What are the shapes and uses of various drills?

The cutting part of the flat drill is shovel-shaped, with simple structure and low manufacturing cost. Cutting fluid is easy to enter the hole, but its cutting chip removal performance is poor. The structure of flat drill has two kinds: integral and assembled. Integral drilling is mainly used for drilling micropores with a diameter of 0.03 ~ 0.5 mm, and the assembled flat drill blade can be replaced and internally cooled, and it is mainly used for drilling large holes with a diameter of 25 ~ 500 mm.

2, twist drill

Twist drill is the most widely used hole processing tool. Usually the diameter ranges from 0.25 to 80 mm. It is mainly composed of a bit working part and a handle. The working part has two spiral grooves, which are shaped like twists, hence the name. In order to reduce the friction between the guide part and the hole wall during drilling, the diameter of the twist drill gradually decreases from the drill tip to the handle, showing an inverted cone shape.

The helix angle of twist drill mainly affects the rake angle of cutting edge, blade strength and chip removal performance, usually 25 ~ 32. The spiral groove can be processed by milling, grinding, hot rolling or hot extrusion, and the front end of the drill bit is sharpened to form a cutting part.

The top angle of standard twist drill cutting part is 1 18, the oblique angle of cross blade is 40 ~ 60, and the back angle is 8 ~ 20. Due to structural reasons, the rake angle is larger at the outer edge and gradually decreases towards the middle, and the rake angle of the transverse edge is negative (up to about-55), which plays a squeezing role during drilling.

3. countersunk drilling

Countersunk drill has many cutter teeth, and the hole end is processed into the required shape by forming method, which is used to process countersunk holes of various countersunk screws or flatten the outer end face of the holes.

4. Hollow drill

In the middle of the drill pipe is a hollow drill bit, which is mainly used for drilling and coring.

5. Center drilling

The center drill is used to drill the center hole of shaft workpiece, which is essentially composed of twist drill and small spiral angle countersunk drill, so it is also called compound center drill.

6, deep hole drill

Deep hole drill usually refers to a tool for processing holes with the ratio of hole depth to hole diameter greater than 6. Commonly used are gun drill, BTA deep-hole drill, jet drill, DF deep-hole drill and so on. The trepanning drill is also commonly used for deep hole machining.

7. Reaming drill

Reamer has 3 ~ 4 teeth, and its rigidity is better than that of twist drill. It is used to enlarge existing holes and improve machining accuracy and flatness.

Extended data:

Bit is the main part of drilling equipment, and its main function is to break rocks and form holes. Rotary drill bit is commonly used in petroleum industry at present. Driven by machinery, the rotary drill bit will rotate, which will drive the whole drill bit to move centripetally, and crack and break the rock through cutting and grinding, thus playing the role of downward drilling.

Bit is one of the main drilling equipment. According to the different working environment and regional environment, the specifications and shapes of drill bits should also be different. When using diamond oil, the drill bit should be selected reasonably and scientifically according to the specific needs and specific design scheme. Scientific selection of drill bit and reasonable determination of drilling fluid in specific drilling work can improve the efficiency and quality of oil drilling, make oil drilling play its own value better and make certain contributions to the development of petroleum industry.

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