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To put it bluntly, a drill bit refers to a special tool used for drilling or drilling. These drills are usually made of metal and are used to drill or bury holes in physical raw materials. So what are the types and main uses of drill bits? Drill cutting method. Drill application. How to maintain the drill bit?
To put it bluntly, a drill bit refers to a special tool used for drilling or drilling. These drills are usually made of metal and are used to drill or bury holes in physical raw materials.
A drill bit, consisting of a shank (1), with a tip, with a cut on two main planes (C-C) and a short core laser cutter on a second plane (E-E) that sits on one main plane (C-C) together head (5.5′). The blade creates a point-core laser cutting bit that is used to enter the product workpiece and align the two ends of the bit. On the shank, set 2 face pockets (6.6′) widening from the top to the bottom. In the other part of the shank, the milling groove is located at the tangentially opposite position of the flat surface of the pipe, the plane of the pipe is widened by 90° with the common land plan (F-F) of the two lands on both sides of the pipe, and the bending stiffness of the shank on this plane is widened by 90°. larger. The second plan view (E-E) of the core laser cutting tip tends to be at an angle of approximately 90° to the plan view of the knife belt or the orientation of the primary bending stiffness (F-F) of the bottom end of the shank.
Types and main uses of drill bits.
twist drill
The twist drill is the most commonly used special tool for hole production and processing. Usually the diameter standard is 0.25~80mm. It is mainly composed of the working part of the drill and the rocker. Part of the work has two spiral grooves that look like marijuana flowers, hence the name. In order to better reduce the friction between the guiding part and the surface layer during the whole drilling process, the hole diameter of the twist drill is gradually reduced from the drill tip to the rocker. The helix angle of the twist drill mainly affects the size of the rake angle of the cutting edge. The strength and milling characteristics of the blade surface are usually 25°~32°. The spiral groove can be produced and processed by cutting, grinding, hot rolling or cold extrusion. The standard twist drill cuts a part of the included angle of 118, the chisel edge inclination angle is 40°~60°, and the rake angle is 8°~20°. Due to the construction, the declination angle is relatively large at the edges. It gradually decreases towards the center, and the chisel edge is a negative declination angle (about -55°), which has a squeezing effect when drilling.
In order to better improve the laser cutting characteristics of twist drills, part of the laser cutting can be rolled into various shapes (such as group drills) according to the characteristics of the production and processing materials. There are 2 types of rockers for twist drills: single edge and tapered shank. During production and processing, the former is clamped in the drill chuck, and the latter is inserted into the taper hole of the lathe spindle or the lathe tool holder. Generally speaking, twist drills are made of spring steel. Twist drills embedded in electric welding carbide tools or crowns are suitable for the production and machining of pig iron, hardened steel and non-metallic materials. Solid carbide tool twist drills are used for the production and machining of instrument panel parts and printed circuit boards.
flat drill
The laser cutting part of the flat drill is shovel-shaped, with a simple structure and low cost of production. The laser cutting fluid is very easy to guide into the hole, but the laser cutting and milling surface characteristics are poor. Flat drills are available in two configurations: integrated and prefabricated. The integrated type is mainly used for microplates with a drilling diameter of 0.03~0.5mm. The prefabricated flat drill head is removable and can be internally cooled. It is mainly used for drilling holes with a diameter of 25~500mm.
Deep hole drilling machine
Deep hole drilling machines usually refer to special tools with a machining depth-to-diameter ratio of more than 6. Common ones are gun drill, A deep hole drilling machine, blowout drill, DF deep hole drilling machine, etc. Sleeve gauge drills are also common in deep hole drilling.
drill
Drilling with 3 to 4 cutter teeth has better bending stiffness than twist drills, which are used to expand the current holes and improve processing accuracy and smoothness.
Countersink
There are many cutter teeth used to produce and process countersunk head holes for various countersunk head bolts, or to level the outer and inner holes of the holes.
Center drill
The center drill is used to drill the core hole of the shaft product workpiece. It is essentially a composite type of twist drill with a small helix angle and a hole drill, so it is also called a composite center drill.
The drill basically applies basic common sense.
1. The drill should be installed in a special package to prevent the vibration from hitting each other.
2. When applying, remove the drill from the package and install it on the spring chuck of the machine tool spindle or the CNC blade library file for automatic replacement of the drill. Put it back in the box immediately after use.
3. Use a tool microscope and other non-contact testing instruments to accurately measure the diameter of the drill bit to prevent the cutting edge from being injured by touching the mechanical equipment detector.
4. Some CNC drills use precision positioning rings. Some CNC drills do not use precision positioning rings. For example, precise positioning rings are used to install deep precision positioning. Pay more attention to this, so that each machine tool spindle drills the same depth. If not, there is a good chance that the drill bit will dig into the table or not into the circuit board, causing damage.
5. The damage of the cutting edge of the drill can be checked with a 40 times stereo microscope.
6. Always check the coaxiality of the machine tool spindle and the collet and the locking force of the collet. Too low coaxiality will cause the small diameter drill to break and the diameter to be large. Weak clamping force will cause the specific speed ratio to be inconsistent with the set speed ratio, and the collet and the drill will deviate.
7. The clamping length of the spring chuck on the spring chuck is 4~5 times the diameter of the drill shank.
8. Always check the presser foot of the machine tool spindle. The contact area of ​​the presser foot should be level, and the spindle of the machine tool should be vertically bisected to avoid drilling cracks and eccentric holes.
9. The dust removal effect of the planer is very good. The dust removal wind reduces the temperature of the drill bit, and the friend takes away the smoke and dust, reducing friction and causing high temperature.
10. The substrate layer comprises a top layer. The lower block should be firmly and accurately positioned in the hole and groove mobile phone positioning system on the planer work table. Apply tape to prevent the drill bit from getting on the belt, allowing the bit to stick to the handle chip, causing the handle chip to drain hard and break.
11. Purchase the drill bit from the manufacturer and check whether 4% is in compliance with the regulations. 100% Check for vacancies, scratches and cracks with a 10-15x high power microscope.
12. Immediately regrinding the drill bit can increase the use and regrinding frequency of the drill bit, increase the service life of the drill bit, and reduce the processing cost and cost. Tool microscopes are often used for precise measurements. Within the total length of the 2 main cutting edges, the damage depth should be less than 0.2mm. Damage 0.25mm when regrinding. Generally, the fixed shank bit can be reground 3 times, and the shovel bit can be reground 2 times. Drilling quality and precision, resulting in damage to the finished pcb circuit board. The actual effect of excessive cutting outweighs the gain.
13. The drill bit is damaged when the diameter is 2% smaller than the original due to damage and wear.
14. The basic parameters of the drill bit In general, the manufacturer gives the speed and speed parameters of the drill bit. The main parameters are only for reference. The specific processing workers will use the main parameters of the drill bit speed and efficiency. Usually, the specific main parameters are different from the reference main parameters. But the difference is not huge.
Drill grinding method.
1. The cutting edge should be level with the grinding wheel surface.
Before grinding the drill bit, first place the main cutting edge of the drill bit and the surface of the grinding wheel on a level surface, that is, to ensure that when the cutting edge touches the surface of the grinding wheel, all the cutting edges should be damaged. This is also the first step in the relative position of the drill bit and the grinding wheel, and then gradually leans against the surface of the grinding wheel.
2. The center line of the drill bit should be inclined 60° to the surface of the grinding wheel.
This angle of view is the sharp angle of the drill. At this time, if the viewing angle is wrong, it will affect the size of the top angle of the drill bit, the shape of the main cutting edge and the inclination angle of the chisel edge. This also refers to the positional relationship between the centerline of the drill bit and the surface of the grinding wheel. Just take 60°. This angle of view is usually very accurate. Here, you need to pay attention to the specific position and direction of the relative level of the drill bit before cutting. Both should be considered comprehensively. Shaky perspective doesn’t have to be ignored, and shaky perspective can’t be ignored.
3. The back is ground by the cutting edge.
After the cutting edge touches the grinding wheel, it is ground from the main cutting back to the back, that is, the cutting edge of the drill bit gradually touches the grinding wheel, and then gradually grinds down along all the back cutting edges. When the drill bit is laser cutting, you can lightly touch the grinding wheel, grind a little edge first, pay attention to the balance of the flame, adjust the working pressure in your hand immediately, pay attention to the cooling of the drill bit, do not grind too much, cause the edge to fade, until the edge Mouth quenched. When the cutting edge temperature is found to be high, the drill should be refrigerated immediately.
4. The cutting edge of the drill should sway from side to side, and the tail end of the drill should not expand or shrink.
This is a standard drill cutting position. The main cutting edge should sway left and right on the grinding wheel, that is, the hand holding the front side of the drill bit should shake the drill bit evenly around the surface of the grinding wheel. However, the hand holding a part of the handle should not be shaken, but it is also necessary to avoid the rear handle tilting upward, that is, the tail end of the drill bit should not be higher than the horizontal axis of the grinding wheel, otherwise the cutting edge will be dull and the laser cutting cannot be performed. This is also the most important step. There is a great relationship between the quality of the drill bit and the quality of the drill. In the case of similar grinding, it is necessary to gradually rub from the edge, and then rub lightly on the relief corner to make the blade more clean.
5. Ensure that the blade tip is aligned with the axis, and the symmetry on both sides is gradually repaired.
After grinding the cutting edge on one side of the drill, grind the cutting edge on the other side. Make sure that the cutting edge is in the middle of the center line of the drill, and the cutting edges on both sides should be symmetrical. The experienced master will observe the symmetry of the drill tip under the light, and gradually cut it. The rake angle of the cutting edge of the drill is generally 10°-14°, the back angle is relatively large, the cutting edge is too thin, and the vibration is relatively large when drilling.