Steel Sheet Inverter and 180-Degree Upender for Heavy Sheet Stacks

Executive summary Our steel sheet inverter clamps a stack of sheets in a C-shaped frame and turns it 180 degrees, so the bottom face comes up or the pallet can come off. It takes stacks up to 3,000 mm long, 1,850 mm wide and 350 mm high, and up to 15 t. A full-size steel stack at that height weighs about 15 t, so the size and weight limits match.

Table of Contents

How the 180-degree turn works

Plants also call this machine a plate inverter or plate turnover machine. The cycle runs in five steps:

  1. A forklift sets the sheet stack on the lower table of the C-shaped frame.
  2. Double-acting hydraulic cylinders close the upper table onto the stack and clamp it.
  3. A motor turns the whole C-frame through 180 degrees on its base, at an adjustable speed.
  4. The machine stops automatically at the end of the turn, and mechanical and electric stop blocks hold the end position.
  5. The clamp opens and the forklift takes the stack away, now upside down.

The video walkthrough follows that cycle end to end: clamp, a 90-degree vertical pass, a 180-degree finish, with the stack held between both tables the whole way.

C-type steel sheet inverter clamping a sheet stack between upper and lower tables
Steel sheet inverter. Hydraulic cylinders clamp the stack between two tables before the C-frame turns.

Why invert a steel sheet stack: face change and pallet swap

We turn sheet stacks for two reasons. The first is to change the face that is up, for example so the underside can be inspected or the next process, such as a steel sheet packing line, sees the right face. The second is a pallet swap: after the turn the pallet is on top and lifts off, and a new pallet or dunnage goes on before turning back.

Stack size and load limits, up to 15 t

Parameter Steel sheet inverter
Stack length 100–3,000 mm
Stack width 250–1,850 mm
Stack height 10–350 mm
Load weight up to 15 t

Steel weighs about 7.85 t per cubic metre. A stack at the largest size, 3,000 × 1,850 × 350 mm, is 1.94 m³, or about 15.2 t, so the size and weight limits meet at about the same point.

Example stack Size Volume Weight
Full window 3,000 × 1,850 × 350 mm 1.94 m³ about 15.2 t
Common sheet 2,500 × 1,250 × 150 mm 0.47 m³ about 3.7 t

A full-size stack is right at the limit, so we confirm the heaviest stack on your list. The basic parameters can also be designed to your load specification.

Technical specifications and integration envelope

Parameter Steel sheet inverter
Turning 180 degrees, speed adjustable
Motor 2.5 kW
Hydraulic system 4.5 kW
Hydraulic cylinder 100 mm (listed as OD), double acting
Machine size about 3,000 × 2,200 × 2,600 mm (L × W × H)
Machine weight about 4 t
Loading by forklift
Control control panel (standard) or remote operation (selection per project)

Hydraulics and safety

Oil pressure, clamp force and contact pressure

The hydraulic oil pressure is up to 14 MPa. That oil pressure acts on the cylinder pistons and creates the press-down force that keeps the load clamped during rotation.

The pressure on the sheet is a different number. It is that force divided by the area in contact with the sheet, so a small contact area gives a very high pressure. Illustrative example for one cylinder with a 63 mm bore (the 100 mm in the specifications is the listed cylinder OD):

Item Value
Oil pressure 14 MPa
Piston area, π ÷ 4 × 63² about 3,117 mm²
Press-down force, 14 × 3,117 about 43.6 kN
Pressure on the sheet through a 100 × 100 mm pad about 4.4 MPa
Pressure on the sheet through a 10 mm² point about 4,360 MPa

That is why the clamp tables press through wide, flat faces rather than points. After a power failure, the machine locks its position automatically and resets softly. Mechanical and electric stop blocks limit the turn. The standards that apply depend on the destination market. For CE markets, ISO 12100 sets the risk-assessment method and EN 415-10 sets general requirements for packaging machines.

Selection checklist for a sheet inverter

  • Stack length, width and height, smallest to largest.
  • Heaviest stack weight.
  • Sheet surface: oiled, coated or bare, and whether the sheets go on to a protective film application machine.
  • Reason for turning: face change or pallet removal.
  • Forklift capacity and access.
  • Local power supply.

Engineering FAQ

Q: How heavy a stack can it turn? A: Up to 15 t, which is about a full 3,000 × 1,850 × 350 mm steel stack.

Q: How thin can the stack be? A: The listed stack height starts at 10 mm.

Q: How is the stack held during the turn? A: Double-acting hydraulic cylinders press rigid flat tables across the stack’s upper and lower faces, keeping a constant clamping force all the way through the rotation.

Q: What happens if the power fails mid-turn? A: The machine locks its position automatically and resets softly when power returns.

Q: How is the stack loaded? A: By forklift, onto the lower table.

Q: How does the clamp avoid marking thin or coated sheets? A: The clamp tables press through wide, flat faces rather than points, so the cylinder force is spread over a large contact area and the pressure on the sheet stays low.

Q: How is the turn controlled? A: From the control panel or by remote operation, with an adjustable turning speed.

Q: How does the machine prevent over-rotation at 180 degrees? A: Mechanical and electric stop blocks halt the C-frame automatically at the completed 180-degree position.

Q: What drives the clamping and rotation? A: A 2.5 kW motor turns the C-frame at adjustable speed, and a 4.5 kW hydraulic power unit drives the double-acting clamp cylinders at up to 14 MPa.

Q: How big is the machine itself? A: About 3,000 × 2,200 × 2,600 mm (L × W × H) and about 4 t.

Next step

We plan your sheet inverter in three steps:

  1. Submit your layout drawing with your stack sizes and weights to info@fhopepack.com.
  2. Receive a proposal within 48 hours, with the frame size and capacity.
  3. Book a site survey to plan forklift access.

Sources

Last reviewed: 2026-10-09

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