| When manufacturing with composites, the material is | | | | bladder is used to prevent collapse under pressure. |
| made at the same time as the structures. The | | | | The vacuum bag is the last item to be placed. It's a |
| material is cured under controlled conditions, controlled | | | | relatively thick plastic layer. |
| for heat, pressure, and vacuum. Whether prepreg | | | | Vacuum leak detectors. |
| layups or wet layups are used, pressure and vacuum | | | | Composites repair equipment such as vacuum leak |
| produce a better laminate. Both help to improve resin | | | | detectors are commercially available to assist with |
| flow, but vacuum draws out the trapped air, resulting | | | | the technicalities of the controlled conditions |
| in a low void content. Heat accelerates curing. | | | | necessary for successful composites vacuum bagging. |
| Pressure is provided by vacuum bags. Compaction | | | | The pressure being applied is measured using |
| pressure consolidates the plies. Release agents applied | | | | pressure gauges. Dropping pressure will tell you if |
| to the tool may be liquid release coatings, release | | | | there is a leak. Ultrasonic vacuum leak detectors will |
| waxes, or barrier tape. | | | | pick up the high pitched sound of air escaping from |
| Vacuum bagging materials. | | | | the bag. |
| Vacuum bagging materials such as bag sealant tapes, | | | | Process advantages. |
| peel ply, release film, bleeder cloth are all known as | | | | Higher fibre content laminates can usually be achieved |
| composite consumables and are used to achieve a | | | | than with standard wet lay-up techniques, and lower |
| vacuum, extract moisture, solvents, and volatiles | | | | void contents are achieved than with wet lay-up. |
| from the curing composites, and then retrieve the | | | | However, composites vacuum bagging adds cost |
| composite structures from the composite moulds | | | | both in labour and in disposable vacuum bagging |
| afterwards. | | | | materials. A higher level of skill is required by the |
| If the structure is being made over a form, an air | | | | operators for mixing and control of resin content. |