The CNC tour is a high-precision and high-efficiency automated machine-tool. The use of a CNC tour can improve treatment efficiency and create more value. The emergence of the CNC tour allows companies to get rid of late treatment technology. that of ordinary towers. The treatment technology is similar, but as the CNC tour is tight once and performs all the filming processes continuously and automatically, the following aspects must be taken into account.
Reasonable selection of the quantity of cut for an effective cutting of the metal, the material to be treated, the cutting tools and the cutting conditions are the three main elements. These determine the machining time, the lifespan of the tool and the quality of the machining. Economic and effective treatment methods must be based on a reasonable selection of cutting conditions.
The three elements of the cutting conditions: cutting speed, advance and cutting depth cause damage to the tool directly. As the cutting speed increases, the tip temperature of the tool increases, causing mechanical, chemical and thermal wear. If the cutting speed is increased by 20 %, the lifespan of the tool will be reduced by 1/2.
The relationship between the advance conditions and the rear wear of the tool is in a very small beach. However, the advance speed is significant, the cutting temperature increases and wear is significant. It has less impact on the tool than cutting speed. Although the impact of the cutting depth on the tool is not as important as that of the cutting speed and the advance, during the cut with a shallow cutting depth, the cut material will produce a hardened layer , which will also affect the lifespan of the tool. .
The user must choose the cutting speed as a function of the material to be treated, the hardness, the cutting state, the type of material, the quantity in advance, the cutting depth, etc. The most appropriate treatment conditions are selected according to these factors. A regular and stable port to reach lifespan is the ideal condition.
However, in real operations, the choice of the lifespan of the tool is linked to the wear of the tool, to the modifications of the machined dimensions, to the quality of the surface, to the cutting noise, to heat heat treatment, etc. When determining treatment conditions, it is necessary to conduct research based on the real situation. For materials that are difficult to machine such as stainless steel and heat -resistant alloys, you can use cooling fluid or choose a rigid blade.
How to determine the three elements of the cutting treatment and how to properly select these three elements is a main content of the course on the principles of metal cutting. WeChat extracts a few key points and the basic principles for the selection of these three elements:
1) Cutting speed (linear speed, circumferential speed) V (m/min). To choose the spindle towers per minute, you must first know what the linear V -speed should be.
The choice of V: depends on the material of the tool, the material of the part, the treatment conditions, etc. Tool material: Carbide, V can be higher, generally greater than 100 m/min. The technical parameters are generally provided when purchasing blades: what linear speed can be selected when processing which materials.
Quick steel: V can only be obtained a value lower, generally not greater than 70 m/min, and in most cases, it is less than 20 ~ 30 m/min. Part material: High hardness, V must be low; Fonte, V must be low, and when the tool of the tool is carbide, it can be 70 to 80 m/min in low carbon steel, V can be greater than 100 m/min; , non -ferrous metals, V can be higher (100 ~ 200 meters/minute). For soaked steel and stainless steel, V must be lower. Treatment conditions: For coarse machining, V must be lower; For the finish, V must be superior. The rigidity system of the tool-machine, the part to be machined and the tool is poor, V must therefore be low. If the S used by the CNC program corresponds to the spindle laps per minute, then S must be calculated as a function of the diameter of the part and the linear cut of cut v: S (spit towers per minute) = V (linear speed cutting) * 1000 / (3.1416 * Diameter of the part) If the CNC program uses a constant linear speed, then S can use directly the linear V -cut speed (m / min)
2) The quantity in advance (quantity in advance) f depends mainly on the surface roughness requirements of the room. During the finish, the surface requirements are high and the amount in advance of the tool must be low: 0.06 ~ 0.12 mm/spit. During rude machining, it can be larger.
It mainly depends on the resistance of the tool, which is generally greater than 0.3. When the main body of the tool is large, the resistance of the tool is low and the quantity in advance cannot be too large. In addition, the power of the tool-machine and the rigidity of the part and the tool must also be taken into account. The CNC program uses two advances in advance: mm/minute and mm/spindle rotation. The units used above are MM/spindle rotation. If mm/min is used, the formula can be used to convert: advance speed per minute = by. spindle rotation. Quantity in advance of the tool*spindle turns per minute.
3) During the finish, the cutting depth (cutting depth) can generally be less than 0.5 (radius value).
During the draft, it depends on the conditions of the part, the tool and the machine tool. Generally, when a small tour (maximum processing diameter is less than 400 mm) runs steel n ° 45 in standardized condition, the cutting depth in the radial direction is generally obtained. does not exceed 5 mm. In addition, it should be noted that if the spindle speed of the Tour adopts an ordinary regulation of the frequency conversion speed, then when the pin speed per minute is very low (less than 100 ~ 200 rpm), the engine output power will be considerably reduced, and the tool will be cut at that time. The depth and quantity in advance can only be obtained very small.
Reasonable choice of cutting tools
1. During the coarse shooting, you must choose high -resistance and good durability tools to meet the requirements of a large rear cut volume and a large amount in advance during coarse shooting.
2. When you finish shooting, choose high precision and good sustainability tools to guarantee the treatment’s precision requirements.
3. In order to reduce the tool change time and facilitate the adjustment of tools, knives and blades tight by machine should be used as much as possible.
Reasonable selection of lighting
1. Try using universal fixings to tighten the parts and avoid using special fixings;
2. The parts positioning data coincide with each other to reduce positioning errors.
Determine the machining route. The machining route refers to the movement trajectory and the management of the tool in relation to the part during the processing of the indexed control machine tool.
1. The requirements for surface treatment and roughness should be guaranteed;
2. The treatment route should be shortened as much as possible to reduce the inactivity time of the tool. The relationship between the processing course and the machining supplier. Currently, when the CNC towers are not yet widely used, the excess of the extra thickness on the draft, in particular the supplier containing hard and flowing hard layers, must generally be treated on ordinary towers.
If it is necessary to use a CNC tour for machining, you must pay attention to the flexible disposition of the program. Key points for the installation of the necklace: at present, the connection between the hydraulic chuck and the hydraulic tightening cylinder is made by a draft. The key points for tightening the hydraulic chuck are: first, use a key to remove the nut on the. Hydraulic cylinder, remove the traction tube and remove it from the rear end of the spindle. Remove it and use a handle to remove the mandrel fixing screws to remove the chuck.
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