CNC Router Nest Optimizer
CNC nesting is different from saw-based cut list optimization. The bit is wider than a blade kerf, the hold-down strategy eats into usable sheet area, and the cut path needs lead-in and lead-out. The optimizer that runs your panel saw cut list will produce a nest your CNC can't actually run.
EZNESTING's nesting output is bit-width aware, vacuum-bed friendly, and exports DXF directly for CAM software.
Bit width vs blade kerf: not the same thing
A standard panel saw kerf is 1/8" (3.175mm). A standard cabinet-grade CNC router bit is 1/4" (6.35mm) or 3/8" (9.5mm). That's 2-3× the material removal per cut.
If you set kerf to 1/8" in your optimizer and run the DXF on a router with a 1/4" bit, the bit's outside diameter eats into the next piece. The parts come out 1/16" undersized on every shared edge.
In EZNESTING, set kerf to your bit diameter for CNC work. Not to your saw blade kerf. The optimizer leaves the right amount of space between adjacent parts.
Worked example: a cabinet box on a 4×8 vacuum table
A typical CNC operator's first cabinet:
- 2 sides @ 23" × 30" (grain locked along the 30")
- 1 bottom @ 22.5" × 23"
- 1 back @ 23" × 29.5" (1/4" stock — separate pass)
- 1 shelf @ 22.5" × 22"
Run through EZNESTING with 1/4" bit (6.35mm kerf) and grain lock on the sides, this lays out cleanly on a single 4×8 with ~9 sq ft of leftover area. The vacuum table holds everything down through the cut.
The 1/4" back panel is a separate job on different stock — don't try to mix material thicknesses in one nest, the bit Z-depth would be wrong.
Hold-down strategy: where parts can go on the vacuum bed
Vacuum-table CNCs hold parts by suction through the spoilboard. Small parts and narrow strips lose suction as the cut progresses and surrounding material gets removed. Two strategies:
- Onion-skin tabs: leave a thin layer (0.020-0.040") of material at the bottom of the cut so the part stays connected to the sheet until the last pass. Trim by hand after.
- Bridge tabs: leave small physical bridges (0.5-1" wide × 0.1" deep) connecting parts to the surrounding material. Trim with a chisel after.
For high-vacuum tables (>20 inHg), small parts can be cut all the way through if they're at least 4-6" in their smallest dimension. Below that, plan for tabs.
EZNESTING's DXF export lets your CAM software (VCarve, Aspire, EnRoute) add the tabs at the right places.
DXF export to your CAM software
EZNESTING exports nested layouts as DXF (R12 format) with separate layers for cut paths, labels, and pieces. Most cabinet CAM packages (VCarve, Aspire, EnRoute, Cabinet Vision) import this directly.
The DXF export has options:
- Outline only — just the perimeter, you add toolpaths in CAM
- With labels — engraved part numbers on each piece for sorting after the cut
- With kerf-compensated paths — the bit center line offset by half the bit diameter
For most CAM workflows, export outline only and let the CAM software handle toolpath generation, lead-ins, and tab placement. CAM is purpose-built for that — EZNESTING is for nesting.
Common-line cuts: when they help, when they hurt
Common-line cutting means two adjacent parts share a single cut. Instead of cutting around the perimeter of each part (two passes between them), the router makes one pass that becomes the right edge of part A and the left edge of part B.
Benefits: half the cut time between adjacent parts. Costs: bit deflection at the corners (a flexing bit cuts a slightly curved line), tabs can't be placed on the shared edge, and chip-out happens on both faces.
For paint-grade work where the cut edge gets banded or painted, common-line cutting is a win. For show-face work, run separate passes with proper lead-ins.
EZNESTING's nest doesn't force common-line cuts — the DXF has separate outlines per part, and your CAM software decides whether to combine adjacent edges.