Smarter Tools STPT-KIT-38PC Manuel d'utilisation et d'entretien télécharger pdf (Page 7)

used with this method. Pressure feed is generally used for spraying heavy bodied

paints or for large size projects.

Siphon Feed – Method of paint feed where atmospheric pressure creates a

partial vacuum to siphon paint to the gun. Only external mix air caps are used

with this method. Siphon feed is used with light bodied paints.

Viscosity – A measurement of the resistance to the flow of liquids.

CONVENTIONAL VS HVLP

Conventional spray guns use a much higher air cap pressure to atomize paint

than HVLP spray guns. This results in more overspray and lower transfer

efficiency.

HVLP, electrostatic and airless processes are currently the only compliant spray

methods that meet the strict 65% transfer efficiency criteria required by some air

quality management districts. This enhanced transfer efficiency results in a

significant material savings com- pared to conventional spraying. Check local,

state and national regulations that may be in effect before performing any

spraying operations.

HVLP spraying is a growing trend in the finishing

industry due to its environmental friendliness. By

definition, dynamic air pressures in the air cap must be

10 psi or less to qualify as HVLP. A soft, low velocity

pattern is produced which increases control and

reduces bounce-back and overspray (See Figure 1). For

these reasons, HVLP is also well suited for spraying

parts with recessed areas.

Spray Gun Set-up

The pressure for atomization is controlled at the air

source. The amount of fluid is adjusted by the fluid

control knob, the paint viscosity and the air

pressure.

The gravity feed cup screws onto the top of the gun

body creating a positive fluid pressure in the nozzle

(See Figure 2).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Pas de commentaire

Smarter Tools STPT-KIT-38PC Manuel d'utilisation et d'entretien Page 7