A living hinge or integral hinge is a thin flexible hinge (flexure bearing) made from the same material as the two rigid pieces it connects.
A living hinge or integral hinge is a thin flexible hinge (flexure bearing). It is made from the same material as the two rigid pieces it connects. It is typically thinned or cut to allow the rigid pieces to bend along the line of the hinge. The minimal friction and very little wear in such a hinge makes it useful in the design of microelectromechanical systems, and the low cost and ease of manufacturing makes them quite common in clamshell containers and other disposable, recyclable packaging. [1]
Plastic living hinges are typically manufactured in an injection molding operation [2] [3] that creates all three parts at one time as a single piece, and if correctly designed and constructed, it can remain functional over the life of the part. Thermoforming can also produce hinged products. Polyethylene and polypropylene are considered to be the best resins for living hinges, due to their excellent fatigue resistance. [4] [5] Acrylonitrile butadiene styrene (ABS) is also common. [6]
A variant on the kerf bend can be used to create living hinges in laser cut wood. The technique is popular for making light-duty hinges with large radii. [7] It is also possible to create a living wood joint by hand, but the result is less accurate. [8]
A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.
Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene.
Acrylonitrile butadiene styrene (ABS) (chemical formula (C8H8)x·(C4H6)y·(C3H3N)z ) is a common thermoplastic polymer. Its glass transition temperature is approximately 105 °C (221 °F). ABS is amorphous and therefore has no true melting point.
Injection moulding is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals, glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed, and injected into a mould cavity, where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an industrial designer or an engineer, moulds are made by a mould-maker from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars. Advances in 3D printing technology, using photopolymers that do not melt during the injection moulding of some lower-temperature thermoplastics, can be used for some simple injection moulds.
Molding or moulding 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 flexure bearing is a category of flexure which is engineered to be compliant in one or more angular degrees of freedom. Flexure bearings are often part of compliant mechanisms. Flexure bearings serve much of the same function as conventional bearings or hinges in applications which require angular compliance. However, flexures require no lubrication and exhibit very low or no friction.
A die is a specialized machine tool used in manufacturing industries to cut and/or form material to a desired shape or profile. Stamping dies are used with a press, as opposed to drawing dies and casting dies which are not. Like molds, dies are generally customized to the item they are used to create.
Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat. Welding of thermoplastics is accomplished in three sequential stages, namely surface preparation, application of heat and pressure, and cooling. Numerous welding methods have been developed for the joining of semi-finished plastic materials. Based on the mechanism of heat generation at the welding interface, welding methods for thermoplastics can be classified as external and internal heating methods, as shown in Fig 1.
Thermoforming is a manufacturing process where a plastic sheet is heated to a pliable forming temperature, formed to a specific shape in a mold, and trimmed to create a usable product. The sheet, or "film" when referring to thinner gauges and certain material types, is heated in an oven to a high-enough temperature that permits it to be stretched into or onto a mold and cooled to a finished shape. Its simplified version is vacuum forming.
A closure is a device used to close or seal a container such as a bottle, jug, jar, tube, or can. A closure may be a cap, cover, lid, plug, liner, or the like. The part of the container to which the closure is applied is called the finish.
A flexure is a flexible element engineered to be compliant in specific degrees of freedom. Flexures are a design feature used by design engineers for providing adjustment or compliance in a design.
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code.
Rotational molding involves a heated mold which is filled with a charge or shot weight of the material. It is then slowly rotated, causing the softened material to disperse and stick to the walls of the mold forming a hollow part. In order to form an even thickness throughout the part, the mold rotates at all times during the heating phase, and then continues to rotate during the cooling phase to avoid sagging or deformation. The process was applied to plastics in the 1950s but in the early years was little used because it was a slow process restricted to a small number of plastics. Over time, improvements in process control and developments with plastic powders have resulted in increased use.
In-mould labelling is the use of paper or plastic labels during the manufacturing of containers by blow molding, injection molding, or thermoforming processes. The label serves as the integral part of the final product, which is then delivered as pre-decorated item. Combining the decoration process with the moulding process cuts the total cost, but can increase the manufacturing time. The technology was first developed by Owens-Illinois in cooperation with Procter & Gamble to supply pre-labelled bottles that could be filled on the product filling line. This was first applied to Head & Shoulders shampoo bottles.
A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo, milk, ink, etc. They come in a range of sizes, from very small bottles to large carboys. Consumer blow molded containers often have integral handles or are shaped to facilitate grasping.
In mechanical engineering, a compliant mechanism is a flexible mechanism that achieves force and motion transmission through elastic body deformation. It gains some or all of its motion from the relative flexibility of its members rather than from rigid-body joints alone. These may be monolithic (single-piece) or jointless structures. Some common devices that use compliant mechanisms are backpack latches and paper clips. One of the oldest examples of using compliant structures is the bow and arrow. Compliant mechanisms manufactured in a plane that have motion emerging from said plane are known as lamina emergent mechanisms or LEMs.
A clamshell is a one-piece container consisting of two halves joined by a hinge area which allows the structure to come together to close. Clamshells can be made to be reusable and reclosable or can be sealed securely.
Thin wall injection molding is a specialized form of conventional injection molding that focuses on mass-producing plastic parts that are thin and light so that material cost savings can be made and cycle times can be as short as possible. Shorter cycle times means higher productivity and lower costs per part.
A Euro container, also called Eurobox, Euro crate or KLT box, is an industrial stacking container conforming to the VDA 4500 standard. The standard was originally defined by the German Association of the Automotive Industry (VDA) for the automotive industry, but was subsequently adopted across many other areas of manufacturing and the shipping industry. The most common sizes are 600 × 400 mm and 400 × 300 mm, which can be stacked together to fill a Euro-pallet measuring 1200 × 800 mm.
Package handles, or carriers, are used to help people use packaging. They are designed to simplify and to improve the ergonomics of lifting and carrying packages. Handles on consumer packages add convenience and help facilitate use and pouring. The effect of handles on package material costs and the packaging line efficiencies are also critical. A handle can be defined as “an accessory attached to a container or part for the purpose of holding or carrying.” Sometimes a handle can be used to hang a package for dispensing or use.
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