Common problems and solutions of PCB drilling?

1. The reason why the drill bit breaks \x0d\ is: the main shaft deflection is too large; Improper operation of CNC drilling rig during drilling; Improper bit selection; The bit speed is insufficient and the feed speed is too high; There are too many layers stacked; There are sundries between plates or under cover plates; When drilling, the depth of the spindle is too deep, which leads to poor chip removal of the bit and hanging drilling; Too many grinding times or over-life use of the drill bit; The cover plate is scratched and wrinkled, and the padding is uneven; When fixing the bottom plate, the adhesive tape is too wide or the aluminum sheet and plate of the cover plate are too small; Excessive feeding speed causes extrusion; Improper operation when filling holes; The ash blocking under the aluminum plate of the cover plate is serious; There is a deviation between the center of welding drill tip and the center of drill handle. \x0d\ Solution: \x0d\ (1) Inform the mechanic to repair the spindle or replace it. \x0d\ (2) A, check whether the beriberi pipeline is blocked; \x0d\ B, adjust the presser foot pressure according to the bit state, and check the pressure data when the presser foot is pressed down, which is normally 7.5kg\x0d\ C, check the change of spindle speed, and see if there is any copper wire in the fixture that affects the speed uniformity; \x0d\ D, detect the spindle speed change and spindle stability during drilling operation; (spindle can be compared with spindle) \x0d\ E, carefully adjust the state between the presser foot and the drill bit, and the drill tip can't be exposed from the presser foot, only 3.0mm\x0d\ F is allowed in the presser foot, so as to check the parallelism and stability of the drill floor. \x0d\ (3) Detect the geometry and wear of the drill bit, and select the drill bit with appropriate length of the chip removal groove. \x0d\ (4) Select an appropriate feed speed to reduce the feed speed. \x0d\ (5) Reduce to an appropriate number of layers. \x0d\ (6) When placing the board, clean the sundries under the board surface and the cover plate, and keep the board surface clean. \x0d\ (7) Inform the mechanic to adjust the drilling depth of the spindle to maintain a good drilling depth. (The normal drilling depth should be controlled at 0.6 mm ..) \x0d\ (8) Control the grinding times (according to the work instruction) or strictly set the parameters in the parameter table. \x0d\ (9) Select the cover and pad with suitable and flat surface hardness. \x0d\ (10) Carefully check the fixing state and width of the adhesive tape, replace the aluminum cover, and check the plate size. \x0d\ (1 1) Reduce the feed speed appropriately. \x0d\ (12) Pay attention to the correct hole filling position during operation. \ x0d \ (13) a. Check whether the presser foot height and presser foot exhaust groove are normal; \x0d\ B, the suction is too large, so the suction can be reduced appropriately. \x0d\ (14) Replace the drill bit in the same center. \x0d\ 2。 The reasons for lost circulation \x0d\ are: take it after the bit is broken; There is no aluminum sheet or reverse bottom plate when drilling; Parameter error; The drill bit is slender; The effective length of drill bit can't meet the needs of drill pile thickness; Hand drilling; Plate is special, which is caused by batch front. \x0d\ Solution: \x0d\ (1) According to the previous question 1, investigate the cause of broken knife and make correct treatment. \x0d\ (2) Both the aluminum sheet and the bottom plate protect the eyelet, so they must be used in production. The usable and unusable bottom plates should be placed separately and in the same direction, and should be checked again before putting the plates. \x0d\ (3) Before drilling, it is necessary to check whether the drilling depth is consistent and whether the nozzle parameters of each bit are set correctly. \x0d\ (4) The drilling rig grasps the drill nozzle and checks whether the clamping position of the drill nozzle is correct before starting. Under normal circumstances, the drill mouth cannot exceed the presser foot when starting the machine. \x0d\ (5) Before starting drilling, visually check the effective length of drilling, and measure and check the stack number of available production plates. \x0d\ (6) Manual drilling and cutting accuracy, rotating speed, etc. Can not meet the requirements, so it is forbidden to drill holes by hand. \x0d\ (7) When setting parameters for drilling special plates, the parameters should be properly selected according to the quality situation, and the feed should not be too fast. \x0d\ 3。 The reasons of hole position deviation, displacement and dislocation \x0d\ are: bit deviation during drilling; Improper selection of cover material, soft and hard discomfort; The substrate expands and contracts, resulting in hole position deviation; Improper use of matching and positioning tools; When drilling, the presser foot is improperly set, and the production plate moves when it touches the pin; The drill bit resonates when working; The spring chuck is not clean or damaged; Deviation of hole position or overall stacking position of production plates and panels; The drill bit will slide when it contacts the cover plate during work; There are scratches or creases on the surface of the aluminum sheet of the cover plate, which leads to deviation when guiding the drill bit to drill; Not nailed; Different origins; The tape is not firmly attached; There is movement deviation between X axis and Y axis of drilling machine; There is something wrong with the program. \x0d\ solution: \ x0d \ (1) a. check whether the spindle is skewed; \x0d\ B, reduce the number of laminates. Usually, the number of double-faced laminates is 6 times of the diameter of the drill bit, and the number of multi-layered laminates is 2~3 times of the diameter of the drill bit. \x0d\ C, increase the bit speed or decrease the feed speed; \x0d\ D, check whether the bit nozzle meets the process requirements, or re-sharpen it; \x0d\ E, check whether the drill tip and the drill handle have good concentricity; \x0d\F, check whether the fixed state between the drill bit and the spring chuck is fastened; \x0d\ G, detect and correct the stability of the rig floor. \x0d\ (2) Choose 0.50mm high-density lime cover plate or replace the composite cover plate material (the upper and lower layers are 0.06mm thick aluminum alloy foil with fiber core in the middle, with a total thickness of 0.35mm). \x0d\ (3) According to the characteristics of the plate, bake the plate before or after drilling (generally145℃ 5℃, subject to baking for 4 hours). \x0d\ (4) Check or detect the dimensional accuracy of the tool hole and whether the position of the upper locating pin is offset. \x0d\ (5) Check the height of reset presser foot. The normal presser foot height is 0.80mm from the board surface, which is the best presser foot height for drilling. \x0d\ (6) Select an appropriate bit rate. \x0d\ (7) Clean or replace the spring chuck. \x0d\ (8) The plug is not installed in the panel, and the plug of the control panel is too low or loose, so it is necessary to reposition and replace the plug. \x0d\ (9) Select a suitable feed speed or a bit with good bending strength. \x0d\ (10) Replace aluminum sheet with flat surface and no wrinkles. \x0d\ (1 1) Nail the board as required. \x0d\ (12) Record and verify the origin. \x0d\ (13) Stick the adhesive tape at a 90-degree right angle to the edge of the board. \x0d\ (14) feedback, notify the mechanic to debug and maintain the rig. \x0d\ (15) Check and verify, and notify the project to modify. \x0d\ 4。 Large hole, small hole and twisted aperture \x0d\ are caused by the following reasons: wrong bit specification; Incorrect feed speed or rotation speed; Excessive wear of drill bit; Too many times to regrind the drill bit or the length of the chip removal groove is lower than the standard; Excessive deflection of the spindle itself; The drill tip collapses and the aperture becomes larger; The aperture is wrong; The borehole diameter was not measured when replacing the drill bit; The drill bit arrangement is incorrect; The position is wrong when changing the drill bit; Aperture diagram not checked; The spindle can't put down the cutter, which leads to the cutter pressing; Wrong serial number was entered in the parameter. \x0d\ Solution: \x0d\ (1) Check whether the drill bit size and control system instructions are wrong before operation. \x0d\ (2) Adjust the feed speed and rotation speed to the most ideal state. \x0d\ (3) Replace the drilling nozzles and limit the number of holes drilled by each drilling nozzle. Usually, 3000~3500 holes can be drilled by pressing two panels (four in each stack); 500 holes can be drilled on the high-density multilayer board; For FR-4 (three in each stack), 3000 holes can be drilled; For the hard FR-5, the average decrease is 30%. \x0d\ (4) Limit the change of regrinding drill number and regrinding particle size. Drilling multi-layer board, allowing grinding once every 500 holes and grinding for 2~3 times; Every 1000 holes can be ground once; For every 3000 holes drilled in the double panel, sharpen it once, and then drill 2500 holes; Grind again and drill 2000 holes. Re-grinding the bit in time can increase the number of re-grinding and prolong the life of the bit. The wear depth of the whole length of the two main cutting edges should be less than 0.2 mm, measured by a tool microscope. When regrinding, 0.25mm should be removed. Fixed handle drill can be reground for 3 times; The shovel teeth were reground twice. \x0d\ (5) Feed it back to the maintenance department of the dynamic deflection tester to check the deflection of the spindle during operation. If it is serious, please ask a professional supplier to repair it. \x0d\ (6) Before drilling, inspect the tool surface with a 20-fold mirror, and grind or discard the defective drill bit. \x0d\ (7) Check the measurement several times. \x0d\ (8) When replacing a drill bit, you can measure the replaced drill bit and measure the first hole drilled with the replaced drill bit. \x0d\ (9) When arranging drill bits, count the positions of the tool magazine clearly. \x0d\ (10) Please read the serial number clearly when replacing the drill bit. \x0d\ (1 1) When preparing tools, check the actual aperture of the aperture diagram one by one. \x0d\ (12) Clean the nip, and carefully measure and check the cutter surface after pressing the cutter. \x0d\ (13) Please check carefully when entering the tool serial number. \x0d\5。 The reasons for missing drill \x0d\ are: the drill bit is broken (unclear identification); Halfway; Program error; Unintentionally delete the program; The rig missed reading when reading data. \x0d\ Solution: \x0d\ (1) Separate the broken drill boards and check them one by one. \x0d\ (2) After stopping halfway, start the machine again and go back to 1~2 hole to continue drilling. \x0d\ (3) Once it is determined that it is an engineering program error, it shall immediately notify the engineering change. \x0d\ (4) During the operation, the operator should try not to change or delete the program at will, and notify the engineering treatment when necessary. \x0d\ (5) After reading the file through CAM, change the machine for production and notify the machine for maintenance. \x0d\ 6。 The reasons for the batch spike \x0d\ are: wrong parameters; The drill bit is badly worn and the blade is not sharp; The density of bottom plate is not enough; There are sundries between the substrates and between the substrates and the bottom plate; The substrate is bent and deformed to form a gap; Uncoated board; The plate material is special. \x0d\ Solution: \x0d\ (1) When setting parameters, strictly follow the parameter table, and check and verify after setting. \x0d\ (2) During drilling, control the service life of the drill bit, and do not use it beyond the service life according to the service life table. \x0d\ (3) Test the density of the bottom plate. \x0d\ (4) Clean up the sundries between substrates when nailing boards, and clean up the surfaces of multilayer boards with rags when stacking them. \x0d\ (5) When the base plate is deformed, it should be compacted to reduce the gap between the plates. \x0d\ (6) The cover plate is used to protect and guide the drilling. Therefore, aluminum sheets must be added when drilling. (Used for drilling holes that can't penetrate aluminum-plated sheets) \x0d\ (7) When setting the parameters of drilling special plates, the parameters should be properly selected according to the quality situation, and the feed should not be too fast. \x0d\ 7。 The hole is not drilled through (not through the bottom plate). The reasons for x0d are: improper depth; The drill bit length is not enough; The bed board is uneven; The thickness of the backing plate is uneven; Half of the broken knife or drill bit is broken, and the hole is not penetrated; Impermeability is formed after the batch of copper is sunk into the hole; The spindle clamp is loose, and the drill nozzle becomes shorter when drilling; Unclipped bottom plate; Two pads were added when making the first board or filling holes, but they were not changed during production. \x0d\ Solution: \x0d\ (1) Check whether the depth is correct. (Total depth and depth of each spindle) \x0d\ (2) Measure whether the length of the drill nozzle is enough. \x0d\ (3) Check whether the bedplate is flat and adjust it. \x0d\ (4) Measure whether the thickness of the backing plate is consistent, feedback and replace the backing plate. \x0d\ (5) Locate and refill the hole. \x0d\ (6) If the source of batch front is checked and eliminated before, polish the batch front. \x0d\ (7) Adjust the tightness of the spindle, and clean or replace the socket. \x0d\ (8) Check whether there is a bottom plate before installing the double panel. \x0d\ (9) Mark it well, and change it back to the original normal depth after drilling the first plate or hole filling. \x0d\ 8。 Curled broken wire chips appear on the panel \x0d\ because the cover plate is not used or the drilling process parameters are not properly selected. \x0d\ Solution: \x0d\ (1) should adopt a suitable cover plate. \x0d\ (2) In general, we should choose to reduce the feed speed or increase the bit rate \x0d\9. The reasons for hole plugging \x0d\ are: the effective length of the drill bit is not enough; The depth of the drill bit drilling into the liner is too deep; Material problems of the substrate (moisture and dust); The liner is reused; Improper processing conditions, such as insufficient dust suction; The structure of the drill bit is not good; The feed speed of the bit nozzle is too fast, and the rising speed does not match. \x0d\ Solution: \x0d\ (1) Choose an appropriate bit length according to the stack thickness, which can be compared with the stack thickness of the production board. \x0d\ (2) The drilling depth should be set reasonably (the drilling tip should be controlled to drill into the backing plate by 0.5mm). \x0d\ (3) Before drilling, select good quality base material or bake it (generally, bake it for 4 hours at145℃ 5). \x0d\ (4) The backing plate should be replaced. \x0d\ (5) Select the best processing conditions, and properly adjust the drilling dust suction force to reach 7.5kg per second. \x0d\ (6) Change the supplier of drill nozzle. \x0d\ (7) Set parameters in strict accordance with the parameter table. \x0d\ 10 and rough hole wall \x0d\ are due to: excessive feed change; Feed speed is too fast; Improper selection of cover materials; Insufficient vacuum (air pressure) of fixed bit; Improper tool recovery rate; The cutting leading edge of the top corner of the drill bit is broken or damaged; The spindle deflection is too large; Poor chip removal performance. \x0d\ Solution: \x0d\ (1) Keep the best feed. \x0d\ (2) Adjust the feed speed and rotation speed according to experience and reference data to achieve the best matching. \x0d\ (3) Replace the cover material. \x0d\ (4) Check the vacuum system (air pressure) of the CNC drilling rig and check whether the spindle speed has changed. \x0d\ (5) Adjust the retracting speed and bit speed to achieve the best condition. \x0d\ (6) Check the use of drill bit or replace it. \x0d\ (7) Check and clean the spindle and spring chuck. \x0d\ (8) Improve chip removal performance, and check the state of chip removal groove and cutting edge. \x0d\ 1 1 There is a white circle at the hole edge (the copper layer at the hole edge is separated from the substrate, and the hole is blasted) \x0d\ Cause: The substrate is partially broken due to thermal stress and mechanical force during drilling; The size of the woven yarn of glass cloth is relatively thick; The quality of base material (cardboard) is poor; Overfeeding; The drill bit is loose and the fixation is not firm; There are too many layers stacked. \x0d\ Solution: \x0d\ (1) Check the wear of the drill bit, and then replace or regrind it. \x0d\ (2) Choose glass cloth woven with fine glass filaments. \x0d\ (3) Replace the base material. \x0d\ (4) Check whether the set feed speed is correct. \x0d\ (5) Check whether the diameter of drill shank and the clamping force of spindle spring clamp are sufficient. \x0d\ (6) Adjusting the superimposed data \x0d\ or more according to the process specification is a common problem in drilling production, so it is necessary to measure and check more in actual operation. At the same time, strictly regulating the operation is of great benefit to controlling the quality failure of drilling production and improving the product quality and production efficiency.