Molding.docx

molding Molding or moulding is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix.[1] This itself may have been made using a pattern or model of the final object. A mold or mould is a hollowed-out block that is filled with a liquid or pliable material such as plastic, glass, metal, or ceramic raw material.[2] The liquid hardens or sets inside the mold, adopting its shape. A mold is the counterpart to a cast. The very common bi-valve molding process uses two molds, one for each half of the object. Piece-molding uses a number of different molds, each creating a section of a complicated object. This is generally only used for larger and more valuable objects. The manufacturer who makes the molds is called the moldmaker. A release agent is typically used to make removal of the hardened/set substance from the mold easier. Typical uses for molded plastics include molded furniture, molded household goods, molded cases, and structural materials. Types of molding include:           

Blow molding Powder metallurgy plus sintering Compression molding Extrusion molding Injection molding Laminating o Reaction injection molding Matrix molding Rotational molding (or Rotomolding) Spin casting Transfer molding Thermoforming o Vacuum forming, a simplified version of thermoforming

(Wikipedia) What is Molding? Posted by pgathings on Aug 4, 2014 in Uncategorized | No Comments “Molding is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix. This itself may have been made using a pattern or model of the final object.” “A mold or mould is a hollowed-out block that is filled with a liquid or pliable material like plastic, glass, metal, or ceramic raw materials. The liquid hardens or sets inside the mold, adopting its shape. A mold is the counterpart to a cast. The very common bi-valve molding process uses two molds, one for each half of the object. Piece-molding uses a number of

different molds, each creating a section of a complicated object. This is generally only used for larger and more valuable objects.” “The manufacturer who makes the molds is called the moldmaker. A release agent is typically used to make removal of the hardened/set substance from the mold easier. Typical uses for molded plastics include molded furniture, molded household goods, molded cases, and structural materials.” Kent Mold & Mfg builds molds used in:      

Blow Molding Compression Molding Structural Foam Molding Injection Molding Reaction Molding Transfer Molding

http://kentmold.com/molding/

Types of Molding Processes Molding is primarily used during the manufacturing process of plastic. Plastic is a synthetic materials, and to form it into the desired shape different molding processes are used. Each process requires the manipulation of molten plastic, and then leaving it to set. Thermoplastics can then be melted down and reformed if necessary, however thermoset plastics cannot be reheated.

Casting Casting is a basic molding process as it requires the least amount of complex technology. Plastic is simply heated so it turns into a fluid, and then transferred into a mold. It is left to cool and the mold is removed. This process can be used for intricate shapes and performed under a low pressure. However, it is a common process used for making plastic sheeting, starting from 0.5 inches thick and greater.

Injection Molding Injection molding is used for creating high-quality three-dimensional objects, that can be commercially reproduced. The molding process begins by melting plastic in a hopper. Then the plastic is injected into a tightly closed, chilled mold. The plastic quickly takes the shape of the surrounding mold. Once it has completely set, the mold is opened and the plastic object is released. Yogurt pots, butter tubs, toys and bottle caps are made using this process. Enterprise Browser Solution for Your Org. Deploy Chrome Now! enterprise.google.com/chrome

Blow Molding Blow molding is a process used for making piping and milk bottles. Plastic is heated until molten. Then it is injected into a cold mold. The mold has a tube set within it, which has a particular shape when inflated. So, while the plastic is molten, air is blown into the tube and the plastic is formed around the tubing. It is then left to cool and removed from the mold.

Compression Molding The most labor-intensive type of molding process is compression molding. Therefore, it is only used for large-scale production purposes, and not for mass production. For example, boat hulls and car tires are made using this method. Molten plastic is poured into a mold. Then a second mold is pressed into it. This squeezes the plastic into the desired shape before being left to cool and removed from the mold.

Rotational Molding Toys, shipping drums, storage tanks and items of consumer furniture are made using rotational molding. Each object is made by coating a mold from the inside. A mold is held in place between two mechanical arms. Then, the arms rotate the mold constantly at the same level, while molten plastic is placed inside. As it turns, the plastic coats the inside of the mold to create a new hollow, plastic object. Sponsored links

invention : Micro-molding Innovations in the Medical Field As the number of noninvasive surgical techniques is increasing, so is the need for micro-molded plastic. Instruments and devices that were once made of metal—like the coils commonly used to block aneurysms—are slowly being replaced by micro-molded foam and plastic components that consist of bio-absorbable polymers. Current innovations in micro-molded plastic material and micro-molding techniques are bringing about new ways to create these tiny yet mighty medical devices. New Materials Because many devices have to be removed from the body at some point following their implantation, the medical field stands to gain from new micro-molded bio-absorbable components. Bio-absorbable devices are absorbed by the body after they have served their purpose, eliminating the need for a secondary procedure to remove the product. Such devices may offer a way around the side-effects of using metal devices, such as screws, which sometimes lead to a negative reaction in the body.

Bio-absorbable materials tend to be quite expensive, but micro-molding uses very little material. Parts can be created at such a small size that literally a million can be made per 2.5 lbs of material, but some specialty resins can cost as much as 22, 000 dollars per pound. Despite the expense, since micro-molded parts use a small amount of material they are sometimes less expensive to produce than alternative options. Although bio-absorbable parts aren’t new, the recent improvements in the way they are made and their overall effectiveness is making them more attractive. There are, however, problems with absorbable materials when it comes to their ability to resist dissolving when exposed to high-temperatures. New Techniques Earlier forms of micro-molded devices lacked the thin-wall technology that now marks current products. Additionally, new standards call for tighter tolerances—no matter how small the part, tolerances approximately range between 0.001 and 0.0001 inches. The need for tight tolerances has led to the improvement in micro-molding machines. Today, many micro-molding machines even remove, package, and visually inspect the parts they create. CNC machines and silicon-water technology are two processes that have been tailored to create precise cavities for the production of micro-molded part. Additionally, studying the techniques used by watchmakers may prove helpful, as both watchmakers and micro-molders work with extremely small and precisely engineered parts. Finishing such a small part poses a bit of a problem since it can’t be done by hand. It is also extremely important that finishing be done properly, as it is potentially dangerous to insert a jagged or unfinished piece into the body. Stereolithography is currently being explored as a possible finishing option. In an attempt to improve the speed at which the parts can be produced and overall part precision, hot and cold runner systems are being adapted to suit micro-molding. As parts are continually micro-molded in smaller and smaller sizes, the processes by which they are manufactured may need to be re-examined and improved upon. http://www.thomasnet.com/articles/plastics-rubber/micro-mold-innovation http://www.aimplastics.com/services/manufacturing/