4. Accuracy
Accuracy control always runs through all stages of mold processing. If rough machining and finishing of large molds are required on one machining center, the positioning accuracy and repeatability of the machine must be strictly controlled. The machining center for large molds generally has a positioning accuracy of ±1.5μm and a repeatability of ±1μm. At the same time, its pitch accuracy should be kept within 5μm.
4. Feedback resolution
The feedback resolution of the machine itself is very important for detecting the accuracy of the machined parts. With a standard 1 μm feedback resolution, the results usually are not very satisfactory. If the resolution can reach 0.05 μm, there is almost no flaw in the finishing result. Moreover, the machining quality of the surface of the part can be further improved by controlling the resolution of the machine, the scale feedback and the small pitch ball screw.
5. Spindle
The spindles used in large mold machining centers must meet the requirements for roughing, semi-finishing and high-quality finishing, and as a reference standard, the surface finish quality that can be achieved should be controlled at a level of 2 μm. In general, the finishing of the mold closing surface and the parting line is very important, but in the traditional process, many mold manufacturers have to use the manual polishing method to compensate for the problem of insufficient tool processing accuracy. Because the cost of large-scale machine tools is expensive, it is obviously unrealistic to purchase multi-function machine tools for this process.
In addition, a reasonable spindle design must maximize the life of the tool so that it can continue to operate with low vibration and low temperature during the machining cycle. For example, when machining automotive dashboard molds on a large mold processing center, such as 16mm CBN insert finishing tools, the processing speed can reach 8m / min, the service life is more than 30h, the processing surface quality can be controlled at 0.336 ~ 3.2μm. It can be seen that, considering the increase of the tool cost when processing a large mold, the use of a specially designed large-scale mold processing machine can not only prolong the service life of the tool, but also can greatly save the cost of processing the tool for each mold.
6. Movable multi-axis machining head
Due to the size and weight limitations of the mold, it usually takes a long time to clamp the workpiece. Therefore, the use of the 3-axis linkage machining center not only reduces the number of debugging and clamping of the workpiece, but also does not affect the machining accuracy of the machine tool, thereby greatly improving the production capacity of the large-scale mold in the workshop.
The movable multi-axis machining head can be used to machine large-sized molds with particularly complicated structures. The machining head designed according to the variable geometry allows 3-axis simultaneous machining. The workpiece can be milled only once, and the machining cavity can be deep. Molds and cooling holes, as well as many other geometrically complex parts that are machined. For example, when the spindle is tilted at an optimum angle, the proximity of the machining head to the milling point can be improved, so that the processing of the inclined hole can be completed by using the multi-axis machining head.
In addition, since the multi-axis machining head processes the surface of the workpiece, the radius of the cutter is used instead of the tip of the cutter, so that the surface roughness can be improved.
7. Chip management
A large amount of chips are generated during metal cutting. If it is not removed in time, it will inevitably lead to secondary cutting and temperature rise of the structural parts of the machine tool or the surface of the workpiece. The large mold machining center usually has 18 chip evacuation holes under the workbench, which can reliably remove the chips regardless of where the table is moved. The machine has four built-in hinged chip conveyors that deliver chips to the front of the machine at high speeds.
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Wear Resistant Cast Steel Ball
Advantages of cast chrome alloy balls include:
1. Cast chromium alloy ball has excellent wear resistance and can maintain a long service life under high wear environment.
2. Cast chromium alloy ball has good corrosion resistance, can resist the erosion of a variety of chemical substances, suitable for a variety of corrosive media working environment.
3. Cast chromium alloy ball has high hardness, can resist greater impact and pressure, is not easy to deformation and damage.
4. Cast chromium alloy ball has high tensile strength, can withstand large tension, not easy to break.
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