White Papers

Check the box next to each paper you want to download. You may download as many papers as you wish. After selecting papers and completing the contact information form on this page, the paper(s) will be e-mailed to you at the e-mail address you provide.

Papers about slumping

• Solder Paste: Meeting The SMT Challenge

  by Dr. Ning-Cheng Lee, Gregory Evans

  This paper focuses on many of the problems facing process engineers today. The experiments used in this study were designed to find the true causes of the problems and headaches which plague SMT assembly today. Data indicate that wicking is caused by a relative hotter component and is aggravated by non-coplanarity. It can be reduced by slower heating rate or more bottom-side heating. Bridging is caused by slumping, and is aggravated by smaller pitch dimension and slower flux wetting speed. Tombstoning is a result of uneven heating. It can be reduced by optimizing pads spacing and by using fluxes with slower wetting speed, or by a smaller print thickness. Problems such as slumping, clogging, solder balls, and white residue are also discussed.

  lead-free, pb-free, white residue, solder balling, tombstoning, bridging, wicking, clogging, slumping, SMT, solder paste

  [Permanent Link to this Paper]

  Posted on 1 Jan 2009

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