Advanced computer technologies, automated assembly systems, and high-quality compressed air systems have changed the automotive manufacturing industry. Consumers can purchase safer, more fuel-efficient and reliable vehicles today than ever before. Using compressed air during manufacturing can also save energy and money during assembly.
Over the last 100 years, automotive manufacturing has been enhanced by the introduction of compressed air in the assembly line to increase worker’s safety and the overall efficiency of the manufacturing plant. It is used as a tool in almost every step in the process of car manufacturing from painting, cleaning, engine and vehicle assembly. It is also used in car tires and in garages/body shops. The typical uses of compressed air in automotive manufacturing include:
Cars are now made of more durable and light-weight composite materials including plastics. During assembly, compressed air tools create the auto parts and power the lifting, positioning, and moving, fastening machines. It is used to form critical vehicle components such as stamping door panels and trunks.
Both cleaning and painting processes utilizes compressed air. The bare vehicle is inspected for defects and cleaned before painting. Any contaminants in the air supply will cause expensive re-work, spoilage, and production loss. Clean, dry, oil and contaminant-free compressed air is used to achieve a perfect mirror finish during painting. The compressed air used must have no water or contaminants while painting the car to ensure an even finish. Garages and body shops also use low pressure oil-free compressed air to operate their spray guns. Compressed air is used to agitate the paint in a bath to prevent clumping and mix the color for consistency. Paint is propelled through guns or robots onto a clean metal car body surface using compressed air. To have a consistent reliable paint spray it is critical to choose the right size and type of compressor. Use a compressed air dryer and coalescing filters to remove any naturally occurring moisture to achieve a high-quality paint finish.
Compressed air conveying system has eased heaving lifting on the assembly line that used to be done by humans. The compressed air conveyor systems use clean dry air to create a thin film of air between the work table and the floor. Using a conveying system, parts are sent through the production line. The major components, including gas tank, suspension, axles, breaks, and steering systems, are installed in the car. Tools such as air-powered wrenches fasten and screw components in place. These tools also remove nuts and bolts with an air ratchet. Grinding and cutting metal is done using a small air powered saw. Robotic machinery now uses compressed air to lift, transport, and position heavy components that were once placed by hand. Compressed air is used to install quarter panels, side panels, and roofs in place. Now that the heaving lifting is done by these air operated machines, the assembly line is much more efficient and safer for workers.
The consistency and reliability of a compressed air tools is the reason for their use in body shops. Often air sanders are used to smooth out rough metal pieces. It is recommended to use a pneumatic sander since it weighs less than their electric version and are much more reliable in dusty environments.
According to the Compressed Air and Gas Institute (CAGI) and the International Organization for Standardization (ISO), the major contaminants in compressed air are oil, water, microorganisms, and solid particles. Microorganisms are beyond the scope of this article.
ISO 8573 has nine sections that describes compressed air. Section 1 provides a list of contaminants and purity classes. The other sections address sampling techniques and analytical methods for various contaminants.
The following is a list of negative results when compressed air is not clean during automotive manufacturing various types of contaminants.
When compressed air draws in atmospheric air, it is compressed about a dozen times the normal atmospheric pressure. Atmospheric air naturally contains moisture. The amount of moisture depends on the location (altitude) and season. In these conditions, the water/moisture will begin to condense since compressed air cannot hold the same amount as normal air. This condensation increases as the compressed air moves through the system/gun and cools. These effects are more evident during the summer with higher humidity. Water can:
NOTE: the condensed water would also have other contaminants collecting in the low point of pipes resulting in a nasty mixture of oil and moisture.
Solid Particles, such as rust, dry particles, and aerosols, can:
It is recommended to replace older units with oil-free centrifugal air compressors piped to heat off compression dryers. The energy savings may not be significant but the benefits of improved air quality and reduced maintenance and water cooling costs.
Reduce compressed air consumption by repairing purge controls on dryers and reducing overall demand. Repair compressed air leaks. Replace timer drains. Replace air operated diaphragm pumps with electric ones. This will modernize air compressors into oil free centrifugal technology able to use heat-of-compression dryers. This reduces maintenance and water-cooling costs with long-lasting and efficient air compressors.
The following simple things can be done to remove oil from your compressed air system:
The following simple things can be done to remove water from your compressed air system:
Solid particles can be removed by:
Determining the demand on a compressed air system is important. To calculate the load profile, do the following:
From the above observations determine the current maximum possible peak, current peak, average production flow, and low production flow in cfm.
To determine where your current compressed air system can be enhanced to save money, consider the following:
NOTE: Older units are more difficult and expensive to maintain since the parts are no longer available
This is a list of items to consider when determining the size of your compressor:
Also consider the location of the air compressing equipment. The compressor should be installed on a level surface. Follow the recommended guidelines for spacing:
Nex Flow recommends several products that can help improve the operations of everything from small body shop projects to the more demanding tasks in the automotive manufacturing site. Here is a look at some of their top-performing products applicable to the automotive manufacturing