Film thickness distribution of water soluble acrylic resin paints dip-coated on extruded aluminum shapes has been investigated, under stationary state, with some theoretical considerations. Test pieces were of bent plates having curved corners, radii of which varied with each specimen over the range of 0.02-0.2cm. Dip-coating was done with withdrawal speeds of 1.03 and 1.50cm/s. Values of Ca (Ca=μVw/σ) were 4.8×10
-3 and 7.0×10
-3, respectively, and values of Go (Go=R(ρg/2σ)1/2) were in the range of 0.08-0.79, where μ is viscosity, σ is surface tension, ρ is density of paint and g is gravitational acceleration. The following results were obtained by the above experiment. 1) A gradual decrease of film thickness from the plane portion to the corner was observed with the minimum value at the apex. 2) Film thickness at the corner (h″
th) can be caluculated theoretically by multiplying the thickness on plane portion (h
th) by a coefficient C′m, that is
h″th=C′m·hth=C′m[0.944Ca1/6(μVw/ρg)1/2] where C′m=1/2.4(Go-0.15)
0.85/1+2.4(Go-0.15)
0.85+0.5/(Go-0.15) Go=R(ρg/2σ)
1/2≥0.15
3) Residual coefficient (K) was found to be almost equal both at the bent portion and on the other flat surfaces if the painting conditions would be the same.
h″
ov=K·h″
th=K·C′m·h
thwhereh″
ov is the measured value.
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