Blank Nesting

A Working Playbook for Blank Nesting and Sheet Utilization

Every extra blank per sheet is nearly free money. This guide covers nesting math, utilization benchmarks, ordering stock to fit the layout, and a re-nesting cadence for your top movers.

Blank size decides material cost before the press ever cycles. Take a 48 by 120 inch sheet, 5,760 square inches, and an 11 by 17 inch blank of 187 square inches. Nest with the 17 inch side along the length and you get 4 across by 7 along, 28 blanks at 90.9 percent utilization. Rotate it wrong and you get 2 by 10, 20 blanks at 65 percent. Same sheet, same part, 40 percent more material cost per blank. At $1,100 per ton on 2 mm steel that orientation call is worth tens of thousands per year on one part number.

Do the arithmetic before tooling, not after. Blanks per sheet in a straight nest equals floor of sheet width over blank width times floor of sheet length over blank length, checked in both orientations and in mixed patterns that combine them. Utilization equals blank count times blank area divided by sheet area. The Blank Size Optimization calculator runs those cases fast; your job is feeding it the true blank, including shear kerf of 3 to 6 mm between blanks on a slitter or blanking die, and the 10 to 15 mm edge margin most lines need for grippers and squaring.

Optimize the blank itself before the nest. On drawn and formed parts the blank is developed, not given, and development trials routinely shrink a first guess by 3 to 8 percent. A blank cut from 320 mm to 305 mm diameter drops blank area 9.2 percent, and every downstream nest inherits that saving. Simulate first, then confirm with a 20 piece trial and measure the trim offal; if you are trimming more than 8 to 10 mm of engineered addendum all the way around on a routine draw, the blank is telling you it wants to be smaller.

Know the utilization ranges. Rectangular blanks from sheet: 85 to 95 percent is normal, above 92 is strong. Round blanks straight nested cap at 78.5 percent by geometry; staggered rows recover 5 to 12 points and can reach 88 to 90 on wide stock. Trapezoids nested head to tail hit 80 to 92. Irregular blanks vary from 50 to 80 depending on how aggressively you interlock them. If a part sits more than 5 points below the range for its shape class, put it on the re-nest list before you negotiate one more penny with the steel supplier.

The quietest lever is ordering stock to the layout instead of nesting into whatever width is on the floor. If the best nest needs 1,485 mm and you run 1,524 mm master coil, 2.6 percent of every ton is scrap by decision. Mills sell custom slit widths at a modest premium, typically $10 to $25 per ton, which pays for itself whenever it saves more than about 1.5 percent utilization on $900 plus steel. Consolidate part numbers onto shared widths so volume stays high, and revisit the width book every time a die or blank changes.

Nest part families together when volumes allow. A large blank leaving a 300 mm wide strip of drop is a donation unless a smaller blank claims it; combination blanking layouts and offal recovery programs commonly add 2 to 5 points of effective utilization. Price the drop honestly: offal sold as scrap returns 15 to 25 percent of purchase cost, offal reused as a blank returns 100. One caution: chasing a second part into the skeleton adds die complexity and scheduling coupling, so reserve it for stable, high volume pairs where both parts run at least weekly.

Failure modes to expect. Engineers copy the old blank onto the new part and lock in yesterday's waste. Kerf and edge margins get ignored in the spreadsheet, so the floor gets fewer blanks per sheet than the quote assumed, and 26 actual versus 28 quoted is a 7 percent cost miss. Rotated nests get approved without checking rolling direction; on parts that split or springback badly across grain, a 5 percent material saving can buy a 3 percent scrap rate. And nobody re-nests after a design change shaves 6 mm off a flange, leaving free money on the table for years.

Run it on a cadence. Daily: operators record actual blanks per sheet or coil versus standard; any gap over 1 blank gets flagged. Weekly: review the top ten material spenders and confirm actual equals engineered nest. Quarterly: re-nest the A parts, revisit slit width orders, and audit kerf and margin assumptions on new tooling. World class looks like utilization within 1 point of the geometric best for each shape class, custom widths on every part consuming over 100 tons a year, blank development sign off before die steel is ordered, and a standing rule that no quote leaves the building on an unverified nest.

Published 2026-07-02.