Use this article when your shop buys stock in a large sheet size and cuts it down on the guillotine before printing, and you want the quoted substrate cost to match that workflow. After this you will know how parent sheets and cut sizes connect, how Estimator picks between buying small or cutting from large, and where the pre-cut step lands on the price breakdown.

What a parent sheet is

A parent sheet is a large stock sheet that your shop trims down on the guillotine to produce smaller working sheets before they go on press. In Estimator, a parent sheet is a normal substrate row that has been switched to Available as parent sheet and given one or more cut sizes. Each cut size becomes its own child substrate that products can use just like any other paper, but it stays linked to the parent so the pre-cut work is priced correctly. Most commercial print shops stock a small number of large sheet sizes — B1, SRA1, or 28×40 — and lean on the guillotine to produce everything from SRA3 working sheets down to small A-series pieces.

The customer-facing toggle lives on the substrate row in Estimate Setup > Substrates. When it is on, a Cut-to-Size Configuration section appears with the Guillotine Machine selector and an Add Cut Size button.

How parent sheets and cut sizes connect

A cut size has four pieces of data: the target dimensions (width and height of the child sheet), the grain direction the child needs, the yield (how many child sheets you can lift out of one parent), and the waste percentage left over. Yield is calculated from parent and child dimensions and the grain constraint, but you can override it if your shop's nesting is different from the default rectangular layout.

Once a cut size is added, two things happen:

A new child substrate appears in the library at the cut-down dimensions. Products can pick it like any other substrate.
The parent–child link is stored, so when an estimate uses the child, Estimator knows it must price the trim operation back to the parent.

A parent can have up to twenty cut sizes. The guillotine machine on the parent is the one that prices every pre-cut.

The math behind it

When an estimate selects a child cut-size sheet, Estimator runs three calculations in order.

1. Parent sheets needed. Estimator divides the child sheets the job requires by the effective yield (rounded up to a whole parent sheet):

parent_sheets_needed = ceil(child_sheets_needed / yield)

2. Cuts per parent. A rectangular layout of columns and rows needs (columns − 1) + (rows − 1) cuts on the guillotine to separate every child piece. Total cuts for the job is parent_sheets_needed × cuts_per_parent.

3. Pre-cut cost. Setup cost comes from the guillotine's make-ready minutes at the machine rate. Run cost comes from total cuts divided by the guillotine's output-per-hour times the machine rate. The two are added to give the pre-cut total that appears as the Pre-Cut step on the price breakdown.

For substrate cost itself, Estimator uses the parent sheet's price (weight × area × price-per-ton) divided by yield to get the per-child substrate cost. The total quote line for substrate becomes that per-child cost times the number of child sheets the job needs, plus the pre-cut step.

When a job's child sheet exists both as a parent-derived child and as a directly-stocked substrate, Estimator compares the two routes and picks the cheaper one for the route comparison. The pre-cut step is added only on routes where the selected substrate is a parent-derived child.

A worked example — Silk 100gsm cut from B1 down to SRA3

Northgate Press stocks Silk 100gsm B1 (1020 × 720 mm, €1,400 per ton) and uses Guillotine 1 (€60/h machine rate, 170 cuts/h) as the primary cutter. The shop quotes 1,000 SRA3 leaflets on this stock.

The substrate row for B1 has Available as parent sheet turned on, Guillotine 1 selected, and one cut size configured: SRA3 at 450 × 320 mm. Estimator computes the nesting as 2 columns × 2 rows, giving a yield of 4 SRA3 sheets per B1. The leftover area is 158,400 mm² out of 734,400 mm², a waste of roughly 21.6%.

For the 1,000-sheet job:

Parent sheets needed: ceil(1000 / 4) = 250 B1 sheets.
Cuts per parent: (2 − 1) + (2 − 1) = 2 cuts to break one B1 into 4 SRA3 pieces.
Total cuts: 250 × 2 = 500 cuts.
Parent substrate cost: the B1 sheet weighs 0.7344 m² × 100 g/m² = 73.4 g (0.0734 kg), so one B1 costs 0.0734 × €1.40 = roughly €0.103. For 250 sheets that is €25.71.
Pre-cut step: setup is the guillotine's make-ready at €60/h; run is 500 cuts at 170 cuts/h × €60/h = €176.47. Setup plus run gives the Pre-Cut total.

If the shop also stocks Silk 100gsm SRA3 directly (at €1,571 per ton, the smaller-sheet stock price), Estimator weighs the two routes:

Direct SRA3 route: 1,000 sheets at roughly €0.0226 each = €22.62. No pre-cut.
Parent-cut route: €25.71 substrate + the Pre-Cut step (€176 plus setup).

The direct SRA3 route wins on price, so Estimator builds the quote off the directly-stocked SRA3 and shows no pre-cut step. The B1 row stays available; it just isn't the cheapest path for this job.

A second example — mandatory pre-cut when SRA3 isn't stocked

Suppose the shop's policy is to stock only B1 for this paper grade — there is no Silk 100gsm SRA3 row in the substrate table at all. The only way Estimator can produce a 1,000-sheet SRA3 job is to cut from the B1 parent.

The quote now uses the child SRA3 (derived from B1) automatically because no other source for SRA3 exists. The price breakdown shows:

Substrate: 250 B1 sheets at €0.103 each = €25.71.
Pre-Cut: Guillotine 1, parent dimensions 1020 × 720 mm, output dimensions 450 × 320 mm, yield 4 sheets per parent, parent sheets needed 250, cuts per parent 2, total cuts 500, plus setup. Total Pre-Cut Cost reflects setup + run.

This is the same calculation as the first example — what changes is the route comparison: without a directly-stocked SRA3 row, there is nothing for Estimator to compare against, so the parent path is used by default. The same outcome happens whenever a shop wants to force pre-cut behavior: remove or disable the directly-stocked smaller sheet and leave only the parent and its cut sizes.

What this affects

Substrate line on the price breakdown. The line shows the per-child cost derived from the parent, not the parent sheet's full price.
Pre-Cut step. When the selected substrate is a parent-derived child, a Pre-Cut step appears before print steps with the guillotine machine, parent dimensions, output dimensions, yield, parent sheets needed, cuts per parent, total cuts, setup cost, and run cost. Total Pre-Cut Cost equals setup plus run.
Route comparison. Routes that use a parent-derived child carry the pre-cut step; routes using a directly-stocked smaller sheet do not. The route review tool compares totals across both, so the cheapest sheet-source for the job wins.
Quote totals. The pre-cut step rolls into the Machine and Labor cost buckets just like any other production step.

What this does not affect

Press selection. Press compatibility is decided by the child sheet's dimensions, not by which parent it came from. A 450 × 320 mm sheet routes to whichever press accepts that size, whether it was cut from B1 or bought directly.
Markup, customer rebate, and finishing step cost. Pre-cut work is its own step at the guillotine. It does not change finishing-step costs further down the route or how customer markup and rebate are applied to the final total.
Inventory. Estimator costs the pre-cut step but does not manage on-hand stock or carton consumption. The decision of which paper to actually pull from the shelf stays with the operator.
Estimates that use the parent sheet directly. If a job is large enough to print on B1 itself, no pre-cut is added. Pre-cut only appears when the selected substrate is a child of a parent.

FAQ

Does grain direction restrict which parent can be used?

Yes. The cut size carries a grain requirement, and a parent can supply that child only if its grain direction matches — long, short, or "either" if the child accepts both. If the grains do not match, that parent will not be offered as a source.

What if more than one parent could fit the same cut size?

Estimator computes the effective per-child cost for each candidate (parent substrate cost + pre-cut cost, divided by yield) and picks the cheapest. Ties are broken by stock priority.

Can I force the cut-to-size path even when a direct sheet would be cheaper?

Yes. The most common way is to remove the directly-stocked smaller sheet from the library so the parent is the only path. You can also leave the smaller sheet in place but make it unavailable to the relevant product categories.

Will the breakdown show the pre-cut as a line item?

Yes. The Pre-Cut step appears on the price breakdown with the guillotine machine name and the same numeric details described in the worked example — parent dimensions, output dimensions, yield, parent sheets needed, cuts per parent, total cuts, setup cost, run cost, and total pre-cut cost.

Does the child substrate inherit the parent's properties?

Yes. The child carries forward the parent's substrate identity — paper type, weight, coat, thickness, FSC, stock type, material, and tags — so any rule or filter that targets that paper grade also targets its children.