What is the difficulty of deep hole machining ?

In the past 20 years of CNC machining experience of Jiesheng Hardware, we often receive some deep hole product consultations. At this time, our engineering team will conduct in-depth communication with customer engineers and designers to discuss the difficulties of deep hole processing. And solutions so that we can assist clients in evaluating each potential design option.

Difficulties of deep hole processing:
1. The tool bar is limited by the aperture, the long diameter of the hole is relatively large, the drill pipe is thin and long, the process system has poor rigidity and low strength, it is prone to vibration during cutting, the drilling is easy to deviate, ripples and taper, which affect the deep hole Straightness and surface roughness;

2. When drilling and reaming, it is difficult to input the cooling lubricant into the cutting area without special equipment, which reduces the tool durability.

3. Chips are not easy to discharge. Due to the depth of the hole and the long path of the chips, it is prone to blockage, causing the drill to break. Therefore, the length and shape of the chips must be controlled, and forced chip removal must be carried out.
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4. Deep hole machining is in a closed or semi-closed state, and the cutting condition of the tool cannot be directly observed. You can only rely on experience to judge whether the cutting process is normal by listening to the sound, watching the cutting, touching the vibration and workpiece temperature, watching the instrument, observing the machine load and pressure gauge, touch vibration and other appearance phenomena

5. In order to ensure the smooth progress of the deep hole in the processing process and achieve the required processing quality, the tool internal (or external) chip removal device, tool guide and support device and high-pressure cooling and lubricating device should be added;

6. The tool has poor heat dissipation conditions, and the cutting heat is not easy to dissipate. In general, 80% of the cutting heat is taken away by the chips during the cutting process, while only 40% of the deep hole drilling. The tool accounts for a large proportion of the cutting heat, spreads slowly, and is easy to overheat. The knife edge temperature can reach 600 degrees, which must be enforced. Cooling method

Therefore, the following points should be paid attention to in deep hole processing:

1) Accurate positioning of the workpiece.
2) The fixture is installed correctly.
3) The blank has no defects such as looseness, pores, blisters, hard spots, etc.
4) Control the size, position accuracy and positioning pin accuracy of the positioning pin hole.
5) Processing drill bit requires center cooling.
6) The drill speed and cutting speed are precisely controlled during secondary drilling.
7) Strictly control the depth of each drill bit.
8) Remove the iron filings from the hole in time.