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180-Degree Steel Coil Upender: Robust 6-Ton Germany

Project Overview

Automating coil pallet exchange without surface marring requires positive mechanical clamping paired with a rigid rotating cradle. This project delivered a custom 180-degree steel coil inverter for a metal fabrication facility in North Rhine-Westphalia, Germany.

The plant slits silicon electrical steel and automotive sheet coils, transferring materials from inbound wooden skids onto clean plastic pallets ahead of high-speed stamping presses. The machine executes a complete 180-degree turnover in 62 seconds, handling slit packs up to 6000 kg without coil telescoping or band breakage.

  • Country / Region: North Rhine-Westphalia, Germany (Heavy automotive stamping sector, strict CE compliance).

  • Client Facility: Precision Automotive Stamping & Electrical Steel Slitting Facility.

  • Equipment Model: Custom 180-Degree C-Frame Mechanical Inverter (Model: SJG-6000-180). Related heavy turnover platforms feature in our Upenders & Tilters Catalog.

  • Key Operating Duty: Pallet-to-pallet inversion of slit coils (outer diameter 1200 to 1800 mm, width 130 to 830 mm) weighing up to 6000 kg, running 14 cycles per hour across two eight-hour production shifts.

  • Safety & Regulatory Baseline: Electrical architecture, two-hand operator console, perimeter chain shrouds, and positive rotation stops adhere to DIN EN ISO 12100:2010 and EU Machinery Directive 2006/42/EC.

  • Power Supply & Plant Interface: Pre-wired for European industrial 400V 50Hz 3-phase five-wire TN-S mains with Harting standard control quick-connectors. Ships in two modular ocean crates: 1300 kg stationary base (2800 × 1800 × 700 mm) and 3700 kg rotating body (2800 × 2100 × 2100 mm) for rapid on-site bolt connection.

  • Color Specification: Heavy structural base finished in Light Blue RAL 5012; rotating C-drum coated in high-contrast Traffic Yellow RAL 1023.

Challenge & Solution

Challenge

Flipping an unsecured 6-ton steel roll through a continuous 180-degree vertical plane is among the most hazardous operations on a metal processing floor. Unlike a 90-degree tilter that rests its load into an upright corner cradle, a 180-degree inverter transfers the load in mid-air, shifting the full mass from pallet A to pallet B. Mechanical backlash, fluid pressure loss, or drive slip can ruin the coil structure and trigger severe machine binding.

  • Violent Gravity Drop at the 90-Degree Inversion Threshold: When the C-frame reaches the 90-degree vertical mark, the 6000 kg coil weight shifts across the center of rotation. In conventional gear-driven tilters with excessive backlash, gravity pulls the load ahead of the gearmotor at this transition point. This abrupt surge shakes the reduction gearbox, cracks drive chain links, and causes the support rollers to jump the track, leaving deep impact dents on outer coil wraps.

  • Coil Edge Pinching vs In-Transit Clamping Pressure Decay: Securing the roll between two transport pallets requires sufficient force to prevent in-transit slip without crushing the strip edges. Standard hydraulic spool valves suffer from fluid bypass as oil heats up under multi-shift operation. A pressure drop of just 2.0 MPa loosens the top clamping platen. The coil layers telescope outward, snap the steel packaging straps, and dislodge the roll during rotation.

  • Four-Roller Contact Fatigue & Ring Drum Skewing Under 9.7-Ton Moving Load: The rotating C-frame drum has a tare weight of 3700 kg. Paired with a 6000 kg steel coil, 9.7 tons of rotating mass rests on four bottom support wheels. Machining these rollers from untreated mild steel or running them against an out-of-round drum ring concentrates contact stresses, causing track pitting and spalling. As roller bearings develop axial float, the C-drum crabs to one side, misaligns the drive sprocket, and threatens to derail the main drive chain.

  • Four-Post Guide Jamming Across the 700 mm Clamp Travel: Accommodating coil widths from 130 mm to 830 mm requires a 700 mm hydraulic clamping stroke across a 2000 × 2000 mm platen. When forklift operators set coils 50 mm off-center, asymmetric resistance tilts the platen. On standard dual-column frames, this skew wedges the chrome guide rods inside their bronze bushings within milliseconds, stalling the hydraulic pump and galling the cylinder rods.

Solution

Eliminating dynamic shock at the 90-degree threshold and preventing coil edge damage required restructuring both the mechanical drivetrain and hydraulic clamping circuits. Engineering the 180-degree steel coil inverter around a dual-cylinder four-post platen, a 1:126 reduction helical-bevel gearmotor, and flanged hydraulic lock valves secured structural stability throughout the rotation arc. The structural geometry and motion profiles were verified through full-load shop testing prior to export packing.

  • Heavy-Duty C-Frame Drum & Forged 42CrMo Support Rollers: The rotating body uses 30 mm Q355B structural steel plates welded into a rigid box section. Outer rolling rings turned on a vertical lathe restrict radial runout within 0.15 mm. The rotating assembly rests on four support wheels forged from 42CrMo alloy steel, quenched and induction-hardened to HRC 52–56. Each wheel runs on heavy-duty HRB UCF210 four-bolt flange units, backed by four adjustable lateral guide rollers that eliminate axial float, maintaining drum equilibrium under 9.7 tons of rotating mass.

  • SR97 4kW Helical-Bevel Drive & Duplex Roller Chain Transmission: Drum rotation originates from an SEW SR97 4.0 kW helical-bevel gearmotor delivering a 1:126 reduction ratio, routing high holding torque through an industrial ANSI 80-2 / 16A-2 duplex roller chain tensioned around the drum circumference. This large reduction ratio self-locks the drum against gravitational overrunning as the coil passes the 90-degree vertical mark, controlling center-of-gravity shifts and completing the smooth 180-degree turnover in 62 seconds without chain snatch or roller liftoff, meeting transmission limits under ISO 606:2015.

  • Dual-Cylinder Clamping with 130 mm to 830 mm Stroke: Vertical clamping across the 2000 × 2000 mm steel platen relies on dual hydraulic cylinders (Ø80 mm bore / 700 mm stroke) powered by a 3.0 kW hydraulic pack. The platen maintains parallel travel through four Ø70 mm induction-hardened, hard-chrome guide columns riding in oil-impregnated graphite bronze bushings. This four-post geometry accommodates 50 mm of coil off-center placement during forklift staging, preventing guide binding while spanning coil widths from 130 mm to 830 mm.

  • Positive Hydraulic Pressure Retention & Coil Protection: Clamping line pressure holds at 12 MPa via manifold-mounted, hard-seated pilot check valves flanged to each cylinder port, eliminating flexible hose burst risks in line with ISO 4413:2010. Pressure drop across the 62-second turnover cycle measured below 0.1 MPa. A proportional relief valve regulates dynamic clamping force up to 60 kN (6000 kgf), clamping transport pallets without surface bite into outer coil wraps.

  • German CE-Compliant Control Architecture & Dual-Platform Interlocks: Electrical controls run on 400V 50Hz European three-phase power, integrating Schneider contactors, overload breakers, and heavy-duty position limit switches. The operator runs turnover sequences through an industrial wireless remote or the main stationary console. The control logic enforces strict safety interlocks: 180-degree rotation cannot initiate until pressure sensors confirm 12 MPa hydraulic lock, and clamp cylinders cannot retract until the drum registers at mechanical zero or 180-degree home stops, meeting DIN EN ISO 12100:2010 and EU Machinery Directive 2006/42/EC requirements.

Technical Specifications

Engineering Parameter Conventional 90° Tilter Baseline Custom 180° Inverter Specification (Gradin) Shop Verification & Quality Metric
Equipment Model & Type Generic Hydraulic Tilter (90°) SJG-6000-180 Mechanical Inverter Serialized export unit stamped with CE data plate
Rated Coil Payload 5000 kg (Restricted static cornering) 6000 kg continuous rated working capacity Proof-load tested at 125% rated threshold (7500 kg)
Coil Outer Diameter Range Ø1000 mm to Ø1500 mm OD Ø1200 mm to Ø1800 mm continuous handling Verified on dual-pallet stacking configurations
Coil Width / Clamping Span Fixed 600 mm pocket profile 130 mm to 830 mm hydraulic clamp stroke Dial indicator verified across full 700 mm cylinder stroke
Platform Deck Clear Dimensions 1600 mm W × 1600 mm D 2000 mm W × 2000 mm D dual platens CNC flame-cut Q355B plates with flush pallet guides
Overall Machine Footprint 2200 × 1800 × 1950 mm 2630 mm L × 2300 mm W × 2820 mm H Base footprint designed for direct anchor bolting
Machine Tare Weight 2800 kg total mass 5000 kg (1300 kg base + 3700 kg rotating body) Certified weighbridge data recorded for export crating
Turnover Arc & Cycle Speed 0° to 90° tilt in 45 seconds 0° to 180° continuous inversion in 62 ± 3 seconds Timed under full 6-ton steel roll via radio remote
Rotation Drive Mechanism Hydraulic ram linkage tilting Industrial ANSI 80-2 / 16A-2 duplex roller chain Double-strand roller chain wrapping C-drum frame
Drive Motor & Gearbox 3.0 kW cycloidal pinwheel drive 4.0 kW helical-bevel gearmotor (1:126 ratio) Low-backlash hardened helical-bevel gearset
Inversion Dynamic Stability Uncontrolled tipping past 45° Positive C-frame rotating drum equilibrium Runout 

≤

 0.15 mm across vertical-lathed rolling ring

Overrunning Load Suppression Counterbalance valve in ram circuit Mechanical anti-backlash reduction geometry Zero motor slip observed through 90° gravity transition
Support Wheels & Housings Cast iron wheels on plain bushings Four forged 42CrMo wheels (HRC 52–56) + HRB UCF210 Induction-hardened treads with 4 lateral guide rollers
Clamping Cylinder Design Unclamped gravity-wedge pocket Dual hydraulic cylinders (Ø80 mm) + 4 guide posts Hard-chrome columns (Ø70 mm) in graphite bronze guides
Clamping Force & Control Open unconstrained corner 6000 kg dynamic clamping force via 3.0 kW HPU Proportional pressure regulation set at 12 MPa
Hydraulic Pressure Lockup Standard spool holding (drift prone) Hard-seated pilot-operated check valve flanged Pressure drop 

<0.1 MPa

 sustained during rotation

Operator Safety Controls Wired pendant pushbuttons Independent floor panel + industrial wireless remote Dual emergency stops with 180° limit auto-stop switch
Electrical Supply & Standards 380V 50Hz 3-phase generic 400V 50Hz 3-phase (TN-S) per EN ISO 12100 European CE Declaration of Conformity issued
Packaging & Export Finish Bare shipment with stretch wrap 2 modular seaworthy wooden crates; RAL 5012/1023 Base: 2.8 × 1.8 × 0.7 m; Drum: 2.8 × 2.1 × 2.1 m

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