MOULD & DIE SOLUTIONS

VIP-Polymers utilise a combination of practical engineering experience and the very latest computer aided design software to develop mould and die solutions.

Continuous investment in the latest design and manufacturing technologies with integrated CAD/CAM systems enable full three dimensional machining of complex forms to be undertaken.

Tooling is at the core of VIP-Polymers manufacturing technology with the ability to develop both low cost prototype and high volume precision tools for every aspect of the production process including:

  • Extrusion Dies
  • Multi-Cavity Injection Moulds
  • Multi-Cavity Compression Moulds
  • Transfer Moulds

RUBBER EXTRUSIONS

VIP-Polymers are long established manufacturers of precision rubber extrusions.

We produce even the most complex profile shapes in a comprehensive range of compounds ranging from EPDM, Natural, Silicone and SBR-based extrusions up to 90 IRHD for a variety of industries:

  • Potable and Drainage Water Pipelines
  • Engineering
  • Marine
  • Flame Retardant Seals for the Rail Industry including London Underground
  • Ministry of Defence Approved (MOD Naval) Products

We understand the numerous applications and environments that our rubber extrusions are used in and can provide the optimum solution by applying engineering expertise, sound business economics with a common sense approach. Our experienced team of compound technologists and development engineers are available to design, develop and ensure the smooth production of profiles using bespoke compounds.

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Where extruded sections are required to be joined, we have the very latest computer controlled, fully integrated cutting equipment and a range of joining presses to facilitate this process. Our extrusion facilities also include continuous inkjet equipment enabling product to be coded with customer part numbers, batch numbers and barcodes.

RUBBER TO METAL BONDING

Using the latest manufacturing techniques, VIP-Polymers provides complete design and manufacturing services for precision rubber products incorporating metal components.

VIP-Polymers Rubber to Metal Bonding VIP-Polymers is a market leader in providing noise and vibration solutions utilising the unique properties of elastomeric components.

Our policy of continued investment in product development and improvements in manufacturing techniques has resulted in VIP-Polymers components being used on all forms of modern transportation systems in addition to many varied industrial applications.

Our products have been used inside marine and defence vehicles, for vehicle suspension and transmission systems, underneath generator sets on-board ships, on construction equipment and even on bridges and major civil engineering projects.

Indeed VIP-Polymers products may have a use on any piece of machinery that vibrates or where a degree of flexible movement is required.

VIP-Polymers have been producing rubber to metal bonded products for over 30 years, serving a diverse range of industries including civil engineering, instrumentation, automotive and pneumatic equipment.

Typical examples of such products are:

  • Linings for Progressing Cavity Pumps (PCP’s)
  • Bonded bridge bearings
  • Automotive anti-vibration mounts
  • Lead and Aluminium roofing flues

Mindful of the environmental impact of traditional solvent based bonding agents, VIP now produce the majority of components using water based systems. All emissions from this process can be contained and process media recycled, making it more environmentally friendly.

DESIGN AND DEVELOPMENT

VIP-Polymers provides engineering and design services employing CAD and analytical modelling and finite element analysis techniques. Engineering programs can then be transferred directly into tooling machine programs for fast and accurate mould making.

Product Design and Development:

In addition to our many years of practical engineering experience, VIP-Polymers utilise state-of-the-art CAD technology for product design including Autocad, Pro-Engineer and Advanced Simulation programs to analyse all aspects of dynamic performance under pressure, deformation, fatigue, stress levels and other criteria.

All tool design takes place in-house, utilising tool modelling programs, stereo lithography and computer simulation to determine analysis of flow and cure in injection moulding.

Material & Formulation Development:

VIP-Polymers designs seals for a wide range of applications including:

  • Microbiological resistance
  • Flame retardancy
  • Impact attenuation
  • Electrical resistivity

VIP-Polymers formulates and mixes its own compounds in-house.

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Laboratory support facilities, including laboratory mixer, mill, rheometers and other equipment, assist the development of new compounds and control processing.

Compounds produced cover a wide range of polymers including:

Natural Rubber, Neoprene, EPDM, SBR, EVA, Polyethylene, Nitrile, Fluoroelastomer, Polychloroprene, Polyacrylic, Silicone and Epichlorohydrin, and meet a series of complex specifications. Although VIP-Polymers usually has compounds suitable for customers’ specific needs, experience in polymer engineering enables the development of new compounds to meet unusual requirements.

VIP-Polymers is also active in formulating industry standards through membership of several British and European standards committees.

RUBBER MANUFACTURING

The methods of manufacturing rubber are similar for all producers World-Wide. Variances however, may occur regarding specific compounds, each manufacturer’s production methods and levels of sophistication.

Formulation and Mixing of Rubber Compounds:

VIP-Polymers process a variety of rubber materials, both natural and synthetic, into compounds suitable to face the most challenging performance and environmental criteria.

Natural rubbers are supplied from traditional countries in the Far East such as Malaysia and Indonesia. Synthetic rubber is primarily manufactured at chemical plants in Industrial Europe and the U.S.A.

On its own, basic rubber is of little use and must be formulated to make it suitable for manufacture and to ensure desired properties in finished products.

Following laboratory development, precise formulations are used in production mixing operations to blend compounds into strip or slab form suitable for later processing. This is accomplished as follows:

  • Blend using a roll milling process.
  • Under computer control, each ‘Batch’ is processed through a series of heavy duty mixing systems to add more ingredients and finally discharge batches at a designated time and/or temperature.
  • Weigh designated formulation ingredients into specified batches using computer control to ensure accuracy.
  • Finally the material is formed into strips or slabs and then automatically cooled.

The processed material compound is now suitable for moulding or extrusion. Test coupons are also sent from each ‘Batch’ to Quality Control and subjected to a testing programme before release to production.

How rubber products are manufactured:

Industrial Rubber components are usually manufactured by one of the following methods:

  • Injection Moulding – Using strip compound produced as previously described.
  • Compression Moulding – Requires secondary operations to process material into suitable forms of the correct weight and/or shape to suit particular products.
  • Extrusion – Using strip compound produced as previously described.

Injection and Compression moulding requires highly accurate single or multi-cavity moulds, typically made in high grade steel and designed and made using CAD/CAM programmes.

Injection Moulding:

Injection moulding has a number of elements operating automatically on timed sequences with moulding temperatures usually between 165°C and 200°C.

Moulding cycle:

  • Mould closes.
  • A plasticising screw rotates to force the injection of an accurate volume of pre-plasticised rubber compound into the mould.
  • Material is directed into the mould via a system of runners to each individual cavity, each having small injection ports.
  • Material is cured for a pre-determined time during which the plasticising screw retracts and plasticises sufficient rubber for the next injection.
  • Mould opens and parts are removed manually or automatically by robotic or other system.
  • Cycle is repeated.

During each machine cycle an operator may perform a variety of operations including: Trimming excess rubber (flash), inspection, packaging or assembly. Alternatively, the part may be forwarded for trimming by other methods.

Compression Moulding:

This simpler process is slower in operation than injection moulding in that special uncured preformed and weighed blanks are used. The process employs hydraulic presses with pre-heated platens at (150-170°C) that in turn heat up the mould.

Moulding cycle:

  • Open mould and remove product from previous cycle.
  • Load required blanks into each cavity.
  • Close mould and move into hydraulic press.
  • Activate hydraulic press. The closing action causes displacement of rubber to fill each mould cavity. To overcome certain conditions, pressure is sometimes released and the mould “bumped” to allow air escape.
  • Cure – Time is determined as a function of material and cross section of part being moulded.
  • Remove part(s) manually or automatically after pulling mould from press.
  • Repeat cycle.

Again the operator may have tasks to perform as described for injection moulding. Compression moulding is generally more suited to low volume production or where tooling costs are to be kept to a minimum. Compression moulding is also not suitable for moulding complex shapes.

Extrusion:

Extrusion is used for either of two functions:

  • Manufacture of long lengths of cured sections for fabrication of items too large for injection or compression moulding.
  • The production of blanks for compression moulding.

Continuous Vulcanisation:

VIP-Polymers utilise a manufacturing process known as Continuous Vulcanisation for production of cured extrusion for conversion into certain finished products as follows.

Two items of machinery are required for this process:

  • An extruder with a barrel and screw, and a die of correct cross-section at the outlet end.
  • A heating source to cure the rubber which may be one of the following:
    • A hot air oven.
    • A microwave unit/hot air oven combination.
    • A specialised bath containing molten salt.

The “Continuous Vulcanisation” process is as follows:

  • Strip rubber is fed into the extruder. It is then plasticised by the screw and extruded through the die orifice. The extruder operates under controlled conditions of temperature and screw speed.
  • The continuous extrudate is passed down the heating medium which causes it to cure. Again, speed and temperature are accurately controlled.
  • The emerging cured profile is cooled and cut to length automatically or rolled onto drums for subsequent secondary operations.

This process invariably involves a line length of as much as l00 feet, and optional operations may utilise a U-format to economise on space.

STANDARDS

VIP Polymers can manufacture pipe seals to any national and international standard including the following:

Standard Country Application
ACS France Attestation de Conformite Sanitaire.
ANSI/NSF Standard 61 USA Drinking water system components health effects.
BS 3734 Class M2 ISO 23302 UK Dimensional Tolerances of Solid Moulded and Extruded
Rubber Products.
BS 4685 Part 1 UK Specification of Gaskets for Pipe Flanges to BS 4504.
BS 6920 UK Suitability of Non-Metallic Products for Use in Contact with Water intended for Human Consumption with regard to their Effect on the Quality of Water.
EN681-1/WA Europe Elastomeric seals Material requirements for pipe joint seals used in potable water applications.
EN681-1/WC Europe Elastomeric seals Material requirements for pipe joint seals used in drainage applications.
EN 682 Europe Elastomeric seals – Material requirements for seals used in pipes and fittings carrying gas and hydrocarbon fluids.
DIN 4060 Germany Elastomeric Sealants for Pipe Joints in Drains and Sewers; Requirements and Testing.
KTW 1.3.13.D2 Germany The evaluation of plastics and other non metallic materials from the point of view of health in the context of the foodstuffs and commodities act for the drinking water sector.
CIROCLARE 102 Italy Hygenic requirements for plastic and rubber materials used with pipes & fittings destined to come into contact with potable water.
ISO 4633 International Rubber seals joint rings for water supply, drainage and sewerage pipelines specification for materials.
ISO 6447 International Rubber Seals – Joint Rings Used for Gas Supply Pipes and Fittings – Specification for Material.
ISO 6448 International Rubber Seals – Joint Rings Used for Petroleum and Fittings.