Name: JACK MATATULA
Test Date: 13 August 2010
Administered by: Shirley Dewi (via e-mail)
Test Questionnaires Revision: 04/08/10
IAF:14 (Rubber and Plastic Products)
NACE:DH 25.1 (Manufacture of rubber products); DH 25.2 (Manufacture of plastic products)
Test Score: 100%
Question No. / Answer / Correct / Partially Correct(Indicate% deducted) / Wrong / Remarks (if applicable)
70. What is rubber molding process? / Rubber molding is a molding process that produces a useable rubber product. Rubber products are made from uncured rubber or elastomers. An elastomer is any material with sufficient resilience or memory for returning to its original shape in response to pressure or distortions. Rubber and elastomers can be derived from natural sources, although they are mostly synthetic, produced through highly controlled chemical processes. Rubber is an excellent material for situations that require a material to expand and return to its original shape. Specific industries that benefit from custom molded rubber are automobile, appliance controls, lawn and garden, sporting goods, medical, electrical, government and recreational. These industries and others benefit from many different products that can be created with this process. / X
71. What is injection molding? / Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity. / X
73. What is injection molding cycle? / The basic injection cycle is as follows: Mold close - injection carriage forward - inject plastic -metering - carriage retract - mold open - eject part(s)
For the injection molding cycle to begin, four criteria must be met: mold open, ejector pins retracted, shot built, and carriage forward. When these criteria are met, the cycle begins with the mold closing. This is typically done as fast as possible with a slow down near the end of travel. / X
74. What is injection molding cycle time? / The time it takes to make a product using injection molding can be calculated by adding:
Twice the Mold Open/Close Time (2M) + Injection Time (T) + Cooling Time (C)
+ Ejection Time (E)
Where T is found by dividing:
Mold Size (S) / Flow Rate (F)
Total time = 2M + T + C + E
T = V/R
V = Mold cavity size (in3)
R = Material flow rate (in3/min) / X
75. What is compression molding? / Compression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured. The process employs thermosetting resins in a partially cured stage, either in the form of granules, putty-like masses, or preforms. Compression molding is a high-volume, high-pressure method suitable for molding complex, high-strength fiberglass reinforcements. / X
78. What is extrusion process? / Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section. / X
79. What is lathe cutting process? / A lathe is a machine tool which spins the workpiece to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation. / X
81. What are the common types of plastics and its uses? / A plastic material is any of a wide range of synthetic or semi-synthetic organic amorphous solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of plastic are either natural or synthetic organic compounds.
1.PET (PETE), polyethylene terephthalate, is commonly found in 2-liter soft drink bottles, water bottles, cooking oil bottles, peanut butter jars.
2.HDPE, high-density polyethylene, is commonly found in detergent bottles and milk jugs.
3.PVC, polyvinyl chloride, is commonly found in plastic pipes, outdoor furniture, siding, floor tiles, shower curtains, clamshell packaging.
4.LDPE, low-density polyethylene, is commonly found in dry-cleaning bags, produce bags, trash can liners, and food storage containers.
5.PP, polypropylene, is commonly found in bottle caps, drinking straws, yogurt containers.
6.PS, polystyrene, is commonly found in "packing peanuts", cups, plastic tableware, meat trays, take-away food clamshell containers.
7.There are also other types of plastics commonly found in certain kinds of food containers, Tupperware, and Nalgene bottles. / X
82. What is Melt Index? / Melting, or fusion, is a physical process that results in the phase change of a substance from a solid to a liquid. The internal energy of a substance is increased, typically by the application of heat or pressure, resulting in a rise of its temperature to the melting point, at which the rigid ordering of molecular entities in the solid breaks down to a less-ordered state and the solid liquefies.
Under a standard set of conditions, the melting index of a substance is a characteristic property. / X
86. What is additives? / Additives is substance added to preserve flavor or enhance its taste and appearance. Some additives have been used for centuries; for example, preserving food by pickling (with vinegar), salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines / X