刮刀或刮板

刮刀，又称刮板，是电子制造中助焊剂涂布系统的关键部件。它是一种精密设计的刀片，用于在焊接操作前将助焊剂膏或液体计量并涂布到印刷电路板（PCB）或其他基板上。刀片的边缘几何形状、材料特性和安装配置决定了助焊剂层的均匀性、厚度和一致性，直接影响表面贴装技术（SMT）和通孔组装工艺中的焊接质量、接头可靠性和缺陷率。

刮刀基于计量涂布原理工作。当基板（如PCB）在刮刀下方移动时，助焊剂材料被供应到刮刀前方。刮刀边缘以特定高度和角度定位，剪切并涂布助焊剂，在表面留下受控的均匀层。刮刀边缘与基板表面之间的间隙决定涂层厚度，而刮刀压力和材料特性确保涂布一致，无条纹或跳涂。

The doctor blade operates on the principle of metered coating application. As the substrate (e.g., PCB) moves beneath the blade, flux material is supplied in front of the blade. The blade's edge, positioned at a specific height and angle, shears and spreads the flux across the surface, leaving a controlled, uniform layer. The gap between the blade edge and substrate surface determines coating thickness, while blade pressure and material properties ensure consistent application without streaking or skipping.