The safety protection system is one of the most critical parts of blister folding machine design, directly impacting the personal safety of operators and the reliable operation of the equipment. Safety protection in modern blister folding machines has evolved from simple guards to multi-layered, intelligent integrated safety systems that comply with numerous international and domestic safety standards and regulatory requirements.

Risk assessment is the starting point for safety design. According to ISO 12100, it involves systematically identifying potential hazards throughout the equipment's entire lifecycle (transport, installation, commissioning, operation, maintenance, disposal). These hazards include mechanical hazards (crushing, shearing, cutting, entanglement, impact, etc.), electrical hazards (electric shock, short circuit, overheating, etc.), thermal hazards (hot surfaces, hot materials, etc.), noise hazards, radiation hazards, and ergonomic hazards. Each hazard undergoes risk assessment, considering severity, exposure frequency, and possibility of avoidance to determine the risk level, providing a basis for designing safety measures.

Inherently safe design aims to eliminate or reduce risks at the source. Moving parts are designed to minimize exposed portions; where unavoidable, safety gaps are implemented, such as safe distances and angles for transmission components, preventing body parts from entering danger zones. Sharp edges and corners are avoided in design to reduce cutting hazards. Hot surfaces are insulated or guarded to prevent burns. Electrical system design complies with IEC 60204-1, employing measures like safety voltage, double insulation, and residual current protection. Control system safety design adheres to ISO 13849 or IEC 62061, using redundancy, self-diagnostics, and other techniques to ensure the equipment enters a safe state upon control function failure.

Guards represent the second layer of risk reduction. Fixed guards are mechanically secured and require tools for removal, suitable for areas not requiring frequent access. Interlocking guards are interlocked with the equipment control system; when opened, they automatically stop hazardous movements, complying with ISO 14119 requirements using reliable structures like positive-mode switches and forced disconnect contacts. Movable guards with interlocks are used in frequently accessed areas; they can be moved but the interlock ensures safety. Sensitive protective equipment like light curtains, laser scanners, and safety mats detect personnel entry via photoelectric or pressure principles and automatically stop the equipment. Light curtains comply with IEC 61496, feature self-checking, and have response times<20ms.<>

Safety control systems are independent of conventional control systems and specifically handle safety-related functions. Safety PLCs (Programmable Logic Controllers) comply with IEC 61508 and ISO 13849, featuring redundant processors, diverse software, self-diagnostics, etc., ensuring a single fault does not lead to loss of safety function. Safety input modules connect to emergency stop buttons, safety door switches, light curtains, etc., while safety output modules control actuators like contactors and valves. Safety bus systems, such as Safety over EtherCAT and PROFIsafe, enable safe communication over standard industrial Ethernet.

Emergency stop systems are the last line of defense. Emergency stop buttons are designed according to ISO 13850, featuring a red button on a yellow background, positioned near operating stations and key locations. They utilize forced disconnect contacts for high reliability. Upon emergency stop activation, all hazardous movements of the equipment cease immediately, power sources are cut off, and the stopped state is maintained until a manual reset. The reset operation must be performed separately and cannot be achieved by the emergency stop button itself.

Safety signs and information provide necessary warnings and guidance. Safety signs comply with ISO 7010, using standardized graphical symbols, including warning signs (yellow triangle), prohibition signs (red circle with diagonal slash), mandatory signs (blue circle), and safe condition signs (green square). Signs must be clearly visible, durable, and may include multilingual text instructions considering the operators' language background. The operation manual contains detailed safety instructions, including safety precautions, operating procedures, and maintenance safety requirements.

Safety verification and validation ensure the effectiveness of safety measures. Design verification uses calculations and simulations to confirm compliance of the safety design. Functional testing involves actual testing of each safety function, such as emergency stop, door interlock, and light curtain functions, with results documented. Risk assessment update re-evaluates risks after implementing safety measures to confirm reduction to an acceptable level. Safety Integrity Level (SIL) or Performance Level (PL) assessments quantify the reliability level of the safety control system.

Compliance with international safety standards is fundamental for equipment access to global markets. The European Union market requires CE marking, complying with the Machinery Directive 2006/42/EC, including safety design, risk assessment, technical documentation, and declaration of conformity. The North American market requires UL or CSA certification, complying with standards like NFPA 79 and the ANSI B11 series. The Chinese market requires compliance with GB series national standards, such as GB/T 15706 (Safety of machinery—Basic concepts), GB/T 8196 (Requirements for guards), and GB 5226.1 (Electrical safety of machinery).