Exceed permission common difference when production work, although do not have,perhaps exceed tolerancepublic errand, but when the maximum that already was close to tolerancepublic errand, the treatment that should checking work right now discovers the germ of the problem in the process. was eliminating to wear away by cutting tool, after the possibility of the problem such as change of accident of workpiece process designing, clamping apparatus and raw material, the rest of is to should decide whether CNC machine tool is the germ that poses a problem. What should make clear above all is, whether does cutting tool move according to the process designing command of workpiece proper place. Install for example in a 3 axes the cutting tool on machining center is gone to by process designing a series of the coordinate position of X, Y, Z. Because the machine tool is of 3 axes, so each axis must be detected. When should undertake assess to individual reference axis, the problem of core is working complexity. Each reference axis has 6 errors possibly: The position error of displacement of the lines, be in perpendicular the linearity error on two orthogonality direction of the axis and a simple move or action, deflexion and scroll 3 angle error. In addition, still need another device to detect machine tool the mutual verticality between 3 reference axis. Accordingly, the machine tool that has 3 reference axis to has 21 probable error causes. machine tool is measured long-term since, use step pitch compasses, straightedge, square iron and instruction sheet to the measurement of the machine tool. Use these tools to undertake detecting, ask to have technology, seasoned detect personnel, although such, also the computational error with big generation of hard to avoid. Because every measure an error to need a separate measurement unit, want to finish 21 errors to measure, time became the biggest obstacle. As a result of production and time restrict, often limitted the error project number that is detected, manufacturing workshop often tries only decide and amend main error source and incorrect machine tool undertakes detecting in the round. The diagnostic tool that exemple as usual uses but feet of adjustable ball lever, message of its opposite to deciding trends sum of errors is offerred reference axis campaign is very effective, still can measure return trip clearance, creeping, staff guage to break match and servo lag error, but measure what it cannot offer the element of geometry of machine tool other besides sex of reference axis orthogonality reliably. All sorts of problems that when uses laser interferometer to assess a machine tool to be able to eliminate use other method to measure machine tool reference axis, appear. Laser interferometer is regarded to be accurate length measure the level with precision of establish displacement of the lines. Use optical assembly of a few appropriative, two errors in the linearity that can measure two orthogonality way and 3 angle error: Error of deflexion of sum of errors of a simple move or action. is the need that nicety of motion of contented machine tool measures, development went all sorts of laser to survey a system. Although applicable a lot of different measurement system, but great majority relies on 3 kinds to survey one of plan, in order to achieve identical measurement result. A kind of plan is the diagonal that measures working space, its precision depends on by the repeatability of assessment machine tool, but the alone error that this kind of method cannot offer each axis, and these errors conduce to the proper machine that perhaps needs to undertake certainly amending (the correction) that is like verticality. Additionally two plan are measured of reference axis of main overweight machine tool directly. Using another reference axis are measured by other system while a few systems measure a reference axis. The 6 dimension laser that an example is API(Automated Precision Inc) after surveys a system. 5 when it can measure a reference axis at the same time or 6 errors, this can reduce the measurement of 80% time. In addition, measuring these errors while still offer its mutual the relation between. After is using API system testing, make clear via analysing a result, perhaps a reference axis compares other the precision of two axes is low much. Normally, use this information enough to decide which reference axis needs to undertake correction. If each error of individual reference axis is less than the workpiece error that wants treatment, but handlers or the work that should decide whether the machine tool can machine qualification, can be synthesized by geometry because of the error and increase (synthesize) with three-dimensional angle, if why the error that must want to understand an axis so produces an effect on additionally two axes. More typical is on CNC machine tool Y axis overlaps the circumstance that goes up at X axis happens. If X axis has linearity error on the direction of Y axis, measure this error with respect to overlay (addition or photograph are decreased) go up to the error of displacement of the lines of Y axis, and in measuring a process, discover these errors impossibly, because of when measuring, a shift is engraved when some an axis. Have again, should analyse assess each potential overlay effect of 21 errors is very complex. error mode analyses software to make job of this kind of analysis becomes special easy. Software can provide figure of error of a space, the put together cooperation that clew gives 21 individual errors that in the machine tool the each location of effective work space measures uses a result. Software can decide whether the machine tool is capable to process the work inside limits of some public errand conveniently. Once correction measure decides machine tool of CNC numerical control is the reason that workpiece public errand changes, must correct machine tool error. To determine the most effective correction method, must the repeatability of assess machine tool. Repeatability is the magnanimity of machine tool stability, machine tool cutting tool commands the position to some according to its stability shift. For example cutting tool receives a command to want to move X=5, y=5 and Z=0, but it moves 4 times every time X=4. 950, y=4.
950 with Z=0, criterion the machine tool that this machine tool is stability of a height, but the machine tool that is not a nicety. Repeat certain error when a machine tool, or contain little change, can use conveniently adjust jussive position to correct an error. is in this example, handlers can command cutting tool arrives X=5.
050, right now cutting tool can be close to the ground to reach the place of expectation on X axis very much. To some stage machine tool character, only support adjustment commands the position will change a course, not be a kind of best method of correction. Accordingly, at present a lot of controller allow to adjust the positional software of coder will correct these errors, what this says normally namely " pitch is compensated " , because the commonly used method of mobile reference axis is,use transmission of nut of motor drive guide screw deputy. The position is decided by the on optical disc computation pulse in coder, coder every turn circuit can give out a large number of pulse, coder turns, the machine tool is mobile a pitch. if an error repeats, can be amended through controller; If a public errand that the error does not repeat or change exceeded expectation is worth, must undertake repairing to the mechanical system of the machine tool or electric part. The machine tool controller of great majority can provide the capability that adjusts position of displacement of the lines to handlers, in order to correct journey error -- namely pitch error. In addition, a lot of new controller can offer the linearity in two orthogonality direction to amend the correction with coordinate orthogonality sex, some controller have the capacity that corrects 21 all errors more. error is repaired often is to be based on three-dimensional reseau means normally, they are a machine tool of effective space one group is nodded. The dot of specific to each in reseau X, Y and Z, give out a correction. Nod to each, 21 individual error put together synthesizes a correction to need to build error pattern and have consideration, they often exceeded a machine tool to operate the ability of technical personnel. Can provide 3 safeguard now error pattern and correction software and these reseau. if all errors that a controller cannot compensate a machine tool and the result that compensation of alone displacement of the lines cannot offer hope, its are amended still can come true, should alternate only by rear sight (coder) the information that the system provides controller can. This need uses the 2nd controller to come true, the 2nd controller will alternate the machine tool that carries supply to be based on error pattern to analyse software is original the information of machine tool staff of controller, the result that gets anyway is identical. comes with laser system CNC machine tool can make assess be mixed quickly comprehensive analysis, if these jobs are done with other method, will very expend time and wasteful. With error pattern software analytic data reduced the complexity that handles a process, can produce an eligible work ceaselessly. CNC Milling
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