— Process Chart Symbols
Symbols for documenting and analysing work — the five ASME process-chart activity symbols, the Gilbreth therbligs used in micromotion study, and the ANSI/ISO flowchart shapes used for process and information flow diagrams.
ASME Flow Process Chart Symbols
| Symbol | Activity | Meaning |
|---|---|---|
| Operation | Something is created, changed, added to, or arranged — a value-adding step, or a setup/positioning step done deliberately. | |
| Transportation | An object, worker, or piece of equipment moves from one place to another (movement that is not part of an operation or inspection). | |
| Inspection | An object is examined or verified for quality or quantity; no physical change is made. | |
| Delay | An object waits before the next planned action — a temporary, uncontrolled hold (queue at a machine, batch waiting for a truck). | |
| Storage | An object is kept and protected against unauthorised removal; retrieval requires a requisition (controlled inventory). | |
| Combined activity | Two activities performed at the same workplace by the same operator at the same time — here operation + inspection. |
On a flow process chart the analyst records, for every step, the symbol, the distance moved, the time, and the quantity. Summarising the counts of each symbol — and attacking transportation, delay, and storage first — is the core of methods improvement. An operation process chart shows only operations and inspections (the two symbols that add value or assure it); a flow process chart adds the other three plus distances and times for one component or one worker.
Therbligs — Fundamental Hand Motions
The 18 elemental motions identified by Frank and Lillian Gilbreth for micromotion analysis. Effective therbligs (those that advance the work) are targeted for speed; ineffective therbligs (search, select, position, hold, delay) are targeted for elimination.
| Therblig | Abbr. | Type |
|---|---|---|
| Search | SH | Ineffective |
| Select | ST | Ineffective |
| Grasp | G | Effective |
| Hold | H | Ineffective |
| Transport loaded | TL | Effective |
| Transport empty | TE | Effective |
| Release load | RL | Effective |
| Position | P | Ineffective |
| Pre-position | PP | Effective |
| Inspect | I | Ineffective |
| Assemble | A | Effective |
| Disassemble | DA | Effective |
| Use | U | Effective |
| Unavoidable delay | UD | Ineffective |
| Avoidable delay | AD | Ineffective |
| Plan | Pn | Ineffective |
| Rest to overcome fatigue | R | Ineffective |
| Find (locate) | F | Ineffective |
Flowchart Symbols (ANSI/ISO 5807)
| Symbol | Name | Use |
|---|---|---|
| Terminator | Start or end point of a process or program. | |
| Process / operation | A processing step, action, or function. | |
| Decision | A branch point; one input, two or more mutually exclusive outputs (yes/no). | |
| Data (input/output) | Data entering or leaving the process, medium unspecified. | |
| Document | Output that is a human-readable document or report. | |
| Predefined process | A named sub-process defined elsewhere. | |
| Preparation | Set-up step that modifies a later instruction (initialise, set a switch). | |
| Manual operation | A step performed by a person without mechanical aid. | |
| Connector | An on-page (or off-page) jump between flowline segments. |