3D Printing vs Injection Moulding: When to Switch

Every product that succeeds eventually asks the same question: do we keep printing these, or do we cut a mould? The answer is mostly arithmetic, and the number that decides it is quantity.

01 The Short Answer

500 units is our minimum for a moulding run, and that floor is not arbitrary. Below it, the tooling cost spread across the batch swamps any per-part saving.

02 Two Different Cost Shapes

The two processes do not just differ in price, they differ in the shape of the cost curve. Printing is close to linear: a hundred parts cost roughly a hundred times one part, less a volume discount. Moulding is a large fixed cost followed by a very low marginal one.

That shape has a practical consequence. With printing, a wrong guess about demand costs you the parts you did not sell. With moulding, a wrong guess about the design costs you the tool.

03 Lead Time Is the Other Half

If you have a trade show, a launch date, or a purchase order with a delivery window inside a month, tooling is usually not the answer regardless of quantity.

04 Design Freedom Cuts Both Ways

Printing imposes almost no constraints on geometry: undercuts, internal channels and hollow cavities are all fine. Moulding requires the part to release from a steel tool, which means draft angles, reasonably uniform wall thickness, and no undercuts a simple mould cannot open around. Every design goes through a mouldability review before we quote final tooling cost, and that review often comes back with geometry changes.

Material choice inverts the same way. Printing gives you the entire FDM and resin range, including flexible TPU and UV-stable ASA. Moulding narrows you to what the process will run.

05 The Path Most Products Take

The sequence that works, in our experience with Australian product businesses:

1. Prototype by printing. Iterate until the part does what it needs to do. Cheap mistakes at this stage are the point
2. Validate with a printed batch. 50 to 200 units through low volume production puts real product in front of real customers with no tooling committed
3. Lock the design. Only when the batch stops generating change requests is the geometry ready to be cut into steel
4. Move to tooling. With demand proven and the design settled, injection moulding becomes a straightforward economic decision

Step two is the one businesses most often skip, and it is the one that protects the tooling spend. A printed batch of 200 answers questions no amount of internal review will.