Between 500 and 10,000 units, six manufacturing paths compete: powder-bed 3D printing, urethane casting, CNC machining, pressure-formed thermoforming, aluminum bridge tooling, and low-cavitation soft steel tooling. Bridge tooling wins most of the time. A $7,000 aluminum single-cavity mold with an $0.85 piece price costs $7,850 for a thousand parts. A $26,000 production steel tool costs $26,620 for the same thousand. Printing the same part costs $16,000 to $22,000.
The reason inventors overspend here is that they compare printing to production tooling and never look at the four options in between.
The Six Paths at a Glance
| Method | Tooling cost | Per-part cost | Lead time | Viable volume |
|---|---|---|---|---|
| MJF / SLS printing | $0 | $8 to $60 | 3 to 7 days | 1 to 1,000 |
| Urethane casting | $800 to $2,500 per silicone mold | $25 to $150 all-in | 1 to 2 weeks | 25 to 500 |
| CNC machining | $200 to $800 setup | $60 to $400 | 1 to 3 weeks | 1 to 300 |
| Pressure-formed thermoforming | $3,000 to $15,000 | $6 to $45 | 4 to 7 weeks | 250 to 10,000 |
| Aluminum bridge tool | $3,000 to $9,000 | $0.60 to $2.00 | 3 to 5 weeks | 500 to 10,000 |
| Low-cavitation soft steel tool | $9,000 to $18,000 | $0.55 to $1.60 | 7 to 11 weeks | 5,000 to 100,000 |
Every one of these is the correct answer somewhere. The trick is matching the method to your volume band, your part size, and how confident you are that the design is finished.
Printing: MJF and SLS
Powder-bed nylon printing has no tooling cost, produces isotropic parts with usable mechanical properties, and turns a file into parts in under a week. PA12 parts reach roughly 80% to 95% of injection-molded PA12 tensile strength.
Where it wins: the first 50 to 500 units, sales samples, regulatory submission units, and any part still under active revision. Also geometry that cannot be molded: internal lattices, enclosed voids, conformal channels.
Where it loses: cost per part flattens rather than dropping. Going from 100 units to 1,000 units cuts the price maybe 25%. Molding cuts it 95%. Surface finish is matte and slightly porous. Dyed black is standard; other colors require post-processing that costs $2 to $8 per part.
Real numbers: a 42-gram housing runs $22 per part at 100 units and $16 at 1,000. A thousand parts is $16,000, which buys two bridge tools.
The full comparison against production molding is worked out in 3D printing vs injection molding.
The Sub-500 Methods: Urethane Casting and CNC Machining
Urethane casting.
Also called vacuum casting or silicone tooling. A master pattern gets 3D printed and finished, a silicone mold is poured around it, and urethane resin is cast into the silicone under vacuum.
Economics: the silicone mold costs $800 to $2,500 depending on part size and survives 20 to 25 pulls before edge definition degrades. All-in per part, including mold amortization, lands at $25 to $150 for a mid-size part.
Where it wins: 25 to 500 units where you need molded-looking surfaces, real color throughout the part, overmolded soft-touch grips, or clear parts. Urethane systems mimic ABS, PP, and rubbers from 30A to 90A Shore. Lead time is 5 to 10 business days after the pattern exists.
Where it loses: dimensional consistency drifts across the mold’s life, silicone molds have tolerances near ±0.3 mm, and the material properties are approximations rather than the real polymer. Not a production process past about 500 units.
CNC machining.
The other sub-500 method cuts the part from solid stock. No tooling in the mold sense, just fixturing and programming.
Economics: setup and programming run $200 to $800. A machined plastic housing costs $60 to $400 per part depending on how much material has to come off and how many setups it needs.
Where it wins: metal parts, optically clear polycarbonate parts that need diamond-polished surfaces, parts requiring tolerances tighter than ±0.05 mm, and quantities under 100 where you need real material properties immediately.
Where it loses: cost barely improves with quantity. Internal geometry that a mold produces for free, like an undercut snap or a thin internal rib, may be unmachinable. Housings with deep pockets and thin walls cost a fortune in cycle time.
Pressure-Formed Thermoforming
Overlooked and often the right answer for large, thin-wall enclosures. A heated plastic sheet is formed over a tool with vacuum and positive air pressure, then trimmed on a CNC router.
Economics: a pressure-forming tool costs $3,000 to $15,000, against $40,000 to $120,000 for an injection tool on a part that size. Per-part cost runs $6 to $45. Lead time is 4 to 7 weeks.
Where it wins: enclosures larger than about 300 mm in any dimension, medical cart housings, kiosk panels, equipment covers, at 250 to 10,000 units a year. Pressure forming holds texture and sharp detail well enough for cosmetic surfaces.
Where it loses: single-sided geometry only. No bosses, no ribs, no snap features molded in. Wall thickness varies across the draw. Anything requiring precise two-sided features needs injection molding.
Aluminum Bridge Tooling and Soft Steel Tools
Aluminum bridge tooling.
The workhorse of low-volume plastics. A single-cavity aluminum mold, built in 3 to 5 weeks, good for 1,000 to 10,000 shots.
Economics: $3,000 to $9,000 for the tool. Piece price runs $0.60 to $2.00, higher than production because you are running one cavity on a smaller press with more setup per unit.
Where it wins: anywhere from 500 to 10,000 units. You get real molded material properties, real tolerances of ±0.10 mm, real surface finish, and a piece price low enough to support retail margins. You also get manufacturing data: cycle time, scrap rate, and gate behavior all transfer to the production tool design.
Where it loses: aluminum wears. Glass-filled resins chew it. Slides gall. Any tool action costs proportionally more on an aluminum tool than a steel one. Textured surfaces do not hold up past a few thousand shots.
The strategic case: run 5,000 units off a bridge tool, sell them, and cut production steel from a design informed by what customers complained about. The alternative is committing $30,000 to steel around assumptions. Bridge tooling is the cheapest way to buy a year of market information, and it is how most disciplined teams handle the transition from prototype to manufacturing.
Low-cavitation soft steel tooling.
The next step up is a single or two-cavity P20 tool, sometimes built into a Master Unit Die frame the molder already owns so you only pay for the insert.
Economics: a full soft steel tool runs $9,000 to $18,000. A MUD insert runs $2,500 to $7,000 because you are not paying for the mold base. Rated life is 100,000 to 300,000 shots.
Where it wins: 5,000 to 100,000 units a year, or any volume where the resin is abrasive enough that aluminum will not survive. It is the natural next step after a bridge tool proves the market.
Where it loses: lead time of 7 to 11 weeks and a cost that starts to rival a real production tool. Above 100,000 units a year, higher cavitation pays back and this becomes the wrong tool.
The full range of tool classes, steel specs, and cavity-count economics sits in injection molding tooling cost.
Total Cost at Each Volume
Same 42-gram ABS housing, four methods, total spend including tooling:
| Units | MJF printing | Urethane casting | Bridge tool ($7,000 + $0.85) | Production tool ($26,000 + $0.62) |
|---|---|---|---|---|
| 250 | $5,250 | $11,500 | $7,213 | $26,155 |
| 500 | $9,500 | $21,000 | $7,425 | $26,310 |
| 1,000 | $16,000 | n/a | $7,850 | $26,620 |
| 2,500 | $38,000 | n/a | $9,125 | $27,550 |
| 5,000 | $75,000 | n/a | $11,250 | $29,100 |
| 10,000 | $145,000 | n/a | $15,500 | $32,200 |
| 25,000 | n/a | n/a | tool life exceeded | $41,500 |
Bridge tooling is the lowest total cost from about 400 units all the way to 10,000. That band covers the entire first two years of most independent-inventor products, and it is the band where the most money gets wasted in both directions: printing too long on one side, tooling too early on the other.
Choosing by Volume Band
Under 100 units: print or machine. Tooling of any kind is not recoverable.
100 to 500 units: urethane casting if you need molded appearance and color, printing if you do not. Bridge tooling starts to compete at the top of this band.
500 to 10,000 units: bridge tooling, close to always. Pressure forming instead if the part is a large thin-wall enclosure.
10,000 to 50,000 units: low-cavitation soft steel. Run the payback against a bridge tool and a production tool with your real numbers.
Over 50,000 units: production steel, multi-cavity. At that point the piece price arithmetic in what injection molding costs governs everything.
Two mistakes account for most of the money wasted in this band.
Tooling before the design is frozen. A tooling change after steel is cut costs $800 to $12,000 and 2 to 6 weeks. If user testing is not finished, if the assembly has not been validated, if you have not shipped a hundred units to real customers and heard back, the design is not frozen. Bridge tooling exists so you can be wrong cheaply.
Printing past the crossover. The inventor who prints 4,000 units at $16 each spends $64,000 to avoid a $7,000 tool, usually because printing feels like no commitment. It is a $57,000 commitment paid in installments.
Both mistakes come from the same place: treating the tooling decision as a single binary choice instead of a sequence. Print 50, cast 200, bridge-tool 5,000, then cut steel. Each stage funds the next and each stage buys information the next one needs.
Before You Commit to Any of Them
Every one of these paths starts with sending your CAD to a vendor. Run a $399 patent search against the USPTO patent database before you do, so you know whether the mechanism is clear, and file a provisional if it is. Filing costs a small entity $130 to $325 and buys 12 months.
Then get real quotes on at least two of the six paths, because the ranges in this article are ranges and your part is a specific part. A quote package with a STEP file, a dimensioned drawing, a resin spec, and an annual volume takes an afternoon to assemble.
Enhance handles the method selection and vendor comparison inside engineering and prototyping, and where the tooling line falls relative to patent, design, and launch spend is laid out in the complete inventor cost breakdown. The U.S. Small Business Administration also runs free counseling and lending programs that inventors use to finance a first tooling buy.
FAQ
What is the cheapest way to injection mold a small quantity?
An aluminum bridge tool at $3,000 to $9,000, or a MUD insert at $2,500 to $7,000 if your molder has a compatible frame. Both give you real molded parts at a piece price under $2, and both are recoverable inside a few thousand units.
How many parts can I get from a silicone mold?
Twenty to twenty-five before edge definition and surface quality degrade. Beyond that you pour a new mold from the same master pattern, which costs $800 to $2,500 each time. That repeat cost is what makes urethane casting uneconomical past roughly 500 units.
Can I use a bridge tool for production and skip the steel tool?
If your annual volume stays under about 8,000 units and the resin is not abrasive, yes, and plenty of products live their whole life on aluminum. Order a spare cavity insert up front, because when the tool wears you want the replacement already sitting on a shelf rather than 6 weeks out.
What about overseas tooling for low volume?
Asian tooling runs 40% to 60% of domestic pricing, which sounds decisive on a $30,000 tool and matters much less on a $7,000 one. At low volume the freight, MOQ, and lead-time costs usually swamp the tooling savings. The full landed-cost math is in domestic vs overseas manufacturing.
Does the resin choice change which path I can use?
Yes. Glass-filled and flame-retardant resins destroy aluminum tools and are not available in urethane casting systems. Clear optical parts need either machining and polishing or a properly polished steel cavity. Pick the resin before you pick the process, because reversing that order is how tools get cut to the wrong shrink factor.