cannon epoxy technology

Epoxy Technology

The recent introduction of new Cannon technologies for the manufacture of Epoxy-based composites found an overwhelming response from the market.
In addition to a significant number of low-pressure dispensing machines sold for the impregnation of the giant blades used for the eolic generators industry, Cannon have introduced three different impregnation systems based on high-pressure technology.
A whole range of solutions is now available to respond to different needs and processes. Cannon supplies today the widest set of tools, including dispensing and mixing devices, preformers, presses, moulds, manipulators, ovens and controls. Exactly two years ago, at Jec 2010 in Paris, Cannon launched their new high-speed RTM technology for Carbon-reinforced composites based on Epoxy resins.
The new process, called ESTRIM (Epoxy Structural Reaction Injection Moulding) was making possible the industrial use of new, fast reacting Epoxy formulations developed to comply with the high productivity required by the automotive industry for their rising number of structural composite parts.
Based on a series of integrated products - Carbon reinforcement handling systems, dedicated preformers, high-pressure dosing unit for Epoxies, multicomponent mixing heads with different distribution methods, polymerisation presses and relevant handling systems of preforms and moulded parts - the ESTRIM process immediately received a positive response from the industry. The possibility to cut almost by ten the curing time of a large moulded part - going from a traditional 30 minutes cycle of conventional RTM down to 3 minutes with ESTRIM - appealed OEMs and Tier 1 companies.  

New Solutions Are Now Available
The intense exchange of experiences matured during these visits stimulated the development of new methods for distributing the liquid Epoxy resins in the Carbon preforms. In addition to the ESTRIM RTM fast injection technology, Cannon have developed two alternative methods for the impregnation of these more or less flat mats, both to be applied in open mould prior to the closing of the press:

 



· ESTRIM SL (Spray Laydown) – the Epoxy formulation is sprayed directly over the reinforcement, covering each square centimetre of mould with extreme precision, applying the desired amount of liquid resin where it is required by the part's geometry. This technique allows for the use of viscous formulations, characterised by low flowability: being directly deposited in-situthe liquid does not need to flow through the fibers, avoiding any distribution problem. A certain degree of part's threedimensionality can be approached without problems, since the head can be tilted on a fourth axis over the vertical sides of a mould during the spraying operation.

· ESTRIM LL (Liquid Laydown) – the Epoxy formulation is laid over the Carbon mat in “liquid ribbons” of varying width,  typically from 40 to 120 mm, impregnating perfectly the reinforcement without the minimum possibility of air inclusions in the moulded part. This technique allows for the production of very large parts, wetting uniformly the huge, almost flat preforms that characterise parts such as roofs, engine hoods, fenders and doors. The reactivity of the systems being controllable on a partto-part basis, this system allows for a comfortable laydown time even for the largest pieces. As in the SL alternative, the formulation does not need to flow through the mould, therefore guaranteeing the most homogeneous distribution of liquid resin in the Carbon reinforcement. We should not forget the development of new alternatives for the traditional high-pressure injection in closed moulds, performed with the original ESTRIM technology. The experiences matured in the past in the field of short-stroke polymerisation presses have allowed for at least three more injection methods:

  1. We can inject the resin with a variable output, commanding the operation by reading the internal pressure in the moulds with a series of pressure sensors. The signal is sent to the unit's computer, that defines the new output value to be applied and commands the dosing pumps accordingly. The press does not move.
  2. We can apply the injection-compression method, by leaving the mould partially open during the injection and applying the final compression stroke at the end of it.
  3. We can inject the resin and apply a low clamping force on the mould, which will tend to open during the liquid-filling phase: at the end of it we apply the full nominal clamping pressure and compress the mould and its content. 

Worldwide recognition 

Up to date, seven different contracts for these Epoxy-dedicated technologies have been signed with major manufacturers of parts and Raw Material Suppliers, in Europe and Japan, in the past 18 months.