LSR Molding Energy Consumption & Cost per Part

How much energy does an LSR injection molding machine use?

A mid-size LSR machine (about 1,000-1,600 kN clamping force) draws roughly 7-15 kW of real power in steady production. Standard fixed-pump hydraulic machines average around 10 kWh per hour, while servo-hydraulic machines average closer to 7 kWh per hour for comparable output. The difference comes from how the pump behaves: in a conventional hydraulic machine the pump runs at full speed even when no motion is required, so real draw sits near 60% of installed motor power. A servo machine varies pump speed to demand, pulling closer to 40% of motor power. In practice servo and all-electric LSR machines save 30-50% of drive energy over the duty cycle.

LSR adds one energy factor that thermoplastics do not have: the mold is heated, not cooled. LSR cures in a hot mold (typically 160-200 C), so cartridge or plate heaters add a continuous thermal load, while the barrel and metering section are kept cool. On small, thin-wall parts this heater load can rival the drive load, which is why mold insulation and platen heat shields matter for energy cost.

How do you calculate LSR cost per part?

Cost per part is the sum of material, machine (energy + depreciation), labor, tooling amortization, and scrap, divided by good parts. Energy per part is the simplest piece: multiply machine power (kW) by cycle time (hours) and electricity price, then divide by cavity count. A worked example makes the scale clear.

Worked example: a servo LSR machine drawing 8 kW real power, 30-second cycle, 4 cavities, at USD 0.12/kWh. Energy per cycle = 8 kW x (30/3600) h = 0.0667 kWh. That cycle yields 4 parts, so energy = 0.0667 / 4 = 0.0167 kWh per part, or about USD 0.002 per part. Even at a high 20-second cycle on a single cavity, energy rarely exceeds a few tenths of a US cent per small part.

The takeaway: chasing energy alone is a small lever. A cold-runner mold that eliminates sprue waste, a stable process that lifts yield from 92% to 98%, and automation that removes an operator each move the cost per part far more than a 1 kW drive improvement.

Why does servo and all-electric drive pay back?

Servo drives pay back through energy, but also through heat, precision, and maintenance. Because hydraulics account for 75-80% of energy in a conventional machine and generate waste heat, cutting pump losses reduces both the power bill and the plant cooling load. Servo and electric drives also hold injection speed and metering more repeatably, which improves LSR shot-to-shot consistency and yield - the larger cost lever above. Lower oil throughput means less hydraulic maintenance too.

A simple payback rule: at 6,000 running hours per year and USD 0.12/kWh, saving 3 kW of average draw is about 18,000 kWh or roughly USD 2,160 per year per machine. Multiply across a shop of machines and the servo premium is usually recovered in 1-3 years, before counting yield and cooling gains.

How do you reduce LSR molding energy and cost in practice?

The highest-return moves combine equipment, tooling, and process. TYM configures LSR machines and full production cells around these levers so buyers optimize total cost, not just nameplate power.

• Specify servo or all-electric drives for any line above ~3,000 annual hours - the energy and yield gains compound.
• Use a cold-runner (cold-deck) mold to eliminate cured sprue/runner scrap; this cuts the largest cost element (material) directly.
• Insulate the mold and add platen heat shields to reduce continuous heater load on hot LSR tools.
• Right-size tonnage: an oversized clamp wastes idle drive energy; size to projected area x cavity pressure with a safety margin.
• Automate demolding and quality inspection to raise the operator-to-machine ratio and stabilize yield.
• Optimize cycle: vacuum-assisted venting and correct cure profiles shorten cure time, cutting both energy and per-part cost.

FAQs

Q: How much electricity does an LSR injection molding machine use per hour?

A: A mid-size LSR machine typically uses 7-15 kWh per hour of real power. Servo-hydraulic machines average around 7 kWh/hour and fixed-pump hydraulics around 10 kWh/hour for similar output. LSR mold heating adds a continuous thermal load on top of drive power, which is significant on small, thin-wall parts.

Q: Is energy a big part of LSR part cost?

A: No. Energy is usually only 8-15% of the total cost per part. Silicone material (40-60%), labor and automation, and tooling amortization dominate. That is why yield improvement, cold-runner material savings, and automation deliver larger cost reductions than drive efficiency alone.

Q: Do servo LSR machines really save energy?

A: Yes. Servo drives vary pump speed to demand instead of running at full speed continuously, cutting drive energy by roughly 30-50% over the duty cycle. They also reduce waste heat and improve process repeatability, which lifts yield. Typical payback on the servo premium is one to three years at normal utilization.

Q: How do I estimate cost per part for a silicone molded part?

A: Add material, machine (energy plus depreciation), labor or automation, tooling amortization, and scrap, then divide by good parts. Energy per part = machine kW x cycle hours x electricity price, divided by cavities. For most small LSR parts, energy is a fraction of a US cent, so focus the model on material, cycle time, and yield.

Q: All-electric vs servo-hydraulic for LSR - which is more efficient?

A: All-electric machines are generally the most efficient, drawing about 55-65% of a conventional hydraulic baseline, versus 65-70% for servo-hydraulic. Electric machines suit precision, cleanroom, and high-uptime medical work. Servo-hydraulic remains the practical choice for most 2026 LSR production, balancing efficiency, clamp force, and cost.