HTV vs LSR Silicone: Which Molding Process Fits Your Parts?

HTV (solid silicone) is molded by compression or transfer — best for O-rings, gaskets, and low-to-medium volumes.

LSR (liquid silicone) is injection molded — best for small, complex, high-volume parts.

Neither is “better.” The right one depends on your part design and quantity.

What Are HTV and LSR?

Both are real silicone rubber. The difference is the form of the material and how it is molded.

After curing, both can meet the same standards — FDA, USP Class VI, and the same temperature range.

HTV / HCR: Solid Silicone Molding

HTV is supplied as solid compound. We mold it by:

• Compression molding — place a pre-formed rubber blank in the mold, close, heat, done
• Transfer molding — rubber is pushed into the mold cavity under pressure
• Extrusion — for tubing, strips, and cord (not molded parts)

Best for:

• O-rings, flat gaskets, simple to medium shapes
• Low to medium volumes (samples to tens of thousands)
• Larger parts (LSR machines have shot-size limits)
• Lower tooling budgets

Limits:

• Slower cycle time
• More manual handling (flash removal, deflashing)
• Less suitable for very small or very complex parts

LSR: Liquid Silicone Injection Molding

LSR is pumped as two liquids, mixed at the machine, and injected into a heated mold where it cures in seconds to minutes.

Best for:

• High volumes (hundreds of thousands and up)
• Small, precise, complex parts — thin walls, fine details, overmolding
• Medical and baby products — the process is closed and very clean
• Tight tolerances and high consistency, part after part

Limits:

• Higher tooling cost (cold-runner injection molds)
• Longer mold lead time
• Not economical for small quantities
• Very large parts may exceed machine shot size

HTV vs LSR: Quick Comparison

Cost: Where Is the Break-Even Point?

There is no single number, but the logic is simple:

As quantity grows, the LSR mold cost is spread over more parts. Somewhere — often between 50K and 200K parts — LSR becomes cheaper in total.

Tips from ZSR: Do not choose the process by unit price alone. Ask for both quotes with tooling included, over your expected annual quantity. We provide this comparison free with your inquiry.

Quality: Is LSR “Better”?

Not automatically. A well-made HTV part and an LSR part can meet the same drawing and the same FDA or USP requirement.

LSR wins on consistency and cleanliness at scale: closed material handling, no manual blank preparation, very low contamination risk. That is why medical and baby products usually go LSR.

HTV wins on flexibility: fast samples, low MOQs, easy material changes (VMQ, FVMQ, different hardness) without big tooling commitments.

How to Choose: Three Questions

Advice from ZSR: Start with HTV for prototyping and market testing. When your design is frozen and volume is proven, we can quote an LSR mold for scale-up. Many of our customers follow exactly this path.

Related reading: What Is VMQ Silicone Rubber? | Platinum-Cured vs Peroxide-Cured Silicone