Manufacturing Key Terms To Know for High Volume Manufacturing

Whether you're at the beginning stages of building your prototype or are ready to go from prototype stage into high volume manufacturing, it's always good to have a handle on the key terms that will often come up with regard to manufacturing.

Updated: 1/1/2020

• Acceptable Quality Limit (AQL): A specified quality level, measured as an expected or allowed level of defects in a production lot or output stream, expressed as a percentage. For consumer products for example, there are usually three different AQLs specified - Critical (safety), Major (functional defect), and Minor (aesthetic defect). AQLs are an important contractual obligation on the part of the factory.
• Assembly Fixtures: Specialty devices used to hold or manipulate sub-assemblies during the assembly process.
• Bill of Material (BOM): Itemized list describing each component and quantity in the device.  In a nutshell, it's the recipe for your product and a great tool that can be used for costing.
• Computer Numerical Control (CNC) Milling:  An automated process for subtractive manufacturing.
• Compression Molding: A process similar to a waffle iron where rubber is vulcanized into flexible components.  An example is the rubber buttons on a remote control.  Less dimensionally accurate and less expensive than injection molding.
• Contract Manufacturer (CM): The primary company who produces, assembles, and packages your product to be sold.
• Coordinate Measuring Machine (CMM): Precise 3D probe measuring machine used to measure components for comparison with dimensional specs.
• Cost of Goods Sold (COGS): The price of the product at the shipping dock including material, labor, profit, overhead, scrap, etc.
• Design for Manufacturing (DFM): A principal within engineering design which considers how each component of a product is going to be produced.
• Die Bonding: An automated process where microscopic wires are bonded between the IC and the PCBA pads. A layer of epoxy is placed over the IC for protection.  Used to save the cost of the IC plastic packaging and pins.
• Die Cutting:  A 2D process used to cut out a shape on a film or piece of cardboard.  This process is often used to create boxes.
• Draft: Measured in degrees (typ 0.5-2.0), the slope of a plastic vertical wall required to release it from the tool without scratching. Dependent on material, aesthetics and texture.
• Ejector Pins: Typically rounded pins that push a part out of the mold. Will leave round witness lines, typically on cavity side of part.
• Electrostatic Discharge (ESD): Typically, 4kV-8kV done as part of a sample based design verification test process.
• Engineering Prototype (EP): Complete assemblies of molded parts and PCBAs built by trained engineers (i.e. not on a complete production line). The goal is to build a complete functioning product using the same parts and materials as the final manufactured product. May include printing and aesthetics.
• Engineering Pilot Stage: The period in which engineering prototypes are produced with early stage components to be used for validation and verification testing. The production line is created and engineering changes are expected during this period. 
• Ex-Factory (XF): Date at which finished goods leave the factory loading dock. Goods are transferred overland to container yard (either Hong Kong or YanTian) where they are transferred to the boat and become FOB. XF is often the trigger date for billing.
• Fiducial Marker:  An artifact placed in the optical field of view to help register a component.
• Final Engineering Prototype (FEP): Final engineering prototype (see EP above) that should meet all requirements for function and quality and should including all features, functionality, deco and packaging.  Should be indistinguishable from the final product. Built by trained engineers, not on an assembly line.
• Final Inspection: Final audit performed usually by the customer or their representative of the finished goods according to predefined specifications on an AQL basis (usually according to US DOD MIL-STD 105E). Failed inspection of goods requires rework and re-inspection of all goods before they can be shipped.
• First Pass Yield: A statistic indicating the number of goods produced successfully without defects or rework divided by the number of total units going into the process.  A measure of quality and production line capability.  This is call “First Pass Yield” because this is measured before the defective product is reworked and shipped.
• First Shots (FS): Milestone where initial plastic parts are created from a new tool. Parts will not include texture or polish. Often may be "short" (incomplete fill). Will be measured for dimensional accuracy using CMM.
• Flash: Thin film of resin that escapes at the parting line. An indication of a worn mold or too small of a press.
• Gate: Passage through which the resin is injected into the mold insert to form the part. Will typically leave a remnant that requires trimming.
• Gerbers:  The standard format used to describe how to manufacture the printed circuit board (PCB).
• Go/No-Go Gauge: Typically two brass gauges: one oversized and one undersized to measure a component's dimensional tolerance.
• In-Circuit Tester (ICT): Also called a "Bed of Nails." Spring-loaded pins connect with test points on the PCBA to measure continuity, polarity and component values as part of in-process testing.
• Injection Molding: Process by which a plastic part is made through injecting plastic resin under high temperature and pressure into a void that is the negative shape of the desired part.
• Life Test: Quality test to measure product life under nominal conditions and document failure modes for product improvement.

• Master Service Agreement (MSA): A contract between your company and the chosen contract manufacturer covering items such as payment terms, manufacturers warranty, and AQL.

• Milling:  A linear 3D subtractive manufacturing process.

• Minimum Order Quantity (MOQ):  The minimum quantity of a component that can be ordered at a set price (for example, a 5k reel of capacitors).

• Panelization:  Laying out multiple PCBs on a single piece to minimize scrap and provide uniformity for automated operations.

• Pick and Place: The process of placing electrical components on a PCB (often known as SMT).

• Pilot Production (PP): Conversion from FEP to a product built on an assembly line or cell.

• Printed Circuit Board (PCB): Bare board. Usually outsourced.
• Printed Circuit Board Assembly (PCBA): Stuffed PCB. Usually done in-house at the factory.
• Production Ramp: Gradual increase in weekly production up to steady state capacity which is often limited by tooling capacity.
• Production Start (PS): Initial production. Often will only run a few days each week during ramp.
• Quality Test Plan (QTP): A document that specifies procedures for on assembly line and full product testing. Tests for functionality, durability, overall life, aesthetics, shipping inspection, and certifications may be included.
• Reflow Oven:  A linear oven that heats up and melts solder paste to form an electrical bond to the components.
• Repetitive Motion Test (RMT): Automated or manual cycle test used for mechanical components.
• Request For Quote (RFQ): A Request For Quote is a business process where potential suppliers are invited to bid to deliver a specified service or product.
• Resin/Melt: Plastic that is injected into the tool to be transformed into the desired component. Typical resins are ABS, PC, PP, POM and PE.
• Runner: Plumbing to move melt from sprue to gate. Also used to transfer melt from sprue to multiple cavities.
• Sprue: Passage through which melted resin is injected into mold base.
• Statistic Process Control (SPC): A statistical method to monitor and control a process to ensure that it operates at is full potential to produce conforming product.
• Surface Mount Technology (SMT): Lead-less components soldered directly on the PCB by a highly automated process.  Typically cheaper and more accurate than Through Hole. Not all components come in a SMT package.
• Test Fixtures: Stations for testing specific aspects of the product’s function that occasionally require specialty test enclosures, jigs, and other equipment depending on the tests. A combination of specialty software, hardware and off the shelf parts are used for these stations.
• Through-Hole: Traditional electrical components that are inserted through a PCB, soldered, and trimmed.
• Tool Release: Milestone where the CAD files are transferred from Engineering to the Mold Shop for review, drafts and rounds and eventually tooling.
• Tool Start (TS): Milestone where the tooling production begins.  Mold base ordered. Insert material selected based on resin, surface finish, life requirements, etc. Tooling design to place the parting line, slides, cooling, sprue, runners, ejection pins, multi cavity balancing, etc. Often "MoldFlow" software is used to insure a complete fill.  Once the tool design is complete, the insert is machined via CNC or EDM.
• Ultrasonic Welding (U/S): Assembly process where high frequency vibrations are used to melt mating parts and form a strong bond.
• Vertically Integrated CM: A manufacturer who has many or all of the capabilities needed to produce your product in-house.
• Witness Lines: Fine, typically undesirable, lines created by a pull or mold modification.

Although we don't recommend going through the manufacturing process without experienced guidance - at least the first time around - having some basic 101 knowledge will help you to successfully navigate this very tricky journey.