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Open Mold

The distinguishing feature of this family of FRP( fiber-reinforced polymer composites) shaping processes is its use of a single positive or negative mold surface to produce laminated FRP structures. Other names for open mold processes include contact lamination and contact molding. The starting materials (resins, fibers, mats, and woven rovings) are applied to the mold in layers, builging up to the desired thickness. This is followed by curing and part removal. Common resinds are unsaturated polyesters and epoxies, using fiberglass as the reinforcement. The moldings are usually large( e.g., boat hulls). The advantage of using an open mold is that the mold costs mych less than if two matching molds wew used. The disadvantage is that only the part surface in contact with the mold surface is finished; the other side is rough. For the best possible part surface on the finished side, the mold itself must be very smooth.

There are several important open mold FRP processes. The differences are in the methods of applying the laminations to the mold, alternative curing techniques, and other variations. The family of open molf processes for shaping fiber-reinforced plastics: (1) hand lay-up, (2) spray-up, (3) automated tape – laying machines, and (4) bag molding. We treat hand lay-up as the base process and the others as modifications and refinements.

(Groover, M.P., Fundamentals of modern manufacturing: materials, processes, and systems, 4th Edition, pg.331-332)

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Open sand molds suitable for casting large metal plates, especially aluminium plates for builfing facades are prepared by using a large roller bearing a model and rolling spaced guides to level a bed of moldable substance therebetween and simultaneously impressing the molding pit in the bed.

(United States Patent US3812902, Apparatus for preparing open sand molds suitable for casting large metal plates, 1974, pg.1)

Intelligent Control

Industrial robots are becoming increasingly intelligent. In this context, an intelligent robot is one that exhibits behavior that makes it seem intelligent. Some of the characteristics that make a robot appear intelligent include the capacities to interact with its environment, make decisions when things go wrong during the work cycle, communicate with humans, make computations during the motion cycle, and respond to advanced sensor inputs such as machine vision.

In addition, robots with intelligent control possess playback capability for both PTP(point-to-point) or continuous path control. These features require (1) relatively high level of computer control and (2) an advanced programming language to input the decision-making logic and other “intelligence” into memory.

(Groover, M.P., Automation, Production Systems and Computer - Integrated Manufacturing, pg.222, Pearson Education Inc,2008)

Fly Cutter

For drilling large holes in pipe or sheet metal, twist drills are not suitable because of the drill tends to dig into the work or the hole is too large to be cut by a standard-size drill. Large holes are cut in thin metal by a hole cutter. Saw- type cutters of this design can be obtained in a wide range of sizes. For very large holes in thin metal a fly cutter is used. Such a cutter consists of tool bits held in a horizontal holder that can accommodate a range of diameters. Both cutters cut in the same path but one is set slightly below the other.

(Amstead, B.H., Ostwald P.F., Begeman, M.L., Manufacturing Processes, 8th Edition, John Wiley & SOns, Inc, pg.510)

Tweak Features

Tweak features deform or alter (“tweak”) the surface of a part. For example, the draft feature adds a draft angle to a surface, or to a series of selected planar surfaces. The Radius Dome option allows a user to create a dome feature. Other Tweak features may include section dome local push ear, offset and draft offset, replace, lip, patch, toridal and spinal bends, and free form.

(Xun Xu, Integrating Advanced Computer-Aided Design, Manufacturing, and Numerical Control: Principles and Implementations, pg.152)