A Rotocure is a shortened name of Rotary Curing Press. This machinery is designed for the continuous vulcanization of technical rubber products.

So, if you are into manufacturing of rubber belts, roof covering, rubber belts with textile inserts, sealing plates, membrane and ship textile, conveyor belts, flat belts, floor covering, etc you would have heard of this equipment (if you are not yet using one in your production line).

As a technical rubber goods producer, vulcanization is critical to your manufacturing. In an earlier post, I had introduced you to Autoclave for vulcanizing of products that you cannot achieve on a standard press-based compression molding process. You install a Rotocure to create continuous vulcanization process where the sheet is heated and vulcanized.

While every technical rubber goods manufacturing plant may not have a Rotocure, those who do have one positions their rotary curing press after the calendar.

Rotocure Line:

A typical Rotary Curing Press Line consist of following component machines – A Winding Let-off Unit, Rotocure, Cooling Unit, Equipment fo edge trimming of product and a Winding-up equipment.

From Winding Let-off Unit, your semi-finished calendered rubber material is led on to the lower roll and from there into pressing space between the heating drum and thrust pressing belt, where it is pressed and vulcanized.

Operating A Rotocure:

Your main vulcanizing machine is always the Rotocure in the set-up and consists of a large, steam-heated, revolving steel drum. This is partly encompassed by an endless steel band. The steel band encompasses approximately 2/3 of the circumference of the drum through the action of two conducting rollers and a tensioning pulley. The drum is heated by means of steam to a temperature of 150 – 200°C. In addition, there is a heating plate bent round approximately half of the surface of the drum and which gives some additional heat, but primarily it prevents loss of heat.

When you operate a Rotocure Equipment, you need to ensure that all the various parts work in precise alignment. It is  crucial for you to maintain all process parameters in their correct tolerance. Because a slight change in the heated roll or in the steel belt that are both in charge of the smooth vulcanization of the sheet can cause your sheet to be unevenly vulcanized. This leads to irregularities and subsequently rejection of your end-product.

Your calendered rubber material is placed between the drum and the band at the lower roller. With the aid of the tensioning pulley, the band is strained so that a pressure (say approximately 0.3 MPa) is obtained between the band and the drum.

The linear speed of this drum can vary from a 0.04-200 m of cured material per hour, all depending on your material’s thickness and rate of vulcanization.

The drum, which is interchangeable, can have completely smooth or patterned surfaces and normally has a diameter of 700-1500 mm and a width of between 1200-2500 mm.

For a normal speed range of 5 – 50 metres/hour and a contact length against the drum of 3 minutes, you may achieve a curing time between 4 – 35 min for your specific compound.

As a user, your will quickly realize that the main advantages of a well-manufactured and correctly operated rotary curing press (or rotocure) machine are its high hourly output, long lifespan, low energy consumption and high reliability.

On the other hand, you could be challenged by the limitation of your product thickness and the pressure sought during vulcanization.

As is normal with other categories of rubber machinery, you get both New and Used Rotocure’s in the market. When you shortlist your suppliers, you could also discuss with Pelmar Engineering Ltd for Used Rotocure or Pracsol Chemicals And Machinery for New Rotocure – more of their details on this site is in our interviews section.

Summarizing, a Rotocure is an important rubber machinery if you are into manufacturing of technical rubber products. I look forward to your thoughts on this continuous vulcanizing machine.

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