Knowledge of Entry and backup board
2017-11-21 08:06Writer: qyadminReading:
Entry and backup board is an essential auxiliary material for PCB (Printed circuit board) drilling. Due to the need for a large number of entry and backup board in the production of PCB drilling, and with the rapid development of PCB drilling technology in recent years, the PCB entry and backup board industry has become a fairly large scale in the PCB raw and An important part of auxiliary materials industry
Entry and backup board history
Entry and backup board in the 40 and 50s born with the PCB almost at the same time. The beginning of the use of the phenolic resin board, and ordinary phenolic resin TG is low, the gradual emergence of drilling and other issues. For this reason, epoxy fiberglass panels were once used in the PCB industry, but they did not completely solve the problem of drilling pollution. And because the drilling rate is getting higher and higher, more and more heat is generated.
In the later period of 80s, the entry and backup board has a thermal conductivity requirements, and the epoxy thermal conductivity is very low, is not conducive to heat, it cannot meet the production requirements, while the cost of epoxy glass fiber board is also higher, so this epoxy The history of the use of glass plate is not very long, it was abandoned.
In the early 1990s, MDF began to be used as a drilling plate due to its advantages of low price, stability, less drilling pollution and heat resistance. Early appearance of low-density wood fiberboard surface hardness is low, burr prone to burr phenomenon, suitable for drilling larger holes; with the hole diameter smaller and drilling rate increasing, in order to reduce burr hole in the well, In the late 1990s, there have been medium and high density wood fiberboard, the surface hardness gradually increased; in order to further improve the surface flatness and thickness uniformity of wood fibroin, wood fiberboard surface sanding process in recent years. At the same time also appeared in the early 90s corrugated plate and other new concept products.
In the mid-to-late 1990s, the choice of entry and backup board used in PCB drilling also began with another type of metal with better thermal conductivity, the metal cover. Initially used ordinary soft aluminum, aluminum thermal conductivity is much larger than the resin, the maximum temperature of the drill can be decrease from 200 ℃ down to 100 ℃ and more, but its material is too soft, easy to scratch, resulting in bit slippage and hole accuracy does not appear Good, broken needles and other anomalies. As a result, its replacement for the better machinability of aluminum alloy claddings has come out and becomes one of the most commonly used entry and backup board today
At the beginning of the 21st century, to meet the requirement of drilling holes with smaller diameters (less than 0.3mm) and higher drilling speeds, the manufacturer of the entry and backup board manufacturers also developed and improved the original phenolic resin paper plate products with the characteristics of material, density, surface Hardness, flatness, thickness uniformity, material, etc. have been improved. move as melamine backup board. At the same time, in order to solve the alloy aluminum cover the surface is too hard, and easily lead to bit slippage problem, developed a lubricating aluminum sheet. This aluminum sheet is still improving the accuracy of the hole bit to solve the problem of drill bit cooling, play an important role. In recent years, the application of lubricated aluminum sheet has been rapidly expanded, and it can be predicted that it will be one of the ideal auxiliary materials for micropore drilling in the future for many years.
With the PCB technology of high-end, functional, specialization development, as PCB drilling auxiliary entry and backup board technology is gradually moving toward diversification, refinement and functional development. Cover / pad quality, variety, to ensure PCB drilling quality, yield, productivity, extend the life of the drill, PCB reliability plays an important role.