Adhesives, Ceramics & Glass - IQS Newsroom

Tube Fabricating: Danner vs Vello

IQS Newsroom — Tue, 23 Sep 2014 13:20:16 +0000

Glass tubes are used in many different industries from medical storage vials, to electric bulb housing, and beyond. Many factories focus exclusively on fabricating glass tubes rather than creating a variety of glass products. Focusing on one specific task can be cost effective because it allows a factory to use equipment just for the creation of tubes and it does not need to stock other glass fabricating equipment.
In the glass fabricating industry, there are two main processes used to create tube glass- the Danner method and the Vello method. Both manufacturing methods are still in use today.
The Danner manufacturing method heats the glass in a furnace until it is soft and pliable, but not fully melted. The flows in a ribbon to a refractory sleeve, which is turned by a blowpipe or rotating hollow shaft. The glass ribbon becomes wrapped around the sleeve creating a smooth layer of glass. The smooth glass travels away from the sleeve and travels through a drawing machine. While this occurs, a blowpipe fills the center of the glass with air, creating the tube shape. The draw machine continues to shape the tube until it takes on the desired properties of the design.
In the Vello manufacturing method, glass travels out of the furnace into a bowl with a hollow mandrel. The glass travels through the air space between the mandrel and bowl, which creates the tube shape and is transported by rollers to a drawing machine that could be over 200 feet away from the furnace. This cools the tube and allows it to travel straight to cutting and processing at the end of the line. In general, the Vello process is better for high production applications, while the Danner process is ideal for precise, small-batch tube orders.

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The Advantages of Hot Isostatic Pressing

IQS Newsroom — Tue, 17 Jun 2014 18:18:00 +0000

There is an array of methods used to shape form ceramic powders including injection molding, extrusion, hot isostatic pressing, slip casting, gel casting and tape casting. Injection molding is known to form many plastic parts found in the average household and extrusion can be used to make a ceramic rod used for building facade. Hot isostatic pressing (HIP) is a forming method that can be used to form both metallic and non-metallic materials into a variety of different products. HIP increases the density of ceramic materials and can reduce the porosity of metals.
Hot isostatic pressing can create high quality casts at lower prices compared to traditional machining methods. To improve overall quality HIP chambers heat, then gradually cool products. Quality jeopardizing gas bubbles are removed during this this stage of the process, ensuring a higher quality part. Ceramic knives with black colored blades are produced with an additional hot isostatic pressing step to improve toughness.
The HIP process involves sintering a compact in a pressure vessel at high temperatures. The pressurized gas used to create the pressurized atmosphere in the chamber is usually either Argon or Nitrogen. Common pressures can go from 15,000 psi to 44,000 psi. To put that into perspective, the U.S. Navy’s best submarines can withstand about 1,500 psi while submerged. Although to be fair, submarines are much larger, making it more difficult to hold back greater pressures.
To cause a consolidation of powder particles, healing voids and pores, hot isostatic pressing combines pressing and sintering. Resulting from the part shrinking and densifying, a high strength structure is formed. This process can be performed without a mold but cold isostatic pressing must be used first to compact the product and then sintered to close the interconnecting porosity. The part can then be processed through hot isostatic pressing.

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Glue Rubber to Metal: Water Based vs. Solvent Based Adhesives

IQS Newsroom — Mon, 06 Jan 2014 13:00:07 +0000

There are various types of gluing agents available on the market each with their own distinct attributes which are ideal for different applications. Water based adhesives have become very popular due to a number of their benefits. Traditionally solvent based adhesives have a greater shear and peel strength compared to water based adhesives, however there have been some recent breakthroughs in the water based field. These innovations have not only improved the strength of water based adhesives but they also enhanced the speed in which the glue will adhere to materials. These water based adhesives allow the rubber to have a greater bonding strength to the metal’s porous surface resulting in deeper penetration. This stronger bond is ideal for applications where strong bonds are needed but also this advantage allows for greater resistance and flexibility to cold and heat.
These versatile water based solutions can usually be extruded, rolled or sprayed allowing for uniformity and consistent strength throughout the structure. Water based adhesives are also considered environmentally friendly because they contain any volatile organic compounds. Water based adhesives are generally used for layflat laminating, labeling, woodworking, and more. This type of adhesive is also recognized as a very economical solution. Although there are clear benefits to water based adhesives there are a range of qualities associated with solvent based adhesives. These solutions are known for their tried and true performance in applications that involve extensive weathering as well as higher temperatures. Solvent based adhesives have a higher resistance to moisture compared to water based adhesives. The key to determining which adhesive is most beneficial for an application is based in the requirements of the project but also in the surrounding environment.

Photo Courtesy of Accurate Products

When attempting to glue rubber to metal there are a number of factors to consider when selecting the right adhesive. The best bonding processes will utilize rubbers and metals that are compatible for long term adhesion and rubber bonded to metal is ideal to increase the longevity of the product. These types of products are typically used in industries such as automotive, storage, electronics, construction, plumbing and much more. Aluminum has been a metal of choice for rubber bonding in certain applications due to the light weight and low cost of this metal. Steel is also a recommended choice because of the high resistant to corrosion and overall durability. When selecting between solvent based or water base adhesives take the time to thoroughly research the best possible solution for your application. These steps will save you time and money in the long run.

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Graphite is More Than Just Pencil Lead

IQS Newsroom — Wed, 23 Dec 2009 09:53:00 +0000

by Jenny Knodell, IQS Editor

When asked about the mineral graphite, one image likely comes to mind: a pencil. This soft, dark grey, greasy material, also called black lead and plumbago, has been used to jot down notes and draw pictures for hundreds of years. Its name is even derived from the Latin term for “to draw/write.” Graphite is only found in a handful of places around the world, including Africa, the British Isles and a couple of U.S. states—including my home state of Michigan. There are 3 main types of natural graphite that are all found in different types of ore deposit. Crystalline graphite is flat with hexagonal edges, amorphous graphite is very thin and flakey, and lump graphite is found in veins of fractures underground. The first pencil was composed of sticks of graphite tied together with string. As you can imagine, this early writing utensil wasn’t exactly user friendly, but it could easily be erased with rubber. It wasn’t until much later that the modern pencil—the wooden kind with a pink eraser top that we use today—became popular.

Raw natural graphite and lead pencil.
The lead we use in pencils is actually a mixture of graphite and clay or wax. The process that transforms raw lead and wood into a pencil is a little more complicated than it seems. First, graphite is ground up into find powder and added to clay or wax and water in a mixer. The water is squeezed out, and the mixture is left to dry. Water is then added a second time to the powder. A thick paste is formed, and extruded through thin metal tubes to become the thin, round lead pencil shape. The wood components of the pencil are cut as halves and glued around the lead. Each pencil has a designated hardness level—most are #2, but the scale may reach 4. This number determines how much graphite is released onto the page per pencil stroke. The higher the number, the less graphite is released and the lighter the pencil line will be. After the wood part is cut to shape and painted, the eraser and metal part are added last, along with the embossed hardness number and logo. And there you have it. A pencil is born.

Extruding graphite for pencil lead.
Although pencil lead may be the most widely known and popular use for graphite, many other graphite products exist. Since graphite is so heat resistant, it is often used to make crucibles, containers that hold material at very high temperatures without being burned, melted or chemically changed. In steelmaking, graphite is used to lubricate the molds used in steel extrusion. It is also sometimes found in paint that coats the inside of a mold, which is used to ease the ejection of a finished molded product. Carbon graphite is often a cheaper alternative to carbon raisers, which are added to steel to raise the carbon content. Synthetic graphite, which is made by heating coal, also finds uses in some other industrial applications. Since man-made graphite is electrically conductive, graphite electrodes are used to heat electric arc furnaces. All graphite, whether synthetic or natural, is easily 100% recyclable. Trim and excess graphite from product manufacturing often finds a second life in electric arc furnaces.

Graphite Electrodes. Photo courtesy of Weaver Industries, Inc.

Graphite products. Photo courtesy of Becker Brothers Graphite Corporation.

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