Four Roll Plate Bending Machine

Unmatched capacity. Superlative precision. Optimal turnout.

Industry 4.0 Ready

Future-ready machines, ready to integrate and automate

Experience Easy-To-Use bending Capabilities

Our top-of-the-line Plate Bending Machines are designed for hassle-free usage and energy saving features; to ensure peace of mind and operational ease for plate bending jobs.

Krrass’s linear guided machines deliver a multi-fold advantage to your fabrication infrastructure – a remarkably efficient and lasting performance, an unbeatable edge bending precision, reduced capital expenditure, and lower ongoing operational and maintenance costs.


Four Roll Design

Roll Movement in Four Roll Design

  • These Plate Bending Machines have four rolls and liner guidance for the side rolls.

  • The Top roll remains fixed, the bottom roll moves vertically, and the two side rolls move in liner guide way to form the shell.

  • The top and bottom rolls are power driven by planetary gearboxes with hydraulic motors.

  • Thin Plates need closely spaced rolls to avoid driving slippage.

  • Location of the bottom roll directly below the top roll ensures very good grip on such jobs.

  • Due to the high productivity of low thickness shells, the four roll machines prove to be an attractive investment for mass production of pipes and shells.

  • Over and above the cones, other non-circular shapes like oil tankers & elliptical shells can be made.

  • This type of roll configuration also facilitates CNC operation.

  • 20-30% higher Investment for the same thickness capacity and span compared to similar three roll machine.

Krrass’s Four Roll Machines deliver par performance and flexibility. They are also extremely durable and accurate, and are therefore ideal for medium-to-heavy duty rolling.

The KRRASS Advantage

16,000 square meters of manufacturing facility in Nanjing, China’s Engineering Hub that strategically allows us easy access to infrastructure facilities like transport, raw materials, skilled workforce, power supply etc.

Our manufacturing excellence is underpinned by continuous product development. We have been leading the industry since over 40 years in design, build quality, performance and value for money. All our designs have been developed in-house and are fully supported by us.

We have manufactured and commissioned over 2500 machines across China and overseas. The first machine we ever sold is still in operation and is proudly supported by us.

We enjoy loyalty of over 400 delighted clients. Beyond excellent performance of our machines, they also enjoy our on-demand service and our ever-ready inventory of a full set of spares for all machines we manufacture.

Enjoy the peace of mind that you are in good hands.

W12 - Series Product Range

ModelMax Bending Thickness
Pre-bending Thickness
Roller Working Length
Plate Yeild Limit

* All Sizes in mm.
* All capacities are as per 260 MPA.

We offer machines with fixed as well as variable speeds according to your application and feed requirements.

Build Quality & Benefits

Sturdy Steel Structure

Krrass machines have a robust steel structure made from heavy metal plates. The frames are connected to each other by a strong box design chassis. The frames have interlocks & strengthening ribs. The roll guideways are machined together utilizing a fixed single reference point which allows for parallelism of all axes and precise surfaces, as well as longevity and precision of the critical characteristics of the machine.


The rolls are the most important elements of our machines. Krrass designs the rolls with optimal diameter and uses forged carbon steel rolls that are machined by high precision CNC lathes. Our rolls have a special spline-based design that is extremely efficient in connecting the rolls with the planetary gear system. This diminishes points of roll failure compared to welded connections provided by other manufacturers.


Our rolls are crowned to compensate for roll deflection during the bending process. Custom crown-machined rolls for different materials or thickness can be selected when ordering.

Hydraulic Gear System

Additional energy saving is ensured in our Four Roll machines by a hydraulic system which can work at less than full capacity when jobs less than maximum thickness are rolled.

KRRASS Planetary driving system ™ used in our machines is efficient and eliminates energy wastage associated with heavy-transmission systems and yet achieves the goal of speed reduction by increasing the stages in gears and pinions. 

Operational Benefits

Pre-Pinching (Pre-Bending)

Edge bending can be done before or after shell rolling depending on operator skill and choice. Thin plates can be rolled and edge-bent in a single pass.

Easy Cone Bending

The cone bending process with the W12 series is simple. The bottom rolls need to be inclined to achieve cone bending geometry. This is controlled and monitored by electronic microprocessor (on some models). 

Our control system also ensures easy and accurate return to parallel setting after cone bending resulting into precision on repetitive jobs.

High Productivity

  • State-of-the-art in forming cylinders and cones.

  • Easy to install, extremely user-friendly and convenient to service. 

  • Simple to learn and operate. No extensive operator training required.

  • Robust construction reduces wear & tear.

  • Readily available spare parts.

  • Tropicalized oil cooling system ensures non-stop operations in hot working conditions.

  • Easy to understand hydraulic and electrical system reduce unwanted down time.


Other than cylinders and cones, other non-circular shapes like oil tankers and elliptical shells can be made using a PLC version. 


  • Due to the exceptional build quality, failure-resistant linear guideway design, high operational precision, and a wide range of jobs that can accurately rolled, the F series machines prove to be the most attractive investment for any type of industry, regular production or a job shop.

  • Due to a variety of accessories that are available to enhance the machine capability, the investment is justified in more than one way. The energy saving features and negligible maintenance cost also promise a low running cost.

Additional Features

Alongside our excellent design and build quality, we provide the following additional features and accessories upon request from our client.


Surface-Hardened Rolls

Induction Hardened Rolls having Surface Hardness between 42 to 55 HRC for additional durability and longevity.


Tilting Table

Tilting tables for support while feeding plates at specific angles. Specially useful for plates of larger lengths.


Complete Windmill Tower Manufacturing Package

Including central and side shell support, tilting conveyors, hardened rolls and PLC/CNC capabilities



Powered Conveyors that provide ease of plate feeding in case of longer plate lengths, improved machine performance and longevity.


Central & Side Shell Supports

Central & side shell supports provide ease of operation, operational cost saving and productivity while increasing safety of workers.


PLC Control

PLC Controllers provide precision, ease of operation, while identifying needs for preventive maintenance to increase machine life and optimize productivity.


Hard Chrome Plated Rolls

Hard chrome plated rolls for special applications in Pharma and Dairy Industry.


All rolls are crowned (cambering) for compensating deflection.

Top roll is counter balanced automatically once the drop end is opened without any jacks or manual arrangement.

DRO (Digital Readout) is housed on the operating console which gives the position of the bottom rolls with respect to the top roll.

Cones can be bent up to the edge-bending capacity of the machine. The bottom rolls can be inclined for the required cone angle.

Some of the electrical bough outs are IP 55 like motors, switchgears etc. The electrical cabinet will be manufactured as per our standard practices and will meet IP 55 protection.

Forward and reverse to the main drive is provided. The bottom rolls can be moved up and down individually.

Hydraulic oil – Enklo 68 Planetary Gear box – EP 90

Operating console houses push buttons for all the operations of the machine. The console is movable so that the operator can keep it at any desired location.

Although the standard machine is not meant for hot rolling, occasional hot rolling can be done (a few jobs per month) provided that suitable precautions are taken.

A. Divide the Actual YP by 26. Find square root of this number. Multiply this value by actual plate thickness to get effective thickness.

If you want a price, fully catalogue or other informations, pls contact us

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