On a 3 m² sheet, if you only use 1.8 m² of parts, you throw 40% of the material in the bin. Nesting is the art of not doing that.
What is nesting?
Nesting is the operation of placing the parts to be cut on the raw sheet as tightly as possible. The goal: maximize the utilization rate, the ratio between part area and sheet area.
Good nesting reaches 80 to 85% utilization. Neglected nesting drops to 55-60%. Over a year, the gap adds up to thousands of dollars in material.
Why utilization matters so much
Material often represents 30 to 50% of a part's cost. Every percentage point gained in nesting flows straight to the margin. And scrap is not only lost at purchase: it takes up space, needs handling, and selling it back by weight returns only a fraction of the purchase price.
The levers of nesting
| Lever | Effect |
|---|---|
| Part rotation | Lets you orient each part to fill gaps |
| Nesting concave parts | A U-shaped part can host another inside its hollow |
| Multi-order grouping | The more varied parts, the more combinations the algorithm finds |
| Common-line cutting | Two parts share a cut line: less length, less scrap |
| Sheet format choice | Matching raw format to parts reduces wasted border |
The grain constraint
Be careful: on some materials and finishes, parts cannot be freely rotated. Brushed stainless has a visible grain direction. Aluminum has a rolling direction that affects bending. Nesting while ignoring grain can ruin the appearance or the mechanical strength. The best theoretical utilization rate is therefore not always achievable.
Manual or automatic nesting?
Manual nesting, in CAM software, is still common but slow and dependent on operator experience. Automatic nesting, algorithm-driven, tests thousands of combinations in seconds and almost always beats a human — especially on varied batches.
Think nesting from the design stage
The best optimization happens before the shop floor. A few design reflexes:
- Favor dimensions that are sub-multiples of the standard sheet format.
- Avoid very long, thin shapes that leave unusable strips.
- Design parts whose concavities can host other parts.
- Standardize thicknesses so parts can be grouped on the same sheet.
Nesting in DRAWLESS
DRAWLESS includes automatic nesting when the cutting file is generated. The DXF produced is already nested, with a utilization rate displayed. You immediately see how much sheet your part will consume — and you can adjust quantity or geometry to aim for better yield.