HKIE Professional Assessment - Manufacturing, Industrial & Systems Discipline flashcards

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

Taylor's tool life equation

V × T^n = C relates cutting speed V to tool life T. The exponent n is about 0.1-0.15 for high-speed steel and 0.2-0.4 for carbide, so higher speeds sharply shorten tool life.

Chvorinov's rule

Solidification time equals a mould constant multiplied by the square of volume divided by surface area. Thicker sections with high volume-to-area ratio solidify last, so risers are placed there to feed shrinkage.

Bend allowance

The developed length of the neutral axis in a bend: (π/180) × (R + K×t) × θ, where R is inside radius, t sheet thickness, K the neutral-axis factor and θ the bend angle in degrees.

Welding heat input

Heat input per unit length equals arc efficiency times voltage times current divided by travel speed. It controls cooling rate, heat-affected-zone hardness and the risk of hydrogen cracking.

Little's Law

Work in process equals throughput multiplied by flow time. It holds for any stable system regardless of arrival or service distributions, making it a universal check on production and service systems.

Economic order quantity

EOQ equals the square root of twice annual demand times order cost, divided by annual holding cost per unit. It minimises the sum of ordering and holding costs under constant demand.

Standard time formula

Standard time equals observed time multiplied by performance rating multiplied by one plus the allowance fraction. Allowances cover personal needs, fatigue and unavoidable delays, so the standard is achievable across a shift.

Learning curve exponent

Unit time for the nth unit equals first-unit time multiplied by n raised to b, where b is log(learning rate) divided by log 2. An 80 percent curve gives b approximately minus 0.322.

Verification versus validation

Verification confirms the system meets its specified requirements, answering whether it was built right. Validation confirms it meets the user's actual need, answering whether the right system was built.

Interface control document

A controlled document fixing physical, electrical, data and protocol characteristics between two configuration items. Changes to it require joint configuration control by both owning parties.

Reliability block diagram rules

In series, system reliability is the product of component reliabilities. In active parallel redundancy, it is one minus the product of the component unreliabilities, so redundancy raises reliability sharply.

Configuration management activities

The four activities are identification of configuration items, control of changes, status accounting of approved configurations, and audits, namely functional and physical configuration audits confirming the delivered product matches its documentation.

Process capability indices

Cp is tolerance width divided by six sigma and measures potential capability. Cpk equals one minus the centring factor k, times Cp, and falls when the process mean drifts from target.

Western Electric rules

Out-of-control signals include one point beyond three sigma, two of three beyond two sigma, four of five beyond one sigma, and eight consecutive points on one side of the centre line.

Acceptance sampling risks

Producer's risk alpha is the probability of rejecting a good lot at the acceptable quality level. Consumer's risk beta is the probability of accepting a bad lot at the lot tolerance percent defective.

RPN in FMEA

Risk priority number equals severity times occurrence times detection, each scored one to ten. Current AIAG-VDA practice uses action priority tables instead of ranking on raw RPN alone.

Expanded measurement uncertainty

Expanded uncertainty is the coverage factor k multiplied by combined standard uncertainty. With k equal to two, the interval corresponds to roughly 95 percent coverage for a normal distribution.

Gauge R&R interpretation

Percentage GRR is the gauge variation divided by tolerance, times 100. Below 10 percent is acceptable, 10 to 30 percent conditional, and above 30 percent unacceptable for the measurement application.

Availability formula

For a repairable system, availability equals mean time between failures divided by the sum of mean time between failures and mean time to repair. Reducing repair time raises availability without changing reliability.

Weibull shape parameter

In the Weibull distribution, beta below one indicates infant mortality, beta equal to one random failures, and beta above one wear-out. It is estimated from the slope of a Weibull probability plot.

Denavit-Hartenberg parameters

Four parameters per link, namely link length a, link twist alpha, link offset d and joint angle theta, define the homogeneous transform between successive robot frames in a serial manipulator.

Robot singularity

A configuration where the manipulator Jacobian loses rank. At a wrist singularity joint rates become unbounded for a finite tool motion, so trajectories must avoid it or use damped least squares.

OEE calculation

Overall equipment effectiveness equals availability times performance times quality. Availability is run time over planned production time, performance compares actual to ideal cycle time, quality counts good parts.

Collaborative robot safety standards

ISO 10218-1 and -2 govern industrial robots and integration. ISO/TS 15066 covers collaborative operation, including power and force limiting with body-region-specific force and pressure thresholds.

Safety stock formula

Safety stock equals the service factor z times the standard deviation of demand during lead time. When lead time also varies, combine demand and lead-time variances before multiplying by z.

Reorder point

The reorder point equals average demand during lead time plus safety stock. In continuous review the order is triggered when inventory falls to this level; periodic review triggers on a fixed cycle.

Bullwhip effect causes

Demand forecast updating, order batching, price fluctuation, and rationing with shortage gaming amplify demand upstream. Remedies include shared point-of-sale data, everyday low pricing and vendor-managed inventory.

Incoterms 2020 scope

Incoterms allocate costs, risks and customs duties between buyer and seller at a named place. They do not transfer title and do not replace the contract of sale.

Capital recovery factor

Converts a present sum into an equivalent annual amount: A equals P times i(1+i)^n divided by (1+i)^n minus one. Used to compare alternatives on an annual cost basis.

Earned value indices

Cost performance index is earned value over actual cost; schedule performance index is earned value over planned value. An index below one signals overrun or delay respectively.

Hierarchy of controls

In descending effectiveness: elimination, substitution, engineering controls, administrative controls, then personal protective equipment. PPE is the last line of defence, never the primary control.

RPE registration in Hong Kong

The Engineers Registration Board administers registration under the Engineers Registration Ordinance, Cap. 409. Registration requires corporate membership of HKIE plus relevant post-qualification experience.