Measuring Flatness and Coplanarity on Flexible Circuits The flatness of a flexible circuit matters at the interfaces where it has to make contact. A flex tail that plugs into a connector must be flat so that all of its contacts touch their counterparts, a flex that is bonded to a…

FPC Design Mistakes That Break Handheld Products A portable product puts a flexible circuit into a space that is shrinking every generation. The cable has to pass a hinge or a sliding mechanism, follow the curve of a battery or a display module, and end in a connector that is…

FPC Design Parameters For Appliance Electronics An appliance is a difficult environment for an interconnect. The inside of a washing machine, a refrigerator or a kitchen appliance is a three dimensional space occupied by motors, heaters, sensors and a control board, and the connections have to run between them without…

Embedded Resistor and Buried Component Design An embedded resistor is formed from a resistive layer inside the board rather than from a component placed on the surface. The technique removes parts from the surface, shortens the connection to the layer it terminates, and improves the behaviour of high speed nets…

Solder Paste Printing Defects And How To Clear Them Solder paste printing is the step that decides how much of the rest of the assembly process will go smoothly. The stencil deposits paste on every pad at once, and if the deposit is wrong on one pad, no amount of…

PCB Design Problems That Block Production Most boards that a fabricator or an assembly house rejects are not rejected for being electrically wrong. They are rejected because something in the pcb design cannot be built or assembled reliably, and the problems repeat across companies and projects. The list below covers…

Solder Paste Storage: Cold Chain, Shelf Life and Stirring Solder paste is a perishable material with a short shelf life, and the way it is stored and handled changes the printing result more than most operators expect. Paste that has been warmed badly, stirred at the wrong moment or left…

Low Temperature Solder: Low Temperature Lead Free Soldering on Flexible Circuits Soldering a flexible circuit with a lead free alloy is a compromise between the process temperature and the materials of the cable. A conventional lead free alloy melts near 217 degrees Celsius, which means a peak above 240, and…

Assembling MEMS Microphone Packages on a PCB A micro electro mechanical microphone contains a moving membrane a few hundred nanometres thick, a back plate with acoustic holes, and an application specific integrated circuit that buffers and digitises the signal. The three are packaged together in a cavity with a sound…

High Tg Thick Copper PCB: When Both Are Needed A high Tg thick copper board combines two separate requirements in one laminate: a resin system that stays rigid at elevated temperature, and copper layers heavy enough to carry current or spread heat. Each is available on its own, and combining…