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Add: Block 7, No.19, Xingnan Road, Wuzhong, Suzhou City, Jiangsu, China
Name：Rebecca Dong
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Mold injection molding processing center. |
1. Cast iron bed structure, the spindle of machine tool has the cooling function.
Cast iron material has high rigidity and heat dissipation characteristics, so it is the most stable material for making machine tool structure. For any machine tool used for milling large parts, it is necessary to have a very strong cast iron structure, and equipped with a main shaft with heat dissipation function.
In terms of machine tool spindle, it must use the built-in cooling technology, from the outside to cool down the main shaft bearing, ensure the long term in machining process, the spindle itself will not be burned or not accuracy loss due to thermal expansion. These factors are very important because the processing of large molds takes a long time, while under heavy cutting conditions, it increases the heat and stress of the mold. Therefore, the structural parts of the machine must have good rigidity and heat dissipation characteristics, which is the precondition for processing large quality molds. Therefore, it is necessary to limit the vibration of machine tools and the heat generated during the process of rapid diffusion. Choosing the right machine tool and cutting tool can achieve both cost and cycle.
2. Thermal stabilization technology.
Because the processing time is too long, the influence of environmental temperature must also be considered. Large mold on the machine in normal, for example, when the environment temperature 10 ℃, will cause a 6 ℃ temperature change of the machine tool column, leading to the main shaft Angle plate parallel degree change of 0.07 mm. Therefore, the design of the machine must take into account the effect of ambient temperature, so as to avoid the influence of ambient temperature on the precision of the machining parts.
Speed of 3.
For a large mold machining center that can move quickly, the spindle speed of the large die processing machine should be at least 20000r/min, and the cutting speed of the metal shall be 762 ~ 20000mm/min.
Accuracy of 4.
Accuracy control is always throughout all phases of mould processing, if you need large injection mould are on a machining center for roughing and finishing, so must be strictly controlled machine tool positioning accuracy and repeat precision. The processing center of large mold is used, and its positioning accuracy can be up to + 1.5mm, and the repeated positioning accuracy should be up to + 1. At the same time, the pitch accuracy should be kept within 5 mu m.
5. Feedback resolution
For high precision curved surface machining, the feedback resolution of the machine tool is very important for detecting the precision of machining parts. With the standard 1 m feedback resolution, the results are usually not very satisfactory. If the resolution can be as high as 0.05, then the finishing results are almost flawless. Furthermore, the machining quality of the part surface can be further improved by controlling the resolution of the machine tool, the feedback of the ruler and the control of the bar ball screw.
6. The main shaft
Used on large mold machining center spindle must be achieved for roughing and semi-finishing and finish machining with high quality requirements, but also as a reference standard, it can realize the surface machining quality should be controlled at the levels of 2 microns. Usually, for die closed surface and parting line part of the finishing is very important, but under the traditional process, many mold manufacturers have had to adopt the way of manual polishing, to make up for the problem of insufficient cutting tool machining accuracy. Because of the high cost of large processing machine tools, it is obviously impractical to purchase multifunctional machine tools for this process.
In addition, reasonable spindle design must be able to extend the life of the tool to the maximum extent, so that it can continue to work in low vibration and low temperature rise during the processing cycle. In big mould processing center processing, for example, when the car dashboard molds, such as using 16 MMCBN edged blade finishing tool, processing speed can reach 8 m/min, the service life of more than 30 h, processing surface quality can be controlled in 0.336 ~ 3.2 microns. Therefore, considering the processing large mould tooling cost, using specially designed large mould processing machine tools, can not only extend the service life of cutter, but also a lot of saving the cost of processing each pay mold tool use.
7. Movable multi-axis machining head.
Because of the size and weight of the die, it takes a long time to assemble the workpiece. Therefore, using three axes linkage machining center not only reduce the number of debugging the clamping workpiece, and shall not affect the machining accuracy of machine tools, machining large mould making workshop production capacity is greatly increased.
Removable multi-axis machining head can be used for large injection mould are particularly complex structure, according to the variable geometry design of machining head allows three axes linkage, the clamping workpiece only once and can milling cavity mould and cooling of deep hole, and many other complex geometry parts machining. For example, when the spindle is tilted at the optimum Angle, it can improve the proximity of the machining head to the milling point, so that the processing of the inclined hole can be accomplished by using the multi-axis machining head.
In addition, the surface roughness can be improved by using the tool's radius blade instead of the tool tip because of the surface of the workpiece.
8. Chip management
When metal cutting is processed, a large amount of chip will be produced. If it cannot be eliminated in time, it will inevitably lead to the secondary cutting and the temperature rise of the structural parts of the machine tool or the surface of the workpiece. Under the worktable of the large die processing center, there are usually 18 chip holes, which can reliably eliminate the chip, no matter where the worktable is moved. The machine tool has 4 built-in hinged chip conveyor belts, and the chip is sent to the front of the machine at a high speed.
9. High pressure coolant.
High pressure coolant plays an important role in large mould processing. For example, when drilling a slanting hole with a 2+3 axis machining method, the cooling liquid of 1000psi (1psi=6890Pa) is required to effectively eliminate the chip and achieve a higher precision cutting. If there is no such high pressure coolant, it is necessary to add extra machine tools when machining the inclined hole, which requires secondary loading, reducing machining accuracy and increasing the cycle cost. According to the above analysis, it can be seen that simple machining of large mould requires more and better functions. Makino and development of new type MCC2516VG3 axis horizontal machining center, the spindle speed of up to 15000 r/min, and adopted the "shaft core cooling" mode and "bearing inner pressure lubrication" function, and its affiliated bearing spindle can get timely and effective cooling.
In addition, the main axis can not only move along the horizontal X-axis, the Y-axis of the vertical direction, and the z-axis direction of the front and back direction, but also coordinate the rotation of A and C axes. Because of the two kinds of indexing functions, it can not only reduce the amount of adjustment, but also can cut the complex structure of the workpiece, such as bumper, instrument panel and automobile headlamp lens.
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