Systematic Error Concept Of Cutting Machine Thermal Deformation Control Measure

- Feb 19, 2021-

(1) Reduce heat and insulation. Heat source that can be separated from the main machine in order to reduce heat in the process system. Such as motor, gearbox, lead screw pair, fuel tank, etc., as far as possible placed outside the machine tool. For a heat source can be separated, such as main bearing, lead screw pair, matching wheel pair, friction clutch and other parts, components, should improve the friction characteristics from the structure and lubrication side, reduce heat.




An important part of cutting machine to reduce thermal deformation. Therefore, make the machine tools, usually adopt static pressure bearing, bearing, low temperature dynamic pressure bearing and air meter with low degree of lubricating oil drum, the bearing temperature control easier * jorge source can't separate from the machine tool, can be in these hot bonding surface of large parts and machine tool installed insulation (heat source heat dissipation is not good, appropriate USES the cooling measures), prevent quantity of heat conduction.




(2) the heat of the cutting machine, so as to control the temperature rise and thermal deformation of the machine. Such as CNC machine tools and machining towel core machine tools, the common use of refrigeration machine to moisten




Forced cooling of the oil greatly reduces heating and deformation of the headstock components.




(3) accelerate the temperature rise and maintain the heat balance. When the internal thermal deformation law is known, after the cutting machine is sent to the thermal balance in the pre-heating stage of the machine tool, the thermal deformation tends to be fixed, and then the processing accuracy can be guaranteed. Out of this, shorten the pre-heating period of the machine tool, is conducive to improve productivity, ensure processing accuracy.




All kinds of single factor machining errors can be divided into systematic errors and accidental errors according to their different properties.




1. System error of cutting machine




When the hydraulic cutting machine processes a batch of parts in sequence, the size of the machine does not change is a regular error called system error monitoring. The forward streamline is a constant system error, while the latter is a system error that changes regularly. For example, with a reamer whose diameter is less than the size O. 02, all the holes are reamed out with diameters smaller than the size O. 02, and this error is a systematic error. Meaning such as the axle, due to the tool wear, turning out of the shaft white diameter is a larger than a larger, the increase of the shaft vertical diameter is a certain rule, so the error caused by tool wear belongs to the regular change of systematic error (change hundred system error). The thermal deformation of Ran Ru Ding Yi system is also a variable value system error.




2. The cutting machine is accidentally wrong




In the addition of a number of parts, the magnitude and direction of such errors vary irregularly, sometimes large, sometimes small, sometimes positive, sometimes negative. Such errors are called accidental errors. For example, when the four-post cutting machine processes the holes of a batch of parts with a reamer, a batch of holes with the same diameter and size are still small under the same conditions. This may be caused by the factors such as the uneven hardness of the blank, the difference in Ajjl 'allowance, and the deformation caused by the redistribution of internal stress. These elements are determined by change. Although the causes of accidental errors are various and the function of the cutting machine is very complicated, the law of accidental errors can be found and controlled by using mathematical statistical force method.