CNC machining: Solve the Problem of Taps and Drills Broken in CNC Machining Parts

Any CNC machining equipment is basically inseparable from the thread, and when it comes to threads, it is inseparable from the CNC machining process of tapping. In the process of CNC machining, broken taps are particularly common. Therefore, in order to ensure the quality of CNC machining parts and the efficiency of CNC machining, it is particularly necessary to remove the broken cone. Here are some reference methods for solving the problem of broken taps.

1. Add lubricating oil to the broken part of the tap, use a sharp hairpin or chop something that can bear the force, and gradually knock it out on the opposite side of the broken. Don't forget to clean the CNC machined parts. This method is commonly used in workshops, but if the hole diameter is too small, the threaded hole or the broken tap is too long, it is not suitable, but it can be tested.

2. Weld a handle or a hexagonal nut on the broken section of the tap, and then slowly turn it out (this method is a good way, but welding is a little troublesome, the same as above, if the hole is too small, the threaded hole may be broken If the tap is too long, it is not suitable).

3. Use a special CNC machining tool: broken tap extractor. The principle is that the CNC machining parts and taps are connected to positive and negative electrodes, and electrolyte is filled in the middle, which causes the CNC machining parts to discharge corrosion to the tap, and then assist needle-nose pliers to take it out. The inner hole hurts very little.

4. Gradually tap the top of the steel roll with a small hammer on the crack of the tap. The tap is relatively brittle, and then it becomes slag. It may be simpler. Directly drill the threaded hole of the broken tap and boring it again. Reaming and tapping from the beginning (some methods Barbaric, if the diameter of the tap is too small, it won’t work, if the diameter is too large, it will be tiring to tap);

5. Weld the threaded hole where the broken tap is located, then grind it flat, and drill from the beginning. Although it is difficult, it will gradually be able to drill in (if the threaded hole can be changed position, when drilling and tapping from the beginning, it is recommended to change to Around the original threaded hole);

6. Chisel a slot on the cross section of the broken tap, and use a screwdriver to reverse it (the slot is difficult to chisel out, and it is even more difficult if the diameter of the tap is small);

7. Drill the threaded hole of the broken tap to a large size, and then inlay a wire thread insert or pin or something, then weld, grind, and re-drill and tap the thread. It can be basically the same (this method is very useful although it takes a lot of trouble. , The size of the tap does not matter);

8. Use electric pulse to knock out, EDM or wire cutting can be used, the hole can be reamed with wire threaded sleeves (this method is simpler and more convenient, as for the coaxiality, don't consider it for the time being, unless your threaded hole is the same Axial degree directly affects the quality of equipment);

9. Make a simple thing and pierce the space of the chip groove of the broken tap section together, and pull it out carefully. For example, you can screw 2 nuts on the broken tap with a square tenon, and use the steel wire (number of threads and the number of tap grooves). Same) pierce into the empty slot of the broken tap and nut, and then use the hinge lever to pull the square tenon in the exit direction to take out the broken tap (the theme of this method is to connect the chip groove of the broken tap, use steel wire, good It is a steel needle to make a wrench for taking broken wires. Of course, if such broken wires often occur in the workshop, it is better to make a wrench like this);

10. The nitric acid solution can corrode high-speed steel wire cones, and does not invalidate CNC machining parts.

11. Anneal the tap with an acetylene flame or a blowtorch, and then use a drill to drill. At this time, the diameter of the drill should be smaller than that of the bottom hole, and the hole should be aligned to the center to avoid damage to the thread. After the hole is drilled, it will be drilled into a flat shape. Or use a square punch to unscrew the tap with a wrench.

12. Rotate with a pneumatic drill to take it out. It depends on the hand feeling, because it is not directly drilled out of the tap, but with a slow speed and a little friction (similar to the semi-convergence of a car) to make the tap turn out.

13. Able to use a grinder to grind the broken wire, and then use a small drill to drill first, and then gradually switch to a larger drill, the broken wire will gradually fall, and after falling, use the original size of the tap to tap the tooth from the beginning. This advantage can eliminate the need to increase the aperture.

14. Weld an iron rod on the broken-in object, and then unscrew it. (Defects: a. The cut-in is too small to be welded; b. It requires extremely high welding skills, and the CNC machining parts are simply burned out; c. The weld is simply broken, and the probability of taking out the broken-in is very small).

15. Pry with a cone-shaped object harder than the cut-in object. (Defects: a. Only suitable for brittle broken objects. Break the broken objects into pieces, and then gradually remove them; b. The broken objects are too deep or too small to be taken out; c. Simply destroy the original hole).

16. Make a hexagonal electrode with a diameter smaller than that of the broken-in object. Use an EDM machine to machine a hexagonal counterbore on the broken-in object, and then use an Allen wrench to unscrew it. (Defects: a. Useless for rusty or stuck interrupted objects; b. Useless for large workpieces; c. Useless for too small interrupted objects; d. Time-consuming and troublesome).

17. Directly use an electrode smaller than the cut-in object, and use an EDM machine to beat it. (Defects: a. Useless for large-scale CNC machining parts and cannot be put into the EDM machine table; b. Time-consuming; c. Carbon deposits when it is too deep and cannot be hit).

18. Drill with an alloy drill (defects: a. Simply destroy the original hole; b. Useless for hard broken objects; c. The alloy drill is brittle and easy to break).

20. There is now a portable machine designed and manufactured by the principle of electrical numerical control processing, which can easily and quickly take out broken screws and broken tap drill bits.

19. If the screw is not too hard, the end face can be flattened, and then find the center point, punch a small point up with a sample, drill first with a smaller bit, be vertical, and then use the broken wire extractor to reverse screw Just get out.

20. If you can't buy a broken wire extractor, use a larger drill bit to continue reaming. When the hole diameter is close to the screw, some wires will fall off with difficulty, remove the remaining wires, and then use a tap to trim it from the beginning. 

21. If the broken thread of the screw is exposed, or the requirements for the broken screw are not strict, and the hand saw can be sawed, the saw blade can be sawed, and the shell can be sawed, and then use a flat-blade screwdriver to remove it.

22. If the length of the broken wire must be outside, and the melting point of the mechanical material is not too low, an extended T-shaped rod can be welded on the screw by electric welding, so that it can be easily unscrewed from the welded rod.

23. If the rust of the screw is very serious and it is not easy to deal with it by the above method, it is recommended to add a little lubricating oil after baking it red, and then use the above corresponding method to deal with it.

24. After many attempts, although the screw is taken out, the hole is also useless at this time. Just drill a larger hole and tap it. If the original screw position and size are constrained, it can also be larger. Put the screw in, perhaps directly weld and tap, and then drill a small hole in the center of the big screw to tap. However, the internal metal structure of the welded body is sometimes difficult to tap.