Máy công cụ gia công lỗ sâu thường được sử dụng

Máy công cụ gia công lỗ sâu thường được sử dụng
Deep-hole processing machine tools are a general term for specialized machine tools that rely on specific machining techniques to produce deep holes with aspect ratios greater than 10. These specific machining techniques include deep-hole drilling, deep-hole rolling, and deep-hole honing. Deep-hole machine tools represent advanced and efficient deep-hole machining technologies. This chapter primarily introduces the structures and principles of gun drills, deep-hole boring and drilling machines with internal chip removal, deep-hole honing machines, and dual-system three-axis deep-hole boring and drilling machines.

4.1 Gun Drills
4.1.1 Working Principle of Gun Drills
Gun drills are typical deep-hole drilling machines with external chip removal. Gun drills are primarily used for drilling small-diameter deep holes. They require high cutting fluid pressure and are one of the most common deep-hole drilling machines. The drilling system of a gun drill machine uses external chip removal. Cutting fluid flows through the hollow drill rod to the drill head for cooling and lubrication, and chips are discharged through the drill bit and V-grooves on the drill rod’s exterior. The diagram below illustrates the operating principle of a typical gun drill machine.

A gun drill machine consists of a bed, a spindle box, a chip collector, an oiler, a drill rod box, a workpiece support, a drill rod support, a feed system, a high-pressure coolant system, a CNC electrical system, and a hydraulic system. The workpiece is held against the spindle box and the conical top plate of the chip collector. The drill bit is driven by the drill rod box to rotate at high speed, achieving cutting motion. A servo motor drives a ball screw to propel the drill rod box, achieving feed motion. The oiler injects high-pressure cooling oil from the rear end of the drill bit, through the drill bit’s inner bore, directly into the workpiece’s cutting area. Drill chips are then flushed by the coolant along the drill bit’s chip guide grooves to the chip collector, where they enter the chip hopper. The coolant then passes through filter paper and magnetic filtration before returning to the oil tank for further use. 4.1.2 Main Parameters of Gun Drilling Machines

Gun drills can drill holes with diameters ranging from 3 to 40 mm, with a maximum drilling depth of 2500 mm.

Typically, the cutting speed v = 1.1 to 1.65 m/s, the feed rate f = 0.015 to 0.03 mm/min, the cutting fluid pressure P = 2.5 to 6.0 MPa, and the cutting fluid flow rate O = 10 to 100 L/min. The main parameters of a typical deep-hole gun drill are shown in Table 4.1.

4.1.3 Typical Gun Drills

In production, gun drills come in a wide variety of types and specifications. The following are commonly used types. 1. Conventional Gun Drilling Machines
Common gun drills are the most common type of gun drills, primarily used for drilling small-diameter deep holes in rotating and non-rotating parts. Based on the spindle layout, whether the drill head rotates, the shape of the workpiece, and the number of spindles, they can be categorized as single-axis horizontal gun drills, single-axis vertical three-axis gun drills, and multi-axis horizontal gun drills, as shown in Figures 4.2 to 4.4.

2. Deep Hole Gun Drilling Machining Centers
Deep hole gun drill machining centers are primarily used for drilling small-diameter deep holes with complex spatial angles in complex housings and machine frames, as shown in Figure 4.5.

4.2 Deep Hole Drilling and Boring Machine with Chip Removal
4.2.1 Working Principle of Deep Hole Drilling and Boring Machine with Chip Removal
A deep hole drilling and boring machine with chip removal is a typical deep hole machining system, capable of deep hole drilling and deep hole boring, primarily used for drilling and boring large-diameter deep holes. The drilling method is typically BTA drilling, but with the replacement of certain accessories, ejector and DF drilling methods can be implemented. Its structure and working principle are shown in Figures 4.6 and 4.7. The machine tool spindle drives the workpiece, while the tool moves in a linear feed motion. High-pressure coolant is supplied through an oiler to the gap between the outer diameter of the tool bar and the hole wall. It then passes through the annular gap between the outer diameter of the tool bar and the hole wall to the drill bit cutting edge, cooling the drill bit and discharging the chips through the interior of the drill bar into the chip removal bucket at the rear of the machine bed.

The main component of a deep hole chip removal drilling and boring machine is the oiler. The structure of the oiler is shown in Figure 4.8. The right end of the oiler is sealed by a drill pipe seal. When the coolant enters, the high-pressure coolant can only flow to the left through the guide sleeve to the drill bit, cooling and lubricating the drilling area. The oiler has three main functions: (1) Centering the workpiece and axially tightening it. (2) Guiding the drill bit at the beginning of the drilling process. (3) Supplying coolant to the cutting area. 4.2.2 Main parameters of deep hole chip removal drilling and boring machine The drilling diameter range of the deep hole chip removal drilling and boring machine is 40~500mm, and the maximum drilling depth can reach 20000mm. The cutting fluid pressure P = 0.5~2.0MPa, and the cutting fluid flow rate O-40~200L/min. The main parameters of a typical deep hole drilling and boring machine are shown in Table 4.2. 4.2.3 Typical Deep Hole Boring and Drilling Machines with Internal Chip Removal
Common deep hole boring and drilling machines include the following.
1. Horizontal Workpiece Rotary Deep Hole Boring and Drilling Machines
Horizontal workpiece rotary deep hole boring and drilling machines are the most commonly used deep hole boring and drilling machines, primarily used to process rotating parts. They are categorized by workpiece size and weight into small, medium, and heavy-duty deep hole boring and drilling machines, as shown in Figures 4.9 to 4.11.

2. Coordinate Deep Hole Boring and Drilling Machines
Coordinate deep hole boring and drilling machines are equipped with precision coordinate positioning devices and are primarily used to process non-rotating parts. Coordinate deep hole boring and drilling machines can be divided into horizontal and column-type coordinate deep hole boring and drilling machines, as shown in Figures 4.12 and 4.13.