REQUIREMENTS
Assembly on the basis of the Blaberk_SMT components:
Assembly on the basis of the customer-provided components Apart from the above mentioned components and documentation, additionally:
In case of departure from any of the above mentioned requirements, we charge extra costs, i.e. for correcting documentation and sticking tape leaders. ATTENTION: We always carry out assembly according to the supplied assembly design with component values indicated. The list of components and design with symbols are helpful but are not decisive. Please check your designs carefully!
The use of an SMT stencil significantly reduces the time of solder paste deposition on the PCB, consequently it reduces the time of the order completion. It also reduces the assembly costs (for the assembly without a stencil we charge 50% of labor costs), but it is not only the financial aspect that counts. Apart from time saving, the main advantage of this type of paste application is better quality of the final connections, even deposition of solder tin and lack of tin drops. There are several ways of making stencils: - drilled stencils – in places of SMD component pitches, holes are drilled in sheet metal by means of a numerically controlled drilling machine. Such stencils are cheapest in production but they are not suitable for IC boards and lead-free soldering. The cost of such a stencil is ca. $ 10 - 15 - chemically etched stencils – these stencils are usually made by PCB manufacturers. The holes for paste are made by double-sided etching like in the case of PCBs. They are suitable for 0.635 mm pitches. The cost of such a stencil amounts to $ 70 - 100. Some PCB manufacturers do not make sheet metal but on request deliver photographic plates needed for their manufacture. - laser-cut stencils – for 0.4 mm pitches. Laser-cut holes have slightly conical openings the wider sides of which face the circuit board. Thanks to such a cross-section, the paste covers pitches with more precision and when the stencil is lifted it neatly slides away. These stencils are made by specialist manufacturers. Their cost is above $ 300. - electronically formed stencils – for any hole density. The stencil is made in the process similar to electrolysis where metal ions move between the anode and the cathode. The holes here are even more conical. Sheet metal can vary in thickness – it is thinner for components with dense raster and thicker where more tin is needed. These stencils are made by very few manufacturers. - laser+electronically formed stencils – they offer a combination of advantages mentioned in points 3 and 4 above. We make chemically etched and laser-cut stencils in co-operation with specialist firms. To make a chemically-etched stencil, our company needs: - design of the panel containing multiple circuit boards (PCB format), or - Gerber files, or the following photographic plates: - positive plate of the Paste-mask layer from the panel design, - positive plate being a mirror image of the above mentioned, On the photographic plate holes should be marked for later anchorage of the stencil in the stencil printer. To make a laser-cut stencil, our company needs: - design of the panel containing multiple circuit boards (PCB format), or - Gerber files past-mask layer of the panel containing multiple circuit boards Click here to download a drawing (.pdf ) of the recommended panel shape and dimensions Click here to download a drawing (.pcb Protel 2.8 ) of the PCB stencil (packages) of ca. 140x220mm Click here to download a drawing (.zip Gerber ) of the PCB stencil (packages) of ca. 140x220mm Click here to download a drawing (.pcb Protel 2.8) of the PCB stencil (packages) of ca. 200x280mm Click here to download a drawing (.zip Gerber ) of the PCB stencil (packages) of ca. 200x280mm |
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