Tolerances feel the heat

1. Getting tolerance

2.Standard for measurement parts 3.Methods of solution the problem

Getting tolerance tighter

•Nowadays tolerances of parts are very tight.

•Temperature greatly affects part dimensions variation.

Temperature growth for three diameters of steel parts

Getting tolerance tighter

Temperature growth for three diameters of aluminum parts

Getting tolerance tighter

• Situation in workshops :

-workers should be aware of temperature affects

-workers must consider temperature expansion of a work piece

-workers must control temperature reduction of a part

Standard for parts measurement

•The standard reference temperature for industrial length measurements is fixed at 20 C

Methods of solution the problem

•Electronic temperature–compensation system advantages and disadvantages :

-this system provides better accuracy for measuring control

-costs less

-takes into account the effective coefficients of expansion of the part and measurement tools.

Methods of solution the problem

• Personnel responsibility

-Designers must make notes on the drawing for temperature-sensitive parts

-Time to cool down the part before measurement

Methods of solution the problem

Time to cool down the part at normal temperature before measurement (depends on the part weight)