The fast-growing medical device industry (8.3% annual growth until 2030) needs safer materials to survive strong sterilization methods. Recent product recalls in the healthcare field have pushed manufacturers to adopt better materials like injection molding of liquid silicone rubber.
Unlike regular rubber materials, this special silicone has a unique chemical structure that naturally resists heat damage and chemical reactions. Its advanced manufacturing process allows the creation of extremely small medical parts that were unachievable before. These technical advantages make it ideal for producing precision components in medical tools, protective equipment, and scientific instruments. Let’s take a closer look at this precision process.
LSR Injection Molding Definition
LSR injection molding is a modern method where liquid silicone gets shaped in special molds. Compared to older methods, this technique creates products with smoother surfaces and more exact sizes because the liquid silicone fills molds completely and hardens quickly. This special silicone material performs well in extreme temperatures, blocks electricity safely, and works with human tissues – making it perfect for medical devices, electronics, and industrial equipment manufacturing.
How does Liquid Silicone Rubber Injection Molding Work?
1. Material Preparation
First, we need two parts: Part A and Part B.
• Part A is like a thick liquid (they call it “base polymer”). Part B has special chemicals to make it hard (called crosslinker).
• Before mixing, we must stir both parts very well. Why? Because if we don’t mix them properly, the chemical reactions won’t work evenly. Imagine making cake batter with lumps — it’s the same problem.
2. Mixing Process
Now, mix Part A and Part B in exact ratio. Usually 1:1, but sometimes different.
• The ratio is super important. If you add too much Part A, the silicone stays sticky. If too much Part B, it hardens too fast. Like cooking rice — wrong water amount makes it mushy or burnt.
• While mixing, avoid bubbles! Bubbles make the final product weak. How? Mix slowly or use vacuum machines to suck out air.
3. Injection Molding
Put the mixed liquid into a mold with liquid silicone rubber injection molding.
• Molds are usually metal (steel or aluminum). The shape must be perfect — even a 0.1mm error can ruin the product.
• Control temperature (120–180°C) and pressure. If the temperature is low, the silicone won’t cure. If the pressure is too high, the mold breaks. It’s like baking cookies — too hot burns them, too cold makes them raw.
4. Post-Processing
After taking it out from the mold, do the extra steps:
• Vulcanization: Heat the product again. This makes it stronger, like turning soft clay into hard ceramic.
• Trimming: Cut off extra edges (“flashing”) with tools. Makes it look neat, like trimming fingernails.
• Quality Check: Look for bubbles, wrong shapes, or color problems. Throw away bad ones — no one wants a phone case with holes.
Key Tips for Better Results
1. Measure twice, mix once
Always check the A/B ratio with digital scales. One student forgot this and made sticky silicone earplugs — they stuck to people’s ears
2. Slow mixing = fewer bubbles
Use a machine mixer at 200 RPM (rotations per minute). Hand mixing takes 15 minutes and makes the arm tired.
3. Mold design matters
A good mold has tiny vents for air to escape. Bad molds trap air — products look like Swiss cheese.
4. Temperature control trick
Use an infrared thermometer to check mold temperature. If no thermometer, wait 2 minutes after heating before injection.
Advantages of Liquid Silicone Rubber Injection Molding Machines
1. High Production Efficiency
Injection molding machines work very fast. They can make many products at the same time in one cycle. Because the machines work by themselves (automation), workers don’t need to do much. For example, some machines use robots to take out finished products automatically. This saves time and allows factories to produce more items every day.
2. Stable Product Quality
These machines control temperature, pressure, and time very carefully. Sensors check everything automatically. If something is wrong, the machine will stop and show a warning light. This means all products look the same and meet the required standards. For medical parts or phone cases, this precision is super important.
3. Low Production Costs
The main material is thermoplastic pellets, which are cheap and easy to buy. Even better, leftover plastic can be melted and reused. Factories save money because they don’t waste materials. Also, machines run 24/7 with few workers, so labor costs stay low.
4. High Precision Manufacturing
By adjusting machine settings, workers can control product size and weight very accurately. Some machines make parts with 0.01mm precision—like the thickness of a hair! This is perfect for making tiny gears in watches or connectors for computers. Even complex shapes come out exactly right every time.
5. Environmentally Friendly
Plastic pellets don’t create dust or dirty water like metal cutting does. Modern machines also use filters to clean smoke and gases before releasing them. Many factories now recycle 90% of their plastic waste. This helps protect the environment and follows green production rules.
6. Wide Application Range
You can make almost any plastic product with these machines. Small items like toy bricks, medium things like kitchen containers, and large parts like car dashboards—all are possible. Different molds let one machine produce phone cases today and medical tools tomorrow.
Applications of Liquid Silicone Rubber (LSR) Injection Molding
1. Medical Industry Applications
Liquid silicone rubber is perfect for medical tools and parts because of its special properties.
• Why it works: It can handle high heat (like sterilization) and kill bacteria, making it safe for hospitals.
• Common products:
◦ Seals for medical devices (e.g., syringe stoppers)
◦ Tubes for IV drips and catheters
◦ Soft parts for artificial organs (e.g., heart valves)
◦ Baby products like bottles and pacifiers (no harmful chemicals, easy to clean)
• Bonus: Doctors trust it because it meets strict safety rules (like FDA standards).
2. Electronics Industry Uses
LSR keeps electronics safe and working longer.
• Key features:
◦ Stays stable in extreme temperatures (-50°C to 200°C)
◦ Blocks electricity (good insulation)
• Examples:
◦ Seals for phone/tablet ports (e.g., waterproof SIM card trays)
◦ Protective layers on cables and circuit boards
◦ Soft touchscreens that resist scratches (like phone screens)
• How it helps: Phones last longer even in rain or heat.
3. Automotive Parts Manufacturing
Cars rely on LSR for tough conditions under the hood.
• Why cars need it:
◦ Handles engine heat (up to 180°C)
◦ Stays flexible in cold weather
• Typical parts:
◦ Wiper blades and waterproof seals (no leaks)
◦ Engine gaskets and air filters
◦ Fuel lines and hydraulic hoses
• Special use: It bonds with metal/plastic parts in one step, saving time.
4. Household Products
LSR makes daily items safer and comfier.
• Why families love it:
◦ Soft texture (like silicone spatulas)
◦ Safe for food and babies (no toxins)
• Products you might use:
◦ Kitchen tools (heat-resistant baking molds)
◦ Baby teething toys and bottle nipples
◦ Durable phone cases and remote buttons
• Design trick: Its moldable nature allows creative shapes (e.g., animal-shaped toys)
Best LSR Injection Molding Service Provider
The products made by the LSR injection molding process have the characteristics of low-compression permanent deformation. This means that they can quickly return to their original shape after being subjected to external forces, without permanent deformation. This feature enables LSR molded parts to maintain stable performance over a wide temperature range, making them ideal for automotive parts in extreme environments.
In industries such as automotive and medical manufacturing, where every micron counts, finding a partner that can provide reliable, high-quality injection molds, such as Fecision, is critical. Fecision focuses on advanced engineering, flexibility, and customer-centric solutions that can be trusted.
Why choose Fecision?
1. Decades of experience, global standards
With more than 20 years of industry experience, they have honed their expertise in a variety of sectors, from automotive to consumer electronics. Their processes meet the most stringent quality benchmarks. The Fecision team offers solutions that pass rigorous durability tests thanks to their deep understanding of material properties and thermal stability.
2. Cutting-edge technology, unparalleled precision
Precision is not just a buzzword here. In Fecision’s workshop, we can achieve tolerances of ±0.005 mm thinner than human hair. This level of accuracy is critical for components such as medical device housings or automotive sensor assemblies, where even minor defects can lead to failure.
3. Uncompromising flexibility
Whether you’re testing prototypes or mass-producing, Fecision has everything you need. Their rapid tooling service can complete functional prototypes in 15-20 days, helping companies iterate quickly on designs. In terms of production, Fecision’s molds are durable and support more than 1 million high-volume order cycles, making them ideal for automotive customers who need a stable production rate.
4. Smarter quality control
They used a real-time monitoring system and 3D scanning to check the molds at each stage. Before cutting steel, their engineers provide a free manufacturability design report, flagging issues such as uneven wall thickness or faulty gate placement.
5. Material technology
From ABS and nylon to advanced polymers such as PEEK and LSR, Fecision’s molds can handle it all. Their engineers help customers choose materials that balance performance and cost.
Ready to work with Fecision? If you need a mold that combines precision, durability, and affordability, Fecision is your choice. Their team works closely with customers to bring ideas to life, whether you’re building 100 prototypes or 10 million parts. Click now to visit and explore their services.
