Nesting Processing Rules

These rules explain why some panels in the preflight report have different dimensions between the cutting list (Excel) and the CNC program (MPR). These are expected differences caused by automated processing, not errors.

Slab-Up

What is it?

Some panels need to be thicker than the available sheet stock. For example, a 38mm worktop when only 19mm sheets are available. Slab-up solves this by cutting two panels from thinner stock and bonding them together to achieve the required thickness.

How are panels sized?

  • The original panel dimensions are expanded by 60mm in both length and width (30mm margin on each side for trimming after bonding).
  • The quantity is doubled — two sheets are needed for each finished panel.
  • The panel label gets -SLAB-UP appended to it.
  • The panel is grouped under the thinner stock material so it shares sheets with other panels of that thickness.

What does this mean in the preflight report?

The MPR file contains the original panel dimensions (the finished size after trimming). The Excel cutting list shows dimensions that are 60mm larger in each direction. This difference is expected and is listed in the SLAB-UP PANELS section of the report rather than as a size mismatch error.

Example:
Original panel: 600 x 400mm at 38mm thick
Stock available: 19mm sheets
Cutting list: 660 x 460mm, qty 2 (label: C101-Top-SLAB-UP)
After bonding and trimming: 600 x 400mm at 38mm

Recut

What is it?

The edgebanding machine has a minimum panel dimension of 140mm. Panels smaller than this cannot be safely fed through the machine. To solve this, panels are cut oversized and then manually trimmed down after edgebanding.

How are panels sized?

  • If a panel has edgebanding and either dimension is below 140mm, that dimension is increased to at least 140mm (or original + 20mm, whichever is greater).
  • The panel label gets a recut annotation, e.g. [Recut W to 95mm], indicating the final size to recut to after edgebanding.
  • Only the dimension(s) that are too small are enlarged — the other dimension stays the same.

What does this mean in the preflight report?

The MPR file contains the original (smaller) dimensions. The Excel cutting list shows the enlarged dimensions needed for the edgebander. The recut annotation in the label tells the operator what size to trim to after edgebanding.

Example:
Original panel: 300 x 95mm with edgebanding
Cutting list: 300 x 140mm (label: C101-Plinth [Recut W to 95mm])
After edgebanding: recut width from 140mm down to 95mm

Understanding the Preflight Report

The preflight report is generated before nesting and checks that every panel in the cutting list has a matching CNC program (MPR file) with the correct dimensions. The report contains these sections:

Section Meaning Action needed
ALL OK Every panel matched with correct sizes None — safe to proceed
MISSING MPR A panel in the cutting list has no corresponding MPR file Investigate — panel will not be nested
SIZE MISMATCH MPR dimensions don't match the cutting list and no processing rule explains it Investigate — dimensions may be wrong
SLAB-UP PANELS Expected +60mm expansion for slab-up bonding None — expected difference
RECUT PANELS Expected enlargement to meet edgebander minimum None — recut after edgebanding
UNREFERENCED MPR MPR files in the zip not matched to any cutting list panel Usually harmless — extra files from CNC generation
BACKDRILLING Panels that need machining on both faces Ensure nesting machine supports panel flipping
END DRILLING Panels with horizontal boring (edge drilling) Ensure these panels are not rotated during nesting