CNC machining process analysis of the general steps
Source：Changzhou Xueming Electronics Co., Ltd. Time：2014-8-25 9:00:22 Hits：
of a knife. Consistency as possible, the higher the precision of the knife. The so-called "knife sites" refers to turning, boring tool tip; diamond tip drill bit; cutter, end mill head underside of the center ball head ball head milling center.
After installing the parts workpiece coordinate system and the machine coordinate system will have to determine the size of the relationship. After the workpiece coordinate system setting, from the coordinate values of the knife point of the first block; knife point for the machine coordinate system coordinate values (X0, Y0). When programming in absolute terms, regardless of whether the knife point and the workpiece origin coincidence, is X2, Y2; press incremental value when programming the knife point
Coincide with the workpiece datum, coordinate value of the first block is the X2, Y2, when you do not coincide, for the (X1 ten X2), Y1 + Y2).
Starting point of the knife is both programs, but also the end of the program. Therefore to be considered in the mass production of the knife-point repeatability, the accuracy of the available points on the knife away from the origin of the coordinate value of the machine (X0, Y0) to check.
The so-called "machine origin" refers to the machine a fixed limit point. For example, on the lathe, means the intersection of the center and front Spindle chuck end face.
When the process requires ATC, ATC shall be specified point. The so-called "tool change point" is the location of Bai turret indexing tool change time. This point may be a fixed point (such as machining centers, the tool change position of the robot is fixed), it can be an arbitrary point (such as lathes). ATC should be located outside the workpiece or fixture, do not touch the workpiece and other parts subject to the turret indexing time. Its set value or calculation methods are available to determine the actual measurement.
Eight, processing routes to determine:
CNC machining, tool cutter workpiece relative to the trajectory of the movement known as the processing route. When programming, determine the principles of processing routes are mainly the following:
1) processing route should be guaranteed accuracy and surface roughness of machined parts, and high efficiency.
2) make a simple numerical calculation, in order to reduce the programming effort.
3) should be processed shortest route, both to reduce the program segment, but also reduce air knife time. Degrees, etc., determine a pass or multiple passes to complete processing and milling is in use or the use climb milling milling and so on.
Point control of CNC machine tools, require only a high positioning accuracy, positioning process as quickly as possible, while the movement of the tool relative to the workpiece route is irrelevant, so these machines should be the shortest way to arrange air feed path. In addition to the axial movement of the tool but also to determine the size, the size of the main parts of the deep hole machining is determined by, but should also consider some auxiliary dimensions, such as the introduction of distance and beyond the amount of the tool.
When threading along the z direction to the rotation pitch feed and spindle should maintain a strict relationship between the ratio of CNC machine tools, and should therefore be avoided in the feed mechanism to accelerate or decelerate the process of cutting. To this end have introduced distance δ1 transcend distance δ2. The value of the dynamic characteristics of the machine drive system and the related, and precision thread pitch and thread related. Generally 2-5mm, large thread pitch and precision whichever is greater; generally take about a quarter. If the thread ending at no undercut, ending at the shape of the CNC system, generally ending by 45o.
Milling plane parts, the general mill side cutting edge. To reduce access knife marks, guarantee part surface quality of the cutting tool and cut out the program requires careful design. When the outer surface contour milling, milling cutters cut and cut out the part contour points should be cut along the curve of the extension line to cut and cut out parts of the surface, rather than directly into the parts along the normal to avoid the machined surface scratches, ensure the smooth contours of parts.
The milling contour surface, cut, and cut out the extension can not, then cutter can cut parts along the normal direction of the contour and cut out, and cut, cut out the tap at the intersection of two geometric processing part contour elements next, the workpiece, tools, fixtures, machine balancing the elastic deformation of the state system, the feed stop, the cutting force is reduced, it will change the balance of the state system, the tool will leave scratches in the feed pause at the part surface, so should be avoided in the contouring feed pause.
When the surface, the ball head knife used a "line-cut method" for processing. The so-called line-cut method is the cut-off point between the tool and the part of the track is the contour line by line, and the distance between the lines is based on the requirements of precision parts machining determined.
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