Introduction
We have developed a wide range of welding consumables and equipment for all processes like SMAW, GMAW, FCAW, SAW in Bangladesh. Our philosophy is to be a solution provider for ship building fabrication. We also have low cost CNC profile cutting, both plasma & oxy fuel cutting machines to increase productivity in plate cutting . Moreover, we have manual plasma cutting equipment for an easy and faster way to cut any manhole in the ship. We have a dedicated and highly experienced team to support you- from selection of consumable, equipment, process support and training your team to produce the best quality ship at lowest cost on stipulated time. We will discuss in this section that changing the present welding process can yield high productivity at lesser cost with assured quality.
Applications
Here are the applications that are mentionable –
- SMAW to GMAW – All positional Welding.(low, medium ,high thickness plate)
- GMAW to FCAW – All positional Welding.(low, medium ,high thickness plate)
- SMAW to SAW – All Plate joining in down handing welding
BSRM wires is a solution provider of welding & cutting
BSRM wires can easily provide solutions in welding and cutting for the following cases –
- Welding Machines
- Welding consumables
- Plasma Cutting & CNC cutting
- Process Training
- Process conversion
- Process quality improvement
- Productivity improvement Training
- Welders training
Present issues in shipbuilding industries
Present issues in shipbuilding industries are manpower, materials and other relevant factors.
Manpower issues generally include these few facts, for instance – how skill workers are very difficult to obtain, how workers are irregular on duty, how they change jobs very frequently.
In terms of Materials, the following issues occur, which are – the non-availability of quality welding machines & other tools, traditional welding machines with less quality, wastage of welding electrodes by welder, wastage of MS plate, gas by gas cutting and how after sales service the availability of machines and tools get almost NIL.
The other issues that arise are – having to face low quality welding (penetration, surface finishing, undercut etc), people management gets difficult (due to high number of workers), suppliers not being able to meet the requirements and above all failing to meet the delivery timeline.
Present welding process in shipbuilding at Bangladesh
SMAW (95%)
It holds advantage for ensuring low investment on equipment
The disadvantages with which it comes up are – low productivity, high weld cost/kg deposit, high wastage of electrode stubs, quality depends on human skill and mood of welder, higher post welding activity cost and cannot be automated.
GMAW (5%)
Advantages of it are – high productivity, lower weld cost/ kg deposit, no wastage of electrode stubs, lower post welding activity cost compared to SMAW and can be automated in many cases.
Disadvantages are the quality depends on the human skill and mood of the welder and investment on equipment is higher.
Modern practice in ship building
The majority of welded joints in ship building is related to producing stiffener panels and welding them together. In production of panels, plates are joined first with SMAW, GMAW, FCAW, SAW, OSW process.
In terms of Global concern, plate joining issues usually prefer SAW and OSW processes for high productivity, no repair, and assured radiographic quality with a high degree of automation.Globally stiffener plates are welded by FCAW, SAW, GMAW process with automation and robotic systems. Some companies also use Vision based robotic systems for welding, as well. The hull structure of ships generally consists of carbon Manganese steel of plate thickness 8- 50mmare also welded with FCAW, GMAW, processed manually or with a low degree of automation.
Solution to overcome issues
To overcome issues, quality – automation, cost- selection of high productive process and delivery – cycle time reduction by higher productive process can be looked through thoroughly.
Solution to overcome the issues (1st step)
In order to come up with a solution to the problem, few things can be put under consideration – Massive use of GMAW and FCAW instead of SMAW for high productivity, use of low cost automation solution to eliminate welder skill, use of SAW in plate joining for plates for assured quality and high productivity, one side welding with ceramic backing strip, use of low cost CNC for plate cutting and use of plasma for plate cutting on deck to work faster.
Solution to overcome the issues (Next step)
For further continuing to provide solutions to the problems, we can also take pragmatic steps, for instance – Automatic one sided SAW system, stiffener welding by Robot, vision based welding system, modern fully automated ship building line.
Ship fabrication steps
In terms of ship fabrication, we can as well take necessary steps, like – flat panel production, double bottom assembly, curved panel production, mini-panel production, Micro-(Web) panel production and profile cutting & finishing.
Issues in ship building fabrication in Bangladesh
The issues faced regularly in terms of ship building fabrication in Bangladesh are – quality – welder skill dependent, cost of productivity low and difficult to meet timeline.
Types of Production System
Flat Plate Production System
Panel size range normally 10×12 m → 16×21 m
Joining of plates – Process
SMAW – Manual
GMAW – Manual
GMAW – with Trolley
FCAW- Manual
FCAW – With trolley
OSW – GMAW, FCAW
SAW – With Trolley single wire
SAW – 3 wire OSW station
Flat Plate production system
Panel size range normally 10×12 m → 16×21 m
Stiffener welding – Process
SMAW – Manual
GMAW – Manual
GMAW – with Trolley
FCAW- Manual
FCAW – With trolley
SAW – With Trolley single wire
GMAW / FCAW – with Robot
Double Bottom Production System
Vertical welding – Process
SMAW – Manual
GMAW – Manual
FCAW- Manual
GMAW / FCAW – with Gantry / Robot
Curved Panel Production System
Process
SMAW – Manual
GMAW – Manual
FCAW- Manual
GMAW / FCAW – with Gantry / Robot
Micro Web Production
Process
SMAW – Manual
GMAW – Manual
FCAW- Manual
GMAW / FCAW – with Gantry / Robot
Robotic Welding of Panels
For welding of – subassemblies with simple geometry, stiffeners/girders on panels, double bottoms and curved panels is useful.
Different programming methods can also be applied, for instance – Welding macros, vision based on-line programming and off – line by nesting with main design software.
Robotized Welding of Panels – Vision System
Conversion of Process Line
Comparison of Process
Case Study 1:
Case Study 2:
