How To Determine The Machining Route In NC Machining

- Apr 06, 2017-

In NC machining, the trajectory of tool cutter position relative to the workpiece is called machining route. When programming, the principle of processing route is mainly the following points:

1 The machining route should guarantee the precision and surface roughness of the machined parts, and the efficiency is high.

2 Make the numerical computation simple to reduce the programming workload.

3 should make the processing route shortest, this can reduce the procedure section, also can reduce the empty knife time. degree and so on, to determine whether a knife, or a number of passes to complete processing and milling machining in the use of shun milling or inverse milling.

To the point-bit control of CNC machine tools, only require high positioning accuracy, positioning process as fast as possible, while the tool relative to the workpiece movement is irrelevant, so this kind of machine tools should be the shortest path to arrange the knife route. In addition to determine the tool axial movement size, its size mainly by the processing of the hole depth to determine, but also should consider some auxiliary dimensions, such as the introduction of the cutter distance and exceed the amount.

In the NC machine tool on the train thread, along the pitch direction of the Z Feed and machine tool spindle rotation to maintain a strict ratio relationship, so should avoid in the feeding mechanism acceleration or deceleration process. For this purpose there is the introduction of the distance Δ 1 beyond the distance δ 2. The numerical value relates to the dynamic characteristics of the machine tool dragging system, and the thread pitch and the precision of the screw thread. Generally for 2-5mm, large pitch and high-precision threads are large values; generally take about 1/4%. If the thread closure has no retract slot, the shape of the closure is related to the CNC system, usually by 45o finishing. String 8

When milling the plane parts, the end milling cutter side blade is generally used for cutting. In order to reduce the knife traces, to ensure the surface quality of the parts, cutting tools to cut and cut out the procedures need to be carefully designed. When milling the outer surface contour, the cut and cut out point of the cutter should be cut to cut into and cut off the part surface along the extension line of the contour curve of the part, instead of cutting the parts directly into the method to avoid scratches on the machining surface and ensure the smooth contour of the part.

When milling an inner contour surface, cut into and out of the outside of the extension, when the milling cutter can be cut along the normal direction of the contour of the part, and cut out the point of the part of the outline of the two geometric elements in the intersection of the machining process, workpiece, cutter, fixture, machine tool system in the state of equilibrium elastic deformation, the feeding pause, the cutting force decreases, the system will change the equilibrium state, the cutter will be left to the pause at the part of the surface of the scratches, so in contour processing should be avoided to the pause.

When curved surface, common ball head knife adopts "line cutting method" to process. The so-called line-cutting method refers to the cutting edge of the cutter and part contour line is a line, and the distance between the lines is determined by the precision of the machining requirements.