JP2011093004A - Nc grinding device having on-board image measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground work superior in dimensional accuracy by blowing air to the ground work before measuring the ground work by on-board image measuring systems to remove droplets, grinding chips, and grinding abrasive residues adhered to the surface of the ground work. <P>SOLUTION: In this NC grinding device 1, the on-board image measuring systems 7, 8 are installed on the extension of a working surface where the surface of a work placed on a work table is brought into contact with a grinding wheel so as to be vertically lifted while a CCD camera and the light source face each other, and the air blow nozzle of an air blow device 6 is installed at a position which is located at the CCD camera side rear a grinding fluid supply nozzle 5 for supplying a grinding fluid to the working surface where the surface of the work is brought into contact with the grinding wheel and from which the nozzle can blow air to the working surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an NC grinding apparatus provided with an on-machine image measurement system capable of measuring a dimension of a ground workpiece.

  The dimensions of the workpiece that has been ground using an NC grinding machine equipped with an on-machine image measurement system are measured, and the dimensions (three-dimensional coordinate position) of the ground workpiece are measured using the on-machine image measurement system. If it is within the dimension, the grinding process is terminated, and if it is out of the dimension, the correction grinding process of the grinding work is resumed to finish the grinding work within the desired dimension.

  For example, Japanese Patent Laid-Open No. 2006-110661 (Patent Document 1) is an NC grinding apparatus in which an imaging apparatus is provided in an NC grinding apparatus equipped with Mitutoyo Corporation's image unit data processing software QSPAK (trade name). As an imaging device, it can move in the left-right direction (X-axis direction) and a workpiece placed on a work table, and can move in the front-rear direction (Y-axis direction), and can be moved up and down (Z-axis direction). A cylinder containing a telecentric optical lens coupled to a CCD camera is rotatable in the vicinity of the grinding wheel head of a grinding device for machining a workpiece by relative movement of a grinding wheel held by the grinding wheel head provided on the support. An imaging apparatus for a workpiece installed in a microscope, the imaging apparatus being connected to a CCD camera equipped with an imaging element via a second adapter, a microscope lens tube, a borescope, or a fan. An illuminating device that couples a bar scope and irradiates light along the optical axis of a telecentric optical lens incorporated in the microscope lens tube, borescope, or fiberscope, and the front of the microscope lens tube, borescope, or fiberscope A cylindrical adapter that fixes the prism inside is detachable, and the image signal formed on the image pickup device of the CCD camera is transmitted to a processing unit that converts the image signal into computer image information coupled through an image processing device. In addition, there has been proposed an imaging device for a workpiece for a grinding apparatus including a display device that displays information from the processing unit. Using this imaging device, the measured three-dimensional dimensions can be displayed on the display screen as an EXCEL table during workpiece grinding.

  Japanese Patent Laying-Open No. 2005-144600 (Patent Document 2) is provided on the side of a processing means of a processing machine so as to be movable to a measurement position and a retreat position by moving back and forth, and to be movable up and down at the measurement position. An apparatus for measuring the workpiece (Wa) of the workpiece (W), the enlargement means (9) mounted on the same axis as the imaging means (8) of the workpiece (Wa), A prism (10) is provided below to enlarge the workpiece (Wa) in the vertical direction of the workpiece W, and the other enlarges the workpiece (W) in the horizontal direction of the workpiece (W). We propose an on-machine measuring device that is characterized by its characteristics.

  Furthermore, on the website of Yuasa Techno Co., Ltd. (Non-Patent Document 1) for Internet search, an on-machine measuring device MOM-1 (trade name) and an NC profile grinding machine installed are introduced. It describes that it can be measured and then corrected. This on-machine measuring device can measure not only the measurement within the screen (in the field of view) but also the counter value of the table (X / Y movement table) of the profile grinder into the measurement software and measure the entire movement range. Measurement software for image measuring machines (QSPAK) can handle all measurement and geometric tolerances, and automatic edge detection tools can reduce individual errors in measurement. Easy measurement with abundant macro icons, image storage function, tolerance comparison of measurement calculation results and various statistical processing for each item. Cross, circle, rectangle and angle templates are available and can be used as images for comparative measurement of projectors. Importing CAD data (DXF, IGES format) created during workpiece design into the measurement software (QSPAK) makes it possible to greatly improve operability and shorten part program creation, and to specify graphic data in the specified CAD format. Can output. Furthermore, the QSPAK measurement result can be converted as CAD data.

  Japanese Patent No. 3786750 (Patent Document 3) is also applied to a processing machine in which at least one of a processing tool or a table on which a workpiece is placed is reciprocated and the processing tool is brought into contact to process the workpiece. And / or imaging means for imaging the processing tool, timing detection means for detecting the timing of the reciprocating workpiece and / or processing tool entering the focal range of the imaging means, and imaging at the timing detected by the timing detection means An image pickup apparatus is provided that includes a capturing unit that captures an image from the unit, an image memory that stores the captured image, and a display unit that displays the image stored in the image memory.

  Japanese Laid-Open Patent Publication No. 4-93150 (Patent Document 4) is a machine tool that performs high-precision machining by numerical control, and moves in synchronization with the tool portion of the machine tool to automatically recognize the shape and positional relationship of the workpiece without contact. A measuring means for measuring, a means for specifying a reference dimension of a position where automatic measurement is performed by the measuring means, a means for calculating a difference between a measured value obtained by the measuring means and the specified reference dimension, and based on the calculation result An NC machine tool having means for calculating a method and amount to be corrected and performing automatic correction processing is proposed.

JP 2006-110661 A JP-A-2005-144600 Japanese Patent No. 3786750 JP-A-4-93150 "Yuasa Techno Co., Ltd./Latest Information / Pickup Product Information-Onboard Image Measurement System MOM-P", [Search September 3, 2009], Internet <URL:> http://www.yuasa-techno.com /newstoku_products/details51.htmlkaihei

  The dimensions of the machined work (including grinding) are measured using an NC machine tool device equipped with the on-machine image measurement system disclosed in these prior art documents, and the dimensions of the machined work are predetermined. When it is within the dimensions, the machining is terminated, and when it is outside the dimensions, when corrective machining is performed until the normal dimensions are obtained, there is no foreign matter such as grinding dust or abrasive particles on the grinding workpiece. Required for more precise dimensional measurements.

  Specifically, since an optical measuring device such as a three-dimensional CCD camera is used, there is a possibility that dust, processing waste, grinding liquid (for example, water droplets) attached to the machined workpiece surface may deteriorate the measurement accuracy. Due to the deterioration of measurement accuracy, the actual dimensions after removing dust, machining waste and grinding fluid (for example, water droplets) from the machined workpiece surface are displayed on the CRT screen even though they are within the desired dimensional tolerance (threshold). Since the dimension exceeds the tolerance (threshold value), correction machining may be started and the workpiece up to a dimension outside the tolerance may be excessively machined.

  The present invention relates to a workpiece machined (including grinding) using an NC machine tool device equipped with the on-machine image measurement system described in Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4. NC grinding is used in the method of measuring the dimensions and ending the machining when the dimension of the machined workpiece is within a predetermined dimension, and performing correction machining until the dimension is normal when it is out of the dimension. An object of the present invention is to provide an NC grinding apparatus provided with an on-machine image measurement system that improves measurement accuracy by adding an air blow device for cleaning a workpiece to the apparatus.

  The invention of claim 1 is an NC grinding apparatus provided with an on-machine image measurement system and an air blowing device, wherein the on-machine image measurement system is an extension of a work surface in contact with a work surface placed on a work table and a grinding wheel. A CDD camera and a light source are provided facing each other so as to be vertically movable up and down, and an air blow nozzle of an air blow device is a position behind a CCD camera side of a grinding fluid supply nozzle that supplies a grinding fluid to a work surface in contact with the workpiece surface and a grinding wheel An NC grinding apparatus provided with an on-machine image measurement system is provided at a position where air can be blown onto the work surface.

  Before measuring the grinding workpiece with the on-machine image measurement system, water droplets, grinding debris, and grinding grain residue adhering to the grinding workpiece surface are removed by air blowing, so that a highly accurate measurement dimension value can be obtained.

FIG. 1 is a front view showing a main part of the NC grinding apparatus. FIG. 2 is a block diagram of a numerical controller of the NC grinding apparatus.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. The NC grinding apparatus shown in FIG. 1 is an NC profile forming grinding apparatus 1. In FIG. 1, a grinding wheel head 2 includes a grinding wheel 3 fixed by a flange to a grinding wheel shaft (not shown) provided on a grinding wheel shaft fixing plate provided on the front surface of a column provided upright from a tool table. The grindstone shaft can be moved up and down (Y-axis direction) and back and forth (Z-axis direction) by driving means. In the radial direction of the grinding wheel 3, there is a grinding fluid supply nozzle 5 provided on the right side of the grinding wheel protection cover 4, and the grinding fluid is supplied by a pump drive toward a work point where the workpiece and the grinding wheel come into contact. An air supply nozzle 6 is provided on the right rear side of the grinding liquid supply nozzle 5 and has a structure in which air is blown toward a measurement location of the workpiece w measured by the on-machine image measurement system. This air supply nozzle 6 is installed in the direction of the left side surface of a fixed base 9 provided with a CCD camera 7 of the on-machine image measurement system below. A CCD light source 8 is provided facing the lens of the CCD camera 7.

  The work stage 30 includes a work chuck table (electromagnetic chuck or permanent magnet chuck) 33 fixed by an L-shaped stopper 32 on a work table 31 that can reciprocate in the left-right direction. 33 can be fixed. Reference numeral 35 denotes a three-way grinding wheel dresser.

  The image picked up by the CCD camera 7 of the on-machine image measurement system is displayed on the image display board (display) CRT of the numerical controller using the contact image between the grinding wheel 3 and the workpiece w as an image. In addition, it has an image storage function with measurement software for image measuring machines, and can display the image on the CRT display by performing tolerance comparison of measurement calculation results and various statistical processing for each item, and grinding processing The tolerance at the part position can be displayed on the EXCEL screen on the CRT display.

  As a driving means for moving the work table 33 left and right, moving the tool table back and forth, and moving the grindstone shaft up and down, a linear motor drive servo motor or ball screw drive can be used.

  The coordinate axis values of workpieces sent as electrical signals from the X (left and right) axis linear scale sensor, Y (up and down) axis linear scale sensor, Z (front and rear) axis linear scale sensor, or displacement sensor not shown in FIG. Is used as a position coordinate value for the thickness calculation of a workpiece that has been ground, and if it is determined that it is within a tolerance value stored in a tolerance memory, which will be described later, a grinding completion command is sent from the output unit of the numerical controller. The grinding process is stopped and finished.

2 includes a system program memory, a grinding program memory, a measurement program memory, a correction grinding program memory, a workpiece shape DXF data memory, a tolerance memory, an input determination unit, a grinding wheel shaft rotation control unit, a grinding wheel. Axis vertical movement control device, tool table longitudinal movement control device, work table left / right movement drive control unit, dressing control unit, air blow control unit, on-machine image measurement management unit, image detection unit, grinding program end determination unit, tolerance It has a threshold value management unit, an image processing control unit, a CAD system, a keyboard, and a CRT display.

  Using the NC grinding apparatus 1 shown in FIGS. 1 and 2, a material to be ground (work to be processed) is placed on the upper surface of the permanent magnet chuck 33 on the work table 31. A target machining software number is selected by keyboard operation from a machining software selection screen displayed on the display CRT screen of the numerical controller 40. Then, grinding conditions displayed on the display CRT screen, for example, a grindstone, a stroke width, a grindstone speed, a tilt angle, a tolerance, and the like are selected or input by a keyboard operation. Next, the dressing condition screen is selected, and the dressing condition is selected or input by keyboard operation. Further, a reference measurement position or the like on the workpiece measurement is selected or input from CAD data or DXF file data by a mouse click operation or a keyboard operation on the measurement programming screen.

Next, grinding of the workpiece w is started, and when grinding is completed, 1.1 to 5.5 kg / cm ² of compressed air is sprayed from the nozzle 6 of the air blow device onto the surface of the grinding workpiece and adheres to the grinding workpiece. The foreign matter such as grinding scraps and abrasive grains to be blown off is blown off, and the water adhering to the grinding workpiece is also blown off to be dried so that the dimensional measurement by the on-machine image measurement system can be performed with high accuracy.

  When the reference measurement position for workpiece measurement is taught, air blow and measurement positions are automatically created based on the data read from the DXF file. The tolerance is an allowable amount, and a program is set so that the final shape dimension plus / minus tolerance value of the workpiece becomes the desired shape dimension of the ground workpiece.

  The NC grinding machine provided with the on-machine image measurement system of the present invention provides a workpiece with good dimensional accuracy of the workpiece to be ground.

DESCRIPTION OF SYMBOLS 1 NC profile grinding machine 2 Grinding wheel head 3 Grinding wheel 4 Grinding wheel protection cover 5 Grinding liquid supply nozzle 6 Air blow equipment 7 CDD camera 8 Light source 30 Work stage 31 Work table 33 Electromagnetic chuck w Work 40 Numerical control device

Claims (1)

An on-machine image measurement system and an NC grinding apparatus provided with an air blow device, wherein the on-machine image measurement system is capable of moving up and down vertically on an extension of a work surface that is in contact with a work surface placed on a work table and a grinding wheel. A camera and a light source are provided opposite to each other, and an air blow nozzle of an air blow device is a position behind the CCD camera side of a grinding fluid supply nozzle that supplies a grinding fluid to a work surface where the workpiece surface and the grinding wheel are in contact with the work surface. An NC grinding apparatus provided with an on-machine image measurement system, which is provided at a position where air can be blown.

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