LSR Clean Room Injection Molding

LSR Clean Room Injection Molding 

As an inert material, Liquid Silicone Rubber (LSR) is hypoallergenic and biocompatible, and can resist multiple substances. LSR components can be found in surgical and medical devices, biotech and diagnostic products, wearable healthcare devices, infant & food and beverage products, micro-electronics, and other applications with hygienic requirements. Depending on the product’s end use the specific hygienic requirements can vary, ranging from use of specialty medical and FDA-approved grade LSRs, hands-free clean manufacturing, to more stringent requirements dictating production in a hygienic and controlled environment.

Contamination can occur at several points during the molding process and can potentially come in contact with the LSR parts. Workers in contact with the molds during machine set-ups and mold changeovers may have oils or other contaminants on their hands or clothing. Dust and grease from the equipment and airborne particles are additional sources of potential contamination. When the injection molding and post-molding processes take place within an environmentally-controlled clean room, the contamination risk is mitigated and traceability enhanced.


What Is a Clean Room?

A clean room is an enclosure with a controlled environment. The clean room controls and minimizes contaminants including dust, airborne particles, and microbes. Usually, the goal of a clean room is to provide the most sterile setting possible for producing products such as medical devices, electronic components, and pharmaceutical products.

The International Organization of Standardization (ISO) establishes standards that define requirements for certification. The ISO Standard 14644 specifies the classification of air cleanliness in terms of concentration of airborne particles within the hygienic environment. The regulations were created in the early 2000s and revised in 2015 to reflect updates in technology and changes in market requirements.

ISO 14644-1 is a classification system for clean rooms based on the amount and size of particles allowed per volume of air in the room. ISO clean rooms range from class ISO Class 1 to ISO Class 9. The size and concentration of airborne particles in a clean room can range from 0.1 to 5 microns depending on the room’s classification.

A clean room uses special filters and airflow methods to reduce dust and other airborne particles. A clean room’s design keeps airborne particles from contacting parts and ensures the room itself stays as hygienic as possible.

Applications for LSR Clean Room Parts Production

LSR’s inertness and biocompatibility make it an ideal material choice for medical devices and other products that come into contact with bodily fluids or the human body. Such parts usually need to be produced in the type of environment provided by a clean room. A few examples of the devices and products requiring hygienic production conditions are:

  • Surgical instruments and devices
  • Pharmaceutical products
  • Biotechnology products
  • Parts and products used for diagnostics
  •  Medical devices that contact the body
  • Fluid management & drug delivery devices
  • Respiratory products
  • Nanotechnology and microelectronic components

Class 8 Clean Room Features

The number of particles present in a clean room’s atmosphere determines its ISO classification. An ISO class 8 clean room can have particles ranging in size from 0.5 to 5 microns. Particles that are larger than 0.5 microns are limited to 3,520,000 particles; for particles exceeding 1 micron in size, fewer than 832,000 are allowed; and for particles larger than 5 microns a maximum of 29,300 are permitted.

Another element of the ISO classification system is the number of air changes per hour in the clean room. An ISO 8 clean room should average 10 to 25 air changes each hour. An air change is measured by the volume of air that passes through a High-Efficiency Particulate Air (HEPA) filter each hour divided by the room’s volume.

  • In addition to air change and particle requirements, an ISO 8 clean room needs to have certain design features. These features ensure a clean and hygienic environment within the room. You can find more details on the necessary elements below:
  •  Air systems: A class 8 clean room for molding and other procedures needs to have an air system such as an airlock system that keeps outside air from getting into the controlled environment, or a positive pressure airflow system that allows air to leave the room without circulating back in.
  • Flat walls and floors: A clean room can have soft-paneled or hard-sided walls. What’s important is that the walls and floors are flat to minimize particle accumulation. Flat surfaces also facilitate easier cleaning to maintain hygiene.
  • Persons entering the room: Strict protocols and procedures must be adhered to for anyone who enters the clean room. These include strict codes of dress and other procedures to minimize the number of contaminants introduced into the room.

SIMTEC Silicone Parts’ ISO Class 8 Clean Room

SIMTEC is a U.S.-based leader in LSR and LSR multi-shot injection molding. In 2019, we added a certified Class 8 clean room for LSR and LSR 2-shot molded parts production and secondary processes such as post-curing and packaging. We added our Class 8 clean room to meet the requests and needs of our medical device OEM (original equipment manufacturers) customers.

We’ve taken a hybrid approach when creating the layout of our ISO Class 8 clean room. Our “smart design” class 8 clean room has a unique layout and material flow that offers the advantages without the limitations of other clean room approaches. The molding machines and ancillary equipment are located outside the clean room therefore tooling changes, material staging, and other machine- and equipment-related activities occur outside the clean room, mitigating the risk of contaminants associated with these activities from entering the controlled environment. The LSR molded parts are robotically removed and transported into the clean room within an environmentally controlled enclosure. During this whole process, the parts have no human touch and are not exposed to the external environment.

Inspection, post-curing, and bagging are all performed inside the clean room. A post-curing oven connects to the clean room, and the parts are then bagged inside and boxed outside, lowering the contamination risk. When designing the clean room, SIMTEC anticipated the need for future expansion and incorporated a modular design and layout to facilitate quick growth and minimal disruption.

Our class 8 clean room is ideal for our customers with high volume medical devices or other products that require an ISO-certified hygienic production environment. For customers that don’t need a clean room, SIMTEC’s highly-automated molding cells minimize human contact and deliver precision, high-output production, and added quality assurance.

Contact us today to learn more about how SIMTEC can work with you to help you meet your hygienic molding parts production requirements. Visit the Webinars page on our website for access to view our informative, 20-minute Clean Room Injection Molding webinar video with a look inside our unique, “smart design” class 8 clean room.