The honest numbers
A 3D printed part typically holds somewhere between 15% and 75% of the strength of the same polymer injection molded — depending on infill and, more than anything, which direction the load comes from. Here's why, and where our forge process fills the gap.
The short version
| How the part is made | Typical strength vs injection molded | Tooling cost |
|---|---|---|
| 3D printed | Only ~20–30% — and weakest across the layers | None |
| Injection molded | 100% — equally strong in every direction | Tens of thousands of dollars, weeks of machining |
| Forged carbon (our process) | Molded-class strength — no layer lines, no weak direction | Printed mold — a fraction of cut tooling |
The 20–30% figure is what a typical print delivers in real-world loading, where the load rarely lines up with the print lines. The full breakdown by infill and direction is below.
The four reasons
A print is a stack of welded layers. The bond between them never reaches the strength of the material itself, so parts split along layer lines long before the plastic gives up. Load a part across its layers and you are testing the weakest direction.
Each extruded line is round, so microscopic gaps remain where lines meet. Even a "100% infill" print is not fully solid — those voids are where cracks start under load.
An injection mold forces molten plastic together under tons of pressure until it freezes as one solid piece. A printer just lays material down and hopes it sticks. Less pressure means weaker bonds.
An injection molded part is roughly equally strong in every direction. A printed part is not — the same part can be twice as strong loaded along its print lines as across its layers. Your part's weakest direction is the one that matters.
Printed vs molded, same polymer
Injection molded = 100%, and roughly equally strong in every direction. The printed columns show what the same material typically delivers as a print.
| Infill | Injection molded | Printed — load inline with print lines | Printed — load across print lines | Printed — load across layers (worst case) |
|---|---|---|---|---|
| 30% | 100% | ~30–35% | ~20–25% | ~15–20% |
| 60% | 100% | ~45–55% | ~30–40% | ~25–30% |
| 90% | 100% | ~60–65% | ~40–50% | ~30–40% |
| 100% | 100% | ~65–75% | ~45–55% | ~35–45% |
Rough planning figures, not test data. Material, layer height, wall count, print temperature and print quality all move these numbers. Your part will vary — the pattern won't: across the layers is always the weakest direction.
The gap
That is the gap most functional parts fall into. A production injection mold runs into the tens of thousands of dollars and weeks of machining — sensible at ten thousand parts, hard to defend at ten. So the part stays a print, and stays weak. This is where the forge process sits.
We 3D print the mold, so tooling costs a fraction of a cut steel or aluminum mold — and complex shapes that are expensive and difficult to machine become practical.
Carbon fiber material is pressed into the printed mold under heat and pressure through our proprietary forging process. Pressure consolidates the material the way an injection mold does — no layer lines, no print-direction weakness.
You get a consolidated carbon part with great surface aesthetics and improved strength, without committing to production tooling or production volumes.
Tell us where it breaks and what it has to carry. We'll tell you whether a better print or a forged part is the right answer.