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Robot Safety

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Manufacturing safety and compliance with the law

"Big machinery requires a thorough approach to safety and compliance"

This ABB IRB 6700 can lift 235Kg and reach out 2.65 metres from its mounting point. It is built mainly from aluminium castings and when it swings at full extent it can reach velocities of up to 4.5 metres per second.

There are some serious safety issues to consider as well as compliance with the law, so Geku Automation needed someone who had experience in engineering, the law and standards, and who could understand quantitative risk assessment, that's not the finger in the air stuff.

I knew I had an interesting challenge on my hands even before familiarising myself with the 24 volt logic, Programmable Logic Controllers, pneumatics and hydraulics, conveyors, guards and safety systems, of the three robot production line under construction.

My time was divided between the shop floor and the office and I was often on the stairs in between.

My big task - making sure that the machine was safe and legal.

Of course I was working with some experienced engineers who knew very well what they were doing 99% of the time and some welcomed me as the guy that was going to read all the law and standards for them, while a few assumed I was there to impose senseless rules on the workplace.

They didn't know that I will never submit to senseless rules on the basic principle that our first responsibility is to do it right, and following senseless rules is a sure way to mess up big time.

I am glad to say that most of the requirements aren't senseless and for those that are, there are ways to deal with them.

Because we are often reducing the chance of failure from once in 100 years to sometimes less than once in 100,000 years we might seem a bit pedantic at times.

"Well it works doesn't it!" is not the same as saying "If my life depended on this working every time, I would be totally confident." A strike on the head from a working robot is likely to be fatal.

We can't let that happen to you, or your son or daughter or friend or anyone else, and that's why I want to know exactly what the "robot move" signal in that cable is and to be sure it can't be sent as a result of a fault of ony sort.

I want to know that the chance of a false signal in a fault condition is about the same as the chance that a drain pipe left out in the wind will play the national anthem.

Click for more about quantitative risk assessment...

The Law

The EU Directives

The law starts from the EU Directives which say that governments should make laws in their own countries that require manufacturers of machinery to do and consider certain things. The directives list those things pretty clearly and so the governments usually just repeat the list. They primarily set safety requirements. The directives that effected us were;

There are others. They are enacted as law in the UK in the form of;

Compliance is intended to be enforced by the HSE but they have plenty to do at the moment meaning that it is very easy for companies to issue Declarations of Conformity and to CE mark non-compliant equipment! That may be what a lot of them do right now, perhaps thinking that to say you have done something is as good as having done it! If they are following good practice After all 95% of the time they will comply with what is in the Directives but 5% of the time they will not.

My first job was to turn the requirements listed in the directives into checklists i.e. filtering out the legal and delivering checklists that could be applied by people in the company to their work.

How a business fulfils the directives requirements is partly up to them however there are already an extensive set of methods embodied in the various BS EN and ISO standards which lay out recommended ways to do things.

If, for example, you choose to ignore

"10218-1:2011 BS EN ISO Robots and robotic devices - Safety requirements for industrial robots Part 1: Robots"

in your work with robots you are hardly likely to convince anybody that when an accident happens, you weren't being negligent.

If on the other hand, you go through it and make a conscious decision to do something differently from the recommendation given, then provided you can justify it sensibly and show why it was better and safer than the recommendation, you have a strong case.

Indeed if you simply follow the recommendations blindly you may well not have a case at all. Directives and standards requires intelligent application not blind obedience.

Geku Automation

"Geku Automation are a leading UK based Industrial Robot integrator and Automation Systems supplier and for many years they have been providing automation solutions to all sectors of manufacturing industry. Whatever your requirements, whether it's the smallest automation project or a large multiple robot based turnkey automation system, Geku can offer a solution."

www.geku.co.uk

The Standards

Standards are everything

My second job was to compile a list of the standards we needed to comply with and there was a few, 29 to be precise. It pretty rare for a business with a turn over under £10m to have to deal with so much and that is why I was called in.

There is a lot of overlap between the standards and they are far from perfect sometimes being verbose and imprecise but they do contain a great deal that should be practised and a very few things which should not. Ploughing through is a mission and then checking what you have read against the machinery another.

At one point I spent an hour or two sitting on the end of a roller conveyor with a printout of BS EN ISO 4413:2010 on hydraulic fluid power and a pencil running between the hydraulics and my perch.

The majority of what is in the standards comes directly from the experience of people who have been in the industry over many years and perhaps can "do it" better than they can "say it".

This is precisely why any successful engineering business is likely to find that it is already 95% compliment. Some industries need to consider just one or two standards but some unfortunately have a greater responsibility and robotic manufacturing is one of these.

Does all this work make a difference? Yes it does. Two examples;

Re-assuring ourselves and the customer that we have taken all the steps necessary; checked the limits of every part to determine the limits of the machinery, set the maintenance schedule, determined the safety proceedures based on real rather than imagined hazards, and advised them appropriately, so their system to run safely for 20 years or more, that is a valuable service and one that makes a product stand out in the market place.

Because there were so many standards to look at I catagorised them under 9 headings. I doubt most engineering businesses would need to comply with all these but I thought I would give you some idea of the work load in robotic production lines.

Risk Assessment

Fire Prevention and Protection

Robots & Integrated Manufacturing

Design and Integration of Safety-Related Parts of Control Systems (SRP/CS)

Design & Construction of Guards

Human Bodies

Hydraulics, Pneumatics & Conveyors

Electrics & EMC

Signs Signals & Instructions