Technical parameters of productionManufacturing method
Stencil manufacturing with laser cutting uses CAD/CAM data as a source including information about land patterns of surface mounted components. After data conversion to GERBER format (if needed), specialized software calculates laser (or rather plasma ball formed by laser in the material) movement coordinates taking in account width of the beam itself, that allowing to form holes of different shapes and sizes in the metal sheet.
Therefore, by making changes in the source file you will get openings in the metal corresponding to those set in the file with high level of accuracy.
Due to such accuracy of replication you have unlimited opportunities in selection of optimized stencil aperture type and size to match well your technical requirements.
Process parameters
Tapering is the difference between tapered opening sizes at the top and bottom side of material. Openings tapering allows easier solder paste release from stencil apertures.
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Stencil is always cut from the side applied to PCB. Therewith, tapered aperture size increases towards PCB. While cutting, cone is arranged with its wide side up, which is just a feature of cutting process.
For laser cut stencils all dimensions are measured on the side, solder paste is applied to, and the printer squeegee travel along (that is you see in the file).
Aperture sizes on the PCB side of stencil are 0.01-0.04 mm larger due to the aperture tapering.
Fiducials and text engraving are always made on the stencil side facing PCB.
Equipment
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Figure 1 Laser cutting machine for SMT stencils LPKF StencilLaser G 6080
Quality control
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Figure 2 View of stencil apertures made with laser cutting in 0.15 mm thick stainless steel sheet. (100X magnification)
During cutting process all stencils pass sampling verification of cutting quality by specialized portable microscope with high optical magnification.
Finally all orders pass verification by specialized Automated Optical Inspection (AOI) system. Each order has verification results report authenticated by stamp and signature of our production engineer.
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