Resin infusion made easy - a schematic animation

Discussion in 'Boatbuilding' started by TriTien, Aug 28, 2012.

  1. TriTien
    Joined: Aug 2012
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    Location: Auckland, New Zealand

    TriTien Junior Member

    We have just posted a schematic animation regarding to resin infusion for composite manufacturing. This guidelines show how Vacmobiles simplify and improve vacuum bagging processes.
    Please visit: http://youtu.be/0CcBvfltdIw

    PS. Our machines were originally developed for New Zealand's boat builders and are now used by boat builders in about 50 countries.
    For more information about Vacmobiles: http://www.vacmobiles.com
     
    Last edited: Sep 3, 2012
    1 person likes this.
  2. TriTien
    Joined: Aug 2012
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    Location: Auckland, New Zealand

    TriTien Junior Member

    Last edited: Sep 12, 2012
  3. latestarter
    Joined: Jul 2010
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    latestarter Senior Member

    It made it clear to me how it works, someone who has never used vacuum infusion.

    However the impression it left was that there is a huge amount of waste of resin involved. The animation suggests there is more waste than went in. Maybe you could tweak it.
     
  4. TriTien
    Joined: Aug 2012
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    Location: Auckland, New Zealand

    TriTien Junior Member

    Hi latestarter, thanks for your comments. Yes, we would never suggest one to make a large amount of waste of resin. The less resin excesses the better. We can easily tweak the animation. However, the animation has another purpose to give the user an attention to have an effective resin trap. Because resin may excess from the part for some reasons (unexperienced usage or trouble to control excess resin for examples), having an effective resin trap can reduce the risk of resin entry to vacuum pumps and central vacuum lines.

    Any viewer needing more information about RT19 resin trap of vacmobile can visit http://www.vacmobiles.com/shop/resin-traps/rt19.html.

    A brief introduction of vacomobile RT19 resin trap:
    1. Easy to clean and mastic free/high integrity vacuum connections.
    2. A rugged vacuum pump connection block and a disposable resin catchpot.
    3. Optional features include vacuum regulation for process control and an optional heavy duty aluminium lid with a glass view port which allows the resin level to be checked at any time. With slightly modified vacuum connections, the RT19 may also be used for supplying degassed resin to parts being infused.

    The RT19 really is the low risk, low maintenance option for serious composites manufacturing professionals.
     
  5. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    If you have a spare minute, could you please tell me more about modifying the vacuum connections so it can be used to degas the resin?

    Cheers
     
  6. TriTien
    Joined: Aug 2012
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    Location: Auckland, New Zealand

    TriTien Junior Member

  7. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    im more interested in seeing how you plumb a resin trap, as a degassing chamber and combined resin trap, off just 1 pump. Also allowing valving to make the inlet into an outlet after infusion and catching the excess resin back into the same degassing chamber / resin trap.

    Got anything like that? :D
     

  8. TriTien
    Joined: Aug 2012
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    Location: Auckland, New Zealand

    TriTien Junior Member

    Hi groper, you may make the process with one vacmobile system, but you need to be extremely careful because excess resin going to the pump will make instant destruction to it and you will risk your part.

    For new viewers to this arisen topic, we always suggest to make the process of feeding degassed resin into an infused part with two vacmobile systems as described in http://www.vacmobiles.com/feeding_degassed_resin.html.

    For groper, subjecting to the above caution, the following is the process with one vacmobile system:
    The vacuum connection(s) to a so called "combined degassing pot & resin trap" for evacuating part and degassing resin is illustrated as the below schematic

    [​IMG]

    Equipments needed for the job:
    • One vacuum system with a suitable vessel for applying vacuum to the part to be infused and degassing resin. This degassing vessel needs at least one O-ring sealed vacuum connection which a resin feed tube can be pushed through (and remain sealed during movement).
    • Desirably a disposable O-ring sealed valve that can be inserted into the resin feed line. (A tube clamp will work, but a valve will be easier to use).
    Tubing preparation:
    Make up a resin feed tube from the part to the degassing vessel, so the tube can be inserted through the lid of the degassing vessel as shown in the above sketch. Note that the bottom end of the tube should be cut an angle to avoid it sealing off on the bottom of the resin bucket. The valve must be positioned at least distance “H” above the top of the gland in the degassing vessel lid.

    Procedure for evacuating the part:
    1. At least 30 minutes before evacuating, start vacuum pump and close valve A. This early start is to ensure the pump is warm before evacuating begins, as a warm pump is better able to handle water vapour and other volatile components which may evolve from the part and resin during evacuating and degassing.
    2. Open the valve A, close the valve C and E for evacuating and leak testing the part via the resin trap and vacuum pump (see above schematic).
    3. After leak testing, open the valve E, close the valve D and A to restore vacuum to the part directly by the vacuum pump.

    Procedure for degassing resin:
    4. When satisfied that the part is ready for infusion, mix the resin and place the resin bucket in the degassing vessel. (Leaving plenty of room for expansion during degassing – as much as 2x to 4x the initial liquid resin volume. Ideally check the volume expansion with a test on a small amount first.)
    5. Adjust the angle cut end of the resin feed tube through the loosened gland. As shown in below sketch, the angle cut end of the tube should terminate just below the lid of the degassing vessel. Once in the below sketch position, the nut on the O-ring gland should be tightened sufficiently to temporarily retain the tube in this position. Note that the angle cut end of the tube must be well above the resin at this stage. This is important, as it allows the air to be removed from below the resin feed valve.

    [​IMG]

    6. Open the valve A to degas the resin and observe progress through the viewport in the degassing vessel’s lid (while the part is still being evacuated). If the resin is to be degassed at maximum vacuum, make sure valve B (below the vacuum regulator) is closed. Note that degassing at maximum vacuum may not be advisable with resin systems which have a high vapour pressure (such as polyester resins containing MEKP). For high vapour pressure resins, preset the vacuum regulator so the degassing pressure is above the vapour pressure of the mixed resin at your ambient temperature. (With pressures measured in absolute pressure terms.)
    7. When the resin has been degassed, slightly loosen the gland nut retaining the resin feed tube. Push the tube until the angle-cut end contacts the bottom of the resin bucket – as shown in next sketch. Retighten the gland nut.

    [​IMG]

    8. Close the valve A, open the valve C above the degassing vessel. Open the valve B slowly under the vacuum regulator and adjust the vacuum level so the air pressure rises (vacuum decreases) above the resin in the degassing vessel. Note that at this step the part is being evacuated directly by the pump and no additional vacuum is applied to the vessel. So, opening the valve B slowly to avoid the high velocity air flow going to the degassed resin because it will make a big mess of the resin.
    9. Just before the resin fills the part, close the valve C immediately, then open the valve A. When full vacuum reached, close the valve E and open the valve D to direct the excess resin to the resin trap.
    After the part has been completely infused:
    a) For low vapour pressure resins which are not affected by maximum vacuum, close the valve B under the vacuum regulator or
    b) For high vapour pressure resins (see note 6 above), open the valve B below the vacuum regulator and hold the vacuum at the safe level for the resin until it has cured.
    If you would like to remove excess resin from the resin feed side of the part, open the valve C. As long as the resin viscosity is still low enough, reapplying vacuum to the resin feed side of the part will apply more consistent vacuum to the whole part. This will eliminate the resin rich area typically found at the resin feed side of the part.

    Note that the resin in the bucket may exotherm up to 300 degrees C. Do not let more than 1kg of resin remain in the catchpot.

    Again, we always suggest to make the process of feeding degassed resin into an infused part with two vacmobile systems as described in http://www.vacmobiles.com/feeding_degassed_resin.html.

    Any viewer needing more information about RT19 resin trap of vacmobile can visit http://www.vacmobiles.com/shop/resin-traps/rt19.html.

    A brief introduction of vacomobile RT19 resin trap:
    1. Easy to clean and mastic free/high integrity vacuum connections.
    2. A rugged vacuum pump connection block and a disposable resin catchpot.
    3. Optional features include vacuum regulation for process control and an optional heavy duty aluminium lid with a glass view port which allows the resin level to be checked at any time. With slightly modified vacuum connections, the RT19 may also be used for supplying degassed resin to parts being infused.

    The RT19 really is the low risk, low maintenance option for serious composites manufacturing professionals.
     
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