Plastic - Foam - Rubber
We are Epoxy 2 part plastics, foam, blown foam, rubber, silicone rubbers, sheet plastic, GRP, Kevlar and Carbon Fibre specialists.
Our Plastics, foam and rubber knowledge has been built up over the past 8 years, we've worked from the bottom up with manual equipment and basic materials and onto automated process's which has seen us make our own equipment to do the job just how we wanted it done.
We either use vacuum or low pressure, except in the Auto Clave which uses medium and high pressure, our approach allows for tooling to be manufactured at sensible costs.
Typically our plastic foam and rubber manufacturing operates between 25hg vacuum and 15 to 45 psi which compares to the plastic injection process that can be 120 tonnes and required very specific metal tooling taking time and costing thousands of pounds. Our tooling can cost as little as 25 pounds and made in a few hours.
We have an Automated Cannon Shelly thermoformer, often called vac formers for short, which uses a series of heater plates suspended above a sheet of solid plastic, by heating it to near melting point it can be "formed" into any shape within reason. Our machine has a 1016mm by 762mm maximum forming area, with plug assist and is suitable for short to medium prototype and production runs.
All our systems (except the vacuum former) use a 2 part liquid system, we can alter the chemical balance of each part to produce simulated materials, for example simulated ABS when ours is actually an epoxy based product with all the same qualities of ABS. We can also introduce a frothing agent to produce a vast array of foams or coloured pigments to make pre coloured parts.
This wet system also makes it very easy to install any fittings required into place and then the liquid as its injected fully encapsulates the fitting and bonds it to the part ensuring it doesn't come loose during use.
Typically GRP moulds that have been used for GRP manufacture can be converted for plastic part manufacture by making an inner mould although it is better that moulds are made from the ground up for the task. However especially for the after market automotive styling kits it is a cost effective way forward as it brings a feeling of better quality and reduces the production costs, by about a third, and times, from a 5 day to a 45 minute turn around, it is an option that recovers its costs typically over a 10 to 20 production run.
We have been working with GRP (glass reinforced plastic or fibreglass as its often referred to) for 20 years now and pride ourselves on our mould making capabilities. we make moulds for hand lay up through to semi automated process such as RIM.
For Carbon-Fibre we can use RIM or we can use pre-preg's and run them through our autoclave. New in 1998 it has a 750mm diameter and a total inner length of 1500mm and it's computer control system is fully programmable for any heat and duration cycle combination.
Our Plastics department works in either vacuum or low pressure. For the vacuum a mould is made, this can be GRP, Silicone or a direct CNC machined mould from solid epoxy or polyurethane. The mould is then placed in one of our 4 vacuum tanks, a small pipe or system of pipes is fed into the mould at specific places, these are then fed out through a self sealing aperture in the tank a clamp placed onto them and then at the end it is placed into the liquid plastic. The whole system is then put under vacuum and once 25hg is reached the clamp on the inlet pipe is released the vacuum draws the plastic through and ensures no air is introduced, as the plastic starts to run out of the exit tube into a catch tank the clamp is closed, typically this takes around 5 to 15 seconds in total.
Resin Infusion Manufacture works by dry laying the reinforcement, be it glass, kevlar or carbon fibre, and then applying a bagging material. We then use a vacuum pump to suck out all the air and introduce the liquid resin via a series of tubes at one end, the vacuum ensures an even and full distribution of resin. It is about the best system for maximising ideal strength as near perfect resin to substrate ratio is achieved, every time. it is also a very clean method of manufacture as the dry laminates are cut to pre designed shapes then laid in place and held there by the application of the vacuum pressure. The resin is then drawn directly from a mixing pot and flows freely through, a small catch tank on the vacuum side ensures that full wetting has occurred.
AutoClave works with both vacuum and high pressure. Initially typically a pre- preg, which is a matting agent usually Carbon-Fibre, but it can be Glassfibre or Kevlar, is then pre impregnated with its resin and stored at a near zero degree's. It is applied by hand to the mould and then a series of cloths and barrier materials added and then it is all encapsulated in a plastic bag. This bagging has a small valve added into it and is then subjected to a vacuum pressure to ensure no air pockets exist, once full vacuum, around 22hg to 28hg, is achieved it is placed inside the AutoClave. The bag is then connected via a skin valve to the vacuum again whilst the AutoClave door is closed and bolted shut, compressed air pressure is then forced in and the vacuum pump removed, pressure is increased dependant on the part and its use between 40psi and 120psi and at the same time a heating element is switched on and the temperature ramped up in timed stages to a pre set top level, held at this temperature typically for 4hrs to fully cure and temper the resin and then ramped down slowly to prevent distortion.
Under "LOW" Pressure
Our Plastics department works in either vacuum or low pressure. For low pressure a mould is made, as with the vacuum system, this can be GRP, Silicone or a direct CNC machined mould from solid epoxy or polyurethane. This is then clamped, typically by making a wooden box with over-centre catches, and the 2 part epoxy plastic is injected in at around 15 to 45 psi. It is fed through a mixing chamber at the injection point and as such needs to have a series of risers to allow trapped air to escape away from the part and for an excess of plastic to ensure full wetting to occur. This system can take from 20 seconds to 2 minutes to inject and is suitable for larger parts, such as a car bumper.
Foam parts, low pressure and blown foams, are a niche that we excel at. Blending epoxy's and then adding a frothing agent allows us to control the growth rate and therefore the foam structure, we operate under low pressure typically under 10psi. The mould is designed to expand to the rate required to achieve the structure and density. For example a centre console made by this method has a silicone rubber mould placed into a GRP it rigid, then a very well polished metal closing plate is suspended above. The foam is injected in a liquid state and as it meets air starts to expand and froth. The metal plate is then pushed down to close the mould and a series of weights added on-top. These weights control the pressure and growth allowing the metal plate to raise and let the excess material and pressure to be released. a simple but highly effective method allowing for easy fine and if necessary constant tuning to take place, it also allows for the structure to be varied for area's requiring additional stiffening.
Blown Foam works by a special type of "spray" gun, the 2 part liquids, held under pressure in 2 containers at around 10bar, come via separate pipes to the fan head and is sprayed out with a nitrogen introduced at the exit of the fan. By varying the amount of nitrogen we can change the foam structure. This foam expands on impact at a rate we predetermine by the mix ratio and the nitrogen level. its ideal for packaging, where a delicate part can be placed on-top of a bag and the foam blown into this bag expands and wraps itself around the item requiring protection.
With an amount of knowledge required we are able to blend rubber and especially silicone rubber formula's to make parts tailored to there intended use. This is a very specialised section of our work and we have developed tooling processes to our advantage to remove the air that is generated in rubber production. Rubber also needs post processing after manufacture to ensure it remains stable during use.
Scroll through our Examples
- Plastic Injection
Injecting 2 part epoxy plastic into a silicone mould to form a mirror unit.
- Rubber Injection
We can vary the ratio to create special rubber compounds.
Foam injected under low pressure can be used for interior parts.
- Blown Foam
Here 2 part foam is being blown into an open mould with a manual gun.
Measuring 1500 by 750 and computer controlled for heat and time cycles.
- Plastic Vacuum
Feeding epoxy under vacuum into a mould into one of our vacuum tanks.
Resin Injection makes complicated shapes easier to manufacture.