Danish Unika company is a medium-sized company with solid expertise in the production of injection molded parts, which is affirmed by customers around the world. With superior quality, even competitors buy products from the company, and ZEISS measurement solutions, including the three-dimensional optical scanning system COMET, safeguard its quality.
Dedicated to accuracy
Frank Fynbo is the manager of the measurement laboratory at Danish plastic parts maker Unika.
It's four in the morning. Frank Fynbo turned on the lights in the measurement room. In Ans in central Denmark, the sun will not rise until four hours later. The measurement lab manager took a sip of coffee and opened the box prepared for him by a night shift colleague at the Lyngbakkevej Street production workshop. Inside the box are various plastic parts and complex metal injection molds used to produce these plastic parts.
While Frank's wife and child were still asleep, he was already operating the ZEISS COMET system to inspect the first parts. "I like to be here so early," said the 54-year-old. "It's quieter in the morning, and I can measure with more concentration."
ZEISS COMET 3D scanner is laser scanning the plastic casing of the pump
Precision is a unique selling point
A few minutes later, the first plastic part was placed on the turntable, emitting a dark blue-purple light. ZEISS COMET's three-dimensional probe projects structured light onto the component, its camera captures the reflection of the light, and then the software uses triangulation to determine the position of each point on the surface—the three-dimensional size, which can be accurate to a few millimeters.
There are many companies producing injection molded parts, but only a few companies have reached Unika's quality level. Accuracy is an important unique selling point; even competitors order here. For example, Grundfos, the world's leading pump manufacturer, produces its own injection molded parts in nearby Bjerringbro. But for complex parts, they also like to use Unika technology and exchange measurement data because Grundfos also relies on ZEISS machines to ensure quality.
Within a short time, the virtual three-dimensional data of the pump housing will appear on the display. With a few mouse clicks, you can get a false color deviation comparison, showing the deviation of the part from the CAD design data provided by Grundfos. The red area is too thick and the blue area is insufficient. Frank Fynbo clicks on some points in the 3D model, and the software displays the exact deviation values of these points. The well-trained toolmaker who has been working at Unika since 1989 is satisfied. Everything is within expected tolerances. Before purchasing ZEISS COMET, Unika had to send parts to an external service provider for inspection, which was costly and took a significant amount of time.
From ZEISS COMET to computer: Accurate images of real parts are converted into 3D models.
Almost everything is green: ZEISS COMET found only slight deviations in this pump casing. The red area is too thick and the blue area is insufficient.
Precautions during cooling
Every minute, new plastic parts are produced here: the upper and lower molds of the injection mold are joined together with a force of 80 tons, and then the thermoplastic is ejected and solidified. Soon after, the mold opens and releases the hot parts.
After leaving the injection molding machine, the plastic parts are cooled on a conveyor. The finished injection-moulded parts are collected in boxes and handed to the customer.
Measurement results are not always so satisfactory. In injection molding, thermoplastic materials with a temperature of up to 350 ° C are injected into molds with a pressure of up to 2000 bar. In Unika's largest injection molding machines, the injection molds are joined together by forces of up to 1,500 tons. Water or oil flows through the mold, reducing the temperature in a controlled manner until the part solidifies. When the robotic arm was removed from the machine after one minute and placed on a conveyor belt, it was still hot and untouchable. It only cools down after 24 hours and forms its final shape.
Until then it can bend or twist and in the worst case it won't work. This situation rarely occurs in Unika due to the rich process knowledge in injection molding and the meticulousness of Frank Fynbo.
At the beginning of mass production of new products, Frank did not rely only on optical 3D measurement of key components. There is also a ZEISS CONTURA G2 coordinate measuring machine in his measuring room for contact measurement. Frank sometimes inspects plastic parts here, more of metal injection molds made by Unika on modern machine tools. Any deviation of the mold will be reflected in the subsequent injection molding process, resulting in product failure.
Unika relies on the precision of ZEISS: With ZEISS COMET and ZEISS CONTURA, high precision measurement of injection molds and parts can be performed.
Tsai driver
Frank has been using the system since Unika purchased ZEISS CONTURA in 2010. He is also responsible for operating a ZEISS DURAMAX measuring machine purchased in 2014 for fast quality control in the workshop. If the measurement tasks increase, there is no doubt that the next machine will also come from ZEISS.
Frank said: "It was the machines and software that moved us, and our biggest customer Grundfos only used Zeiss machines."
Due to its optical measurement principle, the ZEISS COMET system perfectly complements the contact measurement limitations of ZEISS CONTURA. ZEISS colin3D software for COMET is also compatible with ZEISS CALYPSO software for ZEISS three-coordinate machines. The optical measurement data is saved as an STL file and loaded into the ZEISS CALYPSO software. This makes it possible to superimpose optical measurement and contact measurement, and to make more detailed descriptions of target deviation values and actual values. All data is stored permanently and is always available when requested by the customer.
Small parts, big challenges
ZEISS COMET has been in operation since 2017. The part to be measured by this machine is almost as small as a pin: a plastic pin for the hinge of a spectacle frame. Fynbo recalled: "Because its size was too small for me to measure on the ZEISS CONTURA coordinate measuring machine, we chose the ZEISS COMET 3D scanner. Of course, today it can measure not only the plastic needles of spectacle frames, but also various Plastic parts or tools. Four lens groups for different measuring ranges are provided. In a two-day training course from ZEISS, Frank Fynbo learned how to operate a 3D probe. "I can start measuring immediately, but of course I do it every day studying. "
ZEISS COMET also plays an important role in reverse engineering. Sometimes the parts brought by customers do not have CAD data, sometimes they only have wooden models, and their requirement is "make it out of plastic." If design data is missing, you can use the ZEISS COMET system to generate design data. The work is performed in a partially automated manner; the finished CAD files are fine-tuned by Unika's design engineers. Then iterate through the rest of the process. The tool is manufactured from data, which is first measured by ZEISS COMET and compared with CAD data. If everything works, install the tool on the injection molding machine and make some parts out of plastic.
Check these parts again with ZEISS COMET. If there is a deviation, use ZEISS CONTURA to rework the tool and measure with higher accuracy. Then install the tool again, and the whole process restarts until everything is qualified in the end.
Frank Fynbo is currently discussing the purchase of another ZEISS CONTURA with CEO Bo Johansen and Board Chairman Steen Johansen. The machine will be located in the upper shop where injection molded parts are produced. The workshop implements three shift operations, which run continuously for 24 hours, and then the employees continuously check the quality. Frank smiled and said, "I can sleep a bit longer in the morning."
Precision plastic parts require precision injection tools. CONTURA coordinate measuring machines from ZEISS ensure their quality at Unika.