Thermal Expansion

Thermal Expansion

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The fixing detail example shown below takes into account the relatively large coefficient of thermal expansion of Plastics. As a rule of thumb: expansion equals 2mm/10°C temperature difference per 1000mm length.

In case of high temperature variations, the use of short Guide Rail pieces is recommended, so that expansion gaps can be kept small. The Plastic Guide Rails are fixed to the metal C-profile at one end to prevent movement.

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Dynamic coefficient of friction on polished Steel

Transplas U.H.M.W. Pe Nylon P.T.F.E. Nylon/MOS Acetal C
Dry 0.10 – 0.22 0.15 – 0.40 0.04 – 0.25 0.12 – 0.20 0.15 – 0.35
Wet 0.05 – 0.10 0.14 – 0.19 0.04 – 0.08 0.10 – 0.12 0.12 – 0.20
Oil 0.05 – 0.08 0.02 – 0.11 0.04 – 0.05 0.08 – 0.10 0.05 – 0.10
Dynamic
U.H.M.W. Pe on U.H.M.W. Pe 0.25 – 0.35
U.H.M.W. Pe on Mild Steel 0.12 – 0.20
U.H.M.W. Pe on Polyurethane (85°) 0.18 – 0.28
U.H.M.W. Pe on Polyurethane (92°) 0.16 – 0.26
U.H.M.W. Pe on PAZ tooth covering 0.13 – 0.23
U.H.M.W. Pe on AUSF “T” 0.20 – 0.30
Mild Steel on Mild Steel 0.22 – 0.32
Mild Steel on Polyurethane (92°) 0.50 – 0.70
Mild Steel on Polyurethane (85°) 0.60 – 0.80
Mild Steel on PAZ / PAR 0.30 – 0.40