Acronyms 41 to 50


This is our 5th and final installment of “50 Acronyms Used in Electronic Contract Manufacturing”.  In this article we’ll look at the meaning of 10 more acronyms.  The start of the series can be found here.


41. PSW = Part Submission Warrant

This is a form that is issued by a manufacturer to their customer that states and gives evidence that they can meet the customer’s quality requirements as well as other requirements, including delivery dates and throughput.


42. RFQ = Request for Quotation

A company will ask another company to quote a price for products or services based on certain requirements – such as quantity over a period of time.


43. RMA = Return Merchandise Authorization

When a company wants to ship back material to a supplier, typically an RMA number is needed.  When the supplier grants that a company can ship material back, the supplier will typically give the customer an RMA number along with specific instructions on labeling the return material with the RMA number so that when the supplier’s warehouse receives back the product, they will know what to do with the material.


44. RoHS = Restriction of Hazardous Substances Directive

A RoHS compliant component is a component that does not have more lead in it than what is acceptable.


45. CAR = Corrective Action Request

A CAR stands for a corrective action request.  An EMS company will issue a supplier a CAR when they come across a component from the supplier that does not meet the agreed upon quality standards.  In other words, when the supplier erroneously ships to the EMS company a defective component, the EMS company will want to know how that happened, why it happened, and what corrective actions the supplier will do to see to it that that will not happen again.


46. SMT = Surface-mount technology

SMT machines are machines that can place electrical components onto the surface of a printed circuit board (PCB).  Such machines can place parts at a high rate of speed, resulting in high efficiencies.  A much slower way to assemble circuit boards is with humans placing the leads/connections of electrical components through holes on the PCB.


47. SOP = Start of Production

The term SOP usually goes with a date.  For example, “the SOP date is 8/1/2021”.  This refers to the date a design officially goes into production.  It is kind of a confusing term for newbies because a design could be produced several times before the SOP date.  So, why isn’t the earliest of these dates referred to as the SOP date?  The answer is that these earlier production dates are prototype builds; the units produced here don’t go into a customer’s product and sold to an end customer; these prototypes are analyzed by technicians and engineers to see if the design is solid and the manufacturing process is smooth and as error-free as can be.

So, the SOP date is really the date when an EMS company will begin manufacturing for a customer and that the customer will officially use these manufactured units in their product.


48. SPI = Solder Paste Inspection or Serial Peripheral Interface

Depending on who you are talking to, the acronym has different meanings.  For Production people, SPI stands for Solder Paste Inspection.  For Design Engineers, SPI stands for serial peripheral interface (a type of communication standard like USB, or Bluetooth).


49. U/M = Unit of Measure

U/M, also called UM or UOM, is short for “unit of measure”.


50. WIP = Work-In-Progress

The term WIP stands for work-in-progress.  In manufacturing, there are 3 main locations where components may reside: 1) as raw components in the warehouse; 2) as completed units (also called “Finished Goods”) in the warehouse; 3) as WIP – which means components that reside on the manufacturing floor that are in a state of being assembled or used in the manufacturing process.