The Making #1 : Magnets, Thermocol and Ball Point Pens

Today we see how Magnets, Thermocol and Ball Points pens are made.

Magnets : 

When making magnets, the raw materials are often more important than the manufacturing process. The materials used in permanent magnets (sometimes known as hard materials, reflecting the early use of alloy steels for these magnets) are different than the materials used in electromagnets (some-times known as soft materials, reflecting the use of soft, malleable iron in this application)

Just as the materials are different for different kinds of magnets, the manufacturing processes are also different. Many electromagnets are cast using standard metal casting techniques. Flexible permanent magnets are formed in a plastic extrusion process in which the materials are mixed, heated, and forced through a shaped opening under pressure.

Some magnets are formed using a modified powdered metallurgy process in which finely powdered metal is subjected to pressure, heat, and magnetic forces to form the final magnet. Here is a typical powdered metallurgy process used to produce powerful neodymium-iron-boron permanent magnets with cross-sectional areas of about 3-10 square inches (20-65 sq cm):

Preparing the powdered metal

  • 1 The appropriate amounts of neodymium, iron, and boron are heated to melting in a vacuum. The vacuum prevents any chemical reaction between air and the melting materials that might contaminate the final metal alloy.
  • 2 Once the metal has cooled and solidified, it is broken up and crushed into small pieces. The small pieces are then ground into a fine powder in a ball mill.

Pressing

  • 3 The powdered metal is placed in a mold, called a die, that is the same length and width (or diameter, for round magnets) as the finished magnet. A magnetic force is applied to the powdered material to line up the powder particles. While the magnetic force is being applied, the powder is pressed from the top and bottom with hydraulic or mechanical rams to compress it to within about 0.125 inches (0.32 cm) of its final intended thickness. Typical pressures are about 10,000 psi to 15,000 psi (70 MPa to 100 MPa). Some shapes are made by placing the powdered material in a flexible, air-tight, evacuated container and pressing it into shape with liquid or gas pressure. This is known as isostatic compaction.

Heating

  • 4 The compressed “slug” of powdered metal is removed from the die and placed in an oven. The process of heating compressed powdered metals to transform them into fused, solid metal pieces is called sintering. The process usually consists of three stages. In the first stage, the compressed material is heated at a low temperature to slowly drive off any moisture or other contaminants that may have become entrapped during the pressing process. In the second stage, the temperature is raised to about 70-90% of the melting point of the metal alloy and held there for a period of several hours or several days to allow the small particles to fuse together. Finally, the material is cooled down slowly in controlled, step-by-step temperature increments.

Annealing

  • 5 The sintered material then undergoes a second controlled heating and cooling process known as annealing. This process removes any residual stresses within the material and strengthens it.

Finishing

  • 6 The annealed material is very close to the finished shape and dimensions desired. This condition is known as “nearnet” shape. A final machining process removes any excess material and produces a smooth surface where needed. The material is then given a protective coating to seal the surfaces.

Magnetizing

  • 7 Up to this point, the material is just a piece of compressed and fused metal. Even though it was subjected to a magnetic force during pressing, that force didn’t magnetize the material, it simply lined up the loose powder particles. To turn it into a magnet, the piece is placed between the poles of a very powerful electromagnet and oriented in the desired direction of magnetization. The electromagnet is then energized for a period of time. The magnetic force aligns the groups of atoms, or magnetic domains, within the material to make the piece into a strong permanent magnet.

Ball Point Pens

A variety of raw materials are used for making the components of a ballpoint pen, including metals, plastics, and other chemicals. When ballpoint pens were first developed, an ordinary steel ball was used. That ball has since been replaced by a textured tungsten carbide ball. This material is superior because it is particularly resistant to deforming. The ball is designed to be a perfect sphere that can literally grip most any writing surface. Its surface is actually composed of over 50,000 polished surfaces and pits. The pits are connected by a series of channels that are continuous throughout the entire sphere. This design allows the ink to be present on both the surface and interior of the ball.

The points of most ballpoint pens are made out of brass, which is an alloy of copper and zinc. This material is used because of its strength, resistance to corrosion, appealing appearance, and ability to be easily formed. Other parts, like the ink cartridge, the body, or the spring can also be made with brass. Aluminum is also used in some cases to make the pen body, and stainless steel can be used to make pen components. Precious metals such as gold, silver, or platinum are plated onto more expensive pens.

The ink can be specially made by the pen manufacturer. To be useful in a ballpoint pen, the ink must be slightly thick, slow drying in the reservoir, and free of particles. These characteristics ensure that the ink continues to flow to the paper without clogging the ball. When the ink is on the paper, rapid drying occurs via penetration and some evaporation. In an ink formulation, various pigments and dyes are used to provide the color. Other materials, such as lubricants, surfactants, thickeners, and preservatives, are also incorporated. These ingredients are typically dispersed in materials such as oleic acid, castor oil, or a sulfonamide plasticizer.

 Until the advent of the computer, humans have scrambled to find writing instruments to record story and song. The earliest scribbles were made with a burnt stick in sand. By the fourth century B.C. , the Sumerians used wedge-shaped reed pens to cut pictorial shapes into clay tablets. Eygptians painted hieroglyphics with brushes made from marsh reeds and the ancient Chinese wrote with brushes of stiff hair. Ancient Greeks and Romans sharpened stiff reeds to a point, resulting in chirography that was taut and precise.

The quill pen, made from goose or swan feathers, was favored by writers for over 1,000 years. The soft quill was honed to a point, split at the tip to permit ink to flow freely, and constantly resharpened. A monumental improvement over the quill pen was Joseph Gillott’s invention of the steel pen nib in the late nineteenth century, which required no sharpening and could be separated from the pen body and changed as needed. Still, the writer constantly dipped pen into ink, hoping to avoid drips.

Fountain pens store ink inside a reservoir within the pen, the nib thus supplied with a constant stream of ink. Alonzo Cross featured a “stylographic pen” with an ink-depositing needle point in the late 1860s, but blots and smears were still common. However, the ballpoint pen virtually eradicated messes. Ballpoint pens manufactured early in the century leaked, skipped, and dropped ink until 1950, when a new ink was developed that made the ballpoint reliable.

Plastics have become an important raw material in ballpoint pen manufacture. They have the advantage of being easily formed, lightweight, corrosion resistant, and inexpensive. They are primarily used to form the body of the pen, but are also used to make the ink cartridge, the push button, the cap, and part of the tip. Different kinds of plastics are used, based on their physical characteristics. Thermosetting plastics, like phenolic resins, which remain permanently hard after being formed and cooled, are typically used in constructing the body, cap, and other pieces. Thermoplastic materials remain flexible. These include materials like high-density polyethylene (HDPE) and vinyl resins, which can be used to make most of the pen components.

Manufacturing Process

Ballpoint pens are made to order in mass quantities. While each manufacturer makes them slightly differently, the basic steps include ink compounding, metal component formation, plastic component molding, piece assembly, packaging, labeling, and shipping. In advanced shops, pens can go from raw material to finished product in less than five minutes.

Making the ink

  • 1 Large batches of ink are made in a designated area of the manufacturing plant. Here workers, known as compounders, follow formula instructions to make batches of ink. Raw materials are poured into the batch tank and thoroughly mixed. Depending on the formula, these batches can be heated and cooled as necessary to help the raw materials combine more quickly. Some of the larger quantity raw materials are pumped and metered directly into the batch tank. These materials are added simply by pressing a button on computerized controls. These controls also regulate the mixing speeds and the heating and cooling rates. Quality control checks are made during different points of ink batching.

Stamping and forming

  • 2 While the ink is being made, the metal components of the pen are being constructed. The tungsten carbide balls are typically supplied by outside vendors. Other parts of the pen, such as the point and the body, are made using various molds. First, bands of brass are automatically inserted into stamping machines, which cut out thousands of small discs. The brass discs are next softened and poured into a compression chamber, which consists of a steel ram and a spring-backed ejector plunger. The steel ram presses on the metal, causing the plunger to retract and forcing the metal into a die cast mold. This compresses the metal and forms the various pen pieces. When the ram and plunger return to their original positions, the excess metal is then scraped off and recycled. The die is then opened, and the pen piece is ejected.
  • 3 The formed pieces are then cleaned and cut. They are immersed in a bath to remove oils used in the molding process. After they emerge from the bath, the parts are then cut to the dimensions of the specific pen. The pen pieces are next polished by rotating brushes and cleaned again to remove any residual oils. The ball can then be inserted into the point cavity.

Molding the housing

  • 4 The plastic components of the pen are constructed simultaneously with the other pen pieces. They can be produced by either extrusion or injection molding. In each approach, the plastic is supplied as granules or powder and is fed into a large hopper. The extrusion process involves a large spiral screw, which forces the material through a heated chamber, making it a thick, flowing mass. It is then forced through a die, cooled, and cut. Pieces such as the pen body and ink reservoir are made by this method.
  • 5 For pieces that have more complex shapes, like caps, ends, and mechanical components, injection molding is used. In this process the plastic is heated, converting it into a liquid that can then be forcibly injected into a mold. After it cools, it solidifies and maintains its shape after the die is opened.

Ink filling and assembly

  • 6 After the components are formed, assembly can take place. Typically, the ballpoint is first attached to the ink reservoir. These pieces are then conveyored to injectors, which fill the reservoir with the appropriately colored ink. If a spring is going to be present, it is then placed on the barrel of the reservoir.

Final assembly, packaging, and shipping

  • 7 The point and reservoir are then placed inside the main body of the pen. At this stage, other components such as the cap and ends are incorporated. Other finishing steps, such as adding coatings or decorations or performing a final cleaning, are also done. The finished pens are then packaged according to how they will be sold. Single pens can be put into blister packages with cardboard backings. Groups of pens are packed into bags or boxes. These sales units are then put into boxes, stacked on pallets, and shipped to distributors.

Thermocols

Thermocol is a commercial name like Coca-Cola. In 1951 the researchers of a German company named BASF successfully restructured chemical bonding of polystyrene (a synthetic petroleum product) molecules and developed a substance named stretch polystyrene. This substance was named Thermocol, which nowadays is manufactured through a simple process. Thermoplastic granules are expanded through application of steam and air. Expanded granules become much larger in size but remain very light.
 
Thermocol is a good resister of cold and heat but since it is a petroleum product it dissolves in any solvent of petroleum.

Polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum. At room temperature, polystyrene is normally a solid thermoplastic, but can be melted at higher temperature for molding or extrusion, then resolidified. Styrene is an aromatic monomer, and polystyrene is an aromatic polymer.

Courtesy and Sources : Discovery Channel, Here be Answers, Madehow.com

One thought on “The Making #1 : Magnets, Thermocol and Ball Point Pens

  1. Pingback: Propel Steps : Archive : 2013 : Most Read Posts | PROPEL STEPS

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