What it means
Traditional manufacturing is either subtractive, cutting material away, or formative, pushing material into a mould. Additive manufacturing reverses the idea by placing material only where the design needs it, one thin layer on top of another.
The main economic effect is that the mould, or tool, is no longer needed. Tooling for injection moulding can cost many thousands of dollars and take weeks, which locks a design in and makes small production runs expensive, whereas a printer starts from a file and a design change costs only an edit.
This is why most businesses first meet 3D printing in prototyping, where a team can hold a physical version of a part on the afternoon it is drawn. Unit economics run opposite to mass production: there is almost no setup cost but a slow time per part, so printing wins at small quantities and complex shapes while moulding wins at high volumes of simple parts.
Materials now include plastics, resins, metals and composites, and the choice of material drives the choice of machine. Desktop machines print polymer prototypes, while industrial machines print metal parts for demanding uses such as aircraft and medical implants.
Complex shapes such as internal lattices cost no more to print than simple ones, so designers can make parts lighter and stronger. Supply chains also change, because a spare part can be printed near where it is needed instead of being stored in a warehouse or shipped across the world.
The limits are real, though: surface finish often needs post-processing, volume production is slow and material properties can vary between machines, so regulated industries inspect and certify carefully. For a small business the entry cost is low, since an entry-level desktop printer costs far less than industrial equipment and print services will produce parts from an uploaded file.
The sensible path is to pick one pain point, such as slow prototyping, workshop jigs and fixtures or obsolete spares, prove the value there and then expand. Buying a printer in search of a problem is the classic failure.
In practice
Real-world examples.
Example
A product design team at a consumer electronics firm prints a prototype bracket on the same day it is drawn. It tests the fit, changes the design twice that week and only then orders production tooling. The early changes cost almost nothing, whereas a change after tooling would have been expensive.
Example
A hospital prints a patient-specific surgical guide overnight from a scan of the patient. The surgeon has a tool shaped to that one person, and no mould is needed for a single item. The hospital still checks the printed guide for accuracy before it enters the operating theatre.
Example
A shipping company prints an obsolete spare part on board a vessel instead of carrying a stock of rarely used components. The ship avoids waiting weeks for delivery to a distant port, and the company cuts the cost of holding rarely used stock in warehouses.
Formula
Calculation
Breakeven volume = tooling cost / per-unit printing premium, where the premium is the printed cost per unit minus the moulded cost per unit.
Suppose a mould costs $20,000 to make. A moulded part then costs $10 each, while the same part printed costs $12 each, so the printing premium is $12 - $10 = $2 per unit. Breakeven volume = $20,000 / $2 = 10,000 units.
Check: at 10,000 units, printing costs an extra 10,000 x $2 = $20,000, which exactly equals the tooling cost. Below 10,000 units printing is cheaper overall, and above 10,000 units moulding is cheaper.Case study
Seen in the real world.
In this fictional and illustrative case, Beacon Medical Devices spent $60,000 a year on machined prototypes with six-week lead times. The company bought a $4,000 printer to bring prototyping in-house.
Design cycles fell from weeks to days, two tooling errors were caught before production started, and outside machining spend dropped to $12,000 a year, a saving of $48,000 or $12,000 a quarter. After allowing about $1,500 a quarter for materials and staff time, the net saving of $10,500 a quarter more than covered the $4,000 printer within the first quarter of use.
The engineers also learn where printing does not fit. Parts that need a very fine surface finish or certified material properties still go to a machine shop, so the printer becomes a tool for speed and iteration rather than a replacement for every supplier.
Watch out
Common mistakes.
- Buying a printer before identifying the problem it is meant to solve.
- Comparing only the per-unit cost while ignoring tooling cost and lead time.
- Skipping post-processing and inspection in production plans, when a layer defect can be invisible from outside.
Questions
People also ask.
Is 3D printing only for prototypes?
No. Certified production parts are now used in demanding fields such as aviation and medical implants.
When does moulding beat printing?
At high volumes of simple, stable designs, where the tooling cost is spread across many units.
Can a small business start cheaply?
Yes. Entry-level desktop machines or print services cost far less than industrial equipment, and a business can begin with a single use case.
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