gail mold review

Here is a response to your query, drawing on the information from the provided sources:

Debulking in PrePreg – Hand Layup refers to compacting each ply individually, in sequence. Bridging occurs when fibers in the laminate span across a radius or curve in a part, which can happen at inside corners and outside corners.

The difference between a Tool Sealer and a Release Agent is as follows:

• Tool sealer coat is made up of polymers that are bonded to the tool surface. Its purpose is to fill the micro-porous sites on the tool surface.

• Release agents are designed to provide multiple releases. They are low-energy and can be sprayed or wiped on. Semi-permanent agents are available in both solvent and solvent-free formulas and may require being stripped and reapplied. Proper application procedures for release agents are crucial for good performance, as over-applied and/or under cured release polymer can act like an adhesive agent.

PSIG stands for pressure which is greater than atmospheric pressure and is referred to as "gauge pressure". Pressure below PSIG is referred to as vacuum. Vacuum is measured in inches of mercury (Hg). A gauge should be used to check that the required vacuum is achieved. Caution should be taken not to release vacuum when installing a gauge, particularly with liquid resins.

The items used in a typical vacuum bagging process schedule and their functions are:

• Release film/Peel ply: This is the first layer against the uncured laminate and is used as a barrier between the laminate and bleeder or breather layers. A nonporous peel ply is used when no resin bleed is required but evacuating volatiles and solvents is still needed.

• Bleeder: This is a porous layer used for controlled bleed of resin and to absorb resin. It promotes the movement of resin which promotes the movement of air and gas.

• Separator or Blocker Film Layer: This layer is used to restrict or prevent resin flow. A separator layer is placed between the breather and bleeder layers to prevent saturation of the breather layer.

• Breather: This is a continuous breather layer across the area being vacuum bagged. It maintains a breather path throughout the bag to the vacuum source for air and volatiles to escape. The breather should not be allowed to fill with resin. The breather and bleeder layers should make contact with the edges.

• Bagging film: This is used as the vacuum membrane. The vacuum bag... must not be porous.

• Sealant tape: This is a rubberized tape or putty used to seal bagging equipment and the bagging film.

• Vacuum port: This is a machined or cast metal fitting that connects the vacuum bag to the vacuum source.

• Vacuum hose: This is used for drawing air and must be large enough to provide necessary airflow. The overall function of these layers (bleeder, breather, and vacuum bag) is to draw out the excess resin, air, volatiles, and solvents from the laminate and to consolidate layers into a tightly compacted laminate for the final cure cycle.

Based on the sources, here's a comparison of Wet Layup, Vacuum Infusion, and Prepreg Layup:

Wet Layup (“Contact Molding”):

• Process: A surface coat of resin is applied to the mold prior to the wet layup, and plies are “wet-pregged” on a table and transferred to the mold.

• Advantages: The source indicates it is a molding method.

• Disadvantages: Compared to vacuum infusion, it is considered less cleaner and more precise.

Vacuum Infusion (VIP):

• Process: A dry-pack or preform is placed in the mold, and resin is applied through a pressure and/or vacuum injection process. All reinforcements are placed dry, and vacuum is pulled on the bag and preform compacted prior to introducing resin into the laminate.

• Advantages: It is cleaner and more precise than wet layup.

• Disadvantages: Resin flow is dependent on the amount of vacuum, viscosity of resin, and permeability of the fiber preform.

Prepreg Layup:

• Process: This method often uses a vacuum bag and requires an oven or autoclave cure. It often takes place in a temperature and humidity regulated space and can involve material “kitting”, automated table cutting systems, and laser positioning technologies for accurate material placement. It involves debulking, which is compacting each ply individually, in sequence.

• Advantages: It allows for the most precise resin to fiber ratios and the most accurate control of fiber orientation.

• Disadvantages: The source does not explicitly list disadvantages.

The major differences between Automated Tape Laying (ATL) and Automated Fiber Placement (AFP) are not detailed in the provided sources. However, both are mentioned as processes used to apply resin impregnated continuous fibers to a mold-tool or mandrel. The sources do not provide specific examples of their uses.

Three ways to preheat for thermoforming processes are:

• Conduction via contact heating panels or rods.

• Convection heating, using ovens which circulate hot air.

• Radiant heating achieved with infrared heaters.

The types of thermoforming processes identified and explained in the sources are:

• Vacuum forming: This process uses negative pressure (vacuum) to conform the material to the mold. A diagram in Figure 5-15 shows a preheated laminate placed on a mold, and a vacuum is used to conform the sheet to the mold.

• Pressure forming: This process uses positive pressure (compressed air or press equipment) to conform material to the mold.

• Diaphragm forming: This is a lower pressure process suitable for simple geometries which uses air pressure to compress a flexible diaphragm against the sheet and conform it to the mold. Figure 5-16 illustrates this, showing air pressure forming the sheet against the mold using a flexible top diaphragm and a bottom mold.

• Rubber forming, or rubber block stamping: This is a higher pressure process suitable for more complex geometries. It uses air pressure to compress an upper molding surface made from rubber to conform the sheet against the lower metal mold surface.

• Hydroforming: This process uses a pressurized fluid to conform the material. A thick rubber, flexible diaphragm, typically much larger than the part being formed, is attached to the upper platen of a press and supported from behind by a fluid medium, usually hydraulic fluid. The preheated composite material is placed on a lower mold surface, and hydraulic fluid pressure is applied to the diaphragm, forcing the material to conform to the mold. This process can achieve more complex shapes. Figure 5-17 shows a diagram of hydroforming.

• Matched die forming, or matched metal die stamping: This process uses higher pressures and matched upper and lower metal molds. The mold is typically maintained below the thermoplastic melt temperature so that the part is formed and cooled at the same time. Cycle times range from 30 seconds to 15 minutes, with mold temperatures between room temperature and 350°F (23-177°C) and pressures from 100-1,500 psi. Figure 5-18 illustrates matched die forming.

• Twin-sheet forming: This process forms two preheated sheets between two female molds with matching perimeters or contact surfaces. The twin sheets are drawn into the molds using a combination of vacuum and air pressure, and then joined together to make a single hollow part.

• Sheet bending: This uses a folding machine or jig to produce a gently angled or bent surface.

• Drape forming: In this process, the preheated sheet is stretched down over typically a male mold using either gravity alone or application of vacuum.