摘要:
In at least one embodiment, a method of analyzing and characterizing the thermal growth of a CNC machine is provided. The method may include mounting an artifact having a bore onto a CNC machine and performing a test cycle. The test cycle may include probing the bore of the artifact to determine its location relative to the CNC machine and performing a dry cycle including one or more CNC machining processes. The method may further include calculating a deviation of the bore location from a reference relative location between the bore and CNC machine. The method may be used to improve, troubleshoot, or assess the effectiveness of CNC machine thermal compensation mechanisms. The method may start at ambient temperature and include repeating test cycles until a steady state temperature is reached in the machine.
摘要:
A thermal displacement correction method for a machine tool includes: estimating a thermal displacement of a support and a thermal displacement of the movable body independently of each other; acquiring a displacement of an attachment position of a scale that detects a position of the movable body; a movable body actual position acquiring step of acquiring an actual position of the movable body relative to the support after thermal deformation of the movable body; computing a degree of inclination of the movable body at the actual position; acquiring a resultant displacement that is a resultant of the thermal displacement of the support and the thermal displacement of the movable body; computing a correction value based on the resultant displacement; correcting a command position of the movable body based on the correction value.
摘要:
A machine tool includes a spindle side position measuring unit measuring a spindle axial position in a spindle radial direction relative to a first reference position and a tool side position measuring unit measuring the position of a tool post relative to a second reference position. The spindle side position measuring unit includes a first scale extending in the spindle radial direction and a first readout unit, one of a base end portion of the first scale and the first readout unit is disposed at a spindle axis and the other of the base end portion of the first scale and the first readout unit is disposed at the first reference position. One of a base end portion of a second scale and a second readout unit is disposed on the tool post and the other is disposed at the second reference position.
摘要:
In a positioning device in gantry type of construction, due to a special arrangement of the position-measuring devices used for the positioning, errors due to thermal expansion of the positioning device may be avoided to a great extent. In particular, attention is given to the advantageous placement of fixed point of a scale relative to a straightness track of a further scale.
摘要:
A disclosed example method for compensating a temperature-dependent change of position on a machine tool having at least one first linear axis involves detecting at least one first temperature at a first temperature measuring position of the first linear axis of the machine tool. The example method also involves obtaining a first difference in temperature between a first reference temperature and the first temperature and determining a first compensation value based on the first difference in temperature. In addition, the example method involves compensating a temperature-dependent change of position based on the first compensation value, the first compensation value is additionally determined based on an axis position of the first linear axis.
摘要:
A method for determining an nulleffectivenull thermal coefficient of a machine comprises the steps of installing one or more temperature sensors (110) at various locations on the machine, positioning a first machine member (60) at a nullknownnull reference Location, relative to a second machine member (42), installing a linear position measuring device (120) to detect changes in position of the first machine member (60) relative to the second machine member (42) along a first axis of movement, periodically acquiring readings from each of the temperature sensors (110) and from the linear position measuring device (120) during a test cycle and compiling the temperature and linear position data into a table. A statistical correlation analysis is performed to determine which of the temperature sensors (110) experiences changes in temperature are most linearly related to changes in the linear position of the first machine member (60) relative to the second machine member (42) and an nulleffectivenull coefficient of thermal expansion is thereafter determined as the rate of change of position, i.e. length, relative to change in temperature. The present method includes using the machine's nulleffectivenull thermal coefficient to calibrate the motion of the machine to compensate for the thermal characteristics thereof.
摘要:
A method provides an exact measurement of the tool center point (TCP) being carried out, preferably in the whole working area of the robot. In this measurement, the robot moves very slowly so that little heat is generated by the driving assemblies and the temperature gradients are as low as possible. The measurement can be made, for example, using a high-precision laser distance and angle measurement system. The measurement is carried out such that a measuring point is moved to working area points and then the deviations of the positions and/or orientations of the measuring point are determined using the laser distance and angle measurement system, i.e. a nominal/actual comparison is made. The TCP can preferably serve as the measuring point. The point must always be selected so that the positioning and orientation deviations of the kinematic chain with respect to the PCT can be determined with sufficient accuracy.
摘要:
The ratio of executed to skipped measurement movement commands required for actual measurement and a correction value when skipping a measurement movement command are determined and then updated according to past (hysteresis) measurement data. The actual thermal displacement measurement during an executed measurement movement command is performed at a proper rate to improve the machining efficiency of an NC machine tool and minimize an error due to the correction.
摘要:
A position command value is compensated by predicting a thermal displacement amount of each part of a machine tool and adding a thermal displacement compensation amount which cancels the predicted thermal displacement amount to the position command value of a feed axis. This thermal displacement compensation amount is adjusted from the error amount between this compensated position command value and an actual machining point. Upon adjustment of this thermal displacement compensation amount, it is possible to determine whether to increase or decrease the thermal displacement amount based on a direction in which an operator moves a tool image or a workpiece image on a screen.
摘要:
There is provided a wire electrical discharge machine that includes a temperature detection unit, an actual position correction amount calculation unit, a correction amount calculation unit, a correction amount adjustment unit, a position correction amount adjustment unit, and a corrective movement amount calculation unit. The actual position correction amount calculation unit calculates an actual position correction amount for an upper/lower guide section in accordance with reference position coordinates at a reference temperature and with actual position coordinates at a temperature different from the reference temperature. The correction amount calculation unit uses a prepared correction amount arithmetic expression. The correction amount adjustment unit calculates a correction amount adjustment value from the actual position correction amount and the position correction amount.