heat will make the surface of the diamond particles appear a thin layer of graphitization, the hardness of the diamond is greatly reduced, and the wear is intensified;
Local crushing: the surface of diamond particles bears alternating thermal stress and also bears alternating cutting stress, which will lead to fatigue cracks and local crushing, revealing sharp new edges, which is an ideal wear pattern of large area crushing. The diamond grains bear impact load when cutting in and out. The alternating cutting force makes the diamond grains shake constantly in the bond and become loose. The more prominent grains and grains are consumed prematurely and fall off;
Falling off: the abrasion of the bond itself and the sawing heat during sawing soften the bond, which reduces the holding force of the bond. When the cutting force on the particles is greater than the holding force, the diamond particles will fall off. No matter what kind of wear is, it is closely related to the load and temperature borne by diamond particles. The diamond particles on the surface of the saw blade constantly fall off, and more diamond particles are exposed by sharpening the blade to improve the sharpness of the saw blade.
It is precisely because the saw blade is affected by the inevitable external force factors in the process of cutting stone, the saw blade will not become sharper and sharper, but more and more blunt. The efficiency of cutting plate decreases greatly as the saw blade becomes blunt, and the quality of cutting plate becomes worse and worse. In order to improve the efficiency and the quality of the cutting board, the only way to improve the cutting board is to stop the cutting board and use the refractory brick to sharpen the saw blade, so that the emery wrapped in the matrix is exposed, the sharpness of the saw blade is improved, and its rigid use performance is restored.
Many colleagues in the production management work have encountered such problems: the bridge cutting staff or the machining staff will find you and say, "Leaders, how can you not cut a few square meters of boards?"; How can leaders cut many boards with broken edges and corners, and the diagonal line is not good; The sawblade of the leader is not good and sharp. It can't cut this kind of stone at all. Let's change a good sawblade!
In fact, these problems are mostly caused by the fact that the users of the saw blade do not know that the blade needs to be sharpened during its use. They just regard the immobility of the saw blade as a problem of the quality of the saw blade. When these problems occur, just spend a little time grinding the knife with refractory bricks. The sharpness of the saw blade can be greatly improved, and the cutting quality and efficiency can also be improved.
The sharpening of the saw blade seems to be a small thing, but it is also a small thing that should not be overlooked in production and processing, because cutting a broken board is money, which will affect the normal production.
We can often see that there is no edge collapse or corner drop from the surface to the back of the boards cut by some stone enterprises. The appearance quality of the boards is very beautiful and the verticality of the boards is good. However, some stone production enterprises cut boards with more edge collapse and corner drop, poor appearance quality and poor verticality, One of the reasons is that the sense of responsibility of the employees during the cutting process is not focused on finding the causes and solving these abnormal problems, including judging whether the saw blade needs to be sharpened.
The qualified bridge cutting staff immediately sharpened the blade when they knew that the saw blade was not sharp, so as to improve the sharpness of the saw blade. Although it took a little time, the saw blade became sharp, the cutting speed and efficiency were improved, the cutting quality was better, and the effect of getting twice the result with half the effort was really happy!
