Should your part be liquid silicone rubber (LSR) or solid (HTV) silicone? The answer is rarely "one is better" — it depends on your volume, precision, cleanliness and tooling budget. This guide breaks down the real trade-offs so you can have an informed conversation with your manufacturer.
What the Two Processes Are
- Solid silicone (HTV) — a solid, dough-like compound is placed into a compression, transfer or injection mold and cured under heat and pressure. The classic, lower-capital route.
- Liquid silicone (LSR) — a two-part platinum-cured liquid is pumped into a closed mold and cured in place, often with automated dosing and closed-loop control.
Head-to-Head Comparison
| Factor | Solid Silicone (HTV) | Liquid Silicone (LSR) |
|---|---|---|
| Tooling cost | Generally lower — simpler, lower-pressure molds | Generally higher — precision, tight-tolerance, often cold-runner molds |
| Piece price at high volume | Higher — longer cycle times, more handling | Lower — fast cycles, high automation, less labor |
| Cycle time | Minutes (longer cure) | Seconds to low minutes (fast cure) |
| Precision & repeatability | Good, depends on operator | Excellent — closed-loop, highly repeatable |
| Cleanliness / purity | Good (platinum or peroxide cure) | Excellent — platinum-cured, low extractables, cleanroom-friendly |
| Part complexity | Handles simple to moderate geometry | Handles thin walls, micro features, multi-shot |
| Best volume | Low-to-medium, prototyping | Medium-to-very-high volume |
| Hardness range | Very wide | Wide, commonly Shore A 10–70 |
The Cost Crossover
The economics usually look like this: LSR has a higher upfront tooling investment but a lower piece price once the mold is running. That means there is a volume crossover point below which solid silicone wins on total cost, and above which LSR wins. The crossover depends on part size, cavity count and automation, so it is specific to each project — but as a rule of thumb, LSR's advantage grows the higher your annual volume goes.
When to Choose Solid Silicone
- Low-to-medium volume, or frequent design changes and prototyping.
- Very large or thick parts where LSR's fast cure and dosing offer less advantage.
- When tooling budget is the binding constraint and cycle time is not.
- Wider hardness or special-compound requirements that are easier to meet in solid form.
When to Choose LSR
- High-volume parts where piece price and cycle time dominate.
- Medical, baby-care and food-contact parts needing low extractables and cleanroom molding.
- Thin walls, micro-features, tight tolerances or multi-shot / overmolded designs.
- Applications where consistency across millions of shots is critical.
How CYES SILICONE Supports Both
We run both solid-silicone (compression, transfer and injection) and liquid-silicone (LSR) molding in-house, across Shore A 20–80, so we can recommend the process on cost and performance rather than on what we happen to own. During DFM we will compare tooling, cycle time and piece-price implications for your specific part and volume, then let you decide. See our LSR components page, our custom molding page and our LSR process parameters guide for more detail.