VACUUM PROCESS SOLUTIONS
Other than a Hoover or Dyson, the term “vacuum” doesn’t mean a lot to most people. Many people are familiar with vacuum packaged or “cryovac” packages of meat from our local grocer or butcher, and some may even have a vacuum packaging device in their home kitchen to prevent freezer burn on their leftovers. We might, then, be surprised to learn that the extensive use of a “vacuum” or “vacuum process solutions” is critical to manufacturing many of the goods we use everyday.
In many instances, the simplest use of a vacuum is to move products and parts from one place to another, through the use of what we might refer to as “suction” which is actually just a pressure differential between the sides of the object to be moved. At the bank we see this in the use of pneumatic tubes that transfer items between the teller and the driver in the drive-through. In an assembly line, robots often use a vacuum to lift bottle or container lids and place them on product containers after the containers have been filled.
In addition to moving things, a vacuum is frequently used to create an ideal environment that is conducive to processes that take place within. Sometimes the environment is conducive because of reduced pressure, sometimes because of lack of oxygen, a highly reactive element that makes up 21% of the air we breathe. Some common vacuum techniques used by industry to produce the products that we use everyday are listed below.
Vacuum Degassing is a common process that reduces or eliminates air and other gases that are dissolved in liquids, thereby purifying the liquid and making it more effective at whatever it is supposed to do. Adhesives, dielectric oil and even some beverages benefit from degassing before the liquid is used.
Space Simulation describes the process of testing components and manufactured items in a vacuum chamber that simulates the pressure and temperature of their operating environment of a low earth orbit or a geosynchronous orbit.
Similarly, Altitude Simulation is designed to simulate the low pressure packaged goods experience when they are trucked over high mountain passes or that might exist in the cargo hold of aircraft. Vacuum systems built for this purpose help to ensure that product packaging retains its integrity under difficult conditions.
Package Testing consists of several techniques to be sure that product packaging will do it’s job, both of which use a vacuum. In one scenario, a batch of sealed liquid containers is place in a vacuum chamber and a vacuum is pulled to see if they will leak. In another, sealed containers full of air are placed in a chamber which is filled with water and a vacuum is pulled in the space above the water. A technician then counts the bubbles that escape the containers and rise to the surface.
A very common use of vacuum process technology is in Surface Coating. Physical vapor deposition and chemical vapor deposition are frequently used in semiconductor production and also to waterproof consumer items. If your smart phone will survive a dunk in the toilet, you can thank surface coating for not giving you an excuse to go buy the latest version because yours has been ruined.
Vacuum Drying is a technique that is used when a product needs to have very low levels of moisture. It is done under vacuum because the evaporation of liquids can be accomplished at low temperatures. Lyophilization, or freeze drying food and items for long-term storage is a common use of this technique.
A related procedure, Vacuum Bake-Out, is done on products that need to have high-purity which are free from absorbed volatile materials that might contaminate them. Using a vacuum and elevated temperatures can remove tiny amounts of residual water vapor as well as cleaning residues or other contaminants that may have been absorbed onto the surface of the part.
The process of Vacuum Potting is crucial to the success of making sure a resin or potting compound makes it into all the nooks and crannies of a mold by removing atmosphere from these cavities and injecting the compound under pressure. Many manufacturers use this process to protect products from moisture, contaminants and mechanical damage.
Often manufacturing requires that complicated assemblies have metal sections that need to be joined with great precision. Brazing, welding and other joining techniques are often performed in a vacuum or inert gas environment to achieve the best and cleanest joints. This is, not surprisingly, known as Vacuum Joining.
Finally, many Physics Research experiments can only be effectively conducted in a vacuum environment such as plasma, microwave, materials, acoustics, thermal and accelerator applications. These experiments lay the groundwork for the manufactured goods that we and our children will use tomorrow and in the future.