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Internal Envelope Vac Bagging. Findhan Strain. Split Tooling. 5083 Aluminium (cost) CNC’ed Finished with 800 grit Not well polished as good surface finish not essential due to time constraint Multiple layers of Frekote 700 NC. First Layer. Leave material over the edge
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Internal Envelope Vac Bagging Findhan Strain
Split Tooling • 5083 Aluminium (cost) • CNC’ed • Finished with 800 grit • Not well polished as good surface finish not essential due to time constraint • Multiple layers of Frekote 700 NC
First Layer • Leave material over the edge • Trim with v. sharp blade • May require further trimming after debulk • Do not cut tool or release agent
First Layer • Place first layer in tool • Rough Trim first ply on both halves
Debulking • After debulking the initial half layer: 20 mins with perf release film • Further trimming if required along split line – possibly leave all until after debulk
Subsequent layers • Layers laminated on half of tool • Prior to closing • Layers seen here above tool are plies 2, 3 and 4 • Place a layer of non-stick material eg backing film between last inch of each ply (not shown here)
Subsequent Layers • Instead of this approach, could simply close two halves of mould and lay one full layer around mould after the first layer • This product required a localised thickness at the centreline so ply overlap provided this build-up
Tool closure • Bring two halves together carefully • Overlap both ply no.2s from each half • Remove backing film between layer 2 and 3 • Place and overlap layers 3 from both halves • Repeat for plies 4
Tool Closure Detail • Ensure good compaction between overlapping layers • Place bagging materials on carefully • Plenty of slits in perforated film • Ensure film and breather are well taped down to avoid them slipping off when placing the bag through the middle
Bag Preparation • Cut a BIG bag • Takes a much bigger bag than you think! • Place PS tape at one side
Bag Preparation • Close bag over on top of tape • On reverse side of bag, place PS tape on the outside • Inner and outer tapes must connect to ensure no leaks
Bagging Preparation • Place bag through the middle of tool (shown here also going through a cylindrical tool at the same time) • Place vac ports inside bag
Bagging Preparation • Pull bag through and back on itself • Attach bag to remaining tape, ensuring all tape is once again connected at any intersection • Bag now sealed
Draw Vacuum • Draw vacuum • Can place arm up the middle if done correctly!
Finished Part • Tool split with hammer and chisel at non-machined faces • Part removed with ease due to good release, easy geometry and split tooling
Mould Split Line • Can be minimised with pin-point machining • Leave rough cut then hand polish • Final CNC-ing • Can be degraded by Stanley knife when trimming • Usually hard to completely avoid this • This ridge is quite small for 3 bar + vac bag!