Process Control and Right First Time Questions and Answers

Answer: C

Correct answer: 1 and 2 only

Statements 1 and 2 are correct: the software needs calibration dyeings for every dye on every substrate before it can predict anything, and it can generate alternative recipes and rank them by cost, by metamerism or by fastness. Statement 3 is wrong - the prediction is a starting point, and a laboratory dyeing is still made and measured to correct it, as the sequence item shows.

Answer: D

It arises when the two are made with different dyes whose reflectance curves cross rather than coincide. Matching curve for curve is the only way to avoid it and is not always possible. Different dyes with crossing curves are the cause.

Answer: A

Both are true and the reason gives the risk, and the index lets a colourist prefer a slightly more expensive recipe that will hold its match under every light the garment will meet. Store and daylight are the usual pair compared.

Answer: B

Batch size has no bearing on whether a shade comes out right, though it does change the cost of getting it wrong. The other three are the three standard levers a dyehouse pulls. Larger batches simply lose more when they fail.

Answer: C

Operator vision is a reason to measure rather than judge by eye, but it is not a process variable that can be controlled. The other three are all held steady by ordinary quality procedures. Instrumental measurement removes the observer entirely.

Answer: D

Correct answer: False

The eye is excellent at judging whether two colours differ and poor at saying by how much, and it is affected by the illuminant, by the surround, by fatigue and by the observer. Two people disagree and one person disagrees with themselves on different days. Instrumental measurement gives a number that can be recorded, compared and contracted upon - which is what a modern supply chain requires.

Answer: A

Correct answer: 2 - 4 - 1 - 3

The customer’s standard is measured first, because everything else is referred to it. The software then predicts a recipe from its calibration database. That recipe is dyed in the laboratory and measured against the standard, and the correction found is applied before scaling to bulk. Each step supplies what the next needs, and the laboratory dyeing is the check the prediction cannot replace.

Answer: B

Correct answer: a laboratory recipe may not reproduce in bulk

The dyes are the same but the conditions are not: liquor ratio, temperature profile, mechanical action, water quality and substrate lot all differ between a laboratory dyepot and a production machine, and each shifts the exhaustion. A correlation factor is therefore established between the two and applied when the recipe is scaled, and it is checked continually because it drifts.

Answer: C

Both are true and the reason gives the cause, and the factor has to be re-established whenever a machine is changed or a new dye class is brought into use. The factor is specific to the machine pair. Every new machine needs its own factor.

Answer: D

The first two are correct and are standard practice. The third is wrong, since the recipe states what should happen and the record shows what actually did, which is what makes diagnosis possible. Records are what turn a fault into a cause.