The process of making Ni-Cr heating sheat Silicone rubber heater by lithographic etching
Lithographic pit etching is a surface machining technique in which the desired shapes are printed on a brocade chrome sheet by means of photochemical and shoreline etching.
1) Graphic design. Based on the power size, shape and voltage of the ni-Cr heating sheet needed in the instrument and instrument, it calculated the required resistance value, so as to determine the density, strike, line length and width of the line arrangement on the heating sheet, and drew the line enlargement of 211~511, and obtained the negative after taking the picture.
2) Pretreatment of plate making and bare combined gold sheet. First of all, the line chrome film according to the size of the negative, the appropriate amplification of each side, with paper-cut is cut off. Then use magnesium oxide powder to clean the surface oil, and put the iron three oxide solution to the weak bottom corrosion treatment, make the surface more mirror, improve its surface adhesion.
3) Copy the graphics.
Preparation and application of photosensitive adhesive. We use PVA as the material of photosensitive adhesive.
Preparation method: first mix (PVA) with water, then heat to 90℃ in water bath, make PVA fully dissolve, take out and cool to room temperature, then pour dichromate aqueous solution and stir it thoroughly. In order to remove the impurities and bubbles in the photosensitive gel, net light filtration should also be carried out. Generally with three or four layers of gauze filtration twice can be. Next, a photosensitive adhesive is applied in a centrifuge. After that, bake near the electric stove until the glue does not stick.