Idiotic glaze
1. Characteristics of glaze defects
After the sanitary ceramics products are fired in the kiln, the places where the products are connected with the products, ceiling boards, roof supports, etc. are bonded together because of the glaze, which damages one of them.
2. The place where the glaze defect occurs
The foot, water tank cover, mouth of sanitary ceramic products and the place where jacking is required.
3. Causes of Crazy Glaze Defects
(1) After the body is glazed, the glaze at the place where no glaze is needed is not completely cleaned (such as the bottom).
(2) Forgot to rub aluminum oxide on the water tank cover when applying glaze.
(3) During glaze application, the aluminum oxide at the water tank cover mouth was not smeared properly, and there was glaze at the water tank mouth, resulting in glazed products after burning.
(4) The concentration of the aluminum oxide slurry used for coating aluminum oxide during glaze application is improper. Too small concentration will lead to precipitation of the aluminum oxide slurry and uneven composition, which will lead to the loss of the refractoriness and lead to glaze failure.
4. Solution
(1) After glazing, the surface of the body that does not need to be glazed shall be thoroughly wiped clean.
(2) When applying the glaze, the water tank mouth shall be smeared with aluminum oxide according to the process requirements. For example, 1-2 cm of residual glaze shall be left at the two corners of the front of the water tank mouth to prevent the product from being exposed.
(3) The aluminum oxide slurry used for rubbing aluminum oxide shall ensure a certain concentration, and the residual glaze at the base of the glaze body shall be cleaned timely after the rubbing.
Uneven glaze, thin glaze
1. Characteristics of uneven glaze and defects of thick and thin glaze
After the sanitary ceramics are fired in the kiln, the glaze surface of the product is uneven and has different thickness, and the glaze surface presents obvious wavy or fish scale shape.
2. Parts where uneven glaze and thick and thin glaze defects occur
Each part of sanitary ceramics is easy to produce, but its plane position is obvious.
3. Reasons for uneven glaze and thick and thin glaze defects:
(1) The muzzle of the spray gun used during glaze application is too close to the body, and serious ripples appear on the surface of the body after glaze spraying.
(2) The atomization effect of the spray gun used during glaze application is not good (the air pressure is not enough or the amount of glaze spraying is too large), resulting in the thin glaze layer of the glaze body after glaze application.
(3) When glaze is applied, the glaze slurry that has exceeded the shelf life (i.e., metamorphic glaze slurry) is used, which results in obvious glaze flow, glaze accumulation and glaze dripping on the surface of the glaze body when glaze is applied to the surface of the body.
(4) After glaze application, the operation of printing glaze on the glaze body is improper, and sponge is used to print glaze correctly where there is no flowing glaze or accumulated glaze on the glaze body.
4. Solution
(1) During glaze application, the distance and angle between the nozzle of the spray gun and the body shall be adjusted to ensure that the surface of the glaze body after glaze application is smooth without obvious ripples.
(2) Before glaze application, adjust the equipment to ensure that the air pressure is sufficient, the amount of glaze sprayed by the spray gun is appropriate, the gun speed is uniform, and the thickness of the sprayed glaze is uniform.
(3) It is strictly prohibited to use the glaze slurry that has exceeded the service life. If the glaze slurry is found to have deteriorated, the glaze slurry shall be returned to the slurry production department at the first time, and new glaze slurry shall be added for glaze application.
(4) When printing glaze on glaze body after glaze application, sponge shall be used to absorb residual glaze rather than apply glaze when dealing with flowing glaze, dripping glaze and accumulated glaze of glaze body.
Glazing process is a major process in the production of sanitary ceramics. Improper operation will first affect the quality of glaze body, and then affect the quality of fired products. Therefore, how to control the technical problems in the glazing process is what sanitary ceramics factories need to consider.