CNC Lathe programming process processing technology. 1. Determine the workpiece's processing location and specific content
Determine the content of the work to be processed on the machine and the connection with the previous and following processes.
(1) The condition of the workpiece before machining in this process. For example, castings, forgings or bars, shapes, sizes, allowances, etc.
(2) The shape and size of the previously machined part of the previous process, or the reference surface, reference hole, etc. that have been processed in the previous process.
(3) The parts and details to be processed in this process.
(4) In order to facilitate the preparation of processes and procedures, draw out the rough drawing of this process and the process drawing of this process.
2. Determine the mounting method and design fixture of the workpiece. Select or design the fixture according to the determined workpiece processing location, positioning reference, and clamping requirements. CNC lathes often use three-jaw self-centering chucks to hold workpieces; shaft-type workpieces can also use tailstock tips to support workpieces. Due to the extremely high spindle speed of CNC lathes, hydraulic high-speed power chucks are used to facilitate the clamping of workpieces. Because it has passed strict balance in the production plant, it has high rotation speed (limit rotation speed up to 4000~6000r/min) and high. Clamping force (maximum push-pull force is 2000~8000N), high precision, convenient claw adjustment, through hole, long service life, etc. It is also possible to use soft jaws to hold the workpiece. The soft jaw arc surface is randomly formulated by the operator to achieve the desired clamping accuracy. By adjusting the cylinder pressure, the clamping force of the chuck can be changed to meet the special needs of clamping various thin-walled and easily deformable parts. In order to reduce the stress deformation of the slender shaft machining, improve the machining accuracy, and when machining the hole of the shaft with a hole, the hydraulic centering center frame can be used, and the centering accuracy can reach 0.03mm.
3. Determine the processing plan
(1) The principle of determining the processing plan is also called the processing plan. The processing plan of the CNC machine tool includes the formulation of the process, the work step and the route of the knife.
In the processing of CNC machine tools, due to the complexity and diversity of the processing objects, in particular the shape and position of the profile curve, and the influence of various factors such as different materials and different batches, the specific analysis of the specific parts is required when formulating the processing plan. Treated differently and flexibly. Only in this way can the rationalized processing plan be established, so as to achieve the objectives of high quality, high efficiency, and low cost.
The general principles for formulating a processing plan are: first coarse after finishing, first near and far, first inside and outside, least program segment, shortest cutting path, and special treatment under special circumstances.
(1) After the first rough finish, in order to improve the production efficiency and ensure the finishing quality of the parts, the rough machining process is first arranged during the cutting process, and a large amount of machining allowance will be processed before the finishing process in a short time (Fig. The part indicated by the dashed line in 3-4) is removed, while satisfying the requirement for the uniformity of the remaining amount of finishing.
After the rough machining process is completed, the semi-finishing and finishing operations performed after the tool change are arranged. Among them, the purpose of arranging the semi-finishing is to arrange semi-finishing as a transitional process so that the balance of the finishing allowance is small and uniform when the uniformity of the remaining amount after roughing cannot meet the finishing requirements.
When arranging a finishing operation that can be performed with one or more knives, the final contour of the part is continuously machined from the last knife. At this time, the position of the cutting tool should be properly considered. Try not to arrange cutting and cutting or tool changing and pauses in the continuous contour to avoid elastic deformation caused by abrupt changes in cutting force, resulting in a smooth connecting surface. Scratches, shape mutations, or stabbed knife marks.
(2) First, near, far, near and far, in terms of the distance of the processing site relative to the tool point. In general circumstances, especially when roughing, it is usually arranged that the part near the tool cutting point is first machined, and the part far away from the tool point is post-processed so as to shorten the tool movement distance and reduce the idle travel time. For turning processing, the first and the second are far to help maintain the rigidity of the blank or semi-finished part and improve the cutting conditions.
January 13, 2022
