Hole over hole nesting on sheets with holes

Hole over hole nesting places a part with an opening over a hole in the sheet when the hole fits inside the opening with the cutting gap kept all round. Skeletons, remnants and pre-drilled sheets become usable stock again.

See the test results 2D cutting and nesting

Included in Velmar Cut 2D and the full edition from version 1.5, and in the free 7-day trial, which unlocks every edition.

Yesterday's remnant, used again today

The remnant of yesterday's job goes into the warehouse with its outline and holes, and today's job is nested on it with the option off and on. All four steps are Velmar Cut's own screens.

01 Yesterday's sheet

The 140-part test job with hole over hole off used only the left end of a 2000 × 1000 mm sheet.
02 Remnant in the warehouse

Velmar Cut stores the rest of the sheet as an exact-shape remnant. Its outline follows yesterday's cuts, and it keeps six of the sheet's holes, four round and two square.
03 Today, option off

20 of 22 parts fit and 28.9% of the remnant is used. The two large plates with elliptical openings find no place clear of the old holes.
04 Today, option on

22 of 22 parts fit, three of them with their openings over old holes: both cover plates and a frame. 60.7% of the remnant is used.

How hole over hole nesting works

Usual nesting treats every hole in a sheet as a no-go zone and leaves the material around it unused. With hole over hole, a frame, flange, ring or plate with an opening may lie over a sheet hole that fits inside the opening: cutting the opening only widens the hole, and the part comes out whole.

Option off

Option off: a 730 × 430 mm plate with an elliptical opening covers the Ø110 mm hole of a 760 × 460 mm sheet in every position, so it cannot be placed.

Option on

Option on: the hole lies inside the plate's opening and the plate is placed, yield 78.8%.

The cutting gap (kerf plus the extra gap) is kept from every sheet hole, as between parts: 3 mm in our tests, a 0.2 mm kerf plus a 2.8 mm gap.

Two test jobs with the option off and on

Each job ran in Velmar Cut 1.6.0 with the option off, then with it on. The pictures are the program's own Cutting layouts of each run.

140 parts on 2 sheets instead of 3

Frames with round windows, flanges with square bores, link plates with elliptical holes and small fillers, on 2000 × 1000 mm sheets with six Ø120 mm holes and two 100 × 100 mm holes each.

The Fast level, up to 60 seconds per run, 3 mm cutting gap.

Option off 3 sheets · yield 45.0%

Option on 2 sheets · yield 67.4%

144 parts on 4 sheets instead of 5

Four 730 × 430 mm plates with an elliptical opening and 140 small fillers, on 1310 × 650 mm sheets with one Ø110 mm hole each.

The Fast level, up to 60 seconds per run, 3 mm cutting gap.

Option off 5 sheets · yield 65.4%

Option on 4 sheets · yield 81.7%

Nesting on sheets with holes

The option pays off wherever a sheet already has holes in it.

Skeletons and remnants

Velmar Cut stores exact-shape remnants in its warehouse with their old openings. The skeleton of an earlier job can take frames and flanges over the holes it already has.

Warehouse and remnants

Perforated and pre-drilled sheets

A sheet read from a DXF or DWG drawing keeps its holes. Parts with an opening go over the existing holes instead of around them.

Sheets with damaged spots

Mark a damaged spot as a hole in the sheet. Parts keep clear of it or take it inside an opening, and the rest of the sheet stays usable.

One option in the cutting settings

Turn on "Allow hole over hole" in the cutting settings. It works with true-shape nesting, on sheets that keep their holes from a DXF or DWG drawing or from the warehouse. The cutting gap is kept from every sheet hole, as between parts.

Questions about hole over hole nesting

Does the part still come out whole?

Yes. The sheet's hole lies inside the part's opening, so cutting the opening only widens the hole. The material of the part itself never lies over the hole.

What gap is kept from a hole in the sheet?

The same cutting gap as between parts: the kerf plus the extra gap you set. In our tests it was 3 mm, a 0.2 mm kerf plus a 2.8 mm gap.

Which parts can go over a hole?

Any part with a closed opening that takes the sheet's hole with the cutting gap all round: frames, flanges, rings and plates with an opening. Parts without a large enough opening keep clear of the hole as usual.

Which sheets does it work on?

Sheets read from a DXF or DWG drawing, which keep their holes, and exact-shape remnants and skeletons from the warehouse. A damaged spot marked as a hole is treated the same way.

Which editions include hole over hole?

Velmar Cut 2D and the full Velmar Cut edition, from version 1.5. The free 7-day trial unlocks every edition, so you can test it on your own sheets and remnants.

Free trial

Seven days with every edition

Install Velmar Cut, enter the parts and stock of a current job and print the cutting schedule. The trial starts on first run and needs no account or card.

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