CIE flashcards

34 cards. Read the term and the definition here. The deck at the top of this page is optional.

Therblig

One of 18 basic motion elements used in micromotion analysis; effective therbligs advance work while ineffective ones such as search, select, and hold add no value.

Principles of motion economy

Rules for efficient motion: use both hands, keep motions symmetrical and smooth, place tools within the normal work area, and minimize eye travel and holding.

Two-handed process chart

A chart recording left- and right-hand motions on a shared time scale, used to reveal idle hand time and rebalance work between hands.

Standard time formula

Standard time equals normal time times one plus the allowance fraction, where normal time equals observed time multiplied by the performance rating factor.

Sample size for time study

Required cycles n = (z·s/(k·x̄))², using sample standard deviation s, mean x̄, desired precision fraction k, and normal deviate z for the confidence level.

Work sampling formula

Required observations n = z²·p(1−p)/e² for estimating a proportion p within absolute error e; accuracy applies to the proportion estimate.

Predetermined time systems

Systems such as MTM-1 and MOST that assign standard times to basic motions; valid only for the motions and conditions covered by the system tables.

Shadow price

The dual value of a binding constraint in a linear program, giving the marginal change in the objective per unit increase in that constraint's right-hand side.

Hungarian method

An algorithm for solving assignment problems by reducing rows and columns and covering zeros; it is a special case of the transportation problem.

PERT expected time

te = (a + 4m + b)/6 for optimistic, most likely, and pessimistic estimates; variance is ((b−a)/6)² and the critical path is the longest expected-time path.

M/M/1 queue metrics

For arrival rate λ and service rate μ with λ<μ: utilization ρ=λ/μ, average number in system L=ρ/(1−ρ), and average wait in queue Lq=ρ²/(1−ρ).

Economic order quantity

EOQ = sqrt(2DS/H) for deterministic demand D, fixed order cost S, and holding cost H per unit per period; ordering cost equals holding cost at the optimum.

MRP net requirements

Net requirements equal gross requirements minus scheduled receipts minus projected on-hand plus safety stock; planned order releases are offset by lead time.

ABC inventory classification

Pareto-based grouping where A items are few and high-value requiring tight control, and C items are many and low-value allowing loose control.

Safety stock formula

With constant lead time L and demand standard deviation σ_d, safety stock equals z·σ_d·sqrt(L), where z corresponds to the target cycle service level.

Aggregate planning strategies

Chase strategy varies output and workforce to match demand; level strategy holds output constant using inventory and backlog; mixed strategies combine both to minimize total cost.

Assembly line balancing

Cycle time equals available time divided by required output; minimum stations equal total task time divided by cycle time; balance delay equals one minus line efficiency.

Load-distance score

A layout metric summing flow between department pairs multiplied by the distance between them; lower scores indicate better layouts for the given flows.

Systematic Layout Planning

A procedure using relationship charts and closeness ratings (A, E, I, O, U, X) plus space requirements to develop and evaluate block layouts.

Cellular layout

A layout grouping dissimilar machines into cells that produce part families, combining the flexibility of job shops with some flow-line efficiency.

Process capability Cpk

Cpk = min[(USL−μ), (μ−LSL)]/(3σ); a value below 1.0 indicates the process mean or spread cannot meet specifications.

X-bar and R limits

Control limits are X̄̄ ± A2·R̄ for the mean chart and D4·R̄ and D3·R̄ for the range chart, using constants keyed to subgroup size.

Producer's and consumer's risk

Producer's risk (α) is the probability of rejecting a good lot (Type I error); consumer's risk (β) is accepting a bad lot (Type II error).

Gage R&R

A measurement system study separating repeatability (equipment variation) from reproducibility (appraiser variation) and comparing total gage variation to tolerance and process variation.

Capital recovery factor

A = P·[i(1+i)^n/((1+i)^n−1)] converts a present amount to an equivalent equal annual payment over n periods at interest rate i.

Internal rate of return

The interest rate that makes net present value of a project's cash flows equal zero; a project is acceptable when IRR is at least the MARR.

MACRS depreciation

Accelerated depreciation using declining-balance rates with the half-year convention, applying half-year depreciation in the first and last recovery years.

Equivalent uniform annual cost

EUAC converts a project's cash flows to an equal annual cost; in replacement analysis, keep the defender if its EUAC is below the challenger's minimum EUAC.

NIOSH lifting equation

RWL = LC·HM·VM·DM·AM·FM·CM; the lifting index equals load weight divided by RWL, and values above 1.0 indicate elevated injury risk.

Anthropometric percentile selection

Use the 5th percentile for reach and clearance demands and the 95th percentile for strength and clearance constraints so most users are accommodated.

Fitts' and Hick's laws

Fitts' law: movement time rises with distance and falls with target width. Hick's law: choice reaction time grows logarithmically with the number of alternatives.

Overall equipment effectiveness

OEE = availability × performance × quality; it measures how effectively equipment is used relative to its theoretical maximum output.

Takt time

Takt time equals available production time divided by customer demand; it sets the pace at which a process must complete one unit to meet demand.

SMED

Single-minute exchange of dies reduces changeover time by separating internal from external setup, converting internal steps to external, and streamlining remaining internal steps.