The Deep Hole Drilling Features

The processing characteristics of deep hole drills:

1. The Drillstar tool holder is limited by the aperture, with a small diameter and a large length, resulting in poor rigidity and low strength. It is prone to vibration, ripples, and taper during cutting, which affects the straightness and surface roughness of deep holes.

2. When drilling and expanding holes, it is difficult to input cooling lubricant into the cutting area without using special devices, which reduces tool durability and makes chip removal difficult.

3. In the process of deep hole machining, it is not possible to directly observe the cutting situation of the tool. Only by listening to the sound of cutting, observing chips, touching vibrations and workpiece temperature, and observing instruments (oil pressure and electricity meters) based on work experience, can the cutting process be judged to be normal.

4. It is difficult to remove chips, and reliable methods must be used to break them and control the length and shape of the chips, in order to facilitate smooth removal and prevent chip blockage.

5. In order to ensure the smooth progress of deep hole machining and achieve the required machining quality, it is necessary to add internal (external) chip removal devices, tool guidance and support devices, and high-pressure cooling and lubrication devices.

Generally, a hole with a depth of more than 5 times of the hole diameter is called a deep hole. Its difficulty lies in chip removal and cooling. Fried Dough Twists drills can be used for holes with a relatively small hole depth. In order to remove chips smoothly, iron chips should be straight out in a thin strip shape and bring out smaller chips. At the same time, coolant is easy to enter.

The grinding method for drill bits can be relatively simple:

1. Increase the angle between the drill blade to 130-140 degrees to increase chip thickness and change the direction of chip discharge (the direction of chip discharge is perpendicular to the cutting edge)

2. Grinding the horizontal edge to reduce the axial cutting tool while creating a corner near the drill core to facilitate chip separation.

4. Invert the outer corner of the blade by 1 millimeter and 45 degrees to reduce wear and improve smoothness.

5. The drilling speed should be slightly lower, and the feed amount should be larger, so that the chips thicken and are discharged in a strip shape.

6. The nozzle of the coolant should face inward towards the hole to facilitate the coolant to enter the cutting area.

Common problems and solutions editing

Rough surface of the hole

1. Chip adhesion: reduce cutting speed; Avoid blade breakage; Replace with cutting fluid with high extreme pressure and improve filtration; Increase the pressure and flow rate of cutting fluid.

2. Poor coaxiality: Adjust the coaxiality between the machine tool spindle and the drill sleeve; Use an appropriate drill sleeve diameter.

3. Cutting speed too low, feed rate too large or uneven: Use appropriate cutting amount.

4. Inappropriate tool geometry: Changing the cutting edge geometry angle and the shape of the guide block

The orifice is in a trumpet shape

Poor coaxiality: Adjust the coaxiality of the machine tool spindle, drill sleeve, and support sleeve; Use an appropriate drill sleeve diameter and replace worn drill sleeves in a timely manner.

Drill bit breakage

1. Poor chip breakage and inability to discharge chips: Change the size of the chip groove to avoid being too long or too shallow; Promptly detect the situation of broken blades and replace them; Increase the pressure and flow rate of cutting fluid; Use workpieces with uniform material organization.

2. Excessive, insufficient or uneven feed rate: Use appropriate cutting amount.

3. Excessive wear of drill bits: Regularly replace drill bits to avoid excessive wear.

4. Inappropriate cutting fluid: Choose a suitable cutting fluid and improve the filtration situation.

Low lifespan of drill bits

1. Cutting speed too high or too low, feed rate too large: Use appropriate cutting amount.

2. Improper drill bit: replace the tool material; Change the position and shape of the guide block.

3. Inappropriate cutting fluid: Use cutting fluid with high extreme pressure; Increase the pressure and flow rate of cutting fluid; Improve the filtration of cutting fluid.

other

Chip formation in a strip: The geometric shape of the chip groove is not suitable; Improper geometric shape of cutting edge; The feed rate is too small; Uneven material organization of the workpiece: changing the geometric shape of the chip groove and cutting edge; Increase the feed rate; Use workpieces with uniform material organization.

Chip too small: The chip groove is too short or too deep; The radius of the chip groove is too small: it changes the geometric shape of the chip groove.

Excessive chip size: The chip groove is too long or too shallow; Excessive chip groove radius: Changes the geometric shape of the chip groove.