Injection Molding Cost Guide — What Drives Your Quote
Cost & Quoting
What an injection molding quote actually includes
When buyers ask “how much does injection molding cost”, the answer is two numbers, not one: the mold cost (one-time tooling) and the part cost (per piece, recurring). A proper injection molding quote separates these so you can see where the money goes.
Tooling is the upfront investment — design, steel, machining and trial shots. Part cost covers resin, machine time, labor and inspection. Confusing the two is the most common reason a “cheap” quote turns expensive later.
The Snapshot
- Two cost pools: mold cost (one-time, scaled by cavitation/steel) and part cost (recurring, set by resin + cycle + volume).
- Resin is the recurring driver: ABS ~$1.5–3/kg vs PEEK ~$50–100/kg — at 5M units/year that spread dwarfs any mold-price difference.
- Cycle time sets throughput: a 30 s cycle on an 8-cavity tool makes 960 parts/hour; halve the cycle, double output.
- Volume breaks the curve: below 100K/yr soft tool wins; above >500K/yr hardened multi-cavity steel pays back.
Mold cost — what changes the price
Mold price scales with complexity: cavity count, sliders, inserts, tolerance and steel grade. A single-cavity pre-hardened mold for a simple clip costs far less than a multi-cavity hardened tool with hot runner and side actions.
Rule-of-thumb cavity multipliers (single-cavity = 1×):
| Cavities | Relative mold cost | Best for |
|---|---|---|
| 1 | 1× | Validation, <100K/yr |
| 2–4 | ~1.8–3× | Bridge, 100K–500K/yr |
| 8 | ~3.5–5× | Production, >500K/yr |
| 16–32 | ~5–8× | High-volume, >2M/yr |
We run DFM analysis before any steel is cut, so the mold cost you are quoted reflects a manufacturable design — not a number that blows up after the first trial shot. Reference lead times from our programs: rapid tooling 3–5 weeks, production hardened tool 8–12 weeks (a 5M units/year button tool: 12 weeks; a 2M units/year connector tool: 10 weeks).
Part cost — resin, cycle time and volume
Per-part cost is dominated by material and cycle time. Engineering resins (PEEK, PC, PA) cost more per kg than commodity ABS or PP. Cycle time depends on wall thickness, part size and cooling — and it decides how many parts a machine makes per hour.
Higher volume spreads tooling across more pieces, dropping effective unit cost. That is why low-volume bridge tooling and full production tooling are quoted on different curves.
For the same tool, part cost falls fast as volume rises while tooling amortization dominates; at full production volume the curve flattens toward pure resin and machine cost.
Resin cost per kg by grade
Resin is the recurring cost driver at volume. Typical spot ranges:
| Material | Typical price (USD/kg) | Note |
|---|---|---|
| PP / PS | $1–2.5 | Commodity |
| ABS | $1.5–3 | Commodity |
| PC / POM / PBT | $3–5 | Engineering |
| PA66 | $3–6 | Engineering |
| PPS | $8–15 | High-temp |
| TPU / LSR | $3–30 | Flexible / silicone |
| PEEK | $50–100 | High-performance |
At 5M units/year in a 5 g part, ABS resin runs roughly $40–80 per 1,000 parts; the same part in PEEK runs $1,300–2,600 per 1,000. The mold is a one-time cost; resin is forever. A VR remote in PC+ABS / TPE at 800K units/year kept resin in the commodity band and still hit ±0.04 mm.
Cycle time, cavitation and machine tonnage
Cycle time decides throughput and machine cost per part. A typical small-part cycle runs 15–60 s depending on wall thickness and cooling. Cavitation multiplies output:
- 1 cavity at 30 s → 120 parts/hour
- 8 cavities at 30 s → 960 parts/hour
- 16 cavities at 30 s → 1,920 parts/hour
At 20 s the same 8-cavity tool makes 1,440 parts/hour — cycle-time reduction is free capacity.
The automotive connector ran glass-filled PPS / PA66 at 2M units/year — viable only on multi-cavity hardened tooling with tight process control (Cpk ≥ 1.33, IATF 16949). Cavitation is where production tooling earns its keep.
Clamp force (tonnes) scales with projected area and resin pressure. Rough guide:
| Part projected area | Clamp force | Typical resin |
|---|---|---|
| < 50 cm² | 50–150 T | ABS, PP, PC |
| 50–200 cm² | 150–400 T | PA, POM, PPS |
| 200–600 cm² | 400–1000 T | PEEK, glass-filled |
| > 600 cm² | 1000 T+ | Large housings |
Tonnage sets the hourly machine rate — part of recurring part cost alongside resin and cycle time.
Tooling strategy vs volume curve
| Tier | Lead time | Cavities | Best volume | Per-part cost |
|---|---|---|---|---|
| Rapid (soft) | 3–5 weeks | 1 | Validation / <100K | High |
| Bridge | 6–10 weeks | 1–4 | 100K–500K | Medium |
| Production (hardened) | 8–12 weeks | 4–32+ | >500K | Low |
Lead time overlap (bridge 6–10 vs production 8–12 weeks) is normal — production includes more steel machining and full PPAP documentation, not just a longer clock.
How to reduce total cost without losing quality
Optimize for total cost of ownership, not unit price alone:
- Adjust wall thickness — thinner walls cut resin per part and cycle time (within fill limits).
- Pick the right resin grade — spec ABS where PEEK is not justified; the VR remote ran PC+ABS / TPE at ±0.04 mm, 800K units/year, no premium resin needed.
- Match tooling to real volume — don’t buy hardened steel for a 100K pilot.
- Tighten only critical tolerances — specifying ±0.05 mm on a non-locating rib inflates cost 20–40% with zero gain; put the tight number where the part seals or locates (the connector earned ±0.005 mm only on critical features).
- Right-size cavitation — 8 cavities beats 1 cavity at >500K/yr, but 32 cavities is wasted below 2M/yr.
A small DFM change often saves more across a run than squeezing the hourly rate.
Hidden costs to ask about
- Inserts / overmolding: a medical ECG button in LSR and a VR remote in TPE overmold add process steps — budget for them.
- Secondary operations: degating, painting, pad-printing, ultrasonic welding.
- Revisions: in-house tooling keeps revision cost low; outsourced tooling multiplies it.
- Qualification: PPAP / IMDS documentation for automotive adds engineering hours but is non-negotiable for Tier-1.
Get a transparent quote
Upload your 3D file and we return a quote that shows mold cost, material, cycle time and recommended tooling path — with manufacturability risks flagged up front and no surprise line items at qualification.