A cap is a cap. Or is it?

Flat caps, tethered caps, sports caps and complex cap systems

Any engineer will tell you that caps can be a highly complex affair. If you take a closer look at a sports cap or the sealing top of a medicine bottle, for example, and start to take it apart, you’ll quickly see what intricate components it contains. If you then imagine the same process in reverse — assembling the cap, and automating assembly for series production — it should become clear what kinds of challenges are involved in manufacturing these unassuming items. While consumers value convenience, engineers are excited by complexity and feasibility.

Info: Contexo is an international machinery manufacturer which takes on technical challenges on behalf of global brands and businesses.
It specialises in high-performance assembly machines for mass production. Karl Müller began constructing these machines in 1982, and his three sons have headed the business since 2011.
Contexo’s assembly machines stand out for their technical perfection, high cost-efficiency and versatility. Up to 80 tasks can be integrated into a single machine, including mounting, printing, jointing, gluing, welding and lasing. Contexo machines are used in production lines with an output of anywhere from 80,000 to one billion parts per year. “We have to work and plan in line with the complex automation requirements in this field, meaning that we need to create solutions at all stages of development — prototyping, line integration, initial series development, etc. So we also see ourselves as a sort of project implementer or implementation partner,” says Jürgen Müller.

We decided to look into the issue of feasibility, and that brought us to the company Contexo in the southern German town of Winterbach. The local area is a hub of technology and innovation and is home to a whole host of world-famous names: Daimler, Porsche, Stihl, Bosch, Kärcher and more.

We are welcomed by the younger generation of the founding family. Matthias, Jürgen and Steffen Müller have been running the business since 2011. It quickly becomes clear that team spirit and family values lie at the heart of Contexo. Matthias is now responsible for sales, Jürgen for technical matters, and the middle son Steffen for the back office. “Like Q in James Bond,” says Matthias, underlining how crucial this role is for the entire workflow.

Info: Q is a fictional character in the James Bond films and film novelisations.  Q (standing for Quartermaster), like M, is a job title rather than a name. He is the head of Q Branch (or later Q Division), the fictional research and development division of the British Secret Service. Source: Wikipedia

Their parents, the company’s founders, still play an active role in day-to-day business. Their mother handles the finances while their father takes care of the local Germanspeaking customer base. He has an excellent relationship with the company’s key clients: “Walter Knes from ALPLA always phones straight through to my father,” says Matthias. “It’s convenient for both of them that way, and it’s worked well for a long time now.” The three brothers are proud to have taken on responsibility for the business and, in their own words, are “very, very happy that everything has worked out the way it has.”

We quickly land on the subject of plastic and sustainability. “Contexo makes one hundred percent of its revenue on the back of plastic,” says Matthias, “so some might say that we are ‘sinners’ too.” The industry is nervous, it seems. Matthias mentions the Greenpeace campaign featuring a diver holding a PET bottle up to the camera and asking: “Coca-Cola is this yours?” A slight unease is taking hold, raising the question: What role or responsibility does a small business or supplier have in all this? Jürgen talks of a meeting with a major customer where suppliers were made to commit to developing sustainable solutions. As if the customer were passing on the pressure it was under — as if the industry were absorbing some of the public shame weighing it down and using it as motivation to find better answers. 

Jürgen has had similar experiences in his personal life, for example when friends ask him: “What do you mean, you order from Amazon?”

Or: “You don’t need to drive if you’re only going that far.” And when he talks about his job, he sometimes hears: “Oh! You work in the plastics industry?” The young Müllers are engaging deeply with these issues, and they themselves mention “shame”, the word of the hour. “Yes, we have a conscience, we have morals, and that’s what drives us to make things better.” The subject is so complex that we could talk for hours about carbon dioxide emissions, littering, population growth, fine particulates, plastic reduction, the fashion industry, food waste. Everything is connected, so any imbalance or excess leads to problems. As so often in our conversations within the industry, we also talk about the fact that consumers aren’t always consistent in their approach to plastic and packaging, that convenience often has a counterproductive effect. And once again, we end up discussing the solutions.


The Müllers’ first business was an assembly workshop. They turned and milled parts and produced automated metal band saws. The elder Müller quickly thought ahead when he realised that growing competition threatened to pulverise their profit margin. Together with a partner, he set his sights on automation and automatic assembly equipment. They produced machines for assembling ballpoint pen refills, disposable razors and fountain pens, with a focus on bespoke solutions. The business was a success until one of the projects failed to make the leap from pre-series to series production due to technical difficulties. In the end, the first Müller company went bankrupt. But the dedicated owners bounced back and started afresh.

“The more complex and innovative our projects, the more popular they are”

Today, Contexo serves clients in the fields of beauty & home, medical devices, beverages, lab-on-a-chip devices and consumer goods. It was restructured around five years ago to centre around the individual market segments. In the beverage segment, Contexo produces machines for assembling multi-part caps for cartons and pouches (in the latter case specialising in producing the spout base, not in sealing it to the pouch). For PET bottles and containers, too, the company’s central focus is on multi-part caps, sports caps and caps for kegs, as well as special requirements for seals. Finally, there are add-on caps with a reservoir that can be filled with powder.

Info: Contexo machines for sports  caps process up to 60,000 parts  per hour. With a cycle time of  0.06 seconds, this means that  up to 950 caps consisting of two  to five components are produced each hour.

“We love developing innovative solutions. For us, that means complexity,” says Matthias Müller. “We like the project configuration of mould and machine manufacturers together with converters and brands. The collaboration between the engineers and cooperation with developers is hugely enjoyable.” Contexo extracts a lot of potential from its technological portfolio, drawing on knowledge transfer from the various segments and industries. “For example, we developed laser processes for medical technology and later adapted them for use in the beverage segment.” Matthias Müller opens up Contexo’s ‘magic cabinet’, a collection of completed projects. In meetings with customers who bring their ideas to Contexo, these projects are regularly used as examples — and often leave the customers astonished. “The breadth and diversity of the products we’ve developed means we have the confidence to try our hand in areas that other businesses might be reluctant to enter.”

Naturally, production costs are a key concern. “Our beverage customers calculate based on quantity per area over time.” Complex processes drive up the costs of producing a cap. Every automated process step requires space, creating a need for innovative and compact solutions. As a result, Contexo focuses on multi-part caps with up to 60 process steps. The development of innovative cap technologies began in 2004, when Contexo worked with Aptar on a sports cap project for Adelholzener’s mineral water products. Contexo provides almost no standardised services. It typically follows customerspecific requirements, implementing projects in cooperation with subcontractors. “The order volume for these machines isn’t that big. It’s essentially the case that no two machines are identical.”

The proportion of truly complex caps in the beverage segment is also small enough to remain manageable. The Müller brothers say there is almost no such thing as a repeat order — they would consider themselves lucky to produce three identical machines in five years. But it seems to us that these keen innovators would in fact get bored if they started to receive too many repeat orders, fearing a slowdown in new developments. While their focus is on highly innovative and highly complex developments using cuttingedge technologies and manufacturing and assembly techniques, Contexo’s engineers would surely be interested in optimising existing products as much as they possibly can. Alas, this type of progress is less common for assembly and automation projects.

The brothers describe what makes the company special: “We’re good listeners. We take our customers’ ideas and run with them, drawing on our expertise, our capacity to think outside the box and the potential of our specialists to develop our proposals. And our specialists in turn are so good because they are part of an effective team of around 90 staff members.” 

Matthias Müller says that, as with any business, Contexo does face significant challenges from time to time, especially in conjunction with major projects with multimillion-euro budgets and a time frame of 20 to 24 months that take up a lot of the firm’s capacity. “We manage our projects with respect for the trust that our clients have placed in us,” he says. 

Jürgen Müller returns to the topic of sustainability with an example from the beauty and home care segment: the trigger pump. He says it has been developed over time to provide optimum dispensation and user-friendliness. Now, squeeze bottles with a delivery tube and a small hole for dispensation are coming back on the market. Matthias Müller wonders: Can it really be true that we’re returning to the technology of the 1980s? He highlights the paradox with an example. Discolourations in PET bottles caused by the use of recycled material are met with the utmost scepticism by marketing departments, who brand them a no-go with the argument that consumers wouldn’t accept them. But at the same time, consumers are now being expected to accept less convenient dispensation systems. “It just doesn’t add up,” says Matthias Müller.

The development workflow at Contexo

A typical Contexo project, i.e. the automation of a product that may already be in production using manual processes, essentially involves three participants — the filler, the converter and Contexo.

Jürgen Müller calls the first phase of development the MacGyver stage.

Info: MacGyver is a television series which was produced from 1985 to 1992. The protagonist Angus MacGyver is a combination of secret agent, adventurer and emergency responder. His main asset is his practical application of scientific knowledge and inventive use of common items. He uses this gift to find a range of unusual solutions for the problems he encounters. The word MacGyver has become a synonym for an inventor or engineer in a number of languages.   Source: Wikipedia.

Every project that a customer brings to Contexo is put through a “quick and dirty” assessment to decide whether cost-effective implementation is feasible. Only after the test is passed does the Contexo team turn to constructing a prototype, before moving on to a pilot plant or straight to a series production set-up. “That’s the most effective way. In our experience, customers overlook weak points in their products about 98 percent of the time in terms of automation, handling and function.” A major problem with new products, he says, is that the individual components don’t offer the reproducibility needed for automation. 

It is experience that makes it possible to bring a product from the development phase into pre-series and finally series production. The step from pre-series to high-output series production requires particular attention right from the start of the project. It’s essential to identify the risks associated with a one-to-one transfer. “This step is sometimes underestimated by our customers. So it’s crucial for us to flag up anything in the planning phase that, in our experience, will lead to problems on a high-output line in series production,” says Jürgen Müller. He admits it isn’t always easy to persuade a customer that certain modifications are needed for their product to enter high-output series production. “We have to plan as far ahead and as concretely as possible right from the outset. We know that our customers can’t specify every detail at the beginning of a project. At the same time, we can’t implement excessive changes further down the line. So we familiarise ourselves carefully with the plan, show the customer that we understand where they’re coming from, and draw on our experience to help detect potential problems at an early stage.” Matthias Müller offers an example from the inspection stage that makes it clear what kinds of details can come into play — how do you inspect a drilling hole measuring 30 micrometres?

Contract production

Contexo also uses its own machines for contract production. This is a way to provide customers with initial series 


Markus Müller: “We learn a lot about our machines in the process. When we floated the idea to our family, our mother wasn’t very impressed. “

production until they reach a certain sales threshold which makes it worthwhile for them to start up production in-house themselves. “We learn a lot about our machines in the process. When we floated the idea to our family, our mother wasn’t very impressed. “You want to work nights now too?” was her reaction. Today, a whole hall is dedicated to massproducing items such as cable clips, with three working shifts seven days a week.

As our conversation draws to a close, the Müller brothers once again make clear what’s important to them: expertise, reliability, realism and pragmatism. “We know what we’re capable of. We deliver what’s feasible. And we offer honest collaboration with our customers and partners.” There’s one question the Müllers aren’t fond of hearing when it comes to implementing a project: “Can you even build as many machines as we need?” Too many projects have come to nothing as a result.

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