In the process of CNC flame cutting, the subjective and objective factors that can affect the quality of the cutting operation of the CNC flame cutting processing technology are complex and diverse and need to arouse the full attention of relevant technical staff and researchers. In this paper, cutting nozzle selection, cutting nozzle height, cutting speed, oxygen pressure, gas purity, cutting gas selection, cutting sequence and lead wire application and other factors affect the cutting quality of steel plate and their complementary relationship. The method has strong practical performance in actual operation and provides reference and reference for improving the cutting surface quality and achieving high efficiency and low energy consumption during cutting.
Gas purity factor
In the process of flame cutting production and processing technology activities, the actual gas materials that need to be used include not only oxygen materials, but also various combustible gas materials (acetylene materials, propane materials, and natural gas materials). The role of oxygen substances is not only to support and promote the combustion of metal materials but also to completely blow off the oxides produced during the combustion process based on the position of the incision. From this, it can be known that oxygen substances are in the process of cutting processing technology activities. Play a leading role. During the development of gas cutting processing technology activities, the purity of the oxygen substance used is usually set above 99.50%, and every time the purity level of the oxygen substance decreases by 0.50%, the speed parameters in the plate cutting process will occur correspondingly The decrease of about 10.00% will also be accompanied by a significant increase in the actual width of the induced slit structure, a significant increase in the amount of slag below the slit structure, and a significant increase in the amount of oxygen consumption during the cutting process.
During the development of gas cutting processing technology activities, the actual pressure parameter strength level of the oxygen substance should be determined by referring to the typical characteristics of the used cutting nozzle and the actual cutting plate thickness, and it should be determined from the specific face Interpretation and analysis from the perspective of the production and processing technology activity process. Under the condition that the pressure parameter setting level of the oxygen substance is too high or too low, it will usually hurt the actual implementation of the cutting processing technology activity. It will not only affect the cutting of steel plates. The surface structure of the steel will cause deterioration, and it will also induce the width of the slit structure to become larger, and the slag generated during the production process is difficult to be effectively and completely removed.
Cutting nozzle height factor
The height difference between the cutting nozzle and the surface structure of the workpiece to be cut is a representative factor that determines the quality of the cutting structure and the implementation speed of the cutting process.
Under the condition that the height of the cutting nozzle is set too low, it will usually induce the flame core component to directly contact the surface junction component of the technical workpiece to be processed, and induce the upper line part on both sides of the cut structure to collapse, and then the slag Under the condition of splash phenomenon, it will usually cause backfire; under the condition of setting the cutting nozzle height too high, because the temperature of the outer flame component directly in contact with the surface structure component of the technical workpiece to be processed is relatively low, the preheating objectively is directly induced The intensity of the heating technology applied by the flame at the front position of the cut structure is significantly weakened, and the actual effect is insufficient, which in turn induces the actual performance of the relevant technical equipment to significantly reduce the cutting processing capacity, and the slag removal technology operation link is difficult to complete smoothly. The quality performance status of the location causes a certain degree of adverse effects.
Under conventional technical constraints, for the heightened state of the cutting nozzle structure, it should be ensured that the linear distance between the flame core component and the surface structure of the technical workpiece to be processed is between 3.00mm and 5.00mm.
Cutting speed factor
The cutting speed parameter level of the technical workpiece in the cutting processing process is closely related to the actual oxidation process speed state of the metal material inside the cutting technology structure, and the processing can be supported only when the oxidation speed parameter is improved. The material components of the metal materials have been fully burned, and then the speed parameter level has been significantly improved during the actual cutting process.
Under the condition that the cutting processing speed parameter is set too fast, the actual drag amount will usually be too large, and a certain degree of depression or slagging phenomenon may easily appear on the cross-sectional structure formed during the cutting process. Under severe conditions, it may even lead to incomplete cutting; under the condition that the cutting processing speed parameter is set too slow, it will usually cause melting and collapse at the edge of the incision, and technical defects represented by rounded corners will occur at the lower edge.
Cutting nozzle selection
A good cutting nozzle, after adjusting the flame, when the high-pressure cutting oxygen is turned on, you should see a clear, bright, and long straight oxygen jet line. If the oxygen jet line is scattered or broom-shaped, the quality of the cutting nozzle is not good enough, and the cutting surface will be rough during cutting, and it will even be difficult to cut through. When a steel plate is cut, the selection of the cutting nozzle is very important to cutting quality and efficiency. The cutting nozzle selection is mainly determined according to the thickness of the steel plate. The thicker the steel plate, the larger the nozzle model. It is strictly forbidden to use large cutting nozzles instead of small cutting nozzles to cut thin plates, because the large flame heat generated by the large cutting nozzles will cause the deformation of the thin plate parts to increase, and the excessive heat may even melt the cutting lines of the thin plate parts together. The slag is serious and it is difficult to separate the parts. Also, the large-size cutting nozzle has a large aperture, which consumes a large amount of oxygen and is not economical.
Oxygen pressure
The oxygen pressure includes preheating oxygen pressure and cutting oxygen pressure. In actual cutting operations, the preheating oxygen pressure is not very demanding, and it is generally sufficient to keep it at 0.4~0.5MPa. The requirement for preheating oxygen pressure is essentially the requirement and skill of flame power adjustment, that is, the adjustment of the ratio of preheating oxygen to fuel gas. The flame size should be adjusted mainly according to the thickness of the steel plate, the type of cutting nozzle, and the quality requirements. If the flame adjustment is too large, it will not only waste energy and melt the edge of the part cut into a collapsed corner, but also cause the deformation to increase because the part absorbs too much heat; in the case of a certain amount of gas, if the preheating oxygen is adjusted too much, The excessive oxygen has a cooling effect instead, causing the preheating time to be too long when cutting the steel plate, and even easy to break the fire during the cutting process. When cutting ultra-thick (above 60mm) steel plates, due to the extremely slow speed, the flame energy will burn the parts around. In this case, the preheating oxygen must be adjusted to the minimum state during the preheating and cutting, whichever is not to burn the parts.
The quality of flame adjustment plays a decisive role in cutting quality. It is a technical job that requires operators to accumulate experience in long-term practical work.
Cutting gas selection
For the flame cutting machine, the choice of cutting gas also has a great influence on the cutting quality. Currently, available gas options include acetylene, propylene, propane, and MPS. Different gas has different combustion characteristics, so the cutting scenes are different. Appropriate selection of gas is of significance for giving full play to the advantages of gas cutting and realizing high-efficiency and low-cost cutting. Acetylene flame has the characteristics of concentrated heat, high temperature, short preheating time, low oxygen consumption, high cutting efficiency, and small deformation of components. It is suitable for cutting thin plates and introducing shorter parts; while propane flame has heat dispersion, low temperature, and preheating The cutting time is longer than acetylene, the upper edge of the cutting edge is smooth and flat, the lower edge is less dross, easy to remove, and its relative cost is also low. Therefore, the cutting of thick plates and large parts is more economical than acetylene; the propylene flame temperature is higher, and the preheating time is similar. Shorter than propane, slightly increased than acetylene, and because of the high heat content of the outer flame, it is suitable for cutting thick plates and large parts.
Cutting sequence and lead application
A reasonable cutting sequence is conducive to uniform heating of the steel plate, and internal stresses cancel each other, thereby reducing thermal deformation of the parts. Therefore, when cutting the contour of the part, the principle of first inside and then outside, first small and then big, first-round and back, cross-jumping, and first complex and then simple, should be followed to avoid parts displacement, deformation, and size deviation. Reasonable lead position and form are conducive to the complete cut of the part and stable cutting to ensure the contour quality. According to the actual production situation, the introduction position of the outer contour is generally placed at the bottom right of the contour, and the lead form of the inner contour should adopt the arc form.
Comprehensively combine the existing research results, we can know that in the specific operation and use process of the CNC flame cutting machine equipment, the factors that can affect the implementation quality of the CNC flame cutting operation link are diverse because the cutting heat input during the cutting operation The problem of thermal deformation caused by factors is a prominent problem that needs to be faced during the implementation of the technical aspects of flame cutting. Under the premise of a comprehensive and systematic analysis of the effect of cutting technical parameter items on the quality level of the cutting process, combined with the basic experience summarized and refined during the specific cutting process activities, a basic method to control and reduce the degree of thermal deformation during the cutting process is effectively formed. By applying appropriate types of technical control measures, it is possible to effectively control and improve the dimensional control accuracy and surface quality of technical parts during the operation of the CNC flame cutting machine equipment, and improve the overall production efficiency.
