Tungsten carbide rod with coolant hole is made of hard alloy material, which is mainly used to process various hard alloy cooling holes. It works mainly by carbide rod internal spiral cooling hole hole, the coolant under high pressure to the cutting edge, so as to reduce the bit especially the bit at the top of the high temperature. At the same time, the chip can be removed from the side, so as to effectively remove the debris and greatly improve the surface finish of the workpiece.

It is more common to extend the life of drill bit by external cooling process. With the wide application of this process, however, many users find that in this process, because the debris in the manufacturing process of continuous discharge, to some extent hindered the coolant reached the top of the tool, to reach the ideal cooling effect. At the same time, with the increase of machining depth, the effect of external cooling process is worse and worse, and it may hinder the expulsion of chip. Therefore, the internal cooling process is present, and the application of  tungsten carbide rod with coolant hole is more and more extensive.

It has the advantages of good cooling effect, high cutting efficiency and long service life. In the process of carbide bit machining, the coolant is sent to the cutting edge under high pressure through the hole in the drill bit. Such as coolant quickly delivered in a timely manner, can quickly reduce the cobalt high temperature especially the bit at the top of the head, scraps discharge from the side, at the same time can be carried on effectively will produce chip removal, improve the surface finish. According to the research, the hard alloy bit produced by tungsten carbide rod with coolant hole can not only improve the efficiency of the deep hole processing, but also nearly double the service life of the tool.

At present, the production technology of the world's spiral carbide cooling hole rods is:

Mosaic method: the surface of tungsten carbide bar is machined into a spiral groove and then pressed into a hard alloy tube. However, the method is complicated, the expansion coefficient adjustment and control difficulty of alloy mixing are difficult, and the dimension control is difficult. Also can be in machining the spiral groove and casing pressure in the extrusion molding, however, for the combination, the thinner the wall, the better, as the rotation, tooth surface as wide as possible, so the mold manufacturing difficulty, and a set of can only make one size carbide rod cooling hole.

External screw extruding method: 1.the concave mold diameter belt is provided with thread, the material is extruded by rotation; Cooling hole core rod thread slot must cooperate with manufacture and concave die, the technology design of the die is relatively complex, mould die and core rod must be in sync, otherwise will cause out-of-tolerance size parameters, cooling distributed partial or crack. 2. the concave mold active rotation drives the material to rotate, simultaneously guides the nylon wire embedded in the material. The dragon silk (soft core) needs to be guided into the inside, and the shape and size of the screw hole is difficult to control, and if the process limits the screw hole specification and the length of the rod in the later stage of burning; The outer surface quality is difficult to control when the rod rotates forward. External screw extrusion is a kind of molding technology which is widely used at home and abroad.

Internal screw extrusion method: using the special structure of twin-screw extruder, the core rods extends to the screw extruding, use the screw driver core rod rotation or drive core rod elastic needle in the rotation, to shape the screw hole; The die design of this process is simple, but the squeeze parameter is strict, and the extrusion speed and the core speed of the material must be matched. Otherwise, the size parameter of tungsten carbide rod with coolant hole cannot meet the requirement. Because of the difficulty of this technology, only a few foreign companies such as konard friedrichs in Germany can produce, and there is no such technology in China. The technology to meet the speed matching, core rod manufacturing, flexible needle should correspond with the performance of extruder screw extrusion speed and speed matching, limiting the generality of the same equipment and can produce the specifications of the bar is kind.

Posted by: hannahgwendolyn at 09:08 AM | No Comments | Add Comment
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