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What the Heck Is Rubber Creper Machine?

Last month, on a visit to God’s Own Country and Land of Rubber – Kerala, I had the privilege of getting acquainted with a different class of rubber machinery namely the TSR Processing Machinery.

Most of you would know that TSR stands for Technically Specified Rubber. And for few hardcore rubber machinery enthusiasts, like me, TSR also means Twin Screw Roller.

So during my various interactions with rubber entrepreneurs, the words RSS, TSR and Creper were being spelt-out at frequent intervals.

Fortunately for me, RSS and TSR were familiar terms!

If you are into rubber sourcing, you already know that introduction of Technically Specified Rubber (TSR) has standardized the rubber grading and simplified procurement for buyers. This means, you now have the choice of not relying only on visual assessments (read RSS) that are subjective.

Instead, you assess the actual content of foreign and volatile matter in TSR to pick up the right choice of rubber grade according to your product processing requirement.

Depending on the origin, standards may marginally vary. You have Standard Malaysian Rubber (SMR), Standard Thai Rubber (STR), Standard Indonesian Rubber (SIR), Standard Sri Lanka Rubber (SSR), Standard Vietnam Rubber (SVR), Indian Standard Natural Rubber (ISNR), etc which I consciously leave for the rubber experts to comment.

During first few exchanges, I gathered that Creper referred to specific rubber machinery for TSR, while subsequent meetings helped me put together a first-hand perspective.

CREPER

Image: Creper by Hevea Engineering Works Pvt. Ltd.

So, What the Heck is Rubber Creper Machine?

To understand better, let’s start with a holistic view.

Any TSR production line (starting with cup/crumb rubber to bales from stacked rubber sheets) involves a series of main machinery and allied machinery lines as you will observe from the flow chart below.

TSR-Processing-Flow-Chart

Image: Processing Flow Chart From Web

And Rubber Creper Machine is the main TSR processing equipment used for cleaning, thinning and flattening. They are also known as ‘Crepe Rubber Machine’, ‘Macerator’ or just ‘Creper’.

It can flatten your rubber to creping piece which have a certain water and thickness prior to granulating.

Tom C. Abraham, director of Hevea Engineering Works Private Limited informs me, “This machinery can be used as a pre-cleaning or size reduction machine as well as for the blending of crepes prior to final size reduction.”

Tom definitely knows better since Hevea Engineering Works (HEW) is one of the leading TSR Processing Machinery Manufacturers having executed many turnkey projects in the last 20 years.

TSR Processing Units can be seen in Brazil, Cambodia, Cameroon, Congo, Gabon, Ghana, Guatemala, India, Indonesia, Ivory Coast, Liberia, Malawi, Malaysia, Mexico, Myanmar, Nigeria, Papua New Guinea, Philippines, Vietnam, and Thailand.

The sizes of the units do vary.

Construction of a Rubber Creper Machine

Structurally, a Rubber Creper consists of front roll and rear roll that are mounted on Cast Iron (CI) frames, adjusting mechanism, transmission mechanism, gear reducer, motor and heavy-duty Mild Steel base plate.

One Creper unit may consist of 1-5 sets of individual Crepers.

Mostly, the rolls are made of Cast Iron (CI) and the connecting gears are made of EN-8 material.

Operation of a Rubber Creper Machine

The Rolls of this Creper have special grooving that is designed for excellent shearing effect on rubber. The shearing effect reduces crepe thickness of rubber blocks and rubber granule.

Reduction in the size of the thick blankets of crumb rubber crepes happen at the intermediate second stages and final stage of the cleaning process. After several passes through the Creper, the crumb rubber can be easily dried without the occurrence (or appearance) of white spots after the trolley dryer in your TSR production process.

rubber-creper-machinery

Image from Web

The connecting gear mounted, with friction ratio imparts relative movement for the rolls, which makes the material flatten out. The shearing effect of the Creper together with the spraying of water on the rolls further assists in efficient dirt removing of foreign contaminants trapped in the rubber coagulum.

Simultaneously, this speed difference between front roll and rear roll induces knead action and shred rubber material into granulating shape, bar shape and honeycomb shape.

Various equipment suppliers offer you roll diameter sizes ranging from 8-inches to 24-inches with electric motor drives of 10 HP to 125 HP. Roll speeds, drive arrangement, friction ratio and grooving patterns can be customized and selected to suit your requirement.

The throughput of a Rubber Creper varies from 1 to 10 Ton DRC /hour depending on roll speeds. (DRC means Dry Rubber Content). Reputed manufacturers offer robust and accurately built Creper machine to meet your requirements.

Here’s a wonderful short animation video from Golsta that shows the Rubber Creper Machine, quite informatively.

Creper-Animation-Video

Click on the image to see video

While investing, you may have to decide the production capacity of Rubber Creper Machine according to your production line and layout requirements.

Adds, Tom C. Abraham of Hevea Engineering Works (HEW), “For a unit planning 40T/Day, your TSR processing line may need appropriate sizes of Slab Cutter (1 No.), Pre-breakers (2 Nos.), Hammer Mill (1 No.), Rubber Crepers (6-7 Nos.), Shredder (1 No.), Dryer (1 No.), Baling Press (2 Nos.) together with its ancillaries depending on your processing and/or layout. HEW’s advantage is we can consult turnkey and offer all of these machinery under one roof”.

Summarizing, a Rubber Creper Machine is the main machinery used for cleaning, thinning and flattening in your TSR processing. Different customized features are available helping you pick the right equipment meeting your requirement.

Let me know your thoughts on rubber creper.


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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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