The PC based solution - gas related metal fabrications software comes of age

TWI Bulletin, May/June 2002

Martin Bourton joined TWI in 1987 with a degree in Electronic Systems Engineering from the University of East Anglia. As a Senior Software Engineer in the Business Systems and Development Group he manages the design of multimedia applications for training, reference and promotional activities. Martin has also been closely involved in the development of a number of expert systems and web-based software solutions. Clients have been drawn from the automotive and offshore industries, equipment and consumables suppliers and the Health and Safety Executive.

He joined Air Products in 1986 and has been involved in several different research and development programmes, ranging from the fluorination of plastic containers through to his current activity of managing gas-related projects within the welding and cutting section.

There is a vast amount of metal fabrication knowledge that needs to be made available to the welding community, but it is often very difficult to retrieve it. Frequently this information is either confidential or exists only in an expert's head. As Martin Bourton and Richard Wiktorowicz report, to address this problem Air Products and TWI have developed a range of metal fabrication related programs that allows easy access to some of this commonly sought information.

• Be held by fabricators, although it would usually be confidential to that organisation.
• Be held by technology organisations like TWI, although it may be confidential to membership.
• Exist as openly published literature, although it can be very difficult to find.

Even when the information can be found it is often not in a user-friendly form that can easily be understood by the person who needs it.

Where the knowledge resides with a human expert, the information is only accessible once they have been identified. As there may only be a few of them world wide, locating one may take some time. However, you could still not be sure that the answer to any given question would be the same as that from another 'expert'. A further complication occurs when the expert retires or leaves their current employment. This knowledge could easily be lost by the company, requiring time, effort and money to replace.

Air Products recognised that there was a need to make this valuable know-how more readily available to its customers and as a consequence enhance its technical credibility. As a result Air Products commissioned TWI to develop a series of PC-based gas-related metal fabrication expert systems, which could be used locally or accessed via the Internet.

This solution enabled instant access to the combined knowledge of a number of welding experts, overcoming the difficulty described above.

There are many definitions of expert systems, but for the purposes of this paper an expert system is a 'computer program that encapsulates the specialist knowledge of a human expert in a form that can be accessed by other users'. ^[1]

Benefits of the software

• A complete solution to any gas related problems from a single point of reference
• An economic means of resolving a problem
• A fast consistent response using up to date information
• Easy access and use without prior welding knowledge
• Accessibility all year round
• Availability world wide
• Flexibility, as it can be used as a sales tool or as part of a training course

Only a few disadvantages were observed:

• A PC is required. (This is becoming less of an issue)
• Some software requires web access. It is estimated that 500 million people worldwide currently have access to the Internet, of which 220 million are English speaking. It is further estimated that in 2003, 793 million will have access ( www.glreach.com/globstats/)
• Impersonal interaction, but work culture is changing, as more people work from home.

How the software was developed

The Internet versions use streaming technology, in which small packages of information ( eg audio or video) are downloaded, as and when required. This approach prevents long delays and allows the use of relatively large file sizes. The Authorware code is simultaneously compatible with both Microsoft Internet Explorer and Netscape Navigator, reducing the need to tailor the software for different types of Internet browser. Its only drawback is that it requires the user to download a browser plug-in, however this operation is free and only needs to be performed once.

The software

Rapid Response Software

The Minimal Welding Gas Selector and Minimal Laser Gas Selector are used by Air Products to provide a fast response to simple enquiries made either over the Internet or via the telephone help desk. Answers to three or four standard questions are all that is required from the user.

Minimal Welding Gas Selector

This software is used to recommend the appropriate shielding gas for a specific MIG/MAG, TIG or Plasma welding application. Suitable shielding gases are qualitatively ranked without a detailed costing being performed.

It indirectly promotes the concept of using a higher productivity shielding gas, which allows faster welding travel speeds and hence reduced costs.

Gas data and material classification information is also included.

Minimal Laser Gas Selector

For specific CO ₂ and Nd:YAG laser welding and cutting applications, the Minimal Laser Gas Selector recommends the appropriate gas. As with the Minimal Welding Gas Selector, suitable gases are qualitatively ranked without a detailed costing being performed. Similarly gas data and material classification information is provided.

Economic anaylsis software

These programs contain a detailed help facility, giving information on areas such as material classification, recommended current settings, typical duty cycles, etc, to aid the user.

Welding gas selector

In contrast to the Minimal Welding Gas Selector, a quantitative economic ranking (cost per metre of weld) for the suitable shielding gases is provided, along with information on the recommended gas flow rates.

Cutting gas selector

This expert system is used to recommend the most economical cutting gas for the Oxy-fuel, Plasma or Laser cutting based on data specified by the user. ^[3] Like the Welding Gas Selector, it also directly promotes the concept of using a high productivity gas, which allows a faster travel speed and hence reduced costs.

A quantitative economic ranking (cost per metre of cut) for the suitable cutting gases is provided, along with information on the recommended gas flow rates, cutting speeds and cylinder usage.

General advice on cutting and trouble-shooting assistance for specific profiling problems is also incorporated.

Thermal spraying gas selector

The Thermal Spraying Gas Selector not only recommends the most economical thermal spraying gas for a HVOF, Flame, Arc or Plasma spraying application, it also identifies the suitable coating material. ^[4] A quantitative economic analysis for the coating of the specific part is provided, giving a breakdown of the consumable, equipment and labour costs, Fig.7.

Advice is given on the recommended gas flow rates and spraying cost per part, as well as technical help on the four thermal spraying processes covered by the software.

Knowledge based software

Welding fault finder

This software helps the user identify the cause and prevention of weld defects. The system contains information from a number of TWI personnel who have considerable expertise in defect analysis. The system prompts the user to identify the defect and gives advice on the probable causes and preventative measures.

Focus on fume

Focus on Fume is a web site that has been developed to provide information on the harmful particulate fume and gases that are generated by some welding applications.

Most countries place a general requirement on employers to provide a safe working environment for their employees. More detailed regulations usually define exposure limits for specific material types and state what measures have to be taken to prevent or control exposure.

The web site covers:

• The formation and composition of particulate fume and gases
• Exposure limits for Europe, the US and elsewhere
• The regulations for Europe, the US and elsewhere
• Health effects of exposure to fume
• The effect of shielding gases on emission rates
• Control techniques
• Recommended shielding gases to minimise exposure

Training software

Welding fume tutor - Air Products version

The information contained within this package is based on statutory regulations, expert knowledge and practical experience. One of the most important aspects of training is knowledge retention. The interactive nature of Welding Fume Tutor helps students to understand and retain facts about fume.

The following subjects are covered:

• Health effects - What is welding fume? What are the effects on health? What are OELs?
• The COSHH Regulations
• Risk Assessment - How to make a risk assessment for welding fume. What are the consequences?
• Exposure measurement - When and how to measure fume, and how to interpret results
• Controlling exposure - By fume reduction and ventilation

Future developments

The development of an on-line customer database would enable customer profiles to be created. This would facilitate targeted marketing campaigns and provide further insight into future gas sales trends.

Additional knowledge-based software packages under consideration include distortion caused by welding and cutting.

Conclusions

References