1. When the curvature of the bent tempered glass produced shows large errors after long-term use of the bending section.
2. After any repair of the arc motor encoder in the bending section of the glass tempering furnace.
3. After any repair of the arc-adjusting mechanism or arc-forming mechanism of the bending section.
4. After disassembly or repair of the chain links of the arc-adjusting mechanism in the bending section of the glass tempering machine.