When making plastic parts, such as implantable medical devices, it has to be kept as clean as possible, and this part has to be made in a sterile environment, which can be called a "clean room".
A cleanroom is a space where the amount of air pollutants (such as dust and other airborne microorganisms) per unit volume is controlled to reduce the chance of contamination. These particles are controlled according to the cleanroom class specified by the International Standards Organization (ISO) 14644-1, High Efficiency Particulate Air (HEPA) filters the air before entering the cleanroom and is replaced several times per hour.
Cleanrooms designed to keep products free of contamination maintain positive pressure so that particles can escape from the cleanest areas to the least clean areas. However, some cleanrooms maintain negative pressure to prevent nothing outside the cleanroom, such as quarantine stations and chemical analysis facilities.
Plastic parts are manufactured in a dedicated room optimized to reduce the risk of contamination by dust or other particles. This process is called cleanroom molding. In the medical, pharmaceutical and biotech industries, parts must often be manufactured in a sterile environment.
Before diving into cleanroom molding, it is important to understand the differences that exist between ISO 7 and ISO 8 cleanrooms.
ISO stands for International Standards Organization - it is made up of various organizations from different countries that work together to develop and publish standards. In this way, internationally valid standards are created that entrepreneurs must comply with across borders.
The classification of the above clean rooms is based on ISO 14644-1. Classification according to US FED STD 209E (Cleanroom Class 1 - 100,000) is no longer valid as of November 29, 2001; cleanroom classes ISO 1 - ISO 9 have been valid since then.
The standard ISO 14644-1 defines the purity of air. This is set by determining the limits. ISO classification is based on particle concentration per cubic meter. The highest purity is ISO class 1 and the lowest is ISO class 9. This cleanroom class standard is primarily used for cleanroom systems produced in the semiconductor industry.
Most plastic clean room injection molding takes place in a class 7 or 8 cleanroom, and if the plastic parts are very low-resistance to impurities, such as the lenses used in thermal imaging telescopes, a more sterile environment may be required.
An ISO 7 clean room is an enclosed injection molding area separated from the rest of the commercial area by a hard wall. ISO 7 is mainly used for surgical procedures that do not implant foreign bodies, such as low-invasive surgery, vascular, obstetrics, ophthalmology.
The standards for ISO 8 cleanrooms are not as stringent as those for ISO 7 cleanrooms. In an ISO clean room, the store's molds are surrounded by movable curtains. ISO 8 is mainly used for short-term procedures such as visceral surgery, day surgery, and urology.
The environments required for ISO 7 and ISO 8 cleanrooms are lower risk environments such as general surgery, gynecology, patient preparation/wake hallways, intensive care and resuscitation, etc. Instrument calibration adjustments should be made for the treatment system, airflow, air one-way check (filter chamber present), noise and smoke testing.
Points to consider in the desired environment include:
Adequate airflow: To ensure air purity and keep particles low, Class 7 and 8 cleanrooms use positive airflow to insure certain particles.
Use of Electric Motors: In most cleanroom environments, electric motors should be used in place of hydraulic motors. This will prevent more airborne particles.
Coverage Requirements: In an ISO 7 cleanroom, engineers and operators must be fully covered when entering the cleanroom. Such coverings include shoe covers, full-length clothing, and economy covers. Coverage requirements may be more stringent in classroom 8.
Packaging Limitations: Cardboard or coated plastic packaging is common in cleanroom environments. Cleanrooms do not allow packaging, such as some corrugated cardboard materials that generate excess particles.