Optimum Scheme of Extended Bit, Deep Hole Twist Drill-Deep Hole Processing
Release time：2019/4/24 15:47:08 Source:www.fjlgs.com Author：Zhenjiang Zhengda Tools Co., Ltd.
deep hole drilling has become a serious bottleneck restriction in too many workshops, whether it is the cooling water channel of plastic mould, gun barrel, hydraulic cylinder or hollow shaft of jet engine or ship propeller. This problem is particularly evident when using gun drills to process high standard holes. When drilling 4 times the depth of diameter, the chip plugging begins, and the worse it goes in. The bit is located at the end of a slender rod and moves slowly like a snail, while the roundness and position of the hole are not good. These are before the cutting edge begins to collapse.
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The newly developed two-stage deep-hole drill in Iska has prevented these situations from happening. Today's pipe drilling system can completely solve the problem of large diameter and large depth (up to 300 times the ratio of length to diameter). Compared with gun drilling, the efficiency of pipe drilling system is more than 5 times or even more. The latest small helix angle monolithic cemented carbide drill can effectively cover small diameter and the ratio of length to diameter is as high as 22 times. In deep oil hole processing of engine crankshaft, it is 10% faster than welding gun drill, 6 times faster than high-speed steel drill, and its reliability is greatly improved. It has been successfully applied in automobile manufacturing, turbine processing, aircraft landing gear processing, national defense and general machinery processing, as well as in petroleum, mining and agricultural machinery.
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Two Solutions
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Let's look at two-stage deep hole drills.
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In the pipe drilling system, the cutting head is installed on the thin-walled drill pipe with a slightly smaller diameter than the hole. Cutting fluid is pumped into the gap between the hole wall and the drill pipe, and chips are washed out of the hole in the drill pipe. Compared with the small drill pipe of gun drill, this can make the cutting head work on a more solid basis, transfer more torque, bear more cutting force, and expand the chip removal channel. The ultimate benefit is faster processing and smoother chip removal. nbsp;
Case < div >: Using gun drill, a hole with a diameter of 40 mm (1.6 & Prime;) and a depth of 660 mm (26 & Prime;) is machined on Ti6AL4V titanium alloy workpiece. The best workshop can process 12.7 mm (0.5 & Prime;) per minute at a speed of 300 r/min, and it takes 52 minutes to finish one. Traditional cemented carbide bits are slightly improved, but the blade begins to break when drilling the second part, causing the clutch to slip. However, on the same machine tool, using a single pipe drill, the processing efficiency is five times faster, and a drill can complete a whole shift (see figure 5). 
