About the project and the client#
The bottleneck is the engineer's time. Reading drawings by hand, planning the cutting layout, keeping track of steel grades, computing cost per kilogram — project after project. Sometimes a large amount of waste that can no longer be used on subsequent projects.
Before we start writing code, we spend several days on site — we analyze the work on the shop floor and consult the process with Mateusz Ozga, a specialist in producing columns for road construction sites. We understand the problem from the inside — which is why we are able to create tailor-made software.
One tool covering the entire column production cycle — automated cutting-layout calculation, steel waste minimization through optimal cutting, faster production and a warehouse kept split per project. The real final cost per kilogram and per unit — computed from real documents.
What we're tackling#
The largest cost wasn't steel — it was the risk of human error under a flood of orders and detailed specifications. To change that, we have to take on a complex, multi-stage process where every millimeter counts: how to compute the cutting layout with a guarantee of optimality, how to return usable offcuts to circulation, and how to arrive at the real product cost — per kilogram and per unit.
A cutting layout with a guarantee of optimality
Cutting-layout optimization is a combinatorial problem — the mathematical minimum of total bar length and number of sheets is practically unreachable without the right algorithm. The challenge: compute an optimal plan with a proof that it can't be beaten, while accounting for kerf, commercial-length limits and the "2 elements from one segment" mode.
The hard rule of never mixing steel grades
Steel grades (e.g. S235 and S355) must never end up together in a single order line item. The system tracks them separately at every level — from the individual plate, through the column, to the bill for the plasma cutter and the invoice.
Usable offcuts back into circulation
Cutting remnants above the minimum required length aren't waste — they return to a separate offcut warehouse and can cover future demand. The optimization had to distinguish usable offcuts (feeding the warehouse) from shorter ones (counted as loss), and the warehouse had to work split per construction site.
Module coherence at every stage
Demand, cutting, warehouse, production, costs and invoice — each module pulls data from the previous one without manual retyping. The challenge: carry the result of one stage into the next without losses, so that the whole path from the construction site to the invoice is a single coherent process.
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Provable optimization, a demanding production domain and real cost accounting — we know how to structure it into one coherent system.
How we approach the project#
Three principles that guide this project: a deep understanding of the process first, then code — long, detailed consultations on site at the production plant. Well-thought-out algorithms validated on real projects — algorithms designed for a specific production process and tested against the client's real documents. Simplicity of use and integration with the existing production process — one tool covering the whole process, with exports going straight where they're needed.
Understanding the process at the production site
We start with days spent at the client — walking the workshop, talking to operators and engineers, observing the process from the site's demand to the invoice. We only start building the data model and the cutting rules once we understand how the product is actually made.
Well-thought-out algorithms validated on real projects
We design the 1D and 2D cutting algorithms for a specific production process, and we test each one on real projects and the client's real production documents. A solution only goes into production once we've proven how it performs against manual calculations.
Simplicity of use and integration with the existing production process
One tool tying together demand, warehouse, cutting, production and accounting — no switching between systems. The interface walks the operator through every stage, and the result goes straight where it's needed: a DXF export to the plasma cutter, a delivery note to the galvanizing plant, an invoice to Fakturownia.pl, a KSeF e-invoice and a full project documents pack to download (PDF, XML, CSV).
App views#
The full flow from the dashboard, through demand from workshop drawings and cutting optimization, the warehouse, production and costs, to KSeF invoicing and the completed project archive.
Some app screens
Views from the working system — the full cycle from the dashboard, through demand, material and cutting optimization, to production, costs and e-invoices.
What we deliver#
The biggest wins from the deployment — measured in engineer's time, amount of waste, number of errors and coherence of the whole column production process.
Decisions that made the difference#
Four decisions that shaped the quality of the result the most — matching solvers to the problem type, a hard separation of steel grades, splitting long plates into welds and a CAD-compliant export. A web application: React + NestJS, a standard technology stack with no exotic dependencies.
A separate algorithm for 1D cutting and for 2D nesting
Bar cutting is a 1D problem — a MILP solver (HiGHS) delivers a plan with a proof of optimality. Plate nesting is a 2D problem — a layout of differently sized plates (maxrects) in thickness×grade groups plus analytical sheet selection for identical plates.
Two fitted algorithms give a better result than one universal heuristic.
A hard separation of steel grades across the whole process
The steel grade (S235 / S355) is tracked separately at every level — from the individual plate, through the column, to the bill for the plasma cutter and the invoice. Two grades will never end up in a single order line item.
The rule holds throughout the process, because a grade mistake is a real production defect, not a cosmetic one.
Plates longer than a sheet split into segments automatically
Long plates are split into welded segments with an automatic report of the number of welds and welding schematics. Plates with mounting holes are never split.
This makes the optimization result match what can actually be produced, rather than an idealization assuming infinite sheets.
DXF ready for CAM and Fakturownia.pl integration
The cutting layout is exported to DXF in a format compatible with plasma cutters and CNC machines — the file goes straight to the machine, with no manual rework or conversion.
We don't build the accounting from scratch. Full Fakturownia.pl integration via the API and KSeF e-invoice support close the process from the site's demand to the invoice.
Technical core#
Tools chosen for this process — proven algorithms and formats, no exotic dependencies.