The main function of the PCB entry backup board
As an auxiliary material for PCB drilling processing, the PCB entry backup board has five main functions:
① Protect the board surface (protect the copper foil surface of the copper clad laminate, or the copper-plated conductive layer of the substrate) to prevent the pressure foot from crushing the board surface;
②Fix the drill bit to reduce the rocking amplitude and offset of the drill bit during drilling, so that the drill bit can be accurately positioned; improve the accuracy of the hole position and prevent the drill bit from breaking;
③Prevent hole burrs on the substrate;
④Assist the drill bit to dissipate heat and reduce the temperature of the drill bit; ⑤Assist in cleaning the drill bit groove; prevent greasy holes; reduce drill bit wear and drill breakage.
The performance requirements for the PCB entry backup board mainly include: sufficient softness; small thickness tolerance; flatness and resistance to deformation; high temperature resistance; low moisture absorption; no impurities, foreign bodies, obvious defects on the surface, etc.
In the mid to late 1990s, the choice of cover/backing plates used in PCB drilling processing also began to adopt another type with better thermal conductivity, that is, metal cover plates. At first, ordinary aluminum was used. The thermal conductivity of aluminum is much higher than that of resin. The maximum temperature of the drill bit can be reduced from 200℃ to more than 100℃. However, its material is too soft and it is prone to scratches, causing the bit to slip and the hole position accuracy is poor. , Broken needle and other abnormalities. As a result, its alloy aluminum PCB entry backup board, which is a substitute for better processing performance, came out, and it has become PCB entry backup board varieties that are still commonly used.
With the development of high-end, functional, and special PCB technology, the technology PCB entry backup board as a PCB drilling auxiliary material is gradually developing toward diversification, refinement, and functionality. The quality and variety of the cover/backing board play an important role in ensuring the PCB drilling quality, yield, production efficiency, prolonging the service life of the drill bit, and the reliability of the PCB.
