Machining principle of BTA Deep hole drill bit
operation of a BTA deep hole drill on an ordinary lathe. The workpiece to be machined is positioned by the V-shaped iron on the large drag plate of the lathe and is clamped by the bolt press plate. During drilling, the drill pipe is clamped by the special chuck in the spindle and rotated under the drive of the spindle, and the workpiece is driven by the large drag plate for feed movement. A liquid feeder is installed on the machine table and is connected with the left end face of the workpiece through an O-ring seal. The pressurized cutting fluid is injected into the inlet of the fluid feeder, flows into the cutting zone through the gap between the outside diameter of the drill pipe and the hole wall, cools the tool, and the chip is discharged from the drain box with the cutting fluid through the outlet of the special chuck from the hole of the drill pipe. Cutting fluid can use 5% concentration of emulsion; Cutting parameters can be selected V=60~90m/min, S=0.035~ 0.23mm /r. Because the drill pipe is slender and easy to deform, the movable center support is installed on the guide rail of the machine tool, which can support any position of the drill pipe. The liquid feeder is connected with the large drag plate through the coupling plate, and the feed movement is made with the workpiece.
1. Drain box 2. Drill pipe 3. Center support 4. Inlet 5. Inlet
6. Workpiece 7. Connecting plate 8. V-shaped iron 9. Large drag plate
FIG. 2 Processing diagram of BTA deep hole drill on ordinary lathe
3 Deep hole processing points
Since deep hole processing has different characteristics and disadvantages from ordinary hole processing, the following points should be noted when using BTA deep hole drilling:
Deep hole processing can not directly observe the cutting conditions of the tool, so the processing can only be judged by listening to the sound, looking at the chip, observing the machine load and cutting fluid pressure.
The heat dissipation of deep hole machining is difficult, so an effective and reliable cutting heat cooling method must be adopted.
It is difficult to remove chips in deep hole processing, such as chip blocking, which is easy to damage the tool, so it is necessary to choose the cutting amount reasonably to ensure reliable chip breaking and smooth chip removal.
Holes tend to skew during deep hole machining, so guiding devices and measures should be considered in the design of tool and feeder structure.
The length of drill pipe, poor rigidity and easy vibration during deep hole machining will directly affect the machining accuracy and production efficiency, so it is very important to choose the cutting parameters reasonably.
Among the above problems, chip removal, guidance and cooling are the most important. If these problems are solved well, the drilling accuracy can be guaranteed, the tool life can be extended, and the processing efficiency can be improved. Therefore, the following technological measures can be taken in the deep hole processing according to the specific processing requirements:
A shallow hole with the same diameter as the drill bit is drilled before drilling, which can play a guiding and centering role during drilling. This step is especially necessary when machining small holes with high straightness requirements.
When installing and debugging the machine tool, ensure that the center axis of the workpiece hole coincides with the center axis of the drill pipe as much as possible.
According to the material of the workpiece, the cutting amount is selected reasonably to control the degree of chip curling and obtain the C-shaped chip which is conducive to chip removal. When processing high-strength material workpieces, the cutting speed V should be appropriately reduced. The size of the feed has a great influence on the formation of chips, and under the premise of ensuring chip breaking, a smaller feed can be used.
In order to ensure chip removal and cooling effect, the cutting fluid should maintain appropriate pressure and flow rate. High pressure and low flow rate can be used when processing small diameter deep holes; Low pressure and large flow rate can be used for processing large diameter and deep holes.
Start drilling, should first open the cutting fluid pump, and then start the lathe, cutting; When the drilling ends or a failure occurs, the cutting tool should first be stopped, then stopped, and finally the cutting fluid pump is closed.
Overseas manager:linda lin
Email:deepholedrillingstacy@gmail.com
phone:0086-19932252799(whatsapp,wechat line)
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Post time: Nov-30-2024