RTM – polyester resin injection in a closed mould – is a more expensive technique and it is used to produce larger lots of products starting from 100 pcs per month. This method requires special equipment: metal tooling – matrix and punch, and injection equipment to prepare and inject the resin under pressure.
Vacuum RTM or RTM Light is a particular technique with composite tooling, held together by a vacuum.
Impregnating the reinforcement material with resin under a negative pressure ensures the high quality of the product.
This method allows the production process to be speed up and makes it reproducible and not dependent on manual labour skills.
Examples of application:
1. mass production of automotive transport parts 2. rolling stock interior and exterior parts 3. boat hull elements 4. aircraft parts 5. medical equipment parts
Low viscosity orthophthalic pre-accelerated resin. Gel formation time 9-12 minutes.
RTM-specific low viscosity orthophthalic non-pre-accelerated resin. Gel formation time 11-15 minutes.
Isophthalic gelcoat for spraying and brush application. Supplied in any RAL colour. Intended for use in open air.
Three-layer glass mat with a density of 300, 450, 600 g/sqm and polypropylene core with a density of 180 g/sqm. It is well draped. High speed of impregnation.
Semi-permanent release agent for polyester resins. This compound ensures the high gloss of the surface with little effort. It is also very strong, which guarantees many releases.
The release agent specially developed for closed-type moulds. It eliminates resin build-up – a very frequent RTM defect. It ensures a good gloss and can be used for punches.
Mixing and injection equipment for vacuum infusion and RTM.
Advantages of the technique:
1. high productivity, high quality of the final product 2. environmentally friendly, little waste 3. reproducible and low labour cost
Disadvantages of the technique:
1. higher initial investments 2. high requirements for workforce skills