#SOLDER REFLOW PROFESSIONAL#

Secondly, review the thermal profile for the particular product being processed to verify the proper temperatures were met during the reflow cycle. The reflow soldering process for lead-free components is similar to conventional eutectic solder reflow process. One is to review the artwork to determine the metal load on each pad. It may be connected to inner layers of the circuit board, or it may have a buried via within the pad, which is heat sinking the heat away from the solder paste to make a complete solder joint. The reasoning of why this may be happening on only a few pads of a particular component is most likely due to the heat sinking characteristics of the pad/land area.

If the solder paste appears to not have reflowed and is as identified in IPC-A-610 section 5, the issue is that the proper intermetallic has not formed at both the component and pad/land surface interface and this is a defective condition. Reflow Know-How: Prevent and Resolve SMT Process Problems The reflow oven is the key to the soldering process. Furthermore, these results are achieved without breaking the bank or taking up an enormous amount of desk space. The reflow soldering temperature curve refers to the curve of the temperature of a certain point on the SMA with time when the SMA passes through the reflow. Reflow Solder Defects Unsoldered Round SMD Device, Unsoldered Round, PCB surface finish not flat (HASL), component misplaced, not enough solder paste printed.

#SOLDER REFLOW PROFESSIONAL#

This would be related to percentage flux to metal ratio content of the paste rheology.Īs for the solder paste not reflowing and appearing as a solder ball grain structure on the surface of the solder paste, this is due lack of enough applied heat, which will prevent the solder paste becoming totally molten and coalesce forming a homogeneous molten solder volume. Hence the Solder Reflow Plate was born, a PCB-based, MOSFET controlled heater, perfect for easily reflowing SMD components giving surprisingly professional results. Is the incomplete reflow of solder paste as per Section 5.2.3 of IPC-A-610 a defect requiring rework even if the fillet appears to meet IPC standards?Īnswer: I’m not exactly sure of what you mean by flux exhaustion, however my interpretation is, there wasn’t enough flux in the solder paste to prepare the pad/land area and have the molten solder flow over the complete pad or land area itself.

Question: We have some PCB assemblies that show incomplete solder flow due to signs of flux exhaustion.

Solder reflow