“We should have bought this equipment one year ago!” [Customer – Belgium]
Vacmobiles simplify and improve vacuum bagging processes such as resin infusion. Here’s how…
For infusion type processes the critical factors in regard to vacuum are:
1. Avoiding air leakage into the laminate
2. Being able to easily verify that there is no air leakage into the mold or bag prior to infusion
3. Achieving maximum air and vapor removal from the part prior to infusion
4. Avoiding porosity caused by water and solvent vapors
5. Maintaining a controlled level of vacuum until the resin has gained acceptable strength
6. Achieving the foregoing in a productive and cost effective manner.
The first factor is a function of the choice of materials, molding system and laminator skill. Through attending to details such the long term leak tightness of joints, ease of control and system size reduction and mobility (allowing Vacmobiles to be placed physically close to parts), using Vacmobiles optimizes the remaining factors. The benefits delivered by Vacmobiles are:
Please see diagram below for a more detailed explanation of the key benefits of using Vacmobiles.
Examples of design details that improve vacuum bagging processes:
Resin entering a resin trap under vacuum tends to spatter and foam up. Most resin traps do not deal with these problems and become messy and extremely difficult to clean after little use. In contrast, Vacmobile resin traps can remain in service for years with negligible attention.
This is achieved by catching the resin in a close fitting, heat resistant, disposable, internal catchpot and by guiding the air flow path through the resin trap so that spatter is directed on to disposable surfaces.
Dispose of the catchpot – not the resin trap
With a Vacmobile you buy the resin trap once, and then simply use a disposable heat resistant cardboard catchpot or polyethylene resin degassing bucket as required.
Vacmobile Resin Traps are specifically designed to ensure all resin spatter is carefully contained within the disposable catchpot. This keeps the resin trap body clean and tidy, even with continuous use.
Most other resin trap connections require the vacuum tube from the laminate to be fitted over a male hose tail. As a result, resin entering the trap builds up on/inside the hose tail, blocking the hose tail when the resin gels.
In contrast, Vacmobile connection glands are O-ring sealed on the outside of the tube. Furthermore, the completely open end of the
vacuum tube terminates below the underside of the lid of the resin trap.
Resin exiting from the vacuum tube drips without restriction directly into the waiting catchpot.
Remarkably effective resin trap lid connections
As one delighted Vacmobile user remarked …
“The system of putting tubes in the resin trap works fantastic. You don’t need to drill them out and the resin falls directly into the catchpot. We should have bought this equipment one year ago!”
When making high quality composites using vacuum processes, it is usually necessary to perform a leak test (drop test) to confirm that air is not leaking into the laminate.
If the vacuum system itself is a source of leaks a drop test will be meaningless.
The leak-prone points in most vacuum systems are the joints between parts of the system, e.g., valves to manifolds. These loosen over time and develop vacuum leaks, which can be difficult to find and repair.
All permanent joints are mechanically locked
With Vacmobiles, all permanent joints in the machine potentially subject to stress in operation, e.g., valves being open or closed, or parts of the machine which might receive impact, are mechanically locked in some manner.
Even in very severe duty use, permanent joints in Vacmobile machines will not loosen and will not develop leaks.
Manifold mechanically locked to main handle upright (Vacmobile 20/2 machine)
Manifold mechanically locked to resin trap body (Vacmobile MICRO 8/2 machine)
As noted above, a critical preliminary step in the resin infusion process is a drop test to confirm that there is no air leakage into the laminate.
The simple way to perform a drop test is to check the reading of a vacuum gauge or an absolute pressure gauge connected to the resin trap. However, observing the vacuum leakage rate at the resin trap is only meaningful if the resin trap itself is known to be leak tight. With a Vacmobile, checking the vacuum tightness of the resin trap is simple. All you do is temporarily fit blanking plugs into the O-ring sealed tubing glands on the resin trap lid, evacuate the trap, close the valve to the vacuum pump and watch the gauge.
Once the trap has been checked in this way, you can remove the test plugs and fit the vacuum tubing from the part, knowing that the O-ring seal inside a Vacmobile connection gland will seal reliably to the extruded vacuum tubing typically used for resin infusion. If the resin trap has been pre-tested with blanking plugs in the tubing connections, the subsequent drop test will accurately indicate the leak tightness of the part and the tubing from the part to the resin trap.
Combining compactness with single phase power and mobility means that the complete vacuum system can generally be placed alongside the work. This delivers a number of benefits:
The end results of being able to put the vacuum system right next to the work are:
Equipping a laminator with a Vacmobile is similar to a builder replacing a mains powered drill with a good cordless drill. For a builder, the utility of the mains powered drill just does not compare with the utility of a good cordless drill.