Terms
Acronyms, initialisms and useful terms
Atrick Design tries to avoid jargon and use plain terms. When a common acronym or term is the clearest word for the job, it is defined here. Underlined terms elsewhere on the site link to these entries.
- 1D
- Bending tubing with the centerline radius equal to the tubing diameter. 2D is two times the diameter, and so on.
- 3MF
- 3D Manufacturing Format: a newer 3D printing file format that, unlike STL, can carry units, colors and materials along with the shape.
- BOM
- Bill of Materials: what is in the product, as far as manufactured and purchased components, along with alternatives.
- Back purging
- Filling the inside of a tube or part with shielding gas while welding, so the back of a stainless weld does not oxidize and stays strong and clean.
- Breadboarding
- A quick way of testing circuitry. Using a solderless breadboard and jumper wires, complex circuits can be set up. It is very helpful in prototyping an electrical design and allows quick and easy corrections. It does not replace prototype circuit boards; it helps find errors before designing and ordering them. Breadboarding should never be used in products, as it is fragile and easy to accidentally unplug something.
- CAD
- Computer Aided Design: computers take care of the math and geometry, allowing high-accuracy design.
- CE
- The CE marking: a manufacturer’s declaration that a product meets European Union safety, health and environmental requirements.
- CLR
- Center Line Radius.
- CNC
- Computer Numerical Control: machine tools such as mills, lathes and tube benders driven by a program, so parts come out the same every time.
- Core shift
- When the cores that form the hollow inside of a casting move during pouring, so internal features end up out of position. Machining such a casting to the nominal drawing can cut into thin walls and scrap the part.
- CPL
- Component Placement List: a list of component locations and rotations on a circuit board. Sometimes called a POS (position) file.
- CSA
- CSA Group (formerly the Canadian Standards Association): a testing and certification body whose mark shows a product was tested to North American safety standards.
- DFA
- Design For Assembly: it is designed to be assembled. Sometimes simple tasks that should take a few minutes take hours, because something was not thought through.
- DFM
- Design For Manufacturing: it is not just a pretty picture on a computer; it is designed to be manufacturable. A background in manufacturing and fabrication helps a designer understand the challenges and impossibilities in a design.
- DFMA
- Design For Manufacturing and Assembly: DFM and DFA done together, so a part is easy to make and the product is easy to put together.
- DFX
- Design for X, sometimes read as design for excellence: designing for whatever matters over the product’s life, such as manufacturing, assembly, test, service, cost and reliability.
- DIN rail
- DIN translates loosely to German Institute for Standards. DIN rail is a way of mounting wiring blocks, fuse holders and more complex components together to help tidy up wiring. It is sometimes seen as a sign of quality, but should generally be seen as costly, complex, time consuming, hard to troubleshoot and error prone.
- Draft
- A slight taper on the walls of a molded part so it can come out of the mold. An ice cube tray's pockets are wider at the top than the bottom for the same reason.
- DRC
- Design Rules Check: part of circuit board design software that verifies clearances, connections, shorts and manufacturability before the design is finalized.
- Duty cycle
- The share of time a machine or part can run under load. A 100% duty cycle means it can run continuously.
- ECAD
- Electrical Computer Aided Design: software to aid in designing circuit boards.
- ECN
- Engineering Change Notice: the record that a part or drawing has changed, what changed, and which revision and serial numbers it applies to. Often paired with an ECR (the request) and ECO (the order).
- EOL
- End of Life: most products have a sensible life cycle, and at some point they no longer make sense to manufacture.
- ETL
- A safety certification mark from Intertek. An ETL-listed product has been tested to the applicable UL standards.
- FDM
- Fused Deposition Modeling: 3D printing that builds a part from melted plastic laid down layer by layer. Good for large, tough parts.
- FMEA
- Failure Mode and Effects Analysis: going through a design or process ahead of time, listing the ways each part could fail, what each failure would cause, and how likely and how severe it is, so the worst risks get designed out first.
- Ground bond
- An electrical safety test that injects current into a machine’s grounding connections, to verify the grounding can safely handle the supply current in a fault.
- Hipot
- High potential electrical testing: a non-destructive test that applies high voltage to the system to check for shorts and other insulation issues. Part of safety testing every unit built above a certain voltage.
- Hobby grade
- A general label for sub-par part quality. Hobby grade is fine for one-offs and tinkering.
- Injection molding
- Making plastic parts by forcing melted plastic into a steel or aluminum mold. The molds are expensive, but each part after that is cheap, so it suits thousands of parts.
- JIT
- Just In Time: making and delivering parts and subassemblies only as they are needed, so they arrive at the line at the same time instead of sitting in inventory.
- KC
- Korea Certification: the safety and electromagnetic compatibility mark required for many electrical products sold in South Korea.
- Modular design
- Breaking functions down into building blocks (modules) to allow different options, subassemblies, or a level of replacement part.
- MTBF
- Mean Time Between Failures: the average running time between failures of a repairable item. It describes reliability across many units, not how long any one unit will last.
- MVP
- Minimum Viable Product: the simplest form of your product that is still useful, built to get feedback from customers.
- NPI
- New Product Introduction: the work of taking a new design into production, from prototype builds and documentation to suppliers, fixtures and training the assembly team.
- Non-plated through hole
- A drilled hole in a circuit board that is not electrically conductive. Think of it as a screw hole that will not accidentally short anything out.
- Parametric CAD
- A CAD model built from editable dimensions and features, so changing one dimension updates the whole part. Far more useful than a raw 3D scan when a part needs changes.
- Parting line
- The seam where the two halves of a mold meet, in molding and in casting. It leaves a faint line on the finished part, so it is placed where it will not show or get in the way, and it decides which way each half of the mold pulls off the part. In casting, a small raised band is often added along it, so a slight shift between the mold halves does not leave an inside corner on the part.
- PCB
- Printed Circuit Board: one or more conductive layers of circuitry on one or more non-conductive layers. Circuit boards can save a lot of time, complexity, assembly time, component cost and errors by building the circuitry into the board.
- PCBA
- Printed Circuit Board Assembly: a circuit board with its components installed.
- PEM nut
- A self-clinching nut pressed into sheet metal to give it threads. It only holds well when the sheet thickness matches the nut.
- Planned obsolescence
- Purposely designing a product with an artificially limited life. A large driver of e-waste.
- Plated through hole
- A hole in a circuit board with conductive plating added after drilling. It connects through-hole components or connectors to traces on the board.
- PLC
- Programmable Logic Controller: a rugged industrial computer that runs machines and processes.
- Point cloud
- The raw output of a 3D scanner: a large set of measured points on the surface of an object.
- Prototype
- A design validation: it checks function, assembly, whether the design does its job properly and effectively, and reliability. It is the check of whether a design is ready for production.
- QC
- Quality Control: a company’s methods for keeping the quality of the products it builds.
- QI
- Quality Inspection: checking or testing a product or subassembly to verify that it works.
- RCFA
- Root Cause Failure Analysis: finding the root cause, or causes, of a failure.
- Reverse engineering
- Working out how an existing part was designed, from the part itself, so it can be reproduced, repaired or improved.
- Rivnut
- A threaded insert installed from one side of a panel, like a rivet. Easy to install, and easy to replace in production and in the field.
- RMA
- Return Merchandise Authorization: a product sent back to the maker for repair or replacement. Fewer RMAs means fewer failures in the field.
- RS-485
- A rugged wired communication standard for connecting several boards on one long cable in electrically noisy places like machines and factories.
- Safety 3rd
- A phrase Mike Rowe popularized on Dirty Jobs. It does not mean “safety does not matter.” It means your safety is ultimately up to you: when people are convinced someone else is responsible for their safety, they stop paying attention, and complacency causes most accidents. In design, a product first has to do its job; if safety always came first, nothing would ever get built. Safety is then designed in wherever the product needs it, in proportion to the real risk, rather than bolted on as an afterthought or allowed to bury the product in complexity.
- SCARA
- Selective Compliance Assembly Robot Arm: a robot arm with jointed sections that swing side to side like a human arm, fast and stiff for pick-and-place work.
- Simplification
- Removing complexity from a product without affecting its function. It is easy to design something complex that does a job. It is difficult to design in the simplicity to do the same job.
- SLA
- Stereolithography: 3D printing that cures liquid resin with light, layer by layer. Fine detail and smooth surfaces.
- SMD
- Surface Mount Device: a chip or component that mounts and connects to the surface of a circuit board.
- SMT
- Surface Mount Technology: the methods for mounting and connecting surface mount components.
- STEP
- A standard CAD file format (.step or .stp) that keeps a part’s exact solid geometry, so it opens in almost any CAD program, unlike a mesh file.
- STL
- The most common 3D printing file format: the surface of a part described as a mesh of triangles.
- Subassembly
- An assembly of parts that is not yet the complete product. It breaks assembly into manageable chunks.
- Through-hole component
- An electrical component with pins or legs that push through a circuit board and are then soldered. Easier to solder by hand, which helps in prototyping and breadboarding.
- UI
- User Interface: the way the user and the product interact.
- UL
- UL Solutions (Underwriters Laboratories): a safety science organization whose standards most North American electrical safety testing follows.
- Undercut
- A shape that locks a part into its mold, such as a hook, a hole running sideways, or an arm held away from the body. It needs extra mold pieces, a flexible mold, or a design change.
- UX
- User eXperience: overall, how pleasing and simple a product is to use.
- VFD
- Variable Frequency Drive: electronics that control the speed of an AC motor.
- Via
- A plated hole in a circuit board that connects different layers or traces of the board together.