Manufacturing and Measurement Fundamentals

Measuring

Comparing something to a universal and standardized scale.

Variable measuring systems

Systems that measure based on a continuous scale.

Attribute measuring systems

Systems that measure based on information or quality.

Repeatability

The ability to repeat a process and get the same result.

Reproducibility

The ability for someone else to perform a process and get the same result.

Accuracy

The ability to hit the bullseye or get a tight pattern repeatedly.

Precision

The ability to get a result within a desired range of values.

Tolerance

An acceptable deviation from a target result.

Allowance

An acceptable deviation between mated parts.

Bilateral tolerance

Having the same allowable difference both above and below the target.

Unilateral tolerance

Having only one acceptable dimension deviation from the target number.

Limit tolerance

A possibly unequal minimum and maximum acceptable relation to the target.

Block tolerance

Tolerances listed in a blueprint box covering multiple decimal ranges.

Manufacturing

The process of turning raw materials into finished products.

Manufacturing inputs

Raw materials, capital/equipment, labor, and energy/utilities.

Most important manufacturing output

Profit.

Physical properties

Material characteristics observed without changing the object chemically.

Mechanical properties

How a material responds to applied stress, strain, and force.

Hardness

A material's resistance to indentation or scratching.

Tensile strength

A material's resistance to pulling forces.

Compressive strength

A material's resistance to crushing forces.

Elasticity

The ability of a material to return to its shape after being stretched.

Plasticity

The ability of a material to hold its shape when modified or deformed.

Ductility

The ability to be shaped by tensile forces without cracking.

Malleability

The ability to be shaped by compressive forces without cracking.

Micrometer operation

Use a thimble and a clicking knob to measure a precise range.

Caliper readings

Always read in decimals rather than fractions.

Shear strength

Resistance to opposing forces.

Torsional strength

Resistance to twisting.

Toughness

Resistance to having its shape change, aka absorbing or resisting energy.

Impact strength

Keeping its shape while absorbing sudden energy.

Fatigue strength

Resistance to repetitive loads or motion.

Vernier Micrometer tick marks

Large vertical tick for every .100 inch; smaller vertical tick for .025 inch.

Thimble

The part of a micrometer you twist with your hand, with horizontal tick marks for every .001 inch.

Reading a Vernier Micrometer

Match vertical thimble numbers to horizontal numbers; round up to the closest one ahead of the mark.

Caliper scales

.001 scale means 1/1000th of an inch; .0001 scale means 1/10,000th of an inch.

Shear Strength

resistance to opposing forces

Torsional strength

resistance to twisting

Compressive Strength

resistance to crushing

Toughness

resistance to shape change

Impact Strength

keeping shape while absorbing sudden energy

Fatigue Strength

resistance to repetitive loads or motion