# Part-in-part nesting

Using internal cutouts for additional parts while preserving toolpath clearance, support, quantities and material identity.

Reviewed: 2026-11-01

Tags: production, planning, nesting

On a hypothetical **1,000 × 1,000 mm** sheet, a **600 mm** square frame with a **400 mm** square opening uses **20%** of nominal sheet area. Four **150 mm** squares in the opening raise that to **29%**. A **10 mm** internal gap and **20 mm** edge allowances give **350 mm** required span in both directions. Separate child contours add **2,400 mm** of cut and **four pierces** under the stated assumptions. Area gain alone leaves actual sheet savings and process feasibility unresolved.

Next Nesting describes part-in-part as placing a smaller part within a larger part’s opening. Check cutting and recovery after the geometry fits. [Next Nesting Software X technical settings](https://www.nesting-technologies.com/help/next_nesting_software_x_en/files/technical_settings.html)

## Distinguish the planning choices

The child retains its own quantity, revision and acceptance criteria. Deepnest lists common-line cutting separately because shared edges and placement inside an opening describe different choices. [Deepnest product description](https://deepnest.io/)

A useful plan identifies parent and child parts, material specification, thickness, sheet identity, permitted orientation and the machine/process. “Fits in the hole” is only the first check. The cutout may also need space for compensation, leads, pierces, separation and retention features. These allowances are process inputs to establish with the programmer, not universal distances determined by the nesting concept.

## Preserve geometry and process allowances

Use the released finished-part geometry and correct units. Identify internal contours as holes rather than independent stock outlines, and distinguish marking geometry from cuts. Next's documentation separately exposes cutter thickness, polygon approximation resolution and numerical precision. A nesting display can therefore depend on geometry-processing settings as well as the original CAD data. Do not interpret a numerical approximation setting as a manufactured-part tolerance. [Next technical settings](https://www.nesting-technologies.com/help/next_nesting_software_x_en/files/technical_settings.html)

Review the actual compensated toolpaths, not just the unoffset shapes. A child can fit nominally while its lead-in collides with the parent boundary, its pierce damages a required edge or its retained material becomes too narrow. Check both items' edge requirements and the location of scrap. A favorable area calculation does not establish a usable toolpath.

For mixed orders, verify that the material and thickness are truly interchangeable and that rotations or mirroring are allowed by each drawing. Grain, brushed finish, protective-film direction or a handed feature may constrain orientation. Do not accept a more compact layout by silently changing those requirements.

## Support and sequence are machine dependent

Kinetic's PrimecutNE help, explicitly applicable to **version 4.5.359 or later**, describes small-part tip-up on slatted tables and the possibility of a torch collision. Its automatic orientation preference is machine-specific, does not change manual nesting and can be overridden by a grain constraint. This is useful evidence that orientation and support must be checked together; the software preference is not a guarantee for every small child part. [Kinetic, avoiding small-part tip-up](https://kineticusa.com/PrimecutHelp/small-part_tipup.html)

Plan when the child becomes free, when the surrounding cutout is released and how both are supported during subsequent moves. Review retention, cutting order, head clearance and unloading against the actual machine arrangement. A released child or cutout may no longer occupy its original CAD position. Simulation and an established shop method should account for that transition.

TRUMPF's ejector-tool guidance describes small laser-cut parts tipping or sticking in the skeleton and presents a specific punch/laser machine tooling solution for sorting. Its machine and tool scope matters: an ejection method advertised for a TruMatic configuration is not an available feature on an arbitrary laser or plasma table. [TRUMPF ejector tool for sorting](https://www.trumpf.com/en_GB/products/services/services-machines-systems-and-lasers/tools/punching-tools/punching-tools/ejector-tool-for-sorting/)

## Original bounded layout example

Assume a hypothetical **1000 × 1000 mm sheet** contains one square frame with a **600 × 600 mm outer boundary** and **400 × 400 mm opening**. Four solid **150 × 150 mm** child squares are candidates for that opening. Ignore corner radii and use nominal net finished areas for this arithmetic.

The frame's net area is 600² − 400² = **200,000 mm²**. The four children add 4 × 150² = **90,000 mm²**. With the same sheet denominator, useful nominal part area increases from **20% to 29%**. That is **9 percentage points**, or a 45% increase relative to the original 200,000 mm² of useful area. It is not a 45% reduction in purchased sheet area.

For a simple two-by-two child layout, assume an invented 10 mm nominal boundary-to-boundary separation and 20 mm edge allowance on each side of the opening. Required span in each direction is 20 + 150 + 10 + 150 + 20 = **350 mm**, leaving 50 mm within the 400 mm opening. These allowances are teaching inputs, not recommended cutting settings. The fit calculation excludes lead geometry, kerf compensation, support and heat effects.

If each child requires its own closed perimeter, their added nominal cut length is 4 × 4 × 150 = **2400 mm**, plus four pierces under a one-pierce-per-child assumption. The parent already requires its opening contour, so that contour is not counted again as added work. Additional time cannot be calculated from area alone: it needs the applicable speeds, pierce times, motion and handling method.

The example demonstrates improved area use on a fixed sheet. It does not prove that the original order required an additional sheet, that purchase cost falls immediately, or that a 29% layout is optimal. Compare complete feasible nests for the actual order quantities before claiming sheet savings.

## Inventory, recovery and acceptance

SigmaNEST's current product page describes sheet/heat-number tracking, remnant inventory and nesting strategies accounting for clamps and secondary operations. These are named product capabilities; their availability depends on the installed package and configuration. Preserve the same information in the manufacturing record even when the chosen software uses different fields. [SigmaNEST product scope](https://www.sigmateksystems.com/en/sigmanest)

Before release, reconcile parent and child quantities against demand, identify the approved programs and confirm sorting/labeling. A usable internal cutout may instead be retained as a remnant; do not simultaneously credit it as recovered stock and as material consumed by completed children. Allocate material cost consistently when orders share a sheet.

Acceptance still applies to each finished item. Check the relevant dimensions, edges, flatness, finish and material identity after cutting and separation. Track actual good quantities and added programming, cutting and handling effort when evaluating the strategy. The cited web pages are undated and were reviewed on 2026-11-01; the explicit PrimecutNE minimum version is a software applicability statement, not a publication date.

## Related reference

[Production planning guides](index.md)