Assembly Lessons Learned Review A lessons learned review is the cheapest engineering tool available and the one most often skipped. It costs a meeting and some preparation, and it prevents a design flaw or a process assumption from being rediscovered on the next programme. The reviews that fail do so…

Supplier Development for PCB Fabrication Supplier development is the work of making a fabrication partner better rather than merely checking what they send. It is slower than switching suppliers and usually cheaper, because a supplier who understands your product’s critical features will control the parameters that matter without being asked.…

Visual Management on the Assembly Line Visual management is the practice of putting the state of the process where people can see it without asking. On an assembly line that means a metrics board that shows today’s output against plan, a clear signal when a station needs help, standard work…

Tape and Reel Packaging Compatibility for Feeders A taped reel is the interface between the component supplier and the placement machine, and it is specified rather than chosen. The pitch, the pocket and the cover tape all have to match the feeder, and a reel that does not match feeds…

Solder Paste Metal Load and Print Behaviour Paste is a mixture of solder powder and flux, and the proportion of powder is the metal load. It is stated as a percentage by weight, and it decides how much solder a given deposit finally contains. How It Is Specified The figure…

Solder Joint Inspection Under Magnification Inspection under magnification is a trade between resolution and field of view. Choosing the magnification is choosing what you will see and what you will miss, and the choice should follow the defect being looked for. What Each Level Shows A low magnification covers a…

Assembly Line Balancing and Bottleneck Analysis A line that can produce twenty boards an hour produces the number its slowest station allows, and every station upstream of it has to wait. Improving any other station adds work in progress rather than output, which is why the bottleneck is the only…

Solder Paste Slump and Its Effect on Bridging A printed paste deposit is a structure that has to hold its shape from the moment the stencil lifts until the alloy melts. Slump is the loss of that shape, and it is the mechanism behind a family of bridging defects that…

Polarity: Design Rules and Process Limits A reversed component is one of the few defects that is both easy to prevent and expensive to find. A diode placed backwards, a capacitor inserted the wrong way round or an integrated circuit rotated by ninety degrees may damage itself on power up,…

Vapor Phase Reflow and Its Heat Transfer Behaviour Vapor phase reflow heats a board by condensing a boiling liquid onto it. The heat transfer is far more efficient than convection, the atmosphere is free of oxygen and no fan blows across the assembly. Those properties solve problems that convection ovens…