Special Report: 'Multi' units drive innovation for film-thickness testing
Among suppliers of film inspection equipment, “multi” is the latest buzzword. At the K show, Hammer-IMS nv introduced its Curtain multisensor device for measuring thickness, Dr. Collin GmbH launched its Multi-Inspection system and Optris GmbH showed its new infrared thermometer. In addition, SolveTech Inc. is offering its MultiChannel Array Gauge, which uses the company’s proprietary technology to generate a 3-D map of a film web.
The Curtain is a non-nuclear device for inline thickness measurement of film and sheet, said Rob Snoeijs, marketing manager for Hammer-IMS, Hasselt, Belgium. It is part of the portfolio of measuring products that were developed by the new company’s co-founders, Noël Deferm and Tom Redant, using electromagnetic millimeter waves. The turnkey system, shown for the first time at the K show in Düsseldorf in October, has been tested by manufacturers of plastic sheet and film, composites and other materials, according to the company.
The Curtain is suited for situations where conventional technologies — such as ultrasound, radiation or optical technologies — typically fail, are undesirable or unreliable, Snoeijs said. The modular system offers micron-level accuracy when used inline during production and consists of a moving metal frame that incorporates Hammer-
IMS’ Marveloc 602 measuring units. The frame travels back and forth, allowing the device to measure the thickness of sheet or film over the complete width of the material.
“Its multisensor approach is a clear differentiator compared to conventional methods,” Snoeijs said. “Plastic sheet and film manufacturers can decide on the length of the Curtain frame and the number of integrated measuring units. This way, the solution supports high-width production and situations where quick feedback is required.” Additionally, the system measures the thickness deviation over the entire width of the sheet or film, allowing it to detect different types of production flaws.
The contactless device is suited for quality-assurance applications, including measurement of plastic sheet used in the construction market and combined thickness and basis-weight measurement of extruded foam sheet. It can be used with a variety of materials, including PE, PP, PET, acrylic and PC.
“It is applicable in high-temperature conditions close to the extrusion die for quick feedback, thereby reducing material waste” and cutting overall operating costs, Snoeijs said.
Dr. Collin GmbH
The new Multi-Inspection system from Dr. Collin GmbH, Ebersberg, Germany, operates by taking a side stream of melt from the extruder and creating a cast film for inspection. It uses different modules for rheological, optical and mechanical tests. The system provides real-time monitoring of melt viscosity; detection of defects in the film; color monitoring; detection of foreign polymers; and determination of stress-strain values.
The modular design allows the compact system to be adapted to customers’ individual requirements, making it appropriate for a variety of applications. Multi-Inspection can be integrated into an existing film production line by means of the Ethernet for inline quality control or used in the laboratory. It features a simple and clear user interface with user-friendly menu navigation. The Multi-Inspection system, launched at the K show, is constructed for mass flow rates up to 5.5 pounds per hour and line speeds of 16.4 feet per minute.
The optical inspection module features a 5 megapixel camera and LED light source. The unit’s infrared module inspects for the presence of different types of plastics, which is useful in recycling applications. Despite requiring calibration for the expected mixture of polymers, the module offers a cost savings compared to conventional near-infrared spectrometers, according to the company. In the mechanical module, the film is trimmed to a defined width and measured by a contact gauge. The film is then stretched and the stress in the film is calculated.
Dr. Collin also offers the Cofis optical inspection system, which detects defects like gels, black spots or fish eyes inline in flat or blown film by using an LED light source and a camera between the production line’s cooling and take-off rolls. At the K show, the Cofis system ran on a cast film extrusion line, said company spokeswoman Isabella Pichler. The system allows the user to define up to 10 classes of errors and 14 error criteria. It is less expensive that Dr. Collin’s existing Coficos system.
Dr. Collin is represented in the U.S. by its subsidiary, Collin Lab & Pilot Solutions Inc., Norcross, Ga.
At the K show, Optris GmbH, Berlin, introduced a new infrared thermometer designed specifically for noncontact temperature measurement of very thin films made from PE, PP and PS. Standard infrared thermometers are unable to measure the temperature of films with a thickness of less than 1mm due to their transparency, according to the company.
“We developed the optris CT P3 infrared thermometer, which measures in a narrow spectral range of 3.43 micrometers, in order to enable a precise temperature measurement of thinner films made of, for example, PE or PP,” said Thomas Heinke, head of development at Optris.
The optris CT P3 is a miniaturized and rugged pyrometer that can measure film temperatures from 122 to 752 degrees Fahrenheit. The sensing head can withstand temperatures up to 167 degrees Fahrenheit without needing additional cooling. The device is suited for retrofitting into existing equipment and also can be used by OEMs. The thermometer is separate from its electronics box, which features a backlit LCD. Available digital outputs include USB, CAN bus, Profibus DP, Ethernet and relay outputs.
In the U.S., Optris is represented by Micro-Epsilon USA, Raleigh, N.C., and Process Sensors Corp., Franklin Lakes, N.J.
The MultiChannel Array Gauge from Solve-Tech Inc., Wilmington, Del., is used inline to measure the thickness of plastic film. The noncontact device uses capacitance technology, said Rob Lawrence, VP of sales and marketing. “The result is a unique offering to the market that has made it the highest-performance unit for webs under 60 inches wide,” he said.
The use of radiation-free technology yields fast, accurate measurements without environmental or regulatory concerns. The device, which features two measurement heads and a C-frame design, can sense even brief web variations. Quick-response features and a proprietary head design allow the Multichannel Array Gauge to provide continuous coverage of the full film surface. Accuracy ranges between 0.1 and 1 percent, depending on the application, and it can achieve precision better than 0.1 micron, according to the company.
Lisa Jo Lupo, correspondent
Collin Lab & Pilot Solutions Inc.,
Process Sensors Corp.,