Stockstrip Cut Planner
Why does Stockstrip use three bars when two can fit?
Stockstrip places pieces longest first on the first bar with enough room. It never revisits earlier placements, so its bar count can exceed what a different arrangement needs. This six-piece example fits on two bars under the app's kerf rules but produces three. Check individual assignments before treating the result as a purchasing minimum.
Reproduce the extra-bar question
Set Stock length to 1000 and Saw kerf to 3. Enter four part rows: Long at 597 mm, quantity 1; Medium at 497 mm, quantity 1; Short at 297 mm, quantity 1; and Spacer at 197 mm, quantity 3. Choose Generate plan. These six pieces produce three stock bars, with 1000 mm total leftover.
The finished lengths total 1982 mm. Six reserved kerfs add 18 mm, making exactly 2000 mm of modeled material. That suggests checking whether two 1000 mm bars could suffice. However, a combined total alone cannot show that the pieces fit into individual bars. The allocation rule explains the third bar.
Follow the placements in order
Stockstrip sorts pieces by descending finished length. Each consumes its length plus one kerf: the effective sizes here are 600, 500, 300, 200, 200 and 200 mm. Long goes on bar 1, leaving 400 mm. Medium cannot fit there, so it opens bar 2 and leaves 500 mm.
Short needs 300 mm including kerf. It fits on bar 1, the first bar with room, leaving 100 mm. The first two Spacers then go on bar 2, leaving 100 mm there too. The final Spacer needs 200 mm. Neither existing bar has enough room, so it opens bar 3, leaving 800 mm.
The allocator keeps these earlier decisions. It does not move Short elsewhere to make room for two Spacers on bar 1. This is first-fit decreasing in this implementation: sort longest first, scan existing bars in order, then use the first acceptable one or open another.
Check a different arrangement by hand
A two-bar arrangement exists under the same rules. Put Long and two Spacers on the first bar: 597 + 197 + 197 mm of parts, plus three 3 mm kerfs, equals 1000 mm. Put Medium, Short and the remaining Spacer on the second: 497 + 297 + 197 mm, plus another three kerfs, also equals 1000 mm.
Every requested piece appears exactly once. Both bars include the full kerf for every piece, including the last. This demonstrates a smaller bar count for this particular input. Stockstrip has no manual reassignment step to produce this alternative; keep a separately checked arrangement outside the app.
Both alternative bars have zero allowance remaining. End trimming, defects, grain and angled cuts are outside the model. Check the actual material and cutting requirements before using an exact-fill calculation as a cutting plan.
Read leftover as separate spaces
The generated plan leaves 100 mm on bar 1, 100 mm on bar 2 and 800 mm on bar 3. Its 1000 mm total leftover sums those separate spaces. It is not one unused 1000 mm bar that can simply be removed while preserving the assignments.
Use the numbered bars and their exact totals when investigating an unexpected count. For any proposed rearrangement, account for every piece and add one kerf per piece on each bar. Stockstrip supplies a feasible allocation under its assumptions; it does not certify the fewest bars or least waste.
Avoid changes that cannot improve the packing
Reordering these four rows will not make the app discover the two-bar arrangement. The different lengths are sorted again before allocation. Equal-length pieces retain input row and occurrence order, which affects their identifiers and labels rather than their space requirement. Repeated generation with identical inputs follows the same decisions.
Save the generated cut sheet before editing if you need its assignments as a reference. Input edits clear the result and disable export until regeneration. Compare any hand-checked alternative against the same lengths, quantities and kerf. Lowering the kerf merely to force a preferred count changes the problem rather than improving the arrangement.
AI-assisted ForgeHub editorial. App capabilities were checked against its implementation; this guide is not an independent review.
Frequently asked questions
Does enough total length prove the pieces fit?
No. The pieces must fit within each individual bar, including their reserved kerfs. In this example a two-bar arrangement can be shown explicitly; the 2000 mm combined requirement alone would not establish it.
Can changing part labels reduce the bar count?
No. Allocation sorts by length, then input row and occurrence for ties. Labels identify pieces but do not change their space requirements.
Does total leftover include reserved kerf?
No. Each placement subtracts both finished length and kerf from a bar's remaining space. Total leftover sums what remains afterward; reserved kerf is reported separately.