Precautions For Metal Etching
The surface finish of metal etching has a great effect on metal etching, surface roughness, do not need to etch the metal part of the coating of the corrosion resistant gum is difficult to clean, the need for metal etching parts of the surface due to rough, metal etching out of the nicks are also rough, Metal Etching so before the metal etching, the metal surface to be polished, According to the situation and the requirements of the product to develop a polishing scheme and selection methods, specific to the second chapter of the polishing section.
After the metal etching is finished, it is necessary to wash the metal etching pieces in time, with diluted neutralization solution, because the metal etching liquid is highly corrosive liquid. If the residual metal etching workpiece surface, the future will cause corrosion of metal etching products or discoloration, so the washing process is very important, must pay attention to.
Metal etching parts after cleaning to blow dry, and then the most effective way to remove the protective coating, if the use of pasted organic membrane, Metal Etching can be directly sliced peeling; if it is a paint or ink, with effective solvents or chemical solution dissolved.
Metal etching of the workpiece can be based on needs and design requirements for surface finishes. If the surface is clean and bright, can be electrolytic polishing, on the one hand, can completely remove the residue such as corrosion protection materials, but also can remove the metal etching process attached to the surface of the corrosion products. In addition, the brightness of the surface is improved by polishing. If a plain or matte is required, the matte light is used.
The main problems that should be noticed in the process of metal etching are as follows
Problem one, reduce the side erosion and the penetration, improve the metal etching coefficient
The lateral eclipse produces a sudden along. The longer the PCB is usually in the metal etching solution, the more severe the side eclipse (or the use of an old-fashioned swing metal etching machine). Metal Etching The lateral erosion seriously affects the precision of the printed wire, and the severe side corrosion will make the fine wire making impossible. When the pitting and the penetration decrease, the metal etching coefficient increases, and the high metal etching coefficient indicates the ability to maintain fine wires, so that the metal etched wire is close to the original size. Electroplating metal etching inhibitor Whether it is tin-lead alloy, tin, Metal Etching tin-nickel alloys or nickel, the process of excessive will lead to short-circuit wire. Because the synapses are easily broken down, the electrical bridging is formed between two points of the wire.
Problem two, improve the consistency of metal etching rate between board and board
In continuous board metal etching, the more consistent metal etching rate, the more uniform metal etching of the board. To achieve this requirement, it is necessary to ensure that the metal etching solution remains in the best metal etching state throughout the entire process of metal etching. This requires the selection of easy regeneration and compensation, Metal Etching metal etching rate easy control of metal etching liquid. The process and equipment which can provide constant operating conditions and automatic control of various solution parameters can be selected. By controlling the amount of dissolved copper, ph value, concentration of solution, temperature, uniformity of solution flow (spray system or nozzle and nozzle oscillation), etc.
Problem three, improve the uniformity of metal etching rate on the whole board surface
On both sides of the board and all parts of the surface of the metal etching uniformity is determined by the surface of the board by metal etching flux uniformity.
In the process of metal etching, the metal etching rate of the upper and lower surface is often inconsistent. Generally speaking, the lower plate surface of the metal etching rate is higher than the upper plate surface. The metal etching reaction is weakened by the accumulation of the solution on the upper plate surface. Metal Etching Can be adjusted up and down nozzle of the spray pressure to solve the upper and lower plate surface metal etching phenomenon. A common problem with metal etching printed boards is that it is very difficult to etch all the surface of the plate at the same time, and the edge of the board is faster than the metal etching at the center of the board. Metal Etching It is an effective measure to adopt sprinkler system and make nozzle swing. Further improvements can be made by making the plate center and the edge of the plate spray pressure different, plate cutting edge and plate back-end intermittent metal etching method to achieve the entire surface of the metal etching uniformity.
Problem IV. Improving the ability of safe handling and metal etching of thin copper foil and thin laminated plates
In the metal etching multilayer board such thin laminated board, the board can be easily wound in the wheel and the transmission wheel to cause waste. Therefore, the metal etching of the inner plate of the equipment must ensure smooth, reliable treatment of thin laminated laminates. Metal Etching Many equipment manufacturers attach gears or rollers to metal-metal etching machines to prevent such occurrences. A better method is to use the additional sway of the PTFE coating line as a thin laminate transport support. For thin copper foil (for example, 1/2 or 1/4 ounces) of metal etching, it must be guaranteed not to be scraped or scratched. Thin copper foil, such as metal etching 1 ounces of copper when the mechanical defects, sometimes more severe chatter can be scratched copper foil.
V. Problems of pollution reduction
The pollution of copper to water is a common problem in the production of printed circuit, and the use of ammonia-alkali metal etching solution aggravates this problem. Because copper and ammonia complexation, it is not easy to use ion exchange or alkali precipitation method to remove. Therefore, the use of the second spray operation method, the copper-free add liquid to rinse the board, greatly reducing the copper emissions. Then, Metal Etching use the air knife to remove the excess solution from the plate before rinsing the water, thus reducing the water's rinsing burden on the copper and metal etching salts.