CNC milling machine milling technology: circuit board CNC drilling machine milling technology, including the choice of walking direction, compensation methods, CNC Drilling Machine positioning methods, the structure of the frame, the next point. Are important aspects to ensure the accuracy of milling.
1, walking direction, compensation method:
When the cutter cut into the plate, there is a cutting surface is always facing the cutting edge of the milling cutter, while the other side is always against the cutting edge of the milling cutter. The former, the processing surface is smooth, high dimensional accuracy. CNC Drilling Machine The spindle always rotates clockwise. CNC Drilling Machine So whether the spindle fixed table movement or table fixed spindle movement CNC milling machine, in the milling of the external contour of the printed circuit board, to use counterclockwise direction. This is what is commonly referred to as reverse milling. And in the circuit board internal milling frame or groove using the milling method. CNC Drilling Machine The milling plate compensation is the automatic setting of the machine when the milling plate is set so that the milling cutter automatically sets the half diameter of the cutter diameter set by the center offset of the milling line, that is, the radius distance, the milling shape and the program setting be consistent. At the same time, CNC Drilling Machine if the machine has a compensated function must pay attention to the direction of compensation and the use of the command, such as the use of compensation command error will make the circuit board shape more or less equivalent to the length and width of the cutter size.
Positioning method can be divided into two kinds; one is the internal positioning, CNC Drilling Machine the second is outside the positioning. Positioning for the development of personnel is also very important, usually in the pre-production of the circuit board should be identified when the positioning program.
Internal positioning is a generic method. The so-called internal positioning is to choose the printed circuit board mounting holes, plug holes or other non-metal holes as positioning holes. CNC Drilling Machine The relative position of the hole is sought on the diagonal and the large diameter hole is selected as much as possible. Can not use metallized holes. Because the difference in the thickness of the coating within the hole will affect the consistency of your selected positioning hole, while the plate is easy to cause the hole and the hole at the edge of the surface of the coating damage, to ensure that the PCB positioning conditions, the fewer the number of pins The better. Generally small board using two pins, the use of three large pin pin, the advantage is accurate positioning, CNC Drilling Machine deformation of the board shape of small high profile good shape, milling speed. CNC Drilling Machine The shortcomings of the various types of holes in the board need to prepare a variety of diameter pins, such as the board is not available in the positioning hole, in the early production and customers need to discuss the positioning of the hole in the board, more cumbersome. At the same time each board of the milling board template different management is more trouble, CNC Drilling Machine higher cost.
External positioning is another positioning method, is used in the board outside the positioning hole as the milling plate positioning hole. The advantage is easy to manage, CNC Drilling Machine if the pre-production specifications are good, then the milling board template is generally about fifteen. Due to the use of external positioning so the board can not be cut down once, otherwise the circuit board is very easy to damage, especially the puzzle, due to milling cutter and vacuum device will bring out the board damage and cutter broken. CNC Drilling Machine And the use of sub-milling milling joint point method, the first milling board when the milling board is completed after the program is suspended and then the board with tape fixed, the implementation of the second paragraph of the program, the use of 3mm to 4mm drill bit will be drilled. The advantage is that the template is less costly and easy to manage, can be cut all the board without the installation hole and positioning hole of the circuit board, CNC Drilling Machine small craft personnel easy to manage, CNC Drilling Machine especially CAM and other pre-production staff can be simplified, CNC Drilling Machine and can optimize the substrate The utilization rate. The disadvantage is due to the use of drill bits, circuit board shape left at least 2-3 raised points unsightly, may not meet customer requirements, milling time is long, workers labor intensity slightly larger.