OWL EYE® in the steel mill — scrap, slag and bunker volumeOWL EYE® in the steel mill — scrap, slag and bunker volumeOWL EYE® in the steel mill — scrap, slag and bunker volume

Anyone who tries to drop a LiDAR volume measurement from the cement or mineral world straight into a steel mill usually fails in three places: heat, magnetic fields, and the fact that almost every scrap yard has a crane running over it. In Stahl Technik 1/2024 we wrote up what Sachtleben Technology actually does on those sites — this post sums up the three practical points.

1. Scrap piles — multi-material calibration. A scrap pile is not a homogeneous heap. Extrusion offcuts, turnings, baled scrap, body-panel bundles — every class has its own bulk density and its own optical reflectivity. A standard LiDAR calibration against a known clinker tonnage does not transfer. The steel variant of OWL EYE® STOCKPILE ships with a multi-material profile: the operator picks the current scrap class in the dashboard, the system applies the stored bulk density and correction curve. Class change, factor change — all logged, all traceable.

2. Bunkers for bulk additives — ATEX and inlet temperature. Steel mills feed lime, dolomite, coke breeze and alloys through bunkers. Two requirements meet here that the standard catalogue does not cover in parallel: ATEX zones above flammable or dust-laden bunkers, and inlet temperatures that under normal operation reach 60–70 °C at the bunker ceiling. The ATEX variant of OWL EYE® BUNKERS & FEEDERS uses certified sensor electronics, a flameproof enclosure and an inert-gas purge fitting for the optics. The specified temperature range of −40 °C to +80 °C covers most bunkers; on the tap-hole side of the blast furnace we run with active cooling.

3. Crane integration — sensor position and data synchronisation. A magnet or grab crane moves above a scrap yard in two axes. A LiDAR optic mounted fixed to the hall roof sees the crane as intermittent occlusion — it sits between the sensor and the material. We resolve that two ways in practice:

• Multi-sensor layout: two or three optics at offset positions, so the crane never blocks all of them at the same moment. The OWL EYE® software fuses the point clouds and masks the crane out automatically.
• Crane position input: the crane controller delivers its current axis positions over Modbus, and the OWL EYE® software ignores point-cloud regions geometrically covered by the crane. Clean data, no masking heuristic.

Both routes deliver the specified ±1 % accuracy; the choice depends on whether the crane offers an open interface.

What we learned from the steel world. Three things that went into our standard engineering checklist:

• Survey the magnetic field before mounting the optics. Magnet cranes generate stray fields that under unfavourable conditions can disturb the internal IMUs. A magnetometer pass before installation saves later re-engineering.
• Power supply is not trivial. Steel mills have hard load swings, arc-furnace voltage dips, EMC levels beyond what civilian wiring tolerates. For ATEX bunkers we always run separate power and data lines with surge protection at both ends.
• Maintenance has to be possible while the line runs. A steel mill does not stop because a sensor needs swapping. We design the brackets so an optic can be exchanged from a man-lift in under 15 minutes.

Steel is a demanding environment for any sensor. It is also an environment where continuous volume measurement per bunker and per pile quickly generates a six-figure yearly value — through reduced loading and unloading travel, through more accurate material allocation in the MES balance, through fewer empty crane runs.

More on volume measurement for steel plants at /stahl/, plus /stockpile/, /bunkers-feeders/ and /industries/.

Anyone who tries to drop a LiDAR volume measurement from the cement or mineral world straight into a steel mill usually fails in three places: heat, magnetic fields, and the fact that almost every scrap yard has a crane running over it. In Stahl Technik 1/2024 we wrote up what Sachtleben Technology actually does on those sites — this post sums up the three practical points.

1. Scrap piles — multi-material calibration. A scrap pile is not a homogeneous heap. Extrusion offcuts, turnings, baled scrap, body-panel bundles — every class has its own bulk density and its own optical reflectivity. A standard LiDAR calibration against a known clinker tonnage does not transfer. The steel variant of OWL EYE® STOCKPILE ships with a multi-material profile: the operator picks the current scrap class in the dashboard, the system applies the stored bulk density and correction curve. Class change, factor change — all logged, all traceable.

2. Bunkers for bulk additives — ATEX and inlet temperature. Steel mills feed lime, dolomite, coke breeze and alloys through bunkers. Two requirements meet here that the standard catalogue does not cover in parallel: ATEX zones above flammable or dust-laden bunkers, and inlet temperatures that under normal operation reach 60–70 °C at the bunker ceiling. The ATEX variant of OWL EYE® BUNKERS & FEEDERS uses certified sensor electronics, a flameproof enclosure and an inert-gas purge fitting for the optics. The specified temperature range of −40 °C to +80 °C covers most bunkers; on the tap-hole side of the blast furnace we run with active cooling.

3. Crane integration — sensor position and data synchronisation. A magnet or grab crane moves above a scrap yard in two axes. A LiDAR optic mounted fixed to the hall roof sees the crane as intermittent occlusion — it sits between the sensor and the material. We resolve that two ways in practice:

• Multi-sensor layout: two or three optics at offset positions, so the crane never blocks all of them at the same moment. The OWL EYE® software fuses the point clouds and masks the crane out automatically.
• Crane position input: the crane controller delivers its current axis positions over Modbus, and the OWL EYE® software ignores point-cloud regions geometrically covered by the crane. Clean data, no masking heuristic.

Both routes deliver the specified ±1 % accuracy; the choice depends on whether the crane offers an open interface.

What we learned from the steel world. Three things that went into our standard engineering checklist:

• Survey the magnetic field before mounting the optics. Magnet cranes generate stray fields that under unfavourable conditions can disturb the internal IMUs. A magnetometer pass before installation saves later re-engineering.
• Power supply is not trivial. Steel mills have hard load swings, arc-furnace voltage dips, EMC levels beyond what civilian wiring tolerates. For ATEX bunkers we always run separate power and data lines with surge protection at both ends.
• Maintenance has to be possible while the line runs. A steel mill does not stop because a sensor needs swapping. We design the brackets so an optic can be exchanged from a man-lift in under 15 minutes.

Steel is a demanding environment for any sensor. It is also an environment where continuous volume measurement per bunker and per pile quickly generates a six-figure yearly value — through reduced loading and unloading travel, through more accurate material allocation in the MES balance, through fewer empty crane runs.

More on volume measurement for steel plants at /stahl/, plus /stockpile/, /bunkers-feeders/ and /industries/.

Anyone who tries to drop a LiDAR volume measurement from the cement or mineral world straight into a steel mill usually fails in three places: heat, magnetic fields, and the fact that almost every scrap yard has a crane running over it. In Stahl Technik 1/2024 we wrote up what Sachtleben Technology actually does on those sites — this post sums up the three practical points.

1. Scrap piles — multi-material calibration. A scrap pile is not a homogeneous heap. Extrusion offcuts, turnings, baled scrap, body-panel bundles — every class has its own bulk density and its own optical reflectivity. A standard LiDAR calibration against a known clinker tonnage does not transfer. The steel variant of OWL EYE® STOCKPILE ships with a multi-material profile: the operator picks the current scrap class in the dashboard, the system applies the stored bulk density and correction curve. Class change, factor change — all logged, all traceable.

2. Bunkers for bulk additives — ATEX and inlet temperature. Steel mills feed lime, dolomite, coke breeze and alloys through bunkers. Two requirements meet here that the standard catalogue does not cover in parallel: ATEX zones above flammable or dust-laden bunkers, and inlet temperatures that under normal operation reach 60–70 °C at the bunker ceiling. The ATEX variant of OWL EYE® BUNKERS & FEEDERS uses certified sensor electronics, a flameproof enclosure and an inert-gas purge fitting for the optics. The specified temperature range of −40 °C to +80 °C covers most bunkers; on the tap-hole side of the blast furnace we run with active cooling.

3. Crane integration — sensor position and data synchronisation. A magnet or grab crane moves above a scrap yard in two axes. A LiDAR optic mounted fixed to the hall roof sees the crane as intermittent occlusion — it sits between the sensor and the material. We resolve that two ways in practice:

• Multi-sensor layout: two or three optics at offset positions, so the crane never blocks all of them at the same moment. The OWL EYE® software fuses the point clouds and masks the crane out automatically.
• Crane position input: the crane controller delivers its current axis positions over Modbus, and the OWL EYE® software ignores point-cloud regions geometrically covered by the crane. Clean data, no masking heuristic.

Both routes deliver the specified ±1 % accuracy; the choice depends on whether the crane offers an open interface.

What we learned from the steel world. Three things that went into our standard engineering checklist:

• Survey the magnetic field before mounting the optics. Magnet cranes generate stray fields that under unfavourable conditions can disturb the internal IMUs. A magnetometer pass before installation saves later re-engineering.
• Power supply is not trivial. Steel mills have hard load swings, arc-furnace voltage dips, EMC levels beyond what civilian wiring tolerates. For ATEX bunkers we always run separate power and data lines with surge protection at both ends.
• Maintenance has to be possible while the line runs. A steel mill does not stop because a sensor needs swapping. We design the brackets so an optic can be exchanged from a man-lift in under 15 minutes.

Steel is a demanding environment for any sensor. It is also an environment where continuous volume measurement per bunker and per pile quickly generates a six-figure yearly value — through reduced loading and unloading travel, through more accurate material allocation in the MES balance, through fewer empty crane runs.

More on volume measurement for steel plants at /stahl/, plus /stockpile/, /bunkers-feeders/ and /industries/.