When you think about injection molding, you think about things like plastic containers for your leftovers, the packaging of your favorite snacks, or those disposable cups that are useful in cafes. However, there is much more to this process than meets the eye.

For example, when you look at LSR (liquid silicone rubber) injection molding, you will see that it is quite different from other types of molding. Some might even tell you that it's not molding because it differs from traditional injection molding processes.

But regardless of what anyone says, if your focus is on getting a new product to market as quickly and efficiently as possible, LSR injection molding is worth taking a deeper look at.

HCR and LSR

The compression and transfer molding processes, along with the use of plastic and high consistency rubber (HCR), have dominated manufacturing processes in medical, aerospace, electrical, construction, and industrial applications until recently, even though the injection molding method has undergone various modifications.

In actuality, the tide has turned, and producers from various industries now understand the advantages of liquid silicone rubber (LSR) for injection molding and producing molded components. One of its benefits is that LSR creates medium-to high-volume rubber components more effectively and affordably than thermoplastic and other molding methods, which is one of its benefits.

Grades, Properties, and Applications of LSR

Silicone rubber is made of sand and silicon dioxide in its purest form. Sand is converted into silicon metal by material makers, who then react with methyl chloride. Many other types and grades of silicone are produced using various fabrication techniques, such as fluids, polymers, compounds, and completed rubber bases. Silicones differ from conventional polymers in that their structural backbone alternates between silicon and oxygen atoms, and these organic side chains produce curability and other advantageous properties.

LSR differs from the high-consistency, gum-based silicone polymers that once dominated the market because it is made of a high-purity platinum core silicone created by Dow Corning in the 1970s. Instead, LSRs are composed of substances with a silicone oxide basis, and LSR material may be found in a range of sorts and grades, giving businesses a choice of textures for their finished goods, from gritty to smooth. In addition, manufacturers can change LSR to fit certain purposes or standards by changing side groups of the material.

Each material may have unique qualities, even though some characteristics will be identical for all LSRs. For example, LSR and thermoplastics share several processing characteristics. LSR also has a few notable qualities like those of a thermoset.

Other properties of LSR:

• Chemical inertness
• Immunity against germs, UV radiation, ozone, and potentially hazardous radiation
• Superior lighting and light transmission
• Clarity
• Permeability to gas
• Expansive elongation
• Strong dielectric properties
• Excellent tear and tensile strength
• The capacity to remain flexible and work at temperatures between -55°C and +300°C
• Low compression set at a wide range of temperatures
• Both tasteless and odorless
• Biocompatibility with FDA
• Many colors choices
• Hydrophobic
• Hypoallergenic

There are various alternatives for making LSR that are risk-free. Depending on the product's intended use, one such choice is to select among several hardness levels, gauged using a durometer. Another is that silicone may be sterilized using various techniques, including ethylene oxide, gamma radiation, steam autoclaving, dry heat, and e-beam (ETO). Producers can also add additives and other fillers to create LSR materials that can endure greater temperatures, oil, and other circumstances. Phenyl units can increase the low-temperature capabilities of LSR by being added to the material mixture.

Additionally, designers can make goods with intricate undercuts and geometries that are not conceivable with thermoplastic materials. LSR is appropriate for the specialized manufacture of medical device parts, including those for blood analysis devices and surgical machines. Compared to plastics, they do not stick to the patient's skin and do not harm their body hair.

Other grades attributed to LSR:

• Conductive to electricity
• Self-adhesive
• FDA compliant
• Medical grade
• Food grade
• Impermeability (petroleum and oils)
• Excellent Optical Clarity
• Strengthened Fiber
• Self-Lubricating

LSR's Value to Different Industries

Although silicone has been used in the medical field since the 1950s, LSR is increasingly used by medical device manufacturers due to its purity and other unique qualities, such as biocompatibility with human tissue and fluids, stability, hypoallergenic features, and a high level of performance. LSR is also resistant to chemicals, mold, and bacteria.

Because of its flexibility, transparency, and capacity to keep these qualities over time, LSR has started to replace glass and plastics for many optical applications in the lighting sector. In addition to being resistant to cracks, scratches, and discoloration, LSR also enables manufacturers to combine two pieces into one, which lowers the overall cost of production and assembly.

From the gaskets and seals needed for commercial cooking equipment to the bottle dispensers and baking pans used in home kitchens, food-grade LSR possesses the purity, strength, and stress resistance necessary to build kitchen goods.

LSR material made mostly of silica is appropriate for general-purpose applications that need fundamental physical characteristics. This material often possesses mid-properties in terms of temperature resistance, rip strength, percent elongation, solvent resistance, and other qualities.

Key Takeaways

LSR is frequently more expensive than other materials, which makes it initially challenging to choose it as your preferred material. However, compared to plastics and HCR, LSR provides producers with significant advantages, particularly those that fabricate high-volume parts.

The advantages of LSR as a raw material readily justify its usage despite the initial higher cost since producers can complete lengthy production runs with less effort. In addition, it is feasible to make the process run almost entirely automatically; one person may take care of and maintain many liquid injection molding machines.

LSR is the best material option for your production needs because of this cost-saving element, which is crucial for manufacturers due to improved process efficiency and the rise in labor expenses.

Despite apparent drawbacks, LSR offers manufacturers cost-effectiveness and consistency for various applications, including automotive, medical, baby care, electronics, and consumer goods.