Infusion tech – history
Vacuum resin infusion is considered a relatively recent process; it was filed in 1959 in U.S. for the production of swimming pools made in fiberglass (GRP, Glass Reinforced Plastic), using a system of distribution of the resin. In the early 80’s Lotus Cars used a similar process for the production of car body parts. In the same years, one of the first applications in the water was a series of RORC One Design yachts, produced by Jeremy Rogers in Lymington, England.
Main aspects of infusion:
Achievements of vacuum resin infusion
- Process with low emissions of styrene and acetone
- Standardized and repeatable process and pieces
- Excellent composite’s mechanical characteristics
- Weight reduction
- Time and costs reduction
Infused Composite’s Quality
Excellent resin / fiber ratio (35%-65%)
Constant thickness
No use of putty or bonder for fixing the core
Absence of interlaminar air bubbles
Excellent mechanical properties of the laminate due to uniform compression exerted by vacuum.
Environment
- Low emissions of styrene in the air
- Cleanliness
- Reduced costs for PPE and flue gas treatment equipment
- Ergonomics
- No contact with resin by workers
- Reductions occupational diseases (carpal tunnel, etc …..)
Comparison with the main processes:
PROPRIETY | HANDLY LAY-UP | VACUUM BONDING | VACUUM RESIN INFUSION | RTM LIGHT | PREPREG (AUTOCLAVES) |
---|---|---|---|---|---|
Lenght's limitation of the piece | ++ | ++ | ++ | - | - |
No limitations | No limitations | No limitations | Medium sized parts | Size limits depending on the size of the autoclave | |
Industrialization | + | + | ++ | ++ | - |
Waiting time for polymerizzation of the resin for each layer placed | Waiting time for polymerizzation of the resin for each layer placed | Ability to work on shifts whithout waiting for the polymerization | High industrialization | Used for limited production | |
Mechanical properties | -- | - | ++ | + | ++ |
In general, poor and dependent on the human factor | Slight improvement for the gluing phase of the core but same features as the handly lay-up | Excellent properties | Dependenton the amount of fiber inserted into the mold | excellent properties | |
Fiber/Resin ratio | -- | -- | ++ | + | ++ |
Resin: 65% | Resin: 65% | Fiber: >65% | Depending on the amount of fiber inserted into the mold | Fiber: >65% | |
Fibers' workability | - | - | ++ | ++ | + |
Once impregnated layers lose their stability | Once impregnated layers lose their stability | Good | Good | Good, but in short time | |
PROPRIETY | HANDLY LAY-UP | VACUUM BONDING | VACUUM RESI INFUSION | RTM LIGHT | PREPREG (AUTOCLAVES) |
VOC emissions | -- | - | ++ | ++ | + |
High emissions (open mold) | High emissions (open mold) | No emission | No emission | Limited emission | |
PPE | -- | -- | + | + | + |
Masks, sults, gloves. | Masks, sults, gloves. | No special precautions | No special precautions | Gloves | |
High cost to treat the air at the workplace to comply with regulations | High cost to treat the air at the workplace to comply with regulations | ||||
Material fee | ++ | ++ | + | - | -- |
Possibilty of using various products | Possibilty of using various products | Media and multi-axial flow to enhance the features mech | Need to purchase specific fabrics | Prepreg fibers (high cost) | |
Facilities fee | ++ | - | - | -- | -- |
No specific facilities | No specific facilities | Vacuum pump and resin infusion machine | Vacuum pump and RTM machine | Autoclave and refrigeration to stock materials | |
Molds fee | ++ | ++ | + | -- | -- |
Existing molds can be used | Existing molds can be used | Existing molds can be used with minor modifications to widen the perimeter flanges | Necessary to carr out a controlled plece to produce mold and counter-mold | Aluminium molds (in general) | |
Consumables | - | -- | + | -- | |
not used | Takey tape, peel ply and various in the gluing phase | Spray adhesives, peel ply, pipes and channels to convey the resin | Pipe to ingect the resin the mold | Takey tape and nylon for high temperatures |