The glass toughening industry is undergoing continuous transformation, and the market demand has posed unprecedented challenges to this industry. Glass heat treatment has experienced many significant developments, including the evolution from vertical hanging tempering to horizontal roller hearth furnace, from continuous furnace to reciprocating furnace, the introduction of fused silica ceramic rollers, and the development of hot air assisted heating furnace and forced convection furnace. This change is always driven by the market, in order to meet the requirements of improving production capacity, flexibility, and glass quality. Today, these market demands continue to be more challenging, including energy-saving glass, updated reflective coated glass, conductive coating, hydrophilic and non hydrophilic glass, ultra-thin glass, ultra-white glass, and complex curved glass. Various specifications and specifications will also become more stringent.
Manufacturing high-quality and deformation free glass requires good process control and internal management. On the basis of ensuring this principle, in order to continue the development of architectural glass and automotive glass, it is also necessary to have a comprehensive understanding of the basic principles and dynamic theories of processing technology. Along with the development of glass products, the tempering process is also developing. This includes improving the efficiency of the tempering furnace, ensuring accurate straightness of the rollers at working temperature, and paying more attention to the cleanliness and operation of the factory building.
Wave shaped deformation caused by ceramic rollers and roller tracks
With the increasing strictness of glass specifications and the implementation of new regulations, especially regarding wave deformation, the interaction between glass and rollers is receiving increasing attention. There are several possibilities that can cause glass deformation: the glass becomes soft due to overheating and sags between rollers; Uneven roller surface in the furnace causes deformation of glass in the furnace; The relationship between glass heating temperature and roller spacing; And roller table eccentricity, etc. The eccentricity of the roller table may be caused by insufficient accuracy of the ceramic roller shaft head, looseness of the shaft head during production, or excessive thermal runout caused by ceramic quality issues.
Roller table collimation TIR
The TIR (total runout) of the roller table is very important, and there are strict requirements for full runout under hot conditions to avoid causing wavy deformation of the glass. Ceramic materials must be homogeneous and amorphous. If the ceramic roller mechanism is uneven or has too much quartz, the ceramic roller is likely to bend or twist at operating temperature. Having good cold full runout does not guarantee good hot full runout. It is very important to know how to measure full runout and how to distinguish whether there are deformed ceramic rollers in the tempering furnace.
Connection method and selection of shaft head
The connection of the shaft head is crucial for maintaining the overall alignment of the roller table. There needs to be a precise fit between the ceramic roller and the shaft head to avoid shaking due to loose fit, but this fit should not be too tight, otherwise excessive stress will break the ceramic roller from the shaft head assembly. When assembled well, the silicone bonded shaft head can work effectively at low temperatures (the shaft head extends out of the furnace at approximately 100 ℃). Some ceramic roller designs require the addition of an additional mechanical key at the shaft head. These keys are backup measures for silicone failure that may occur due to high temperatures. The selection of shaft head structure depends on the structure of the tempering furnace and its application environment.
High precision roller table production of high-quality glass
The glass tempering furnace is an engineering system that accurately fires for the production of high-quality heat-treated glass. This system is particularly important and sensitive for producing high-performance and energy-saving glass. Any modification of the design parameters of the tempering furnace will seriously affect the operating system and ultimately affect the glass quality and production capacity of the tempering furnace.
Ceramic rollers also adhere to the ISO9001 quality assurance system and undergo precise design, manufacturing, and assembly to meet extremely strict specifications, dimensions, and tolerance requirements. The surface polishing of ceramic rollers is achieved by grinding with diamond grinding wheels to achieve a smooth and flat surface. The typical diameter tolerance is controlled below ± 0.05mm. Full runout is usually controlled within a maximum of 0.2mm, while shipped products are usually within 0.1mm. High quality glass requires a high-quality roller table. This type of roller can only achieve high-precision specifications by processing high-purity and high thermal stability ceramic blanks.
Roller maintenance
The maintenance of the roller table is crucial for maintaining quality and optimizing lifespan and performance. The roller table can be cleaned with water, and the use of 3M soft synthetic cleaning cloth is very effective. But do not use any soap or cleaning agents! To avoid the generation of water vapor, the roller table must be thoroughly dried before heating up, otherwise it may cause damage to the ceramic rollers. Finally, it is recommended to polish the ceramic rollers with sandpaper and remove any small dust and debris with adhesive cloth.
Plant cleaning and operation operations
The dust inside the factory must be strictly controlled, including debris that falls off the insulation materials inside the furnace and the insulation and sealing materials on the furnace walls. Before entering the furnace, the debris, dust, and materials used to separate the glass must be completely removed. Effective use of glass cleaning equipment and adherence to recommended operating and maintenance schedules are also crucial for the surface quality of ceramic rollers. We also recommend daily cleaning of exposed transfer rollers to avoid dust accumulation. The printing ink should not be too much, and the edges of the printed glass must also be clean to prevent it from flowing onto the surface of the roller after heating, and ultimately imprinting on the glass surface.
Good pre-treatment is also very important, including complete edge grinding, ensuring smooth edges and no debris on the protruding parts of the glass, otherwise it may cause glass cracking during the production process. The glass dust and debris on the ceramic roller surface will be adhered away by the glass. Good business management and operation can bring the following rewards: reduced maintenance and cleaning times for ceramic rollers, stable glass quality, and corresponding improvement in production capacity.
summary
The glass tempering process is constantly developing, and ceramic rollers play an indispensable role in the production of high-quality tempered glass. The glass industry is introducing high-performance energy-saving glass, and the glass specifications are becoming increasingly strict. The development of specifications for glass deformation will also come. Correspondingly, the requirements for the quality of ceramic rollers are absolutely decisive, and there is no alternative to good production practices, housekeeping, or maintenance plans.
