Interview with Dipl.-Ing. Christian Müller, Managing Director of W. MÜLLER GmbH
The blow molding industry has changed dramatically in recent years. Increasing cost pressure and current material trends are constantly presenting blow molding machine manufacturers and their customers with new challenges. At the same time, the current development towards multi-layer extrusion and weight-saving product designs opens up numerous new opportunities that need to be exploited. We asked Dipl.-Ing. Christian Müller, Managing Director of W. MÜLLER GmbH and also Chairman of the VDI Technical Committee on Blow Molding Technology, about current challenges and industry trends - and how the company he runs with his sister is getting fit for the future.
Mr. Müller, how has the blow molding market changed in recent years?
Christian Müller: From my point of view, very clearly. In the 1980s/1990s, 80% of all blow molding machines came from Germany. In those days, customers were literally allocated their machines by just a few manufacturers. Thank goodness that no longer exists today! Today, the Federal Republic of Germany only has a market share of about 1/3 or less worldwide. A large part of the machines now come from Asia. Italy is also very strong. The market has therefore changed massively since then: Today we have to prove ourselves in a buyer's market. That's good for competition, of course.
Perhaps a more important development is the recent trend away from polyolefins and towards PET, for example for bottles and small to medium-sized containers: PET is very clear and also cheaper than polyethylene. However, this polyester is stretch-blown, i.e., it is not processed on classic extrusion blow molding lines. Practically all the major blow molding plant manufacturers are suffering from this at the moment. Of course, there are attempts to counteract this development, for example with modified polyesters such as PETG or extrudable PET (E-PET), but this is still in its infancy.
Have there also been positive developments?
Christian Müller: Absolutely! For example, there has been significant movement in the market for multilayer blow molding. We are registering growing interest in barrier applications, for example. Oxygen barriers increase the shelf life of many perishable products. The motto is: walls instead of preservatives! This is not yet a real boom, but it is a steady development.
We also see a clear trend towards the use of recycled materials, for example, in the middle layer in three-layer operation. This saves pigments, for example, and results in less production waste. In addition, the rinsing times are shorter. These are all solid reasons for this development, which, by the way, is evident in all container sizes. Multilayer is absolutely the trend!
Those who want to be part of this trend naturally need more complex systems. As one of the technically leading retrofit suppliers, we benefit greatly from this, because we offer our customers an extremely economical way of remaining competitive in this sector.
Has contact between blow molding machine manufacturers and their customers become closer in recent years - as it has with colleagues in the injection molding sector, for example?
Christian Müller: No, unfortunately it's not as close as it used to be. You practically only see each other at events.
Like, for example, the 2017 VDI Blow Molding Conference, which you, as Chairman of the VDI Expert Committee on Blow Molding Technology, played a leading role in organizing ...
Christian Müller: Yes, exactly. This conference was indeed once again an excellent opportunity to deepen one's network. In my opinion, conferences are much better suited for this than trade fairs, because you can gather much more information in a shorter time. That's why I'm very happy to be involved in the VDI blow molding specialist committee.
But outside of such events, there is less and less genuine exchange of ideas. There are many understandable reasons for this, but, in my opinion, it could actually become a problem for the industry one day. Instead of developing technical solutions for customers, cooperation is increasingly limited to the mere filling out of tender forms. Decisions on acquisitions or investments are often no longer made by the engineer or foreman who is familiar with production, but by the purchasing department - which often has completely different priorities than the specialist on the factory floor. In this way, however, one ultimately cuts oneself off from innovation processes and also damages one's competitiveness in the long term. This development should be corrected.
We at W. MÜLLER are not yet affected by this to any great extent, because, as a retrofit manufacturer, we serve a very specialized market. We are therefore very often on site at the customer and in close contact with the technically responsible people there. But looking at the industry as a whole, this development can be worrying.
Keyword: innovation processes: Another example of promising processes that are being discussed in the industry is, in addition to multilayer blow molding, foaming technology. W. MÜLLER is known to be very involved in this area. How are things progressing here?
Christian Müller: Good question! This technology is of course attracting a great deal of interest, even in the small packaging sector. With the typical batch sizes in the industry, savings in the gram range are already worthwhile - something is definitely on the way. However, the changeover is still rather slow. Of course, one wants to get to know the bride better first.
But even multilayer and foaming are not the end of the line. The design of blow-molded containers is also changing. The aim here is no longer just to save weight. Today, many products are also sold through their packaging: Design is at least as important as advertising! The aim is to attract the end customer's attention with colors and design gimmicks, which makes the products more and more individual. Package sizes also vary because people in the supermarket have different needs and demands: The variety is much greater than it was 20 years ago. This creates a paradoxical situation: throughputs are increasing, but batch sizes are getting smaller and smaller.
What challenges does this pose for the blow molding industry?
Christian Müller: First of all, of course, purely practical ones: Some inks and pigments are simply more difficult to process than others - leaving aside the challenges posed by higher throughputs for the moment. The demand for heads with a specially hardened surface is therefore increasing - to name just one example. The plastics used for production are also changing. It can be quite a challenge to optimally process the best materials for the application. One example is tough, highly rigid plastics: If you want to process them reliably with high throughputs, you have to reach deep into the blow molding box of tricks. Here, of course, our long experience counts double!
Ultimately, we respond to these developments as we always have: by constantly and proactively developing economical and highly innovative technologies, for example, for the production of bottles with color gradients or containers with varying wall thicknesses - specifically reinforced walls can help to increase their stability and still save weight on the bottom line. We see the new trends as an opportunity and actually owe many new orders to the increasing product diversification.
Are you supported in this by the material manufacturers?
Christian Müller: Not necessarily. Blow molding is rather uninteresting for the large raw material suppliers, unless we are talking about large-volume products such as canisters. There are certainly suppliers who support us with their know-how, but they do not yet convert their reactors for us blow molders, although there are exceptions. Bimodal polyolefins, for example, can now be processed quite well. However, we usually have to work out the optimum temperatures, speeds, etc. ourselves. The process know-how lies with us - and we rise to the challenge.
But I also see a positive development here: since polyolefin manufacturers do not usually offer PET, they have to try to make their material palatable to users again. Perhaps they will succeed in weakening the trend towards PET with new polyethylene grades.
While we are on the subject of raw materials: What role do sustainability and "bio-plastics" play?
Christian Müller: That is definitely interesting! We have already gained a lot of experience with bio-plastics and have had no problems whatsoever with processing. It works very well! The industry is also wide awake in this regard - I'm sure the topic will become even stronger. However, I still see limitations with regard to availability and prices.
W. MÜLLER has made a good name for itself primarily as a retrofit supplier. Is the importance of this approach increasing?
Christian Müller: Yes, absolutely! Because retrofits drastically increase the customer's technical flexibility. And they are also cheaper than purchasing a completely new system.
Think, for example, of a canister manufacturer that now has to meet the increasing demand for multilayer wall structures: Thanks to retrofits, it can trim virtually any of its machines to multilayer and doesn't even have to purchase a new system to do it. With us, the user also finds an almost ideal balance between the joy of innovation and economic efficiency, because as a rather small supplier, we are particularly flexibly positioned and also attractively priced due to the comparatively low overhead. At the same time, we usually even customize our "problem solvers".
Finally, a question that is currently on the minds of many in the plastics industry: What is your opinion on the keyword "Industry 4.0"?
Christian Müller: This is a very important development, which naturally plays an important role for us. In the tough competitive environment, everyone has to utilize their capacities as efficiently as possible, for example, by reducing maintenance intervals.
Our products have of course long been designed with this in mind. All data, such as running time, loads, torques, etc., are tapped and recorded as needed; the user only has to process them. Industry 4.0 has been part of our daily routine for a long time. Living culture, so to speak!
Which path would W. MÜLLER like to take in the coming years?
Christian Müller: We will definitely remain in extrusion blow molding! But in the long term, we want to focus more on large containers, from canister size upwards. We have excellent technologies for this. With our spiral mandrel distributors, for example, high throughputs can be achieved even with stiff materials.
A particularly important challenge, which we would like to face up to more intensively, lies in extruder technology. Current developments demand extruders with ever higher outputs, both horizontally and vertically. These units are the sometimes underestimated but decisive component in extrusion blow molding: In blow molding, not only the throughput, but also the homogeneity of the extrudate is extremely important. The higher the melt stability, for example, the more reproducible the process. Nevertheless, the extruders used in blow molding technology and the concepts behind them were for a long time adopted more or less 1:1 from film technology. In this case, however, it is mainly a question of throughput, and the homogeneity of the mixture has a completely different significance. As already mentioned, blow molding technology has much higher requirements.
But this is only one aspect. If the cycle times are getting shorter and the machines are getting faster and faster in order to increase output, this also requires smart cooling concepts, for example. Faster color changes are another point. These are also things we are keeping an eye on, of course.
Enough to do for the next 40 years ...
Christian Müller: Yes, definitely, because the requirements are also developing further. In the past ten years, the focus has tended to be on head technology, while extruders in general have fallen somewhat behind in the industry. But our 40 years of experience will also help us in the new projects to offer our customers cost-effective and reliably functioning solutions in the end. We already know the levers we need to tighten to achieve this. I am very curious about the future!