Control Requirements for Sterile Cleanrooms in Medical Consumable Injection Molding
This specification is formulated in accordance with medical device GMP, YY0033 standards for sterile medical apparatus production and ISO14644 cleanroom criteria. It applies to injection molding of all sterile plastic medical consumables, focusing on controlling dust particles, microorganisms, oil stains and cross-contamination, standardizing full-process production and ensuring product sterility and safety.
1. Cleanroom Layout and Classification Control
Two core grades are adopted for production zoning. ISO Class 7 (10,000-grade) serves as the core injection molding zone for Class II sterile medical consumables, with strict limits on airborne particles, planktonic bacteria and settling bacteria. ISO Class 8 (100,000-grade) covers auxiliary processes including raw material drying, pre-treatment and semi-finished product storage to reduce pollution load in core zones. Non-clean areas for outer packaging, warehousing and equipment maintenance are fully physically isolated with no cross access.
Three separate one-way channels for personnel, materials and waste are implemented to avoid reverse flow and cross-contamination. A positive pressure gradient is maintained: higher cleanliness zones stay pressurized relative to lower-grade areas to block backflow of polluted air. Walls and ceilings use dust-free color steel plates with rounded internal corners, while anti-static epoxy self-leveling flooring eliminates dust accumulation, withstands disinfection and enables easy cleaning.
2. Temperature, Humidity and Air Purification Management
Constant temperature is maintained at 18–26°C with relative humidity ranging from 45% to 65%. High humidity triggers mold growth, while low humidity generates static electricity that adsorbs dust; monitoring records must be logged regularly. The air purification system adopts three-stage filtration (primary, medium and HEPA filters), with regular inspection and replacement of filter elements to meet air change rate standards.
Space disinfection is conducted after production via UV lamps and hydrogen peroxide atomizers. UV lamps must be replaced after 800 cumulative operating hours and are prohibited during production shifts.
3. Personnel Access and Behavioral Regulations
Only staff who complete training and assessment on cleanroom operations and microbial control may enter. Personnel with skin inflammation, colds or open wounds are barred, and all visitors require escorted registration. The full gowning procedure includes shoe replacement, outer garment removal, disposable cleanroom coveralls, double-layer masks, bouffant caps and nitrile gloves. Jewelry, watches and cosmetics are forbidden; damaged gloves must be replaced immediately.
Eating, excessive movement and direct bare-hand contact with product contact surfaces are prohibited inside clean zones. Special dust-free notebooks are used for on-site records, and cleanroom garments are zone-specified with documented regular washing and sterilization. Air shower cycles last no less than 30 seconds; operators rotate bodies to remove surface dust, and interlocking double doors cannot be opened simultaneously. Air shower filters undergo periodic cleaning and maintenance.
4. Raw Material and Semi-Finished Product Control
Medical plastic pellets and auxiliary materials must come with biocompatibility test reports and quality certificates. Medical and industrial raw materials are stored separately with three-color labels distinguishing qualified, pending-inspection and defective stock. Outer cartons of raw materials are removed in non-clean zones; inner packaging is disinfected and transferred to clean areas via self-cleaning transfer windows. Moisture-sensitive materials are dried under controlled temperature, and all hoppers and barrels use sealed stainless steel containers sanitized per shift.
Sealed dust-free turnover boxes are used for material transit. Semi-finished products are covered immediately after molding to prevent dust exposure. Waste and defective goods are placed in sealed collection bins. All materials are stored off floors and walls under a first-in, first-out inventory system.
5. Injection Equipment and Mold Sanitation Control
Injection molding machines are fully enclosed for dust prevention with sealed oil circuits to stop oil dripping. Material suction systems adopt closed negative-pressure delivery, while granulators and mold temperature machines are placed in independent isolated rooms. Equipment surfaces are wiped with 75% alcohol for dust removal after every shift.
Cavities and parting lines are wiped with medical alcohol after daily shutdown. Complete mold deep cleaning and microbial testing are performed during product changeovers. Molds for long-term shutdown are fully disassembled, cleaned and sealed for storage; ordinary industrial cleaning agents and polishing compounds are banned from contacting molding surfaces. Equipment maintenance is scheduled during production stops where possible. If online repair is required, isolation barriers are erected, tools pre-disinfected, and full room sanitization plus environmental re-inspection are mandatory before production resumes.
6. Cleaning, Disinfection and Sanitation Standards
Color-coded dedicated cleaning mops and cloths are assigned to different cleanliness grades to avoid cross-use. Dust-free wiping cloths are sterilized daily. Spilled materials are cleared instantly during production; full wiping of equipment, floors and turnover tools is completed after each shift. Deep cleaning of air outlets and walls is performed weekly, and full workshop hydrogen peroxide vapor disinfection monthly.
Approved disinfectants including 75% ethanol, hydrogen peroxide and quaternary ammonium salts are used on rotation to prevent microbial drug resistance. Disinfectant concentrations are verified daily with preparation records retained. Floor drains in clean zones are continuously filled with bacteriostatic solution, sealed with covered lids and flushed weekly to block microbial backflow contamination.
7. Environmental Monitoring, Recording and Deviation Handling
Daily testing covers airborne particles, planktonic bacteria and settling bacteria; differential pressure, temperature and humidity are monitored 24 hours non-stop. Production halts immediately for pollution source investigation once indicators exceed limits. HEPA filters undergo PAO leak testing every six months and are replaced when resistance doubles primary standards; primary and medium filters are cleaned or replaced per differential pressure readings.
Complete records of gowning, disinfection, environmental testing, mold sanitization, raw material drying and filter replacement are retained for at least one year beyond product shelf life. Any incidents including microbial overrun, oil contamination or disinfection failure trigger deviation investigations to assess product contamination risks, with corrective and preventive actions tracked and verified.
8. Waste Disposal Specifications
Cleanroom waste and defective products are stored in covered airtight containers and transferred to dedicated waste buffer rooms at fixed intervals. Transport tools are fully disinfected after exiting clean zones. Domestic waste, plastic scraps and hazardous waste such as waste hydraulic oil are sorted separately. Hazardous waste is handed over to certified disposal agencies with complete transfer documents archived.
