Robotics in Materials Testing

Zwick is the world leader in the field of automated material and component testing. With more than 450 robotic testing systems installed at customer sites around the world, Zwick has delivered exceptional value to customers seeking the quality and cost advantages associated with automation. Privately-held, the company’s consistent focus on innovation and commitment to outstanding quality have supported its growth in markets worldwide.

In this interview Dr. Cameron Chai, Chief Editor of AZoRobotics speaks to Robert Kaifler, Product Manager, Robotic Testing Systems at Zwick Roell about how robotics have changed the face of materials testing.

Can you paint us a quick picture of the types of testing equipment that Zwick manufacture?

Zwick is one of the world’s leading manufacturers of testing machines utilized to characterize the properties of materials and components. Systems manufactured by Zwick are installed at customer sites across more than 20 industry sectors within both the product development and quality assurance areas. In addition to the support we lend to customers in industry, our company also provides testing systems for academic research.

In addition to the standard suite of test machines, you also offer systems that are paired with robotic elements. What made Zwick consider the development of automated solutions?

The beginnings of our efforts in this area resulted from discussions with a customer account that expressed interest in running tests overnight to optimize departmental handoff of quality certificates. With testing completed during off-hours, the quality certificates would be ready at the start of the operational day, optimizing outbound shipments of product and streamlining the workflow of the quality assurance lab. Zwick listened attentively to customer needs in this area and converted the idea into a solution.

Who typically uses materials testing systems with robotic assistance and what do they test?

Customers in several industry sectors are turning to automation as a means of enhancing product quality. The types of tests conducted are dependent on each customer’s measurement goals and the types of specimens that are to be tested. In the case of material testing – standardized tensile tests are often performed. In the area of component testing, functional tests on assemblies that are used to deliver a specific dose of medication have been optimized through automated solutions developed by Zwick. In the area of food science, we have developed robotic systems to support quality tests on butter blocks. So there is certainly a wide range of applications that we are able to address with our solutions.

What advantages does a robotic testing machine have over a more conventional machine?

The value propositions for robotic testing are enhanced throughput, minimization of scatter in the results, and an overall reduction in the cost of testing. Many industries are subject to regulations that require testing to support the manufacture of products that are safe for consumer use. In these cases, it is critically important that tests be conducted in a consistent manner. Automation delivers precision and consistency which ultimately supports accuracy in measurement. For example, when an operator handles a specimen prior to testing, there is the potential for heat transfer from the operator to the specimen, which influences the test result and creates inconsistency in the results. The robotic specimen handling solutions that we have developed eliminate the possibility of unintentional changes in the thermal conditions for the samples that are to be tested.

How much have your robotic testing machines changed since the first one Zwick manufactured and commissioned?

Our first robotic testing system was delivered in 1985 and the control unit that was provided with this system was state-of-the-art for its time. For the past 27 years, electronics have undergone dramatic changes and computers have evolved. We have kept pace with these changes and we incorporate modern control platforms and computers with each robotic testing system we ship. So the changes have been primarily in the control of the robotic system and the elegance in testing routines that results from incorporating sophisticated control platforms.

Robots are often utilized to streamline the performance of routine tasks. Aside from this area, how do robotic materials testing machines create value for customers?

Some customers have unique needs due to the nature of their business. We have systems installed at customer sites that are operational 24 hours per day and seven days per week. When manufacturing processes depend on the results from routine measurements, it is critically important that the testflows supporting those measurements are optimized. Robotic testing accomplishes this – generating efficiencies in testing operations and enabling accuracy without sacrificing throughput.

Robots are excellent at performing repetitive tasks. How easy is it to program a Zwick testing machine to address testing of different samples or to perform different tests?

The degree to which a robotic system may be programmed to accommodate different samples or to perform different tests is dependent on the application. It is possible to achieve this and we work closely with our customers to define the requirements for testing so the end result is a true solution. It is also worth noting that integrating up to three load frames with different types of tests – such as tensile, bending, and impact – is our daily work. Complex integration is an area of domain expertise for Zwick and we apply this in support of customer requirements. If a customer requires differing test parameters for different specimens, this may be accomplished on an individual basis through a simple host-connection in the control routines. The majority of applications, however, are focused on repetitive, high throughput measurements that must be made with a high degree of accuracy and customers turn to Zwick to leverage the expertise we have cultivated in this area.

Can you give us a couple of examples of robotic testing systems that you have manufactured and what they have been used for, as well as why these applications required robotics?

Certainly. Impact testing is a common test in the plastics industry. Some applications are high throughput in nature and to address this, we have supplied plastics manufacturers with fully automated pendulum impact testing systems that are fitted with a robotic specimen-feeding cartridge. These systems are capable of performing completely automated Charpy or Izod impact bending tests on plastics specimens.

Figure 1. roboTest H pendulum impact tester with automated specimen loading cartridge.

The following video is a demonstration of automated Charpy impact testing of plastic specimens.

At the other end of the market, we have developed entire turnkey robotic testing systems, which we refer to as roboTest R (Polar), to support continuous tensile testing of metals and metal alloys or tensile and flexure tests on plastic specimens. Systems we have installed in this application space often run 24 hours per day and seven days per week in support of manufacturing operations.

Figure 2. A roboTest R (Polar) system supporting high throughput tensile tests on metal specimens.

A solution that we developed for the medical device market is the roboTest R, which performs fully automated torsion function tests on insulin pens. The system is comprised of the robot with mechanical grip for specimen transport, a specimen magazine, and the Z2.5 kN testing machine with a torsion drive for superimposed tests in both tensile compression and torsion directions.

A video of the roboTest R conducting automated functional tests on insulin pens is showm below.

How common are robotic testing machines in the materials industry and how do you see this changing in the next 10 years?

Looking into the future, I’m quite certain that for repetitive, manual tasks more and more industries will turn to the use of robotic testing systems because of the cost advantages that they uniquely offer. The efficiencies in testing operations, coupled with the consistency in measurement that may be achieved, make robotic testing solutions attractive to customers engaged in delivering value to their respective markets. So I forecast that we will see continuous growth in this area.