Keeping a lid on things: Screening in the Food Industry
Genius is largely the product of hard work. When it comes to machine design, this work also requires tackling the User Requirements Specifications (URS). This also applies to Rychiger, which has proven its creativity, flexibility, and expertise in designing and building an innovative lid-filling and sealing machine for Swiss biotech company NEMIS Technologies AG. NEMIS develops, produces, and sells rapid tests (N-Light™) for screening food production environments and equipment for the presence of dangerous bacteria on site and without the need for a lab. It aims to increase food safety during production and protect food manufacturers from having to recall products through the use of innovative technologies and consumables.
How the rapit test works
The design and way NEMIS’ rapid tests work provide a first glimpse of the complexity of the task entrusted to Rychiger: the first step of its contaminant test involves taking a sample of the surface using a swab. The top of the swab is then broken off and placed inside a test tube filled with a special nutrient solution. This test tube is then immediately sealed with a specially designed lid to ensure that any potentially hazardous bacteria are safely contained. After a few hours of incubation, a tablet with the reagent is dropped into the sample. This tablet is sealed off inside the lid and then pushed through the lid’s seal, meaning that the reagent is added to the sample without any need to open the tube. If the sample contains the bacteria that is being tested for, the patented AquaSpark™ molecules introduced by the tablet will react with the sample and start to glow. The NEMIS luminometer can then be used to further analyze the sample.
The machine fundamentals
Rychiger was asked to design and build a machine for filling and sealing the tube’s lid. This task came with the following specifications:
- A 100% reliable mechanism that would fill the lid with one or several tablets (Ø 3 mm, 12 mg).
- The option to fill the lid with a liquid reagent instead of a tablet.
- A reliable mechanism for sealing the lid with an aluminum sealing foil (punched, with a diameter of approx. 14 mm. When doing so, the sealing tool has to move several millimeters down into the lid. The seal has to be applied with extreme precision).
- The option to seal the opening with a second foil with a pull tab made of PET and a print.
- A compact and hygienic design (operated in a clean room).
Rethinking the norm: the LT 20 shows what it is made of
As a specialist machine designer, Rychiger has several platform technologies in its portfolio that can be adapted to meet customers’ specific requirements. After taking a look at NEMIS’ URS, the Rychiger team in charge of the project – Dominic von Bergen (Concept Engineer) and Wolf Koeke (Director Sales LifeScience) – quickly realized that the LT 20 would provide the perfect basis for designing a machine that would meet all of NEMIS’s requirements. The LT 20 is based on a stand-alone and extremely compact linear production and conveyor system.
This runs through the entire system. The fact that the production and conveyor system is linear makes it possible to position the lids with extreme precision without any need for workpiece holders, rotary tables, or pick-and-place robots. Rychiger’s one-stroke punching and sealing technology is a proven system for producing seals from blanks and meets the required levels of precision and reliability without requiring any additional modifications. As Wolf Koeke points out: “Although the system we designed for NEMIS is unique, at its core, it is based on the LT 20, which is linear and modular. This will allow NEMIS to add to the processes being performed on our LT 20 at any time. NEMIS will be able to do so by fitting the unoccupied module stations that we have already integrated with the relevant systems. Thinking ahead in this way ensures that NEMIS will be able to quickly adapt this system in the future to meet any additional requirements as they arise.”
Small and ingenious: the lids
NEMIS’ system was developed by an interdisciplinary team, the greatest challenge for which was working out how to get the lids delivered to the system, individually checked for quality, and then transported in the exact right position down the line for further processing. The quality control module was extremely important, because the lids, which are injection-molded, can have a number of flaws (e.g. holes in the membrane, press button in the wrong place, lid open, blemishes, etc.). Hence, it was important to make sure that flawed lids would be removed from the system before processing.
Handling the tablets: good vibrations
Rychiger also needed to rethink how to approach the tablet module. Initially, NEMIS had suggested the use of a vibrating plate for separating the tablets. This was to include a camera to record the tablets’ positions. Von Bergen: “We quickly realized that, although camera-controlled handling is an excellent and popular solution, a simple vibrating feeder would actually be more reliable and efficient to do the job in this case.”
Hence, the tablets are now transported into the system by a linear vibrating conveyor. They are then separated so that they can be picked up with a vacuum tool and, at an output rate of 20 tablets/min., placed inside the lid cavity. The lids are then transported to another module on the LT 20 where they are heat-sealed before being transported out of the system.
A reliable production line and a happy customer
Daniel Baer, Head of Productions at NEMIS, explains: “This project was a pretty big risk for our small start-up. Rychiger proved an excellent partner for us and always responded quickly and constructively to all of the ideas and requirements we put forward. No matter whether we were talking hardware, electronics or software, we were always able to work directly with Rychiger’s engineers and technicians who were actually building and installing our machine. The LT 20’s linear transfer system and one-stroke punching and sealing module allowed us to create a very compact and easy-to-operate machine that has been extremely reliable from the word go.”
About NEMIS Technologies AG
NEMIS develops, produces, and sells rapid tests for screening food production environments and equipment for the presence of dangerous bacteria on site and without the need for a lab. It aims to increase food safety during production and protect food manufacturers from having to recall products through the use of innovative technologies and consumables. At present, NEMIS’ N-Light™ range consists of the four test systems N-Light™ Listeria monocytogenes, N-Light™ Salmonella Risk, N-Light™ E. coli, and N-Light™ ATP. The company is currently in the process of developing further test systems based on the same technology platform as NEMIS’ N-Light™ range.
