Surface mounting process for flexible circuit board and used magnetic tool and steel mesh

Surface mounting process for flexible circuit board and used magnetic tool and steel mesh

  • CN 101,384,136 B
  • Filed: 10/17/2008
  • Issued: 04/02/2014
  • Est. Priority Date: 10/17/2008
  • Status: Active Grant
First Claim
Patent Images

1. a Flexible Printed Circuit (FPC) surface mount process (SMT), it is characterized in that, the magnetic tool that described attachment process adopts comprises clinching cover plate and magnetic pallet, described magnetic pallet is for being with magnetic substrate, the sheet metal of clinching cover plate for being attracted by substrate, on clinching cover plate, be provided with the slotted eye for Flexible Printed Circuit print solder paste and paster, described clinching cover plate is can be by the steel disc of attraction;

  • Described steel disc is stainless steel substrates, its thickness is 0.05-0.1mm, hardness is 480-700 Vickers hardness, steel disc is for adopting austenitic stainless steel or martensitic stain less steel to make through cold working, and the chemical composition of the steel of selecting is as follows;

    C;

    Si;

    Mn;

    P;

    S;

    Ni;

    Cr;

    Fe=(0.08-0.15);

    (0.75-1.00);

    (1.00-2.00);

    (0.04-0.045);

    (0.025-0.030);

    (6.00-10.00);

    (16.0-19.0);

    (68.0-76.0);

    Described magnetic pallet is to adopt aluminium alloy, synthetic stone or glass mat to inlay the substrate that resistant to elevated temperatures permanent magnet is made, and further, its processing step is as follows;

    (1) before printing, magnetic pallet is fixed on above positioning base, then put successively Flexible Printed Circuit and clinching cover plate, allow base location hole and the alignment pin of magnetic pallet fasten, allow corresponding cover plate location hole, FPC location hole overlap with pallet nail location hole, allow mark location hole overlap with the optical markings point in Flexible Printed Circuit, after accurate positioning, Flexible Printed Circuit is taken out from positioning base together with magnetic tool, put into printing track, etc. Flexible Printed Circuit, enter after certain printing track, the printing machine that is provided with steel mesh starts to carry out paste solder printing;

    The fixed-direction of described Flexible Printed Circuit is chip component vertical direction, SOT and SOP horizontal direction;

    On described printing machine, be provided with optical positioning system, this optical positioning system can be identified the optical locating point in Flexible Printed Circuit;

    The scraper of printing machine is steel spatula, and the angle of described scraper and Flexible Printed Circuit is 60-75 degree;

    The print direction of printing machine is left and right or fore-and-aft direction, and print speed printing speed is 10mm/s-25mm/s, and squeegee pressure is 0.1kg/cm 2-0.3kg/cm 2;

    The stripping rate of printing machine is 0.1mm/s-0.2mm/s;

    (2) be completed for printing rear Flexible Printed Circuit and enter chip mounter with magnetic tool, chip mounter carries out component mounter to Flexible Printed Circuit;

    (3) entering reflow soldering after having mounted is welded and fixed the solder joint in high-temperature components and Flexible Printed Circuit;

    Wherein, reflow process comprises warm-up phase, constant temperature stage, welding stage and cooling stage, warm-up phase, and temperature is raised to 110 degree from room temperature, and rate of rise in temperature is 1 ℃

    /S-2 ℃

    /S;

    In the constant temperature stage, temperature rises to 150 degree, temperature retention time 60s-120s from 110 degree;

    The welding stage, 1-2 ℃

    /S of temperature rising speed;

    Maximum temperature is less than 230 ℃

    , keeps temperature 20s-40s at 200 ℃

    -220 ℃

    , keeps temperature 3s-5s at 220 ℃

    -230 ℃

    ;

    Cooling stage, temperature reaches after maximum temperature and naturally declines, 2 ℃

    of decrease speeds/S-5 ℃

    /S;

    (4) reflow soldering is taken out cooling magnetic tool from track after completing, and takes down clinching cover plate, takes out Flexible Printed Circuit, and magnetic tool enters circulation next time.

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