Xinxiang Ceramic Mug Manufacturer, in the previous section we talked about the phenomenon of orange peel glaze on ceramic mugs. One reason for this is the glazing process. Our common ceramic mugs are glazed, professionally this kind of mug is called color glaze mug. Many people said, we see the color glaze mug very little ah, are like: sublimation mug, printing mug, travel cup, stoneware mug, etc.. In fact, these ceramic mugs have a layer of glaze on the body, strictly speaking, they all belong to the color glaze mug. Only, on the basis of color glaze mugs, they have their own independent characteristics, so they are named after their characteristics. Well, let's talk about the glazing process of ceramic mugs, the glaze developed into a glaze paste, attached to the ceramic mug billet process, called glazing. Common glazing methods include dip glaze, spray glaze, brush glaze, pouring glaze and so on. Today we focus on a talk: dip glaze process.

1. Glaze before the preparation
Before the formal dip glaze, ceramic mug factory is to do some preparatory work. The purpose of these preparations is to ensure the success of the glazing process, reduce the rate of defective products. These preparations are mainly divided into 4 parts:

1.1. Clean ceramic mug raw blanks
In the previous article we will have, after the clay made of ceramic mug billet, to carry out the “Ceramic mug clay billet drying and billet repair process”  During the drying process, the blanks may be dusted. If the dust on the mug is not cleaned up, then the adhesion of the glaze is reduced and the ceramic mug we get in our hands is prone to problems. In this process, the raw blanks need to be cleaned with an air gun. At the same time, but also to detect the water content of the raw ceramic mug, the most suitable glaze water content is: 3% -5%. Raw billet water content is too low, it will be excessive water absorption, damage the structure of the glaze; water content is too high is prone to pinholes, flowing glaze and other problems.

1.2. Raw ceramic mugs
Whether the raw ceramic mugs should be plain fired, we have explained in the previous article. “What is plain firing of raw ceramic mugs?”.  Some ceramic mugs with complex shapes or special requirements for the thickness of the mug, need to be fired before glazing. Vegetable firing process, can enhance the quality of the ceramic mug billet, in the later glaze, hand-painted, paste underglaze flower paper and other processes, is essential, this link is not all ceramic cups, only for high-end ceramic cups.

1.3. Prepare glaze
Quartzite, feldspar, kaolin, after powdering, sieving, mixing slurry, etc., made of glaze paste, these specific operations in the “Glaze raw materials, production, classification and quality”  explained in detail. Before glazing, the glaze paste should be stirred and tested, mainly checking the color and fluidity of the glaze paste.

1.4. Cleaning the workshop
The glazing workshop in a ceramic factory is cleaned separately before formal glazing. It is the same as ceramic mug raw cleaning, in order to guarantee the cleanliness of the glaze on the ceramic mug. The main thing is to clean up the dust, control workshop temperature and humidity. Workshop temperature is generally controlled at about 25 ℃, humidity control at about 50%.

2. Ceramic mug dip glaze
2.1. Basic principle
Utilizing the water-absorbing properties of ceramic mug blanks, the surface is uniformly adhered to by immersing the glaze paste, similar to the principle of painting oil paintings. The glaze paste penetrates into the pores of the ceramic mug under capillary action, forming a 0.2-0.3mm thick glaze layer.

2.2 Scope of application
Dip glaze on the shape of the ceramic mug is required, regular cylindrical, conical ceramic mugs, using dip glaze. Dip glaze because the operation is simple, with automatic dip glaze equipment, for large orders, often used dip glaze process.

2.3 Operation steps
Mechanical arm grips the upper edge of the mouth of the mug at 1/3, the raw billet is vertically immersed in the glaze paste, keep the glaze surface 5mm away from the mouth of the mug, hold it for 2 seconds, and then lift it away from the glaze surface at an even speed. After lifting, the mechanical arm rotates 3-5 turns at 60 rpm to shake off the excess glaze. During this process, keep the mouth of the mug tilted downward by 15 degrees to discharge the accumulated glaze using gravity.

3. Drying and finishing
3.1 Drying
After glazing, place the raw ceramic mugs horizontally on the grid drying rack, and require the ambient temperature to be about 25℃ and humidity to be about 50%, drying for 2 hours. Then, raise the ambient temperature to 40℃, humidity 30%, and activate the circulating fan to accelerate the drying for 5 hours.

3.2. Finishing
Use sponge, scraper and other tools to clean up the mouth and bottom of the mug, excess glaze.

4. Quality Inspection
Grade A standard: glaze without pinholes, bubbles (diameter <0.2mm); thickness fluctuation <±0.05mm; mug roundness error <0.3mm.

5. Common Problems
5.1: Glaze accumulation at the mouth of the mug (“glaze circle”)
Causes: insufficient rotating speed of dumping glaze / too deep immersion glaze
Countermeasures: Increase the speed to 80 rpm; install limiters to control the depth of immersion.

5.2: Lack of glaze on the handle
Causes: Air bubbles attached / Mechanical arm clamping obscured
Countermeasures: ultrasonic vibration to remove bubbles before dipping glaze.

5.3: Glaze layer peeling off
Phenomenon: after drying the glaze appears spider web cracks
Root cause treatment: adjust the glaze paste formula (add thickener)

5.4: Uneven thickness
Means of detection: every 30 pieces with a thickness gauge sampling test
Process optimization: the specific gravity of glaze paste is stabilized at 1.45; add automatic replenishment pump to maintain a constant liquid level.

5.5: Glaze pollution
Pollution source tracking: 60% from workshop dust; 30% from impurities in the glaze tank.

6. Analysis of advantages and disadvantages of glaze dipping method
6.1 Core advantages
Outstanding efficiency: single machine handles 800-1200 pieces per hour
Low cost: the utilization rate of glaze material＞95%.
Stable quality: pass rate up to 92%-95%.

6.2 Inherent limitations
Weak adaptability: not suitable for relief/shaped mugs
Edge defects: the mouth of the mug needs to be processed twice.

The immersion glaze method is still the mainstream glazing process for ceramic mugs after centuries, and its essence lies in the combination of “standardization” and “refinement”. As the old craftsman said: “dip glaze three points by equipment, seven points in the management.” Even the most sophisticated equipment, but also need people to manage. The production of ceramic mugs is a process of detailing. From raw material selection, glaze preparation to glaze process, each link has Xinxiang ceramic factory people on the details of the control. Xinxiang ceramic mug factory believes that the only way to find the best balance between efficiency and quality is to transform the process parameters into enforceable SOPs and continuously optimize every detail.