Practical Methods for Selecting Cutting Tools OF CNC Machines
The choice of tool is one of the important contents in the numerical control processing technology. It not only affects the machining efficiency of the machine tool, but also directly affects the machining quality of the part. Because the spindle speed and range of CNC machine tools is much higher than that of ordinary machine tools, and the spindle output power is larger, compared with the traditional processing methods, higher requirements are put forward for CNC machining tools, including high precision, high strength and rigidity. Good, durable, and requires a stable size, easy installation and adjustment. This requires a reasonable tool structure, standardization of geometric parameters, and serialization. The numerical control tool is one of the preconditions for improving the machining efficiency, and its selection depends on the geometry of the part to be machined, the material status, the fixture and the rigidity of the tool selected by the machine tool.
The following should be considered:
Select the tool reference
(1) Select the tool according to the cutting performance of the part material. Such as car or milling high-strength steel, titanium alloy, stainless steel parts, it is recommended to choose a good wear-resistant indexable carbide cutting tools.
(2) Select the tool according to the machining stage of the part. That is to say, the roughing stage is mainly based on removing the margin, and the tool with better rigidity and lower precision should be selected. The semi-finishing and finishing stages are mainly used to ensure the machining accuracy and product quality of the part, and high durability and accuracy should be selected. For high cutting tools, the accuracy of the tools used in the roughing stage is the lowest, and the accuracy of the tools used in the finishing stage is the highest. If the same tool is used for rough and finish machining, it is recommended to use the tools that are eliminated from the finishing process when the rough machining is performed. The wear of the tools that are eliminated during the finishing process is mostly due to the slight wear of the blades, the wear of the coating is lighted, and the continued use will affect the finish machining. Processing quality, but less impact on roughing.
(3) Select tools and geometric parameters according to the characteristics of the processing area. When the part structure allows, a tool with a large diameter and a small aspect ratio should be selected; the over-center end edge of a thin-walled, ultra-thin-wall part should have a sufficient tangential angle to reduce the cutting of the tool and the cutting part. force. When processing aluminum, copper and other softer material parts, choose an end mill with a slightly larger front rake and do not use more than 4 teeth.
When selecting a tool, the size of the tool must be adapted to the surface dimensions of the workpiece being machined. In production, the peripheral contours of plane parts are often machined with end mills; when milling planes, hard alloy insert milling cutters are selected; when machining bosses or grooves, high speed steel end mills are selected; surface roughing or rough machining is performed. In the case of holes, corn milling inserts with carbide inserts can be selected; for the machining of some three-dimensional profiles and variable bevel outlines, ball-end cutters, ring cutters, taper cutters and disk-type cutters are often used.
In the free-form surface machining, since the cutting speed of the end of the ball-end tool is zero, the cutting distance is generally small in order to ensure the machining accuracy, so the ball-end milling cutter is suitable for the surface finishing. The end mill is far superior to the ball end mill both in terms of surface machining quality and machining efficiency. Therefore, in the premise of ensuring that the parts are not over-cut, the rough end and semi-finishing surfaces are selected as much as possible. Milling cutter. In addition, the tool's durability and precision are highly related to the tool's price. It must be noticed that, in most cases, selecting a good tool increases the tool cost, but the resulting increase in machining quality and machining efficiency. , you can greatly reduce the cost of the entire process. Of course, if you want to maximize the tool performance during processing. Just as a good saddle needs a good horse, choosing high-quality machining programming software is also one of the keys. The tool path generated by WorkNC is concise, safe, and stable. It can protect the tool well, and can prolong its service life and improve machining efficiency.
In the machining center, all the tools are pre-installed in the magazine, and the corresponding tool change actions are performed through the NC program's tool selection and tool change commands. The corresponding standard tool holders suitable for the machine tool system specifications must be selected so that the tools for CNC machining can be quickly and accurately mounted on the machine tool spindle or returned to the tool magazine. WorkNC provides a powerful tool path post-editing function that eliminates the need to recalculate the entire tool. It requires only local calculations, cutting, isolating, reversing the direction of the tool path, deviating, changing speeds, further optimizing the tool path, and improving efficiency. Reduced the work of the programmer's task, but it has improved work efficiency.