(A) The thickness of the photosensitive adhesive has A great influence on the development and coloring of the exposure in the future. Too thin is easy to fall off, does not have the protective effect, too thick is photosensitive insufficient, the line is easy to blur.
(B) The drying degree of photosensitive adhesive also has a certain influence on the quality. The book is not completely dry, during the exposure, the film will often stick to the bottom of the film, so that kang kang dug. This, in turn, can cripple the ni-Cr graphics. And the drying time is too long, it will cause in the coloring and cleaning process after the town of chrome alloy sheet is difficult to show a complete figure.
(C) Nickel-chromium alloy sheet coated with photosensitive adhesive after baking should be placed in a dark place away from light, so as not to be sensitized and blur the lines during development.
(2) exposure. Spread the falx gold plate coated with photosensitive adhesive on the bottom plate, attach it to the film surface of photographic plate (be careful to prevent light scattering, so as not to cause blurred lines), and then put it under a cold light to be sensitive. The power of the lamp source is 250~300 watts, the distance of the lamp source from the film is about 20cm, and the time is 3 minutes. In addition, in hot days, the sun can also be used for 3 to 5 minutes, so as to form the desired shape of the "shadow"
4) solid membrane. The exposed nickel complexed gold sheet was washed with warm water and immediately put into 0.5% eosin aqueous solution for staining. Rinse with warm water to remove the photosensitive adhesive from the end of alloy sheet, and immediately immerse it in the fixative solution after the lines are clear.
After 20 seconds, remove the operating alloy sheet. After the bottom is washed with water, the surface water flag is dried with a hair dryer, and then put into an electric drying oven, and baked for 1 hour at 140℃. After the above baked alloy sheet, the line color is brown, the purchase is very strong. After taking out, the excess part on the alloy sheet line is gently removed with a repair knife, and the residual part is filled with white nitro paint.
5) Silicone cloth. The ni-Cr heating sheet substrate we use is a semi-finished product coated with Haoji silicone rubber on the glass cloth without thinning.
(1) Manufacturing process of silica gel glass cloth
(A) Detumescence: The thickness of general silica gel glass cloth can be selected according to product requirements. The glass cloth we use is 0.06m/m thick twill non-alkali glass cloth, after the temperature of 250℃ for about 10~15 minutes, until no smoke. This will fully evaporate the wax off the glass cloth.
(B) Chemical treatment, dip the waxed glazing cloth in the treatment solution for 3-5 minutes, take out and leave to dry.
<C) Glue coating, the glass cloth after removing the eyes and chemical treatment can be well combined with silicone rubber. After the glue coating on both sides of the machine, the total thickness of the glass cloth is 0.19~0.20m/m.
(2) Surface treatment of Bin Chrome sheet. The bottom of the ni-Cr sheet is scrubbed clean with acetone, and placed for 5 minutes, and then evenly coated with a layer of chemical viscosifier.
The pH value of A-151 is adjusted to the range of 2~3 by HCI, while the pH value of a-151 is in the range of 5~6 in general, with poor viscosification effect. After coated with nickel-chromium piece of viscosifier, it is stored at room temperature for 30 minutes, and then put into A 60℃ electric dry transfer box for wrinkling air insulation for 1 hour. The treated chrome sheet was taken out and glued tightly together with the selected silica gel glass cloth with uniform surface adhesive layer and placed in the two layers of PTFE film. The air bubbles in the interlayer were removed with a cow bone scraper.
(3) For the bonding of nickel-chromium sheet and silica gel cloth, the above single-side silica gel cloth collector was placed in an electric drying box with a temperature of 135℃, and the air was blown for 10 minutes to keep the temperature, so that the chromium media sheet and silica gel glass cloth were firmly bonded together.
5) Chemical corrosion. After rinsing the ni-Cr heating sheet with water, a weak corrosion was made with ferric chloride solution. FeCl and water were then mixed and adjusted to read 36~38 on Vemet's table, the temperature was controlled at 60~70℃, and the e-shrink air was used for chemical corrosion. Take about 10 minutes to remove the unwanted parts. It must be pointed out that in addition to the fluidity of dissolution, the degree of clearing on the surface of ni-Cr has a great influence on the speed and quality of corrosion.
7) Cleaning treatment. Wipe off a yellow film on the ni-Cr line with sweet swallow water, or use 60% sulfuric acid solution, moisten for 30 seconds at 70℃, remove the yellow film, and then rinse off with water.
8) Determination of welding lead line and resistance value. Welding lead wire (length of lead wire according to design requirement) at the beginning end of the media chrome sheet.
The resistance value of the heating sheet is measured by the Whiston bridge. If the resistance value is greater than the index value, it shall be eliminated and the qualified ones shall be glued.
9) Compound benefit gluing. The qualified nickel-chromium heating sheet is then covered with a silicone glass cloth of the same size on the side with the nickel chromium wire running. After pressing, drain out all the bubbles in the middle with a cow bone knife, and then put them into an electric drying oven with a temperature of 135℃. Blow the air to keep the air warm for 10 minutes, and then take them out.