1. Inspection: After receiving the glass fiber reinforced plastic resin sculpture from the previous process, the operator should perform visual inspection.
See if it can meet the standard of topcoat inspection. If there is any defective product, return to the previous process for repair immediately.
2. Cleaning: Because the glass fiber reinforced plastic resin sculpture is exposed to the air, the surface will be covered with dust, oil, and other substances that affect the quality of the glass fiber reinforced plastic resin sculpture. It must be removed before spraying the topcoat.
Methods as below:
Place the glass fiber reinforced plastic resin sculpture in the baking room;
Wipe the surface of the glass fiber reinforced plastic resin sculpture with a special dust-free cloth for painting, and dip a little degreaser or isopropyl alcohol. Pay attention to the grooves and corners of the glass fiber reinforced plastic resin sculpture.
Dry the Fiberglass resin sculpture surface with clean compressed air.
Wipe the surface of the glass fiber reinforced plastic resin sculpture with a sticky cloth, the method is the same as above; spray it after completion.
3. Topcoat spraying: Adjust the required paint according to the paint adjustment instructions, filter it with a 200-mesh wire mesh into a clean container for use, adjust the spraying air pressure within the range of 0.28-0.35PaM for spraying, and the spraying distance is 250mm The left and right three-time film formation cannot be sprayed at one time. So as not to cause uneven film thickness and sagging.
This step requires the experience and craftsmanship of the sprayer. For example, a large area of flat surface requires a high level of spraying, otherwise the overall sculpture is uneven, and the degree of smoothness is extremely poor, resulting in the final garbage sculpture.
The first pass is for overall mist spraying, the second pass is for overall uniform spraying (only the surface to be sprayed is moist and visible), and the third pass is for supplementary spraying, with an interval of about 30 to 60 seconds.
The topcoat is sprayed into a semi-wet film. Do not spray too wet, so as not to cause fish eyes and beads.
For example, during the spraying process, the viscosity of the paint must be re-calibrated when the operation time exceeds 30 minutes, so as to avoid the volatility of the solvent and the viscosity of the paint in the later stage, which will affect the leveling and orange peel phenomenon.
The thickness of the paint film is generally about 25 to 35 microns.
4. Inspection: After the topcoat is sprayed, the whole body should be carefully inspected for leaks, oil, spray, and large particles on the surface. If it needs to be processed in time, it can be entered into the next process after completion.
5. Flash drying: After spraying the topcoat, dry the paint film according to the requirements of the construction process;
The “Du Pont” paint used by Bosong Sculpture Factory has a flash-drying time of about 15 minutes at room temperature. The varnish can be sprayed only after the paint film is not sticky, so as not to cause color difference and surface floatation, and the varnish does not dry after spraying and baking. The phenomenon.
6. Varnish spraying: This process needs to be very professional, to protect the final spray effect to make the glass fiber reinforced plastic resin sculpture better and brighter. First, the varnish should be filtered according to the proportion requirements of the varnish deployment instruction book. After the adjustment, filter it with a 300-400 mesh screen. Clean the reactor for use, adjust the air pressure and oil output of the spray gun, and spray, and the method is to form the film three times;
The first pass: mist spraying, the second pass: increasing the amount of oil in the gun for uniform spraying, and the third pass: making up spray.
When spraying varnish, the air pressure and distance must be well controlled. The air pressure will blow the paint film out of waves and fail to level. Too close will cause the paint mist to sag. Too far after the paint is sprayed out, most of the solvent will volatilize on the way, causing orange peel. .
After the film is formed, the thickness of the paint film is about 35 ~ 55 microns. Too thin will affect the brightness after drying, and it will not look full. If it is too thick, it will sag and anti-stick.
7. Inspection: After spraying the varnish, it is necessary to conduct an overall inspection to see if there are any leaks and large particles. Before the next process is performed, it must be processed.
8. Leveling: After the varnish is sprayed, it should be leveled and flash-dried at room temperature. If the leveling is not sufficient, it will cause ripples, orange peel, pinholes and other undesirable phenomena.
PU varnishes naturally flash dry, and the leveling time is generally about 15-20 minutes before baking.
9. Baking: In order to accelerate the drying speed of Fiberglass resin sculpture, good Fiberglass resin sculpture needs to be heated and baked. According to the characteristics of the Fiberglass resin sculpture material and the efficiency of the drying equipment, the baking temperature is reasonably set.
Material of Fiberglass steel: The temperature resistance of Fiberglass material is up to 80 ℃. Due to the structural limitation of the car spray baking room used by Bosong Sculpture Factory, the maximum temperature can not exceed 60 ℃. Therefore, the baking temperature of Fiberglass sculpture should be set at 55 ℃ ~ 60 ℃, and the baking time should be 1.5 ~ 2 hours. Allow to cool out to room temperature before turning out of the baking room
ABS plastic: The maximum baking temperature of 78 ℃ should not exceed 75 ℃ for 30 ~ 40 minutes (if the equipment has the highest temperature limit, the baking time will be long)
3PP plastic: PP plastic is more resistant to high temperature, up to 95 ℃, general baking temperature is 80 ~ 82 ℃, effective baking time is 15 ~ 20 minutes (if the equipment does not allow high temperature, the baking time is longer)
10. Circulation: Fiberglass resin sculpture is transferred to the next process