Hole drilling is a type of metal treatment with rotating tools. This operation is divided into deep drilling and conventional. In the first embodiment, the depth of the hole is more than 10 cm or has a size of more than 5 available diameters (d * 5). Drills it turns out to achieve grooves of different depth and diameter (with several edges of the section).
Scheme drills for metal.
Drilling holes in the metal is possible in one of the following ways:
- Carry out the rotation of the workpiece and at the same time produce a longitudinal feed non-rotating tool for drilling.
- The rotation of the workpiece is not carried out, it takes a fixed position.
- Simultaneous movement around its axis and mechanism, and details.
In practice, these technologies are quite in demand. The process of forming deep holes is in great demand in such areas as pipe manufacturing, metallurgy, the aerospace and oil and gas industry, production of heat exchanger plates, etc. Deep holes often have to be made on the following details: axles, sleeves, bandages, shafts, rotors, bushings, cylinders , metal shells, etc.
Deep hole drilling: classification
The scheme of drilling metal.
- By the type of removal of the drilled content (chips) emit: ring and continuous procedure. In the second method, the drilled content is displayed like particle particles, in the first method, the annular plane is partially removed like a rod, and the other part is removed with chips.
- According to the cutting method emit technology:
Odnoshtangovaya (STS). This method is optimal for the manufacture of blanks in a high-performance or mass production process. The problem here is that you have to use an oil receiver with a variety of supply hoses while simultaneously rotating the part. This system is recognized as the most effective in the formation of high quality holes.
Ejector. Deep processing option with the parameters of products of average quality. Machining is carried out on lathes with a variety of complex functions. The system involves the use of additional mobile or installed pumping station. This method allows you to get holes with a diameter of 2 to 6 cm in depth to 120 cm, including intermittent form.
Guns (tubular-blade) drills with the supply of coolant from the inside. This option is suitable for small enterprises in which the conditions of the technology plan to produce small-diameter holes.
Table selection of coolant when drilling different types of metal.
Drills with a single cutter easily embedded in the machine universal principle of action. The cutter is made of hard alloys and has a V-shaped groove throughout the core. The refracting angle of the latter can reach 110-1200º. The recommended diameter for drilling is 3.5-4.0 cm, length - d * 50. This method does not allow for deployment and reaming operations.
Automatic process control allows you to select: deep impact with an automated change of one or many operating parameters (lubricant supply, rotational speed, etc.).Back to table of contents
Characteristics of the deep drilling process
When deep processing comply with the basic principles of the process.
Initially perform the selection of the rotational speed of the drilling equipment or the maximum possible cutting speed (feed drills).
Monitor the provision of normal crushing chips, the withdrawal of the contents of the grooves completely.
An important nuance at the time of excision of waste is the safety tool cutter. In this part of the drill should not have damage, as well as burrs and other flaws. Another key criterion for the effective treatment of metal surfaces is the supply of cooling and lubricating fluid according to the rules.
Since the parts are drilled accompanied by the supply of a cooling and lubricating fluid with a certain pressure and a predetermined flow rate, the system introduces the work of pumping devices — oil pumps or pumps for pumping viscous substances.
The power of the system is selected based on the expenditure of fluid and the required amount of pressure to supply lubricant.
Fluid supply is an indispensable point of technology:
- The correct chip output from the working area is carried out via lead channels.
- The friction force between the contacting elements is reduced.
- Excess heat generated during the long drilling procedure is removed, while the drill is preserved.
- An additional processing of the excavation.
Some difficulties of the process
With increasing depth, there are more difficulties with digging.
With deep drilling, a specialized tool is used that is technically equipped with additional possibilities of using cutting and other types of devices. This is necessary for the reason that the use of standard tools does not allow to obtain high performance of the process, and sometimes makes it impossible.
To solve technological problems often requires the participation of non-standard devices, which can be equipped with special equipment.