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There Is Lot of Innovation In The Rubber Machinery – Prof. Dr. Andreas Limper

There is a lot of innovation in the rubber machinery and its adaptation in the industry, says Prof. Dr.-Ing Andreas Limper, Member of the Board of Management, Harburg-Freudenberger Maschinenbau GmbH in an exclusive interview with Rubber Machinery World.

Prof. Dr.-Ing Andreas Limper is a dynamic and well-respected business leader steering HF Mixing Group for over a decade now. A tall technical authority on rubber and polymers, acclaimed author of a few books on rubber, key-note speaker, educationist and much more, Dr.Limper is an inspirational figure.

Hence, this opportunity to present before you his interview, is a privilege to me and a prestigious addition to “Know A Rubber Leader” series.

Know A Rubber Leader

In this engaging interview, you will find him speak passionately about success, challenges, customer frustrations, plans of HF Mixing Group, innovations for tire and non-tire industry, quality and tackling piracy.

Here is  Prof. Dr.-Ing Andreas Limper’s complete interview.

  1. Hello Dr. Limper. First of all thank you for accepting an interview with Rubber Machinery World and sharing your thoughts. The journey from a Mechanical Engineer, specializing in Polymer processing (1981) to Member of Board of Management (2004) of an Organization with 155+ years of legacy is a remarkable one. So let me start with a personal question – What would you say was a key to your success and how you reached the very top spot?

Everybody who has passion for his kind of job will be successful. When I started my career at the IKV (Aachen University), rubber processing was a focal point of activities. It has been very fascinating to transfer methods of engineering to the rubber industry. At that point of time (beginning of the 80’s) the rubber industry was dominated by chemists and a lot of process understanding had to be developed. Being a part of this paradigm change had been very inspiring and motivating. To the new generation, my advice is whatever you do, stop doing it if you do not like it (or can’t change it). The Rubber Industry is an attractive field of work, since it requires multi-disciplinary thinking (chemistry, physics, mechanical engineering, electrical engineering, product design, etc).  

  1. Through organic and inorganic growth (acquisitions), HF currently enjoys an enviable leadership status for its portfolio of products. What’s a challenge you spend a lot of time thinking about these days?

Excellent solutions require holistic thinking in the mixing room. We could show that, for example, by the tandem technology it is possible to save considerable mixing time and even mixing stages in some cases. The integration of the abilities of modern control systems, drives, hydraulics and machine concepts is necessary to achieve lowest possible costs at highest quality. Many customers are still ignoring these facts and tend to keep buying mixing lines as in the old times. In those days, steel and iron, controls and peripheral aggregates have been sourced individually and there have not been a lot of synergistic interactions.

It is a challenge for us to convince customers to leave the archaic way of purchasing and to go for holistic “turnkey” offers.  With our investment into a first class technical center, the building up of a big group of system engineers and control system specialists, we are today well prepared for widespread offers.

HF Tandem Mixer

HF Tandem Mixer

  1. Recently, a reader wrote to me saying “Ever since the inventions of Banbury® and Intermix®, rubber mixing machinery have not witnessed any spectacular invention”. Would you agree with this statement? Where do machinery stand today vis-a-vis the progress (or lack of progress) in rubber technology?

This reader was definitely wrong! Imagine, somebody saying: “Cars today still have four wheels, a motor , a brake and an autobody, I cannot see any new technical concept..”  Would you agree??

Only out of a very big distance the mixers from 1920 and today look similar. We have

  • hydraulic instead of pneumatic rams
  • a controlled ram pressure and a controlled ram position
  • dust stops , which have far less leakages as in the past
  • machines running at least with double speeds as 100 years ago
  • have rotors being at least 250% more productive
  • a tight process control, which uses to control the process parameters to achieve a very high batch-to-batch uniformity
  • a wear protection, which has doubled the lifetime of the mixer components

Apart from the common feature, many people address to the rubber industry, I see a lot of progress in the mixing room. Tangential mixers are offering new rotors with enhanced capabilities for cooling and a higher productivity. Tyre producers are using mixers as reaction vessels (silica compounding) and are introducing intermeshing mixers. The tandem technology is getting an increasing importance and a steep rising market share. Twin screws have conquered the downstream area in many mixing rooms. I have seen a mixing room for final mixing without any roll mill.

Summarizing these shows, there is a lot of innovation in the rubber machinery and its adaptation in the industry!

HF Twin Screw Extruder

Twin Screw Sheeter

  1. What is the biggest frustration today for buyers of tire machinery? How are HF Tire Products and Services addressing this?

As I already mentioned, a missing “holistic view” can be very frustrating. Customers seem to save money, when they purchase their mixing lines “in slices”. This is only a short-term thinking. Normally their own engineering work is not taken into costing consideration or valued to be for free. Also the cheapest product can have the highest “costs of ownership”, since in many times the availability of low-price solutions can be poor. Availability is not only reached by robust and well-engineered products, it is also a function of service. This means customers should also value, what would be the reaction of a supplier, when it would come to problems. By installing a network of own service stations and service partners all around the world, we show a high commitment to achieve highest possible availability for our customers.

To allow our customers the look to a complete line, we have installed two lines in our technical center, where customers can use all components of a mixing line (material feeding, mixer, peripheral aggregates, different downstream solutions, a complete automation system including material and recipe management, process control, lab data etc.) to analyse his personal advantages in practical tests.

Such a detailed practical test had not been possible in the past. Often customers had to use industrial field installations for complete studies, which had a lot of limitations.

  1. How does HF propose to change the rubber and tire industry in the years to come?

I would be very happy, if a broader view on solutions would take place. In our case this would be an entire look at a mixing line – including controls, order and material management. It could be that the rubber industry will lose a part of its market to the TPE industry. In such cases, rubber processors could think about own compounding facilities for these materials.

In the tyre industry, we expect even new challenges from newer materials, as functionalized polymers or surface activated fillers. To develop solutions, which will assure the ability to compound these new recipes at acceptable costs, remains to be a real challenge.

Energy Efficiency will be a big theme in mixing. The relative costs might be only a few cents per Kg, but the absolute costs are approaching very high values in practice. We have developed new drive solutions with considerable higher efficiencies. Besides this we have a quite big research work in which we have analysed the complete energy flow in the mill room. The first results are very promising! By the optimisation of processes, the more intelligent process control (for example the ram-position control possible by iRam), a better use of hydraulics, we see specific energy-saving potential of up to 40%.

All in all, these examples show again, that we should be prepared to look in the bigger scope to the mixing line – then a lot of substantial optimizations are possible.

Know A Rubber Leader - Dr. Andreas Limper

Read PDF

  1. Can “superior-technology” and “low-cost” ever go hand-in-hand in rubber and tire machinery/equipment?

If we are speaking about high quality demands, it is a must!! Look at the major tyre producers. They have analysed the total costs of ownership and keep buying high quality machinery.  For low-quality products, which have to fulfill low requirements, perhaps a cheap solution also works. But for me, even this way is questionable.  A rubber mixing line has a high investment and a very long lifetime. Customers, serving today a low-requirement market, might see the demand for higher sophisticated solutions in a few years. With a line of sight at a low-standard, they are limiting their ability to follow market trends.

  1. Most analysts opine that the production has shifted from west to east in case of rubber goods production. However the customer awareness levels on advances in machinery and its availability, superior technology and its adoption is seen to be better in the west. So, on a scale of 1 to 10 (low to high), where do you rate the practices of manufacturers of the east? What do you think of this disparity and how is HF working to expand your market on newer technologies in the East?

We are actively supporting our customers wherever they go. We have own service activities at our new facility in Slovakia and an own service station in Qingdao/China. The higher personal costs are producing a higher pressure for modernization on western facilities. So in general terms, there is a certain routine for optimizations and process improvements. In eastern facilities, which in many cases are much younger, these skills must first be developed.However, I see eastern European facilities learning very fast. If the western companies in best cases are at a scale of 10, eastern facilities today are achieving results of at least 7.

If I look at Asia – which means predominantly India, China and Southeast Asia, conditions are comparable. These countries have been used by OEM’s, for example car manufacturers as source for easy and inexpensive parts. Companies being active in such business fields are working with very simple and inexpensive solutions. I am deeply convinced, with increasing quality demands there will be a strong requirement for modernisations and upgrades. New technologies, a wide use of automation concepts and new mixing procedures create the necessity to qualify as well the operators and people responsible for the mixing room. By installing our own training center, we are preparing our customer operators for the use of new technology. We see that this is as important as the technology itself.

Rubber Mixing Room

A Rubber Mixing Room

  1. One of the greatest threats to any business is copying of design and features from original manufacturer and offer at a fraction of price. Some politely call it “re-engineering” but any imitation can be quite intimidating. As a respected industry pioneer, I am sure you too would have your share of concerns and challenges. How does HF face this and protect your revenue or profitability?

I like the general thoughts of John Ruskin, who said, “There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man’s lawful prey”.
A mixer is – with a superficial view – not a complicated machine. Its geometry can be copied simply. What “pirates” ignore?  A lot of secrets are in the production methods! Think about hard coating, high precision machining of hardened surfaces, sophisticated controls for ram hydraulics, etc. Also, the correct assembly involves a lot of manual skills which need a lot of experience. If we apply our quality demands, a production of a key component is usually not decisively cheaper in a low-cost country. This means the production of this key components in own premises is the best know how protection.

  1. What do you envision for HF Group in the next 10 years?

I am convinced the market will ask more and more for “solutions” instead of “machines”. This means our group has to be able to deeply understand our customers’ requirements. Our understanding has to include not only the mill room but as well the general product specifications and the value chain of its production. The HF Mixing Group is preparing itself by building up more engineering power and more engineering competence. Our production of key components will be further developed to achieve lowest costs at highest quality. We will as well develop and use our world-wide purchasing network to accomplish the best costs for our customers.

  1. Great! And one last question, what would you advice on machinery selection to buyers and users of rubber and tire equipment?

Let me again answer with a worldly wisdom of John Ruskin. “It’s unwise to pay too much, but it’s worse to pay too little. When you pay too much, you lose a little money – that is all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do. The common law of business balance prohibits paying a little and getting a lot – it can’t be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that you will have enough to pay for something better”.

xxxxxxx

Download the full interview in PDF here.

A highly influential persona up to First World War, John Ruskin’s ideas and concerns are today widely recognized as having relevance in environmentalism and sustainability. Significantly, both are key challenges for the rubber machinery industry as well.  And continued innovation in rubber machinery, I think, is the best way to protect environment and also ensure overall sustainability. With this food for thought, I look forward to hearing from you on this chat with Prof. Dr. Andreas Limper.


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The Anatomy of a Great Batch Off Cooling Line

A Rubber Mixing Room in any tire and modern rubber goods manufacturing unit is incomplete without a Batch Off Cooling Line. This is true especially if you use an internal mixer for your masters, final and remix production.

If you ask a rubber compounding expert, he will summarize for you the functionality of a great batch off in just six words – Dip, Cool, Dry, Stack and Cut.

Perplexed? Read on.

A Batch Off Cooling Line is a robust and powerful rubber machinery that accepts sheets or strips fed into it from a Two-Roll Mill or Twin Screw Sheeter (TSS), placed underneath a internal mixer. These sheets or strips of your rubber mix compound could have temperatures up to 160°C.

At such high temperatures, it is difficult and risky to allow your operators to handle them manually. I say this specifically, because rubber product manufacturers in developing countries who use rubber dispersion kneaders and does not achieve such high temperatures do not adopt a batch off.  Instead they prefer to dip the strips into a cooling tank and deploy labour to do the stacking.

Your batch off cooling line does the job of cooling these compounds to ambient + 5°C and stacks it up neatly in the most effective way with short cycle times.

Thus, you increase your productivity and efficiency.

Typically two types of Batch Off Machines are offered by prominent manufacturers. The most popular one is the Tunnel Batch Off  where the rubber sheets or strips hanging from cylindrical bars moves through a “tunnel”. You also find Cantilever Batch Off with its bars attached to one side only (cantilevered) and electrical cooling racks equipped with number of cooling fans.

Batch Off Rubber Machinery

Image: VMI Holland

Prodicon has two short informative animations on their website to help you understand the difference between the two types of batch off machinery.

The anatomy of a great (Tunnel) Batch Off Cooling Line is as below

Anatomy of a Batch Off Cooling Line

Image: Bainite Machines

Your rubber sheet or strip is passed through dip tank filled with water/antitack solution and then fed into the cooling racks (or festooners). There are cooling fans mounted on the sides (and on top) blowing air into the hanging rubber sheets passing through the tunnel. This gradually cools down the moving sheets or strips.

An auto-gripper assembly grips and lifts the cooled sheet, and feeds into a booking conveyor. This gripping accessory is even more useful, when you have a transport conveyor to take the master batch compound sheets on to the first floor. These sheets would later be fed again into the mixer as part of your two stage mixing for finals.

At one of the booking conveyor, an auto sampling unit helps you to collect a sample of the batch using a punch. These samples (mostly round in shape) is what you send to your R&D for testing and records.

The sheets from final booking conveyor passes through a wig-wag system, that aids in stacking your rubber sheets and strips. Once the required weight of a stack is achieved on the pallet, you cut the sheet (or strips) and replace the filled pallet with an empty pallet to continue.

Optional accessories like Auto Sampling, Auto Gripper, Auto Cutting, Auto Palleter and Auto Stacker further automate your batch off cooling line and reduces labor requirement.

Here is a short video you may want to watch. When you focus on details starting from 3:21 min of this video, you could comprehend effortlessly the above description in action. More importantly, you could visualize how to benefit from the various accessories of a batch off cooling line.

You get both new and used batch-off cooling lines in the market.

Your choice of a Batch Off Cooling Line (and its features) to Dip, Cool, Dry, Stack and Cut your rubber sheets or strips is best configured in consultation with your selected manufacturer or rubber machinery supplier and customized to your requirements.

Picture of a Batch Off

An Image From The Web:  Batch Off Cooling Line

Let me know if you found this post informative.

Or contact me if you seek more details on this machinery selection and their manufacturers.


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Why We Love Twin Screw Sheeter (And You Should, Too!)

Twin Screw Sheeter replaces the dump-mill and sheeting mill combination in a traditional rubber mixing line (an image you had seen in my earlier post – Single-Stage or Two-Stage Mixing?). This means you could visualize Twin Screw (Extruder) Sheeter, as a rubber machinery that accepts mix compound directly discharged from an internal mixer into its hopper chute and converts it into a continuous, seamless rubber sheet that is then fed into a Batch-Off Cooling Line.

For those who have been following my blog, you have already viewed a video of this equipment in action in my earlier post Rubber Mixing Room.

When you explore this equipment for purchase, you should not be surprised with different OEM’s calling it in similar sounding names. For example, you will get a Conical Twin Extruder (CTE) with Roller Head from Colmec SpATwin Screw Roller Head Extruder (TSR) from KobelcoTwin Screw Discharge Extruder (Convex™) from HF Mixing Group or simply Twin Screw Sheeter (TSS) from other rubber machinery manufacturers like Bainite Machines.

In construction, they all appear similar as shown below.

Kobelco Make TSR

Kobelco Make TSR with description

For reading simplicity, let me address this machinery simply as “TSS” for the rest of this article.

You will find the TSS to be ideal for conventional and diverse applications including tire manufacturing, custom compounding, hose & belt manufacturing and technical rubber goods production.

So, here’s why we love Twin Screw Extruder Sheeter (And, I feel, You Should, Too!).

  • Energy Saving: Rubber compounding is a energy-intensive process. So, any technological advancement that has the potential to reduce energy consumption receives my first preference (and I hope you will agree with me here). Let me help you with a quick back of the envelope calculation. If you are using a 270 Liter Tangential Internal Mixer, you are engaging at least two units of 26″x84″ two-roll mills in the downstream section. Each 26″x84″ two-roll mill, requires around 180 kW (minimum) motor power – totaling to 360 kW (=180 x 2) only for the mills. For a similar capacity mixer, a TSS downstream will not seek more than 300 kW power (again, there is energy-efficient models available here). So, this rough calculation, when a TSS replaces the traditional dump-mill with sheeting mill set up, straightaway gives you 16.7% savings in energy (60 kW less).
  • Labor: The second aspect is the reduction is labor cost. Unlike two-roll open mills (with or without ), where you will need two separate operators, a TSS can be set up to perform sheeting function of rubber sheet without an hands-on operator at its vicinity. Even if not fully automated, you do not need an operator once the discharge of rubber sheet from TSS is fed into a Batch-off.
  • Reduced Contamination: In open two-roll mixing mills, your rubber mixing is exposed to the environment and it is difficult to control any dirt or moisture absorption by the compound during milling process. In a TSS, this is eliminated. Your rubber and its recipe constituents are mixed and sheeted-out in a closed environment under temperature controlled conditions right from the time you feed it into your internal mixer. Hence, with reduced contamination, you get a guaranteed higher quality of your mix compound.
  • Self-Cleaning Feature: The Screw and Barrel of the TSS is at a downward inclination (15º) angle from the feed chute section to exit of the roller die head. This incline ensures that compound flow to the exit of the barrel is reinforced and no material remains inside the TSS – hence, the self-cleaning feature.
  • High Mixing Line Efficiency and Productivity: When you install a TSS , your compound batch from the internal mixer is converted into a continuous sheet and the working of TSS can be automatically synchronized with rubber mixing line speed. This in turn, improves the mixing line performance making it more efficient. The continuous sheeting without operator involvement increases your mixing line throughput and overall productivity. Original Equipment Manufacturers (OEM) can offer you customized TSS models beneath internal mixers with throughput capabilities from 500 Kg per hour to 21000 Kg per hour (….and that’s a vast range by all means).
  • Effective Temperature Control: Your rubber compound discharge temperatures from TSS is reduced while sheeting out the material because no additional work (hence no additional heat) is introduced into your compound. Additionally, there is circulation of tempered (or chilled) water inside the conical twin screws, barrel and the peripherally drilled rolls of the roller die. This flowing water facilitates an effective heat exchange to take away the heat from the rubber mix and reduces the compound temperature at the discharge sheeting section.
HF Twin Screw Extruder

HF Make Twin Screw Extruder

  • Compact Layout: Most manufacturers offer various drive options, making the design of the TSS very compact yet sturdy. This means that a TSS can be accommodated under most internal mixers starting from the lowest production range of 16-25 Liter capacities based on the OEM standards.
  • Easy Maintenance: Further, the screw tips of the energy-efficient conical twin-screws do not touch each other and hence there is minimized wear of the screws. A rapid action hydraulic cylinder arrangement for clamping and moving the roller-die calender on rails facilitates the cleaning of the screw tips and insides of the barrel tip during your scheduled maintenance. Also, the TSS does not require external pushers, as in case of single-screw dump extruders. These features make a TSS maintenance easy for you.
  • Additional Features: With increasing trend of Silica usage in rubber compounding, you need to be cautious of the metallurgy and surface treatment characteristics of any rubber compounding machinery you buy. Hence, explaining the major ingredients of your recipe to your OEM is of paramount importance. For example, in TSS you can seek rollers that has hard-surfaced rolls if you are processing silica compounds. This will minimize the compound sticking to the TSS roll and increase its life.

Lastly, this physically very sturdy and robust, rubber machinery is designed for intrinsically safe mixing line operation.

Summarizing, with its capabilities for conventional and diverse applications, a TSS is emerging as the standard downstream equipment in the rubber compounding process for masterbatch and final mixing lines. And that is why we love Twin Screw Sheeter.

How about you?


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7 Must-Ask Questions When Buying Used Rubber Internal Mixer

An Internal Mixer, whether it is a Banbury mixer or Intermix mixer, is the heart of your rubber processing plant. The market for used rubber internal mixer is wide with sellers spread across. You can find an excellent quality pre-owned rubber mixer that can produce high-quality compound mix, without spending excessively.

Rebuild Farrel F270 Mixer From Pelmar Engineering Ltd

Rebuild Farrel Make F270 Mixer – Pelmar Engineering Ltd

Your purchase decision on used or pre-owned machinery has to be thoughtfully made. Because you will see that even in the secondary market for internal mixers, the costs are relatively high considering there could be additional rebuild costs (if not already refurbished by the rebuilder). In any case, you are making a significant investment from your affordability standards and hence you need to consider a variety of factors to help assess the mixer’s value to your rubber compounding requirements and, ultimately, to your bottom line.

Here are 7 Must-Ask Questions when buying used rubber internal mixer that will help you appraise the second-hand or rebuilt mixer value and usefulness to your rubber compounding operations.

  1. What are my mixer requirements?

You need to have a clear idea of what you wish to buy. This entails knowing capacity, the mixing process for your rubber compounding requirements, matching upstream and downstream machinery availability in your rubber mixing room and the remaining useful life of the equipment you are willing to live with.

(Read my post on the Internal Mixer Selection Questionnaire where you can also download a template. You can modify this template to clarify your needs and refine your decision process).

  1. What is my budget?

Your budget will be a crucial purchase factor including the brand, exact model and vintage of the mixer that you can buy. You should have clarity of breakup of costs associated with your batch mixer purchase.

This includes the cost of additional space required (in case you are expanding operations), cost of dismantling (if mixer is running at a particular location) and transporting the mixer to your factory, actual cost of mixer, its controls and accessories to be paid to the seller; plus various duties applicable, to name a few.

  1. Should I partner the right people – the pre-owned equipment sellers?

Given the global nature of rubber compounding business, there are internal mixers available across the key global markets. Hence, it is not possible for you to be informed about the best deals out there in terms of overall cost and mixer quality. This is where pre-owned equipment sellers or dealers come in to help you.

I think, a good dealer will be able to present you with multiple options and help you select the best used mixer for your requirement.

  1. Is the mixer I am considering to buy in Good Working Condition?

Whether buying used or rebuild mixer, you must always test them whenever feasible or you should ask for a start-up guarantee assurance. This is a precaution to be sure that the mixer is in good running order before your final purchase decision.

If you are buying a running mixer, you can easily test them on-site before dismantling. Or if you are buying from a warehouse, many of the reputed used rubber machinery dealers provide arrangements to allow you to test the mixer at least on a test-bed (if not on-site) to help you make a quick purchase decision.

Else, the last resort is a start-up guarantee assurance from the seller. Reputed used machinery dealers  will be transparent on the condition of the mixers they sell, but it is always smart that you check.

When buying with motor and controls, you should verify the operations and safety of electrical components and software licences along with its adaptability to your country of installation. (If not working properly of found unsuitable, you need to factor in the cost of its replacement into your purchase cost)

Another key aspect to check is whether the pre-owned mixer that you propose to buy comes with complete set of manuals, schematics and diagrams. (You may read my earlier post on mixer maintenance here.)

  1. Should I do Visual inspection?

Absolutely. Though the internet has made your communication easy and you can conduct a lot of your business communication online. You can even demand pictures and videos of your mixer in consideration through email. However, there is no alternative to physically inspecting the machinery you are going to purchase.

Used mixers are usually not warranted. This means you need to know the extent of rebuild or refurbishment, and get an idea of the actual state of the internal mixer.

You should insist on a test run of the mixer in your presence and keep your eyes and ears open for tell-tale signs of machine ill-health such as unusual vibrations or noise. Question the maintenance practices of the previous owner and keep your eyes open for worn out parts and leakages.

Additionally, your visual observation of the machinery empowers you to negotiate better with the seller.

  1. Should I Buy a Standard Model of a Brand Name?

When it comes to buying pre-owned mixers, brand plays an important role. Buying standard models of branded and reputed manufacturers of used mixers can assure you about its quality. In addition to this, you will find it very easy to get spares and servicing for a standard internal mixer models in case of future repairs.

On the other hand, if you go for non-branded or non-standard rubber internal mixer, buying and maintaining the spares can prove a difficult task.

Kobelco Make Mixers

Kobelco Make Mixers – Image From Web

  1. Should I get everything on paper?

I think this is a very important step whether you are buying new or used rubber machinery.

You should get everything on record, from the first formal quotation, the details of the rubber machinery, the accompanying accessories, delivery terms, mode of payment, extent of buyer liability, seller liability, etc. It could be an exhaustive document or a simple set of key clauses basis your comfort – either way they are critical to your purchase. (You may wish to explore the rubber machinery purchase and sale agreement here. Preview – Rubber Machinery Purchase and Sale Agreement Template  To buy the full agreement kindly email me directly.)

Once you have answered these questions satisfactorily and determined which factors are most important in your current purchase decision, you can confidently negotiate and purchase a pre-owned mixer that will meet your rubber compounding requirements.

Summarizing, when buying used rubber internal mixer, you need to conduct a proactive due-diligence; identify and partner the apt seller for your needs, and have proper documentation in place. When you make an informed used or pre-owned internal mixer purchase, you avoid buyer’s remorse. 

Happy Buying!


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Top 15 Skills Required For An Internal Mixer (or Kneader) Operator

Rubber Mixing is a capital and energy intensive operation. And mixing machinery are the mother equipment. This could be an Internal Mixer (Banbury or Intermix) or Rubber Dispersion Kneader depending on the size of your organization and/or products manufactured.

Hence, the cost of errors or omissions are very high when compounding a batch in a mixer. You need a skilled operator. Ever pondered on the skills that make a mixer operator successful?

Internal Mixer Operator

Here is the list of top 15 skills for an successful batch mixer (or kneader) operator. (Updated on 23rd Dec 2015: Flip through this post in our digital edition and download here)

  1. Control of Operations – Your mixer operator should be able to adjust ram pressure, control the mixing process, set parameters and ensure its completion as per SOP (temperature or time or energy as programmed/specified).
  2. Monitoring Operations – The most important skill of your operator should be to have a keen eye for watching gauges, dials, or other indicators in the control panel or HMI to make sure the mixer is working properly. He has to ensure that the mixer is kept clean, safety features are functional,  upstream and downstream equipment along with all accessories (like cooling water, hydraulic/pneumatic system, temperature control unit (TCU), lubrication system, etc) are ready
  3. Active Listening – Your operator should be a skilled listener. He should actively listen to the sounds of the mixer and its motor during a mixing cycle; pay full attention to what his supervisor (or you) or his colleagues on the mixing room safety are saying, take time to understand the points being made, and ask relevant questions.
  4. Speaking – Your operator should be able to talk to you (or his supervisor) to convey information effectively be it to report data/problems/incidents as applicable in a timely manner
  5. Reading Comprehension – An operating and maintenance manual is normally supplied together with the rubber mixer. This is a crucial document. Again your compounding process may involve specific work related instructions or SOP. Or there could be a training manual in some instances. Your operator should be able to understand written sentences and paragraphs in these documents. Hence, reading skills is very important for a successful operator. It is not necessary (while it is preferred) that they read English, because you could translate these documents to your operator’s local language for ease of reading.
  6. Troubleshooting, Judgment and Decision Making – Your operator is the first point of contact with your mixer in operation. Hence, he should have the experience or knowledge on mixers to determine/read the causes of any operating errors when they occur, judge the gravity of the error and also decide what to do about it – whether to reset the mixer, or escalate to supervisor or raise a service visit request of the manufacturer’s engineer.
  7. Critical Thinking – Operating a rubber mixer requires critical thinking skills because your operator should use logic and reasoning to identify alternative solutions, conclusions or approaches to problems he faces while mixer is in operation.
  8. Quality Control Analysis – Your operator should have basic skills on quality control with an outlook to meet your set mix quality parameters in every batch. This may involve need for appropriate fine tuning like helping you fix the batch weight, or sending the sample of specified compound/ batch in specified form to lab for testing.
  9. Social Perceptiveness – Emotions could run high in the rubber mixing room. Your operator should display “awareness” of others’ reactions and understanding of why they react as they do in a particular circumstance.
  10. Repairing – Your mixer operator should be able to use the required tools to both repair and assist repair of mixers when needed in the most urgent manner.
  11. Time Management – Your operator should manage his own time and display sensitivity to the time of other co-workers involved in the mixing room.
  12. Mixer Maintenance – Performing routine maintenance on mixer and determining when and what kind of maintenance is needed is an important skill that your operator should posses.
  13. Active Learning – Your operator should display active learning skills. This is because, mixers get upgraded, automation and new controls might get introduced or new methods of mixing could be introduced all of which he might have to learn or get trained in.
  14. Writing – If you could get an operator who could communicate effectively in writing to you (or his supervisor) or to other departments, then I would say you have a great asset.
  15. Complex Problem Solving – Your operator should develop skills to identify and solve complex problems when they occur at site and support maintenance department effectively over a period of time. This reduces the downtime of your mixer.

Do you agree the above listed 15 skills, required for an Internal Mixer or Kneader Operator, are comprehensive? Let us know.


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Rubber Mixing Room

Think rubber mixing room, and the image that conjures up in your mind is that of a “black room“!

Factories that have open two roll mill mixing have carbon black particles all over the place, lending credibility and authenticity to “black mixing rooms”. Dust collection system reduces this to a large extent.

When an internal Banbury mixer or Intermix mixers with semi/automatic carbon feeding, filler feeding, oil dosing and effective dust collection systems are deployed, they present a safer and cleaner environment. Maintenance is easier and mixing rooms need not be “black” any longer.

A representative image of a mixing room is as below.

ThyssenKrupp Mixing Room Image

ThyssenKrupp Mixing Room Image from the web

Depending on the technology and layout adopted, the set-up could vary. And if you are curious to visualize how the complete system works, here is a video of a rubber mixing line.

Automated Mixing Line From Bainite Machines

Automated Mixing Line From Bainite Machines

Newer and most state-of-the-art rubber mixing and compounding factories invest in automated rubber mixing rooms to reduce reliance on labour, increase efficiency and production.


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