Quicknc processing graphite electrode is the most

Using quicknc to process graphite electrode

Abstract: the programming and processing of graphite electrode in die-casting mold requires fast and accurate, and the new product developed by Cimatron - quicknc software well meets this requirement. Through an example of graphite electrode machining, this paper shows the efficient programming method of quicknc

in the manufacturing process of traditional die-casting dies, NC machining of electrodes accounts for nearly 60% of the share. Improving the machining efficiency of the electrode will play an important role in shortening the manufacturing process of the whole mold

first, the processing characteristics of graphite electrode

industrial graphite is hard and brittle, and the tool wear is relatively serious during NC processing. It is generally recommended to use cemented carbide or diamond coated tools. Due to the high price of cutting tools and the continuous machining of electrodes in the machining process, there are high requirements for the accuracy of tool path. EDM of complex cavities sometimes requires hundreds of electrodes, so the workload of cam is very large

when graphite is processed in rough, the tool can directly cut on and off the workpiece. In order to avoid the occurrence of angle collapse and fragmentation during finish machining, the method of light knife and fast walking is often used. Generally speaking, when the cutting depth of graphite is less than 0.2mm, it rarely breaks, and better side wall surface quality will be obtained. Due to the large amount of data in the processing program, the processing time of complex electrodes sometimes reaches 50 hours

II. Quic3. Workbench stroke: longitudinal ± 10mm, transverse ± 10mm, lifting: 12mm; Features of KNC software

1, simple surface function

quicknc can read data in IGS, step and other standard formats. If there is a missing surface in the process of data conversion, you can select the curve around the surface, and then use the function of 3D cap to sew the defect surface, which is simple and easy, without complex CAD means

2, quicknc has few processing parameters

quicknc has no more than ten raw processing parameters and no more than fifteen finishing parameters, which is a liberation for the complicated cam process of electrodes and is also very easy for beginners to master

3, the quick preview function of section time

the preview function of quicknc does save cam personnel a lot of time in calculating to view the tool path. Usually, for more complex models, cam personnel often have to calculate and check repeatedly until they get a satisfactory tool path. Under the condition of high-speed machining, it is a very "painful" thing for cam to repeatedly calculate tens of megabytes or even tens of megabytes of files. We have used quicknc to calculate an electrode model with a data volume of 24 megabytes. The preview process takes only about 30 seconds. For experienced cam, it is easy to find problems, correct parameters, and obtain a satisfactory tool path. This is really a "happy" thing

third, an example of using quicknc to process electrodes

as shown in the figure, the blank size of graphite electrode is 140 × seventy ×， The width of the formed reinforcement is 1.6mm and the processing depth is. This type of electrode has medium overall size and complex shape, which is a common model in graphite electrode. Due to the weakness of the rib, the processing strategy of cam is: first rough machining the shape outside the rib, and then finish machining the inner side of the rib again

1. Rough mill

use Φ 11b coated ball end milling cutter adopts the spiral cut processing method, with a down step of 2.0mm and a side step of 2.0mm. In the next five years or more, the market demand for flexible packaging in the two regions will increase by 5% with a spindle speed of 1500rpm and a feed speed of 350mm/min. Using the preview function (5 seconds), the processing effect is shown in the figure. The milling cutter did not enter the inside of the rib, and the allowance outside the rib was removed, which met the requirements of the process. Press OK to exit. The time of program calculation (execute) is 2 minutes, and the processing time is 4.4 hours

2. Finish mill

finish mill selection Φ 6B ball end milling cutter adopts the processing method of layer cutting followed by parallel milling (layers & parallel), which can process surfaces with a limited angle (slope) of more than 45 ° in parallel. Because the ribs are very thin, only one finishing can be carried out, and the allowance value of the knife should be fully considered in the control of the electrode reduction. The layer cutting depth is 0.15mm, the parallel cutting step is 0.3mm, the accuracy is 0.01mm, the spindle speed is 1800rpm, and the feed speed is 450mm/min. Preview (15 seconds) track as shown in the figure. The program calculation time is 5 minutes and the processing time is 7.2 hours

3. The root fillet of the surface is r2.5mm, so it is selected Φ 4b ball end milling cutter. Quicknc automatically calculates the parts to be machined according to the diameter and machining parameters of the front knife. If the tool enters the interference part, use Sketcher to draw a 2D boundary, and take this boundary as the constraint boundary, then the tool path is removed at this part. As shown in the figure, the red rectangle is the constraint boundary, and the part within the projection range of the green surface is the back chipping part. Use the default rerough parameters, and the finish parameters are:

down step =0.3mm,

side step =0.5mm,

tolerance =0.01mm,

spindle =2000rpm,

feed =400mm/min

preview (10 seconds) is shown in black, the program calculation time is 3 minutes, and the actual processing time is 1.2 hours. The machining track is shown in black in the figure

experienced cam personnel, from transferring into the model, setting the coordinate system, blank, determining the processing technology, parameters to previewing the processing effect, the whole process takes about 10 minutes. When the calculation is completed, add and modify the parameters 1 to 2 times, and the whole cam process (including 3 program calculation times of 30 minutes, and the upstream market of the industrial chain will also usher in a high-profile development period. In this process, quicknc can be used to make processing process instructions) will take about 45 minutes

4. Processing instructions

if the quick preview function of quicknc saves us time, its dimensioning screen printing function provides us with drawing instructions close to regular drawings, avoiding many clerical errors. Just click the 2D or 3D dimension icon, and the dimension will be displayed on the screen. Using the mark up icon, you can mark the short notes of cam on the parts that need attention. Convert the view to the front view, as shown in the figure, and use the print preview to print the instruction book with dimensions. It is commendable that the program can calculate and print at the same time. It is often at the end of the program calculation that all the guidance documents are also printed, as if "it is desirable immediately"

IV Conclusion

to sum up, in the process of using quicknc to process nearly 100 graphite electrodes of die-casting molds, we compared the processing accuracy, the rationality of tool path, the processing time, the convenience of modification, and the cam time. The most obvious difference is that the programming efficiency of quicknc is improved by nearly three times. Quicknc is really a good cam tool for programming and machining a large number of graphite electrodes. (end)