When LSR Injection Molding is a Better Choice for Your Project?

LSR Injection Mold also known as Liquid Injection Mold (LIM), Silicone Injection Molding, LSR Mold, Liquid  Silicone Mold, Liquid  Silicone Injection Mold, which is an advanced mold processing compared to traditional Rubber Compression Molding, and is an ideal process for many silicone parts and components with complex geometry, high precision dimension requirement and high safety material request. Liquid Injection Mould has significant advantages in flexible tooling design, excellent liquid silicon rubber properties, high production efficiency & safe closed production environment and tight tolerance/precision, LSR 2-Shot (2K) or LSR Multi-Shot injection molding (also known as LSR overmolding), etc. 

Liquid Silicone Inejection Molding is much expensive than compression molding, but why we will suggest customers to choose liquid silicone rubber injetion molding for production? Let's move forward to following situations for details:

Situation 1:

Complicated Structure/Design

When the silicone parts is complicated with complex geometry, can not demold by compression molding, or the product will not have good quality and function by compression, we will suggest customers to choose Liquid Silicon Injection Molding as the first choice. For example, one of our customers liquid silicone bellows that is used for sticker label on fruit, and with side holes and undercuts in the top, which is important structure for the silicone bellow, as the air outlet from pneumatic system to stick label on fruit. If there are rubber flashings in the holes, the air can not go through smoothly will affect the suction and the sticker label can not stick on fruit successfully.

Liquid Silicone Injection Molded Silicone Bellow can achieve flashless on the holes and holes can directly demolded. By compression molding, the holes is difficult to demold, need to decutting by die cutting tool, which can not locate the holes well and also will have some rubber flashings on the holes.

Liquid Injection Mold Complex Design- undercut

For silicone bellow with undercut, especially the undercuts in the inside of product, which is a difficult manufactuability and moldability point. During design analysis, Engineers need take this technological difficulity into consideration, then achieve feasibility and the easiest demolding during production. The liquid silicone rubber material used for Silicone Injection Molding has excellent physical properties, such as high tensile strength and elongation, etc. 

Therefore, For the low undercuts, we can eject component from mold directly without any special mold structure. For many products involving high undercuts, draft angle is usually no need to consider, but tend to choose middle-plate or slider & splits structure for achieving demoulding.

Situation 2:

Small  Wall Thickness Products

 When the wall thickness is less than 0.5mm, the compression molding can not suitable for production. Usually the maxium wall thickness that moving core can achieve is 0.5mm.

Liquid Silicone Rubber Injection Molding with feeding system to fill the cavities automatically, and not not need to place material by hand, so for the bellows/suction cups with small thickness and have strict requirement for the wall thickness, LSR injection Molding is a better choice. By compression molding, the wall thickness may be uneven and offset, especially when workers did not place the material well. And for small wall thickness product, which is difficult to demold, and the mold core will be damaged easily during demolding. Silicone Injection Molding, the mold core usually with S136 Heat Treatment that will have longer mold life.

Situation 3:

Tight Tolerance

For compression molding, the tightest tolerance of the wall thickness we can achieve by using good quality metal steel is ±0.1mm, if the required tolerance is 0.05mm, we have to choose LSR Injection Molding. And even for some High Precision LSR Seal, Silicone Gasket and Sealings that need tight tolerance (±0.01mm to ±0.03mm), Silicone Injection Molding is the only choice. Liquid Silicone Rubber Injection Mold has better clamp force, and the upper and lower molds clamp better than compression molding. Plus the feeding system and needle valve to control the material amount preciserly, so liquid injection molded parts will with tighter tolerance.

Situation 4:

High Safety Material Demands

For medical accessories such as Medical grade CPAP Full Face Mask, CPAP Nasal Mask, and Baby Care products that need medical grade required approvals, such as FDA10993,UPS Class VI, BFR XV, FDA 21 CFR 177.2600 etc will choose LSR& liquid silicone rubber as material by Liquid Injection Mold.

Liquid Silicone Rubber a high-purity and non toxic materials with lower compression set, lower outgassing, high heat resistance (working temperature: -40°C ~ 230°C), good tensile strength and tear resistace. LSR is a kind of clean, plasticizer-free, tasteless, odorless and can proof water, resist oxidation and some chemical materials like acids and alkali.

EL LR3003.pdf

3003-50BMSDS.pdf

3038-50 ISO10993-10.pdf

Situation 5:

Large Quantity, Semi-automatic Production, Automatic Production

Liquid Injection Molding’s Cold Runner system plays the same role as Hot Runner system for Plastic Injection Molding. Cold runner system of Liquid Injection Mold keeps the liquid silicone cold until the Liquid Silicone Rubber inject into the hot cavities of the mold. So cold runner system can save a lot of material. Reduce waste.

Liquid silicone Injection molding is a closed loop system and molded under pressure by computer controlled repeatable equipment. Which is high efficient, and can save manpower, is suitbale for mass production.

Liquid Silicone Injection mold has higher production efficiency. Do not need work to place material anymore, and cycle time is shorter.