USE CASE · SCRAP-SLAG AI

Scrap metal classification AI
for steel-mill yards.

A portal-mounted LiDAR + camera pair distinguishes ferrous scrap from cooled slag in real time — per truck, per delivery, per heat. Feeds the EAF charge-mix planner, reduces sorting labour on the yard, cuts off-spec heats before they get charged. Custom-built for your scrap categories and your plant integration.

< 5 cm centroid accuracy
85–95 % typical classification accuracy
1 LiDAR + 1 cam per portal
EAF-ready feeds the charge planner
USE CASE  ·  Scrap-slag classification · LiDAR + camera fusion

Scrap-vs-slag, sorted at the portal, before it hits the charge bucket.

Scrap-slag classification AI is a portal-mounted perception pipeline that distinguishes ferrous scrap from cooled slag in real time on a steel-mill yard, using fused LiDAR and camera data to feed the EAF charge-mix planner.

The pain is well-known to every EAF operator: scrap deliveries arrive contaminated with cooled slag, refractory debris, oxidised fines and the occasional non-ferrous lump. When this mix gets graded the wrong way, the charge bucket carries the wrong mass of actual iron — the heat ends up under- or over-charged, the energy balance drifts, fluxes have to be adjusted on the fly, and in the worst case the tap goes off-spec. The cost shows up as wasted electricity per tonne, extra refractory wear, and slag pits that fill faster than the schedule predicted.

Our approach fuses two sensors at the yard entrance. A 3D-LiDAR scans the load geometry as the truck rolls under a portal — bulk density signature, surface texture, void structure. A high-resolution colour camera adds material colour, oxidation tint, and visible refractory or slag signatures. A custom classifier — trained on your scrap categories (shred, bushelling, plate-and-structural, heavy melt, turnings) and your slag types — returns a per-truck breakdown: tonnage estimate per category, slag fraction, contamination flags. The result writes directly into the charge-planner or MES over OPC UA, REST or MQTT.

This is not an off-the-shelf SaaS. Every steel mill has its own scrap sources, its own slag pit, its own EAF charge model. We treat every engagement as a discovery + fixed-scope build, descending from our hub service Industrial Perception AI. Typically four to twelve weeks from contract to live tool, with the code and the model handed over to you at the end.

„A bad charge mix is the most expensive way to learn what was actually in the truck."

Built by the same team that delivers our LiDAR wagon-detection pipeline — six lid centroids, sub-5 cm error, two-second response.

Three stages

From truck to charge bucket — three stages of the pipeline.

1 · Sensor portal at the yard entrance

One LiDAR plus one calibrated colour camera mounted on a steel portal at the scrap-yard entrance or weighbridge. Trucks drive through at normal speed — the system captures load geometry and surface imagery on the fly, no stopping required. IP65+ housings, dust-tolerant optics, runs in fog, snow and night light.

2 · Classification + segmentation

The fusion classifier separates the load into your scrap categories — shred, bushelling, plate-and-structural, heavy melt, turnings — plus cooled slag, refractory debris and unknown contamination. Per-truck tonnage estimate per category, segmentation mask for visual audit. Models retrained on your labelled data, not on a public benchmark.

3 · Charge planner + MES integration

Classification results write into the charge-planner or MES over OPC UA, REST or MQTT — same shift, before the bucket is filled. The charge model sees real category masses instead of operator estimates. Off-spec deliveries are flagged before they enter the mix; aging slag-contaminated trucks get routed back to the supplier with the evidence attached.

Pipeline architecture · #how-it-works

How the pipeline works — concretely.

We keep the architecture boring on purpose. Three loosely coupled stages, each one independently testable, each one swappable when the sensor stack changes. Built on the same stack we use across all our perception work: PCL, Open3D, OpenCV, PyTorch.

01

Portal scan capture

The LiDAR delivers a 3D point cloud of the full truck load — typically a million-plus points per pass at portal speed. The camera adds a synchronised colour image, lens-calibrated and time-stamped. Raw data writes to local storage with a per-truck UUID for audit trail and re-labelling.

02

Fusion classifier

The point cloud goes through ground removal, voxel down-sampling and a PointNet-style classifier trained on your scrap categories. The colour image goes through a CNN trained on the same labels. The two heads are fused into a single per-voxel prediction — typically 85–95% classification accuracy on production data, depending on how clean your scrap categories actually are.

03

Charge-planner write-back

Per-truck output: estimated tonnage per category, slag fraction, contamination flags, audit images. Writes into the EAF charge planner over OPC UA — or into the MES, the ERP, the yard-management system, whatever the plant already runs. The charge model now reads real category masses instead of operator estimates.

All three stages run on an industrial PC at the portal cabinet. No cloud dependency, no external API, no licence dial-home. The code is yours at handover.

What you get

Three deliverables — from the same pipeline.

Per-truck classification report

Every delivery gets a structured record: scrap-category mass breakdown, slag fraction, contamination flags, audit images, supplier ID, weighbridge ticket cross-link. Drops into the supplier-quality dashboard, into ERP, and into the yard-acceptance workflow.

Yard-level inventory heatmap

Across many trucks, the yard accumulates an aging map: which bay holds which scrap mix, how long it has sat, how much slag contamination is sitting in each pile. Same temporal model we use on stockpile monitoring — applied to scrap categories.

Charge-mix recommendation per heat

For every planned heat, the system proposes a charge mix that hits the target chemistry within typical fines and slag tolerances — drawing from real yard inventory instead of assumed averages. The metallurgist still approves; the planner does the bookkeeping.

Why custom

Why a custom build — not an off-the-shelf product.

Every steel mill has its own scrap sources, its own EAF charge model and its own existing yard sensors. A generic classifier solves the generic case; your case is not the generic case.

Material-specific calibration

A shred pile in one mill looks different from a shred pile in another — different shredder, different feedstock, different oxidation history. We calibrate the model on your material under your lighting and dust conditions, and we re-calibrate when the supplier mix changes.

Plant-specific labelling + training data

We bring the labelling tooling and the engineering hours. You bring the operator who actually knows what's in each truck. The result is a labelled dataset that belongs to you and that you can keep using as the model evolves — no vendor lock-in on the training data.

Integration with existing yard sensors + cranes

Most steel-mill yards already have weighbridges, RFID gates, ANPR cameras and overhead cranes. We fuse the classification output into what's already there — we do not replace your yard-management system. OPC UA, REST, MQTT and analog outputs all supported.

IP ownership + clean handover

You own the source code, the model weights and the labelled dataset at handover. We document the system, train your team, and walk away clean. No black box, no monthly per-truck licence, no service contract you can't exit. See our FAQs on IP and engagement model for the standard terms.

FAQ

Questions about scrap-slag classification.

The engagement-model questions we hear from every steel-mill customer considering a custom perception build. Need something more specific to your yard? Ask us.

Industrial Perception AI

What does custom perception AI software cost? +
We don't publish list prices because every project is scoped against your data and your decision logic — but we work to three predictable tiers. Discovery & Assessment — a 1–3 day workshop, on-site or remote, fixed price in the low-four-figure range. You receive a written feasibility note, a recommended next step and (if applicable) a fixed-price quote for the follow-on project. Useful even if you don't then go ahead — many customers use the note to evaluate two or three vendors. Custom Pipeline / Tool — a 4–12 week project delivering a working perception pipeline (parser + algorithm + dashboard or OPC UA integration). Fixed scope, fixed price, you own the code at handover. Typical project size is in the mid-five to low-six-figure range depending on data volume, sensor count and integration depth. Long-term Partnership — a monthly retainer for ongoing development and on-call support. Sized to the team capacity you need (typically 0.5–2 FTE equivalent). Quarterly road-mapping included. All three tiers include source code, written documentation and a clean handover — no licence dependence on us. See our Industrial Perception AI service for the full engagement model.
How long does it take to build a custom perception pipeline? +
From signed contract to a working tool in production, expect 4–12 weeks for a standard custom-pipeline engagement. The spread is driven by three factors. Data readiness. If you already have labelled data or representative recordings, we start training in week 1. If we need to set up data collection, add a sensor, or label from scratch, the front end adds 1–3 weeks. Integration depth. A standalone dashboard with REST output is the fastest path — typically 4–6 weeks. OPC UA integration into a running control system, with interlocks, factory-acceptance tests and a customer change-management process, is closer to 8–12 weeks. Sensor count and site complexity. One LiDAR + one camera in a clean indoor environment is faster than a six-sensor outdoor portal with dust, snow and dynamic lighting. We scope the difference up-front in the Discovery workshop. For a faster first signal we recommend the Discovery & Assessment tier — 1–3 days, fixed price, written feasibility note within a week. See Industrial Perception AI for the full model.
Who owns the code and IP we pay you to build? +
You do. Our standard contract transfers full ownership of the project-specific code, model weights, training data (where the data is yours) and documentation to you on final acceptance. We don't keep a back-door licence and we don't lock you into a maintenance contract. What we retain is our pre-existing toolbox — reusable libraries, calibration utilities, generic data parsers, the OWL EYE® core — which we license to you, royalty-free, for use on the delivered tool. This is the same boundary that any reputable engineering firm draws: we bring the toolbox, you keep the deliverable. If you want a different IP arrangement — for example a joint patent on a novel algorithm, or a co-developed model that we both reuse with consent — we structure that explicitly in the project contract. Tell us up-front in the Discovery workshop. Full engagement details on our Industrial Perception AI page.
Can you use our existing cameras and LiDAR sensors? +
Yes — in most cases. Our toolchain is sensor-agnostic on the data layer. If your sensors deliver a standard format (PCD, LAS, E57 for point clouds; RTSP, GigE Vision, USB3 Vision for cameras) we can ingest them in a day. We've worked with Riegl, Livox, Faro, Hesai, Velodyne, Ouster, Basler, FLIR, Allied Vision and IDS cameras. We'll tell you honestly when the existing hardware isn't the right tool. Common cases where we recommend a replacement: - The existing LiDAR is too narrow (FoV or range) to cover the area you want classified — usually solved by repositioning before buying anything new. - The camera is auto-exposing on a high-contrast scene (sun + shadow at a gate), which breaks classification reliability — solved by switching to a manual-exposure industrial camera with HDR sensor. - The existing sensor's vendor lock-in (proprietary stream format, no documented SDK) makes integration cost more than a Livox replacement. We don't earn a margin on reselling hardware to you. If you do want us to source new sensors, we do that through our normal Hardware & products channel at list price. See Industrial Perception AI for how we scope it.

Send us a scan from your yard.

A few sample point clouds, a few truck images, a description of your scrap categories — we come back within two business days with a written feasibility note and a fixed-price scope for the discovery workshop. Part of our Industrial Perception AI service.

info@sachtleben-technology.com +49 7831 969 22-190
Send us a message

Tell us about your scrap yard.

Sensor setup, sample point clouds, your scrap categories, your charge-planner interface — anything you have. We come back within two business days with an honest first assessment and a fixed-price scope for the Discovery workshop.

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