The requirement of the rigid structure of numerical control machine tool
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source:TECHEN CNC Machining
In the first phase that numerical control machine tool develops, the change with its machinery structure and more how old than doing not have photograph of general purpose machine tool, just mix in automatic gearshift, tool carrier the respect such as automatic dislocation and handle operation makes workbench some of change. As the development of numerical control technology, the control way that considers it and use characteristic, just raised taller requirement to precision of the productivity of the machine tool, treatment and life. The main body orgnaization of numerical control machine tool has the following characteristic: Because 1) used main shaft of high-powered infinitely variable speeds and servo transmission system, the ultimate drive structure of numerical control machine tool simplifies greatly, transmission catenary also shortens greatly; 2) machines productivity to suit to successive automation is machined and rise, structure of machinery of numerical control machine tool has taller static, dynamic stiffness and damp precision, and taller wearability, and heat is out of shape small; 3) chafes to reduce, eliminate transmission clearance and obtain taller treatment precision, used efficient drive disk assembly morely, be like ball guide screw deputy with scroll slideway, disappear unoccupied place positive drive deputy etc; 4) works for improvement condition, reduce auxiliary time, improvement to operate a gender, improve labor productivity, used cutting tool library of automatic clamp device, knife and trade the auxiliary unit such as knife device and unit of automatic platoon bit automatically. According to the applicable circumstance of numerical control machine tool and orgnaization characteristic, because raise the following requirement,logarithm controls machine tool construction: One, taller machine tool is static, the statement that uses data-in means to offer according to numerical control process designing or hand undertakes use machine tool of stiffness numerical control automatically machining. As a result of rigid structure (wait like machine tool lathe bed, slideway, workbench, tool carrier and main shaft box) geometrical precision and in be out of shape the fixed position error of generation is machining a process, cannot adjust for the ground with compensation, accordingly, must everywhere the flexibility that rigid structure part produces is out of shape control is in minimal inside, in order to assure the treatment precision of a requirement and exterior quality. To raise the stiffness of main shaft of numerical control machine tool, not only often use the 3 structures that prop up, and choose the biserial with steel very good sex bearing of short columnar roller and horn contact join with a hinge of afferent thrust bearing to go out believe errorring force bearing, be out of shape in order to reduce the radial of main shaft and axial. To raise the machine tool is big stiffness, use close interfacial lathe bed, use fluid equilibrium to because the position changes positional machine tool is out of shape,reduce mobile part. To raise a machine tool the osculatory stiffness of each component, increase the carrying capacity of the machine tool, use the contact that blows grinding method to increase unit area to go up to nod, bring to bear on between combinative scale enough big increase load beforehand, in order to raise osculatory area. These measure raise osculatory stiffness effectively. To develop the efficient process capability of numerical control machine tool adequately, can undertake stabilizing cutting, below the premise that assures static stiffness, still must raise dynamic stiffness. Commonly used measure basically has the stiffness that improves a system, increase damp and adjust component part wait from Zhen Pin rate. The experiment makes clear, raising damp coefficient is improvement is fought brace up effective method of the gender. Of armor plate solder the structure can increase static stiffness already, reduce structural weight, can increase the damp of component part itself again. Accordingly, used armor plate to solder on numerical control machine tool in recent years structural lathe bed, pillar, beam and workbench. Seal arenaceous cast to also be helpful for oscillatory attenuation, fight to rising brace up the gender also has better effect. 2, below the heats up the heat source outside be out of shape inside effect that reduces a machine tool, each component will produce the machine tool the heat of different level is out of shape, make the opposite motion concern between workpiece and cutting tool breaks ring, also be machine tool quarter drops. To numerical control machine tool, because full treatment process is calculative instruction pilot, hot metabolic effect is more serious. Be out of shape to reduce heat, adopt the following measure normally in structure of numerical control machine tool. The generation when reducing interior of calorific machine tool to give out heat heats up metabolic main heat source, ought to go out heat source as far as possible from the depart in lead plane. After control temperature rise was taking a series of step that reduce heat source, hot metabolic circumstance will be improved somewhat. But the heat source of inside and outside that should eliminate a machine tool completely is very difficult normally, it is impossible even. Must be heated up through coming loose goodly so and refrigeration will control temperature rise, in order to reduce the effect of heat source. Its are mid more effective method is the calorific place in the machine tool cools compulsively, also can adopt heating method in part of machine tool low temperature, the temperature that makes the machine tool is nodded each tends consistent, can reduce the warpage that causes as a result of difference in temperature so. Improve machine tool orgnaization to be below likewise calorific condition, machine tool orgnaization is out of shape to heat also have very big effect. The odd pillar orgnaization that if numerical control machine tool goes,uses is possible be replaced by place of double column orgnaization. Because control semmetry, the main shaft line after be heated of double pillar orgnaization divides the translation that produces perpendicular way outside, of other direction be out of shape very small, and the correction that the axes shift of perpendicular direction can use a coordinate conveniently undertakes compensating. Axial heat is out of shape on the perpendicular way that produces in cutting tool to be cut. This can make main shaft heat is out of shape the influence to machining a diameter is reduced minimal. Still should reduce main shaft center and main shaft as far as possible on the structure the distance to the ground, in order to reduce hot metabolic gross, should make the around temperature rise of main shaft box concurrent at the same time, after avoiding main shaft to be out of shape, appear tilt. The ball guide screw in numerical control machine tool often is in predicting load big, rotate speed is high and medicinal powder the job below the condition of hot difference, because this guide screw is easy calorific. The consequence that ball guide screw heats up production to cause is serious, it is especially in open loop system, it can make feed system loses fixed position precision. At present certain machine tool reduces the heat of guide screw to be out of shape with the method that helps beforehand. Be out of shape to adopting afore-mentioned measure to still be heated up indelibly, can try to amend according to measuring a result to give out compensation pulse by numerical control system. 3, reduce motion to chafe and eliminate workbench of machine tool of transmission space numerical control between (or procrastinate board) displacement measures the equivalent in 11 arteries and veins to be most of subsection, ask again normally can move with the speed of base. To make workbench can right the instruction of numerical control device is made accurate answer, must take corresponding step. Slideway of current and commonly used sliding slideway, scroll and static press slideway to existing in respect of attrition damp character apparent difference. Slip guide screw is replaced to also can get similar result with ball guide screw in feed system. Current, numerical control machine tool uses transmission of ball guide screw without an other place almost. Numerical control machine tool (especially the numerical control machine tool of open loop system) treatment precision depends on greatly the precision of feed drive catenary. Besides the machining error that reduces transmission gear and ball guide screw, another important step is to use unoccupied place transmission of very close to each other deputy. The accumulation to pitch of ball guide screw error, use pulse to compensate device to undertake pitch is compensated normally. 4, the life that improves a machine tool and precision maintain a gender to maintain a gender to raise the life of the machine tool and precision, in the wearability that component of airport of mature numerical control answers when the design, especially the wearability of the component of main shaft of chance of port of wait of machine tool slideway, feed main part that affects plan. In use process, should assure numerical control machine tool each part is lubricant and good. 5, those who reduce auxiliary time and improvement to operate machine tool of function numerical control is odd a treatment is medium, auxiliary time (be not the time that cut bits) have larger proportion. Want to improve the productivity of the machine tool further, must adopt make utmost ground reduce auxiliary time. At present already machine tool of a lot of numerical control used much main shaft, much tool carrier, and those who take knife library is automatic the device that change a knife, change knife time in order to decrease. To cutting the numerical control machine tool that bits dosage increases, lathe bed orgnaization must be helpful for discharging bits. CNC MillingCNC Machining