Keyword: PCB drill, PCB drilling manufacturing, PCB factory
PCB drill is mainly used for PCB drilling manufacturing, general nc drilling machine of PCB factory of bit types are as follows: straight shank twist drill, shank twist drill bits and handle shovel (undercut) bit. Straight shank twist drill bits are used for single head drilling machine, drilling and simpler PCB or single panel, now has rarely seen in the large PCB factory, the drilling depth can be up to 10 times the diameter of the drill bit. In the case of base plate lamination is not high, using drill bush can avoid slant drilling. Most manufacturers use nc drilling machine, CNC drilling machine using hard alloy on a bit, its characteristic is to realize automatic bit change. Positioning accuracy is high, do not need to use the drill sets. Big spiral Angle, clearance speed, suitable for high speed cutting. Within the scope of the chip removal slot length, bit diameter is an inverted cone, drilling with the hole wall friction small, drilling quality is higher. Common drill shank diameter is 3.00 mm and 3.175 mm.
Good PCB drill with the hard alloy material with good quality, high rigidity, hole of high precision, good quality of hole wall, fine features, such as long life now introduce bit material: PCB drilling bit generally adopt carbide, because epoxy glass cloth composite copper foil surface tool wear particularly fast. So-called cemented carbide with tungsten carbide powder as the base, with cobalt powder binder through pressure, sintering and into. Usually contain 94% tungsten carbide, cobalt containing 6%. Because of its hardness is very high, very wear-resisting, have certain strength, suitable for high speed cutting. But toughness is poor, very fragile, to improve the performance of hard alloy, some use chemical vapor deposition on the carbide substrate of a layer of 5 ~ 7 microns hard titanium carbide (TIC) or titanium nitride (TIN), make it has higher hardness.
Some with ion implantation technique, titanium, nitrogen, and carbon into the matrix a certain depth, not only increase the hardness and strength and the injection during drills resharpening ingredients can move inside. And the use of physical methods on the top of the drill bit to generate a layer of diamond film, greatly improves the bit of hardness and wear resistance. Hardness and strength of cemented carbide not only related to the ratio of tungsten carbide and cobalt, are also associated with powder particles. Ultrafine particles of carbide drill bit, the tungsten carbide is the average size of grains in 1 micron. This kind of drill bit, not only high hardness and compressive strength and bending strength are improved. In order to save cost now many drill shank welding structure, the original bit for whole hard alloy, the drill shank adopted at the back of the stainless steel, now cost is greatly reduced but due to the different material its dynamic concentricity less than solid carbide drill bits, especially in the aspect of small diameter.
The use of drill bit:
1. Bit should be packed in special boxes, to avoid vibration collide each other.
2. When using, from the box bit shall be installed to the main shaft of the spring clamp head or drill tool change automatic garage. Finished then back in box.
3. Measure the bit diameter with tool microscope and other non-contact measuring instruments, to avoid the cutting edge contact with mechanical measurement instrument was bruised.
4. Some nc drilling machine using the locating ring CNC drilling machine, do not use the locating ring, such as using the depth of the locating ring of the installation location must be accurate, if you don't use the locating ring its bit loaded on the spindle elongation to adjust, multiple spindle drilling machine more attention should be paid to this, to make each spindle drilling depth. If inconsistencies might make a drill or can not drill wear circuit board scrap to mesa.
5. Can use at ordinary times 40 times the stereoscopic microscope check bit cutting blade wear.
6. To check the concentricity of the spindle and spring collet and collet chuck clamping force, concentricity is bad to can cause small diameter bit breaking of a rod, and large aperture, etc., the clamping force is bad cause actual speed and the set speed does not conform to, chuck and slippage between drill bit.
7. Set the shank drill in spring clamp head clamping length of 4 ~ 5 times the diameter of the drill shank can clip.
8. Always check the spindle presser foot. Presser foot interface to the level and vertical spindle can't shake, to prevent the breaking of a rod and slant hole drilling.
9. Drilling dust absorption effect is better, vacuuming wind it can decrease the temperature of the bit, take away the dust in high temperature reducing friction at the same time.
10. The base plate laminated including upper and lower plate to a hole in the work in the drilling machine a groove positioning system (GPS) positioning in the prison, and flat. Use adhesive tape to prevent the drill bit on tape adhesion chip, chip removal difficult and breaking of a rod.
11. Bit manufacturers of orders, the factory inspection to check the its 4% compliance with regulations. And 100% with 10 to 15 times the microscopic examination of the gap, abrasion and crack.
12. A bit timely resharpening, can increase the use of the bit and the number of resharpening, extend the service life of drill bit, reduce the production cost and expenses. Usually measured with tool microscope, in two main cutting edge length, wear depth should be less than 0.2 mm. When heavy grinding mill to 0.25 mm. Ordinary shank drill can resharpening 3 times, shovel head (undercut) bit resharpening twice. Double grinding its drilling quality and precision will decline, too much will cause the product's scrap circuit boards. Excessive grinding counterproductive.
13. When due to wear and the wear compared with the original diameter reduced 2%, the bit scrap.
14. Bit parameter setting in the general case, manufacturers provide a copy of the plant in the production of drill bit drilling speed and the speed parameter list, this parameter is only a reference, the actual technology personnel through actual use to draw even a bit conforms to the actual situation of speed and speed parameters, usually have difference between the actual parameters and the parameters of the reference but not too much difference.
At present, the bit a lot of manufacturers, domestic and imported. Slightly gaps when compared with domestic products and overseas products, the price is a little expensive imported some, of course, there are produced by Taiwan and Hong Kong, and part of Taiwan's production hit the United States and Europe brand drill, compared the use of Europe and the United States and Japan imported bit stable quality, our price is a bit expensive but for technological personnel content is worth somewhat, due to the bit in the process of actual use probability is very little, the quality problems of products such as production to demand higher recommend the use of imported drill bit, bit higher hardness and soft Japan Europe and America, and Europe and the United States of bit adamant use is not easy to happen in slant hole but to break some probability, Japan drilling bit of flexibility is very not easy to break but prone to slant hole slant especially little bit. In the process of actual use could be selected according to the requirements.
Source: //www.seekic.com
