As demand for vehicles continues to grow across various markets, a quick fix for OEMs looking to increase production volumes in existing plants is to add to the existing depth of automation. Reducing the human element in the production process mix can substantially increase throughput, while quality can also be positively affected, reflected in a reduced amount of rework and in overall finished vehicle quality.
Those are the benefits. The drawbacks to increasing the number of robots and robot-assisted operations, aside from the required capital investment, are that while this will reduce the number of processes completed by hand, there are few examples where people can be completely eliminated from the factory floor.
Body-in-white is a case in point. Many modern plants boast BIW shops that are 100% automated, but while this means that there is precious little human intervention in the actual welding process the robots must still be maintained, which by default means that humans must enter potentially hazardous areas. Even with self-assessing robotics that can check and replace worn welding tips, cables and other peripherals must be examined and replaced by staff in order to avoid expensive down-time due to automation failure.
Further to this, there are other cases where despite the addition of automation, there remains an inherent link between man and machine. Tier One companies producing smaller pressed parts for delivery to OEM bodyshops are a prime example, as in many cases it would be unfeasible to replace an operator with a robot in order to add blanks and remove parts as they are produced.
At the headquarters of Sick in Freiburg, Germany, Claus Melder, of the company’s Industrial Safety Systems division, outlines what the series sensor and scanner manufacturer can do to reduce the potential of an accident occurring in an area where workers and robots are required to interact. “Our core function is to protect people, usually fingers, hands, feet and legs. Our main mission is to stop the machine when someone is detected.”
According to Melder, safety-related consultancy activities represent nearly 15% of Sick’s annual turnover. While the division can advise companies on how to achieve the necessary safety standards in order to start exporting into a region outside their own manufacturing area, another key area is the analysis of customer installations in terms of potential safety hazards. Unfortunately, he explains, this is rarely a proactive request. “Imagine you are a part producer or an automotive OEM, and then you have an accident in your plant. The management realizes that their plant is not as safe as they thought it was; typically, the trigger for our services to be called in is an accident.”
At this point, Sick is invited to help make production processes safer, usually by conducting a plant walkthrough, though even this consultative service has its limitations. “If we went by the book, we could make the plant 100% safe, but this could be a huge investment. We would like to do that, but then we would be in the situation of if you call us, it’s like calling the devil. So we make the plant safer and help prioritize the budget.”
Melder goes on to explain that upon completion of the walk-through, the next step in the process is to generate a document identifying the major problem areas and how the company in question would be best served by directing the available investment capital towards the processes most in need of added safety. “Typically, one or two days after we produce a chargeable document, we will receive an order to work on one part of the production process.”
The fact that not everything highlighted in the walkthrough is corrected could in of itself be a problem, so care is taken to make recommendations in an advisory capacity, that problems ‘could be corrected’. Essentially, theis offers companies with limited resources the choice to address the most important safety concerns.
Automotive, he continues, can create an interesting dilemma for the company’s consultancy process, due to the possibly remote geographic location of the headquarters in relation to the end user. “Headquarters will prescribe the safety systems that must be delivered from Sick,” says Melder. “This note then goes to the plants, which may be in Germany, China or Brazil, and it is up to the staff there to figure out how to set up and use the equipment. What we can do is inspect to make sure the equipment is installed correctly – it’s no good having a safety product if it’s not installed in the correct way. We can go through the plant before start of production and check the safety functions, then go back as part of an on-going, rolling service every one or two years.”
These periodical checks must be carried out by trained personnel at the customer’s site – while 3D simulations can replicate exactly what a machine is doing, it is the local arrangement that makes the difference. As Melder says, in theory everything should already be setup correctly and the consultancy service is only onsite to verify as much. That aside, incorrect installation is still common, the equipment having been put in place by untrained personnel, or related equipment has been deliberately bypassed in order to improve ease of installation.
Of course, the key question is that if Sick advises that a certain package needs to be installed, is the company liable for anything that goes wrong after the changes are implemented?
“The answer is yes and no,” says Claus Melder. “The key to services such as these is to treat them as a product; you must describe exactly what the service does. There are services we offer where we become liable, and there are services we offer on a consultancy basis.” Essentially, consultancy of this type consists of three elements: Limitations, training and process.
“You and your customer have to know what the service can and cannot do. You describe the technical features, what the product does and that it will only work under certain conditions. What’s true for equipment is the same for services; we do this, but not this. If you want to offer these services, you must have trained personnel. You must be clear that the person doing the plant walk around has the required knowledge and that knowledge has been assessed on a regular basis, to where they demonstrate a certain level of competency.
Individuals must achieve certain classes of competency, because not every person can do every service. Lastly, there must be a process, the service has to follow rules and principles. Some of the things we’re liable for will require signatures. All this must be documented and there must be a process by which this is archived. These are some key elements in making sure the customer gets what he wants while we make sure we don’t run into a liability case.
“Of course, we are insured, but insurance is only for after the fact. We have never had a liability case. Our goal is to not need our insurance, this is our main task.”
While safety is a critical element to the services offered by Sick, they can also assist with various other compliancerelated issues. This is generally related to companies gaining the correct certification paperwork in order to start exports into regions outside their home territory.
“The main problem is that you have a machine builder in another region that is not familiar with European norms and standards or American versions. So you need to make his machine safe, as if he wants to export into Europe he needs to have a ‘CE’ sign. For a CE sign, he has to have all his paperwork ready, and we can help.
“We can provide a safe work environment on the shop floor. We can help our customers reduce the risk of being sued. Even if there are no rules and procedures in a country and somebody has an accident, he can sue. This becomes more important with big companies, even if they are not legally obliged to do this. If a big automotive company such as GM comes to China, even if they’re not obliged to have certain safety standards, they still maintain certain standards as this is their company policy. They want to provide a safe workplace where the potential for accidents is reduced to a minimum.”
Although Melder uses China as an example of a country where there are few safety standards companies are required to meet, he notes that as the world becomes more focused on safety in manufacturing, Chinese companies are looking to improve their own safety standards. He cites the example of FoxConn, the world’s largest producer of electronic components. Larger than either GM or Toyota in terms of employees and turnover, the company has been investing to provide employees with an improved workplace.
Sick sells its safety products, light bars, sensors, etc., to a wide range of industries, including automotive, food and beverage, electronics, solar and machine tooling. Yet the same safety theory can be applied to a vehicle plant or a packaging facility, in that the measurement standard remains constant. For example, if there is zero automation, there is no need for safety equipment, as every operation is completed without machine assistance and there is nothing in the given plant to protect against. Without factoring in the need to maintain robotics and other automation, a plant with 100% automation falls into the same category, as there is no potential for man/machine interaction during standard operations.
Yet despite this, Claus Melder observes that where many plants had looked to achieve 100% automation for the associated benefit of reduced costs and improved quality, this type of installation can severely limit the level of flexibility – to some measure, it was completely removed. With that in mind, he says that the need for safety equipment is at its highest when the depth of automation is between 60 and 80%. “We found this to be true across a range of industries. In steel production, there is a lot of safety needed. If there’s a conveyor transporting hot material, or a transport for molten metal, this is a very dangerous situation.”
Melder says that in addition to field service and repair functions, the company employs approximately 150 people trained to assess the safety needs of individual plants. “This is quite a lot of people, but when you have a safety issue, you not only need someone who knows the products, but you also need someone who understands safety consultancy. We analyze and inspect about 10,000 machines per year, which helps us to understand various industries, what the machines do and, importantly, what they don’t do.”
The basic rule is that safety equipment is designed to separate the given machine from any potentially dangerous movement performed by an employee. In any industry, including automotive, this means that between the operator and the machine there is a safety installation - when that individual creates a potentially hazardous situation by placing themselves between the safety equipment and machine, the machine stops. Melder: “This is still how 80% of equipment is designed.”
The latest safety technology, which is already in use across the automotive sector, involves flexible safety areas – where movements are considered dangerous in one section but not another within the total area surrounding a given machine. “You have the robot doing something, the person is working. Then it changes, you have a station that at one part of the movement is dangerous, while the operator can work when the robot is not there. So you have those logical functions in flexible areas. For this you need more powerful, flexible safety equipment, because it has to detect dangerous situations and movement.”
A typical case where this occurs is in the press shop. Clearly, the press itself does not present a hazard; it is only when the tool is in the downstroke motion that it presents a danger. This means that the light curtain must measure where the machine is at any given point, and whether it is in the upstroke or downstroke movement. “This is a flexible safety area,” says Melder. “It’s very complex and as a safety provider, you are not allowed to make an error. Judge incorrectly and there will be an injury. You have to add logic and assessment to equipment and you’d better do it right.” Continuing, Melder says that the ‘dream’ is to have full co-operation between man and machine in the same area.
For this, three-dimensional stereo systems would allow the robot to ‘see’ where the operator was at any given time, and stop (or at least slow down) should it predict contact. Unfortunately, the support for this depth of intelligence is, he says, still not available. “Making the robot safe is not enough. The robot knows where it is, but you still need to define safety areas. Depending on where the robot is going to go, you can activate successive safety areas around the cell. It’s not 3D, but it’s getting close.”
That leaves the human operator as the weak point in the equation. Robots will repeatedly perform the same series of choreographed and predictable movements; the same cannot be said of a human operator. This further complicates testing procedures to determine whether a given safety installation provides the necessary level of protection.
“With safety you have to be 100% sure. Not 99%. If you’ve a robot that completes 10,000 cycles per week and there is a 1% error margin, that’s 100 injuries per week. Once the equipment is installed, you have to be sure it is 100% accurate, zero mistakes.”