The rationality of the machine design determines its service life and its ability to exhibit good stability and excellent handling in harsh environments. For manufacturing and assembly processes, it is the implementation and implementation of the designer to complete the entire manufacturing process. A system engineering, manufacturing and assembly process determines the final static geometry accuracy and dynamic accuracy of the machine tool, which is more important for the CNC machine tool. 1. Different processes lead to different results CNC gantry pentahedron machining center is an ideal choice for machining box parts and complex parts of cavity, but it has strict precision requirements for new machine tools, and the accuracy index and factory pre-acceptance of new machine tools when installing at the user site. It is difficult to achieve consistent accuracy. To this end, manufacturers have tried their best in the manufacturing and assembly process. Germany's Waddris Coburg Equipment Co., Ltd. has its own set of solutions. Here, we only analyze and compare the movement of the CNC gantry pentahedron machining center. Figure 1 shows the mobile surface equipment of the Vadrich Coburg CNC Gantry pentahedron machining center in Germany. At present, the machine bed and the column are connected in two typical forms. One is that the two columns are directly connected to the bed, and the integral frame structure is formed by the connection of the beams, so that high rigidity during strong cutting can be achieved. In the process of secondary installation, it is easier to find the mutual position of the machine bed and the column without causing misplacement and deviation. However, in the actual application process, the machine bed will be deformed due to temperature changes, resulting in the forward or backward tilting of the two columns, especially when machining the box parts, which will seriously affect the accuracy of the coaxiality. figure 1 The other is the form in which the machine bed and the column shown in Figure 1 are not directly connected. The biggest advantage is to avoid the processing accuracy of the product due to temperature problems. However, the problem is that the positioning of the machine bed and the column is more difficult, because the German Vadrich Coburg CNC gantry pentahedron machining center has a special column shape with irregular triangles (see Figure 2). The four guide rails of the column are not on the same plane, which brings great difficulties to the installation, so a mounting process for controlling the multi-directional freedom of the machine bed and the column is adopted. Control the degree of freedom of the four plane guides and the bed rails of the two columns, ensure the vertical straightness of the guide rails and ensure that the bed rails are at the center of the two columns. The process device of Figure 3 is used, and the two sides of the device are fixed on the columns by two ends. On the machined surface, it is an equal length pipe (see Figure 3a), and the other end is machined on the machined surface parallel to the bed rails and maintains equal clearance (see Figure 3b). figure 2 image 3 This not only ensures the installation accuracy but also overcomes the rotation of the two columns themselves. In controlling the positioning of the two columns relative to the front and rear guide rails, the contour is fixed on the plane which is processed and parallel to the two column guide rails and has the size requirement. The relative bed is measured by the contour ruler. The distance between the positioning pins on the process hole pre-machined on the guide rail determines the front and rear placement positions of the two columns, as shown in Fig. 4. Finally, after careful adjustment, the factory standards and requirements can be met. Figure 4 However, some of our manufacturers do not pay attention to the details, there is no good process guarantee, the technical requirements of the next process are seriously neglected in the assembly, and the four plane guides and the bed rails of the two columns after the secondary grouting occur The vertical straight line is seriously out of the standard. The 14 basic screws on the two sides of the column have been close to the base hole of the column and cannot adjust the rotation of the two columns, resulting in the user's distrust of the quality of the manufacturer. At the same time, in order to check the quality of the machine tool foundation and the foundation screw, Figures 5 and 6 are the work done to prevent disputes during the inspection of the machine tool. Figure 5 Figure 6 2. The design concept determines the effect For the rolling grinder, two basic conditions must be met to produce a good product: one is that the grinding machine has complete functions and the grinding performance is outstanding; the other is that the mold and the device are reasonable and rigid regardless of the method used. In order to meet the requirements of roll grinding and grinding. We tracked and analyzed a new 3t mill with unsatisfactory grinding and found that it has two principle problems: most of the structure of the machine is similar to that of an ordinary cylindrical grinder, and the countertop is divided into two layers. A rotating central shaft is arranged in the center of the workbench, and a plurality of sliding bodies are evenly arranged in the middle of the table, so that the upper mesa can be swung around the central axis of rotation under the action of an external force. The upper deck is provided with a head frame and a tailstock for supporting the product workpiece, and the lower platform mainly carries the weight of the upper workbench and the workpiece and is responsible for left and right movement. According to the different technical requirements of the rolling, the rolling mill can control the size of the grinding workpiece by the mold scale (see Figure 7) which can adjust the inclination in its own design. The general rolling ends are both small and medium-high. The state, for different occasions and applications, in the region of approximately 0.03 to 0.18 mm, the dimensional accuracy of both ends should be controlled to about 0.01 mm. Figure 7 However, we found in the grinding that the dimensional accuracy of the ends is difficult to control, and the dimensional tolerances are not regular. The maximum error sometimes exceeds 0.16 mm, which is 16 times the technical requirement. According to the structure of the machine tool, it can be analyzed that when the workpiece is longer and heavier, the upper table is rotated under the action of the external force and the spring force, and the rotation of the die is centered on the axis of rotation, so that the grinding state is high. The accuracy of the left and right table swings determines the dimensional accuracy of the ends of the workpiece. When there is no regularity test for dimensional tolerances, it is found that when the master contact of the upper table is moved against the die, the base of the die is poorly rigid (see Figure 5), and the right shelf of the bed. The slight drift, especially when moving to the ends of the die, is more serious, causing the upper workbench to drift as well, and does not move linearly according to the die, making the dimensional accuracy of the ends of the ends difficult to control. After finding the cause, the corresponding measures were taken to completely solve the phenomenon of over-difference. The dimensional accuracy error of the ends of the processed products reached 0.005mm. 3. Design and actual deviation The so-called gantry pentahedron machining center can only realize the pentahedron processing of the workpiece in one-time clamping by configuring various types of accessory milling heads. The accuracy of the accessory milling head determines the accuracy of the workpiece, and the function of the accessory milling head determines the degree of automation of the machine. At present, the gantry pentahedron machining center we use can realize the automatic loading and unloading of the accessory milling head, and the automatic loading and unloading tool is also realized by the robot. However, in actual use, we often encounter situations where the tool cannot be loaded onto the spindle and the tool cannot be removed from the spindle, either automatically or manually. There are many reasons for this type of failure, both caused by electrical signals and mechanical parts. Only one phenomenon is analyzed here, that is, the tool cannot be removed from the spindle. At present, the typical broach form of the gantry machining center is to use a disc spring to tighten the tool, and use the linear motion of the hydraulic cylinder pressure to open the disc spring to tighten the tool, so as to realize the function of the automatic broach and the loose knife under the program control. . All the signals, hydraulics and other related parts of the fault were checked for such faults, and no problems were found. The phenomena can be analyzed step by step and the principle of action. Figures 8 and 9 show the phenomenon after decomposition, and the surface has been repaired. Mainly during the execution of the program processing, when the first tool is finished, the tool should be automatically replaced. At this time, the spindle motor rotation has not completely stopped. The tool and the disc spring tensioning device also operate with the spindle, and the hydraulic cylinder is controlled. The relay and the electromagnet perform the PLC program, and under the action of the pressure, the device that pulls the disc spring to tighten the tool, because the device of the disc spring to tighten the tool rotates following the main shaft, and the hydraulic cylinder portion is fixed and does not rotate. Long-term operation of this part of the plane in a rotating state, the two planes should have a gap distance of 7 ~ 9m m, due to surface friction and heat to bond together to form a unit, so that the device of the disc spring tensioning the tool can not complete the opening broach Claws, complete the function of the loose knife. The design is considered very well, but in the application, the hydraulic cylinder return speed is too slow, there is no guarantee of 7 ~ 9m m clearance, and the next step is executed when the spindle is not completely stopped, it should be considered to add the spindle stop. Add a delay before the tool is replaced or before changing the tool program to prevent the formation of sticking due to surface friction. Figure 8 Figure 9 4. Machine head first look at the features The quality of the machine tool components reflects the overall strength of a country in the equipment manufacturing industry; the long-term quality stability and service of a machine tool reflects the overall level of a manufacturing plant. In today's situation, it is the best time for manufacturers to improve their technical level. The problem of neglecting quality in the early stage is solved as soon as possible, giving users a good reputation and forming a “first use†in the manufacturer. My equipment is the fault of the user, and the second one does not need my equipment to be the wrong manufacturer's sales concept. Figure 10 and Figure 11 show the problem that the quality of the functional components caused the machine to not work properly. Figure 10 Figure 11 Yaskawa SGM7G type servo motor Wuxi Trenty Machinery & Equipment Co., Ltd. , https://www.elec-inverter.com
Yaskawa Medium inertia, large torque servo motor SGM7G