Circuit Boards PCB or Printed Circuit Boards in Sn-3.5Ag-0.7Cu, Sn-4Ag-0.5Cu and Sn-3Ag-0.5 Cu system.

... gold flash over the entire contact, and finally a selective heavy gold plating in the desired contact area. | SEMI-ADDITIVE-PROCESS | An additive process | CIRCUIT BOARDS | for obtaining conductive patterns which combines an electroless metal deposition on an unclad substrate with electroplating or with etching, or with both | SMOBC SOLDER | CIRCUIT BOARDS | MASK OVER BARE COPPER. | A method of fabricating a printed wiring board which results in the final metallization being copper with no other protective | CIRCUIT BOARDS | metal but the non soldered areas are coated by a solder resist, exposing only the component terminal areas. | SOLDER LEVELING |The process of dipping | CIRCUIT BOARDS | PCB's into hot liquids, or exposing them to liquid waves to achieve fusion. First, flux is applied to the board by dipping or brushing. Then | CIRCUIT BOARDS | the board is preheated in a liquid (maintained at 250 F). Next, the board is immersed in fusing liquid at 430 - 500 F. Finally, | CIRCUIT BOARDS | it is dipped in another 250 F liquid to cool it and reduce thermal shock. Thin fused coatings can be ...
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... question as to which surface protection is the right one. This is partly due to the changing technical demands on PCBs in further processing. | CIRCUIT BOARDS | Also, as of 1. 6. 2006, EU-Regulations restricting the use of dangerous materials in electronic appliances are to include the prohibition of materials containing lead, | CIRCUIT BOARDS | and is, therefore, another reason why alternative surfaces have been developed. One of these is immersion tin. Procedure A layer of tin is applied to | CIRCUIT BOARDS | the PCB by means of a special process, in which the copper atoms of the exposed conductors and contact areas are exchanged for tin atoms | CIRCUIT BOARDS | by adding thiourea. The chemical reaction ends when the copper surface is 0,6 to 1,2 my. Between the tin and copper layers there is an | CIRCUIT BOARDS | inter-metallic copper-tin phase after this process, i.e. blended metal. There are a number of reasons in favour of applying tin chemically. One advantage is the | CIRCUIT BOARDS | uniform smoothness of the surface. This feature enables the application of fine pitch components with ...
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... occurred naturally or have been induces by pressure or bending. | ANNULAR RING | That portion of conductive material completely surrounding a hole. | | CIRCUIT BOARDS | ARTWORK | An accurately scaled onfiguration used to produce a Master Pattern. Generally prepared at an enlarged scale using various width tapes and special shapes | CIRCUIT BOARDS | to represent conductors. | ARTWORK GENERATION | The process of transferring the idea for a circuit pattern into a precision, reproducible artwork master for mass | CIRCUIT BOARDS | production manufacturing. Generation can be executed by the traditional manual drafting and photographic technique, or via electronic means. | ARTWORK MASTER | An accurately-scaled (usually | CIRCUIT BOARDS | 1:1) pattern which is used to produce the production master. | ARTWORK REGISTRATION SYSTEMS | Equipment of various sizes and complexities used to achieve artwork | CIRCUIT BOARDS | registration. Accuracy, repeatability of precision tolerances, and loading and unloading simplicity and speeds are significant aspects. A| SPECT RATIO | A ratio of ...
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