Porosity sealing How vacuum impregnation supports environmental responsibility
Author / Publisher: Ralf Versmold / Nicole Kareta
Automakers realize that being environmentally friendly and cost effective are not mutually exclusive. Being environmentally friendly can lead to better growth, cost savings, better brand recognition and increased profitability.
The environmental impact of the responsible use of resources is beneficial for all and car manufacturers play a leading role. Being environmentally conscious occurs at all channels of the production process. Examples include:
Audi’s closed loop recycling manufacturing process. The company launched its “Aluminum Closed Loop” in 2017. The scrap aluminum sheet produced in the press shop is returned to the supplier. The supplier then recycles the material into aluminum foil of equal quality, which Audi then uses in production. In 2019, Audi saved around 150,000 tonnes of CO2.
Ford’s closed loop recycling manufacturing process. The company collects enough scrap aluminum to produce more than 37,000 new Ford 150 truck bodies every month. While using fewer natural resources and reducing energy consumption.1
Aluminum die casting manufacturers are reducing their carbon footprint through the use of green aluminum. Green aluminum is made using less carbon intensive hydropower rather than carbon intensive fossil fuels. Producing one tonne of aluminum using hydropower releases around two tonnes of CO2 equivalent. While making one tonne of aluminum with fossil fuels releases up to 18 tonnes of CO2 equivalent.
(Source: Godfrey & Wing)
Manufacturers can also further reduce waste and conserve resources through vacuum impregnation.
Whether caused by shrinkage, cold closures, embedding, or trapped gases, porosity is inherent in the casting process. The interconnected porosity leads to defects, which are the main cause of waste and scrap. This waste increases the carbon footprint of the casting process.
Vacuum impregnation is a low impact method of sealing leak paths that form during the casting process. More precisely, it seals the internal porosity path of interconnection, which crosses the pouring wall. The technique seals the porosity without changing the dimensional or functional characteristics of the molded part.
(Source: Godfrey & Wing)
While there are many reasons why vacuum impregnation makes businesses environmentally conscious, three stand out:
- 1. Allowing design freedom to lighten parts, engineers specify aluminum alloys and thinner walls in critical components. Meanwhile, in order to achieve new design standards, these components have higher performance requirements and lower acceptable leak rates. These more stringent requirements result in the rejection and scrapping of more parts due to the porosity of the die-casting. Vacuum impregnation allows engineers to work with thinner, lighter designs while meeting quality standards without worrying about the effects of porosity. Design freedom allows engineers to design vehicles that are more efficient and fuel efficient.
- 2. Maximizing the use porosity of parts in castings deprives manufacturers of the ability to put 100% of their parts into production. A 15% “drop” of parts manufactured means that an additional 15% of aluminum castings will be scrapped and profits will be wiped out. The vacuum impregnation process allows manufacturers to use molded parts that would otherwise have been discarded.
- 3. Eliminate fusion and remanufacturing. Vacuum impregnation eliminates the costly melting and reflow of the material into manufacturer replacement castings. Vacuum impregnation also eliminates all carbon and waste costs associated with cutting, sanding, machining, testing and washing spare parts.
These areas represent an opportunity to minimize waste, improve a company’s profitability and have a positive impact on the environment.
Automakers must continue to aggressively dispose of waste and conserve resources to be competitive and grow in today’s economy. Manufacturers should look for other opportunities, throughout the production process, to be cleaner, safer and more efficient use of resources. One of these opportunities is the use of vacuum impregnation. It allows manufacturers to considerably reduce their waste and control their resources by returning nearly 100% of the parts to the production line.
1Hydroelectric smelters charge higher prices for “green” aluminum. (2017, August 2). United States https://www.reuters.com/article/us-aluminium-sales-environment/hydro-powered-smelters-charge-premium-prices-for-green-aluminium-idUSKBN1AI1CF