The common methods of drilling deep holes are as follows：
(1) Cooling water holes and heating holes of small and medium-sized moulds are usually processed by ordinary or lengthening drills on vertical drills and rocker drills. During processing, chips should be discharged and cooled in time, and feed should be small to prevent hole deviation.
(2) Holes of medium and large moulds are usually processed on rocker drills, boring machines and deep L drills. The more advanced method is to process holes together with other holes on machine tools of machining centers.
(3) Over-long low-precision holes can also be drilled from both ends after scribbling.
(4) Holes requiring higher verticality should be guided by certain technological measures, such as using drill jigs.
Attention should also be paid to drilling deep holes:
A. When the drilling depth is 3 times of the diameter, the bit should be put forward for chip removal, and after a certain depth, the bit should be withdrawn from chip removal, so as to prevent the bit from breaking due to chip blockage.
B. Some of the deep holes are deeper than the total length of the bit or deeper. At this time, lengthened rod drills or connecting rod drills can be used to drill holes. These two kinds of drills can be purchased or made by ourselves.
C. For some special deep holes, such as some through holes, special equipment or machine tools are usually used. At this time, special lengthening rod drills are needed. This kind of drill bit should be developed by itself according to the specific conditions of the workpiece. Generally, deep hole processing technology can not process the whole hole depth with one cutting tool. It must be divided into several feeds to solve the problems of chip removal and cooling, and the processing accuracy is low. The gun drill can solve these problems, so in die manufacturing, deep holes with diameter less than 20 mm, such as cooling water holes, can be processed by gun drill. Wechat Public No. hcsteel Gun Drill. The working part of the gun drill is formed by butt welding of high-speed steel or cemented carbide with the drill pipe formed by pressing seamless steel pipe. The workpiece is fed by a rotary drill while the high-pressure cutting fluid is injected into the tail of the drill pipe. After cooling the cutting zone, chips are washed out along the groove of the drill pipe.
The characteristics of drilling holes are as follows:
The length-diameter ratio of the hole can reach 100:1 or larger.
High production efficiency, only one process can be used to obtain high quality holes;
After continuous processing for a long time, the size of the hole changes very little (within O.02-O.05 mm);
When the hardness of the workpiece material is up to 45HRC, it can still be processed.
The quality of the hole is very good, usually no further processing is needed.
No skilled operation skills are required;
_Tool durability is 10-15 times higher than twist drill, and hundreds to several dry parts can be processed every grinding.
The position accuracy of the hole is the same as that of the adjustment.
