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The problem part in question was a manifold, a major component in vehicles. Gravity casting is used to make these Aluminum Manifolds. Machining and polymer infiltration processes are also used in their manufacturing.

Casting Application: Aluminum Manifolds

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Product overview:

The problem part in question was a manifold, a major component in vehicles. Gravity casting is used to make these aluminum manifolds. Machining and polymer infiltration processes are also used in their manufacturing.

Issues :

Three issues were faced regarding this product:

  • (i) Shrinkage porosity during the gravity casting process
  • (ii) Dimensional specifications
  • (iii) Leakage

Shrinkage Porosity issues and the solutions

Shrinkage porosity was caused by the inappropriate design of the running system. Sprue, gates, and risers design had to be improved in order to avoid shrinkage porosity from our manifolds. Since manifolds have round and curved shapes, it is usually difficult for molten metal to be evenly distributed throughout the cavity if sprue and risers designs are incompatible. Therefore, shrinkage porosity issues were tackled by redesigning the running system.

Software simulations were also used. We ran simulations to optimise the filling of cavities through improved running system designs and predicted the occurrence of shrinkage porosity. To be more specific, porosity usually occurs on the faces or 0.5-1.0 mm deep below the faces. Good feeding, running, and gating system design reduced the common porosity issues from our manifolds.

Aluminum Manifolds Close Up

Leak Testing Aluminum Castings

At Omnidex, ‘Leaking Tests’ are used to ensure leak-free castings meet the castings’ intended pressure-testing requirements.

It involves submerging a casting in a liquid, usually water, after the casting is pressurized with air. An operator examines the submerged casting and looks for any bubbles that may escape from the casting. In addition to preventing casting defects from reaching a customer, this process also prevents any casting that may contain a casting defect from reaching any assembly or production line.

Omnidex has developed a number of leak test systems for testing auto parts such as engine blocks, aluminum or steel sump housings, water pump housings, battery cooling systems, etc.

The product specifications (dimensional) issue was resolved by using precise and accurate fixtures and replacing the 3-axis CNC machine with a 4-axis CNC machine. Sand core position while casting is very critical in determining the runners’ position and surface finish of the manifold.

These two factors have a strong effect on the aluminum manifolds performance and must be considered while designing the fixtures. Hence, after redesigning the fixtures and using the advanced CNC machines, product dimension issues were rectified.

Finally, leakage issues were resolved when we started using the polymer infiltration process after machining. In addition, we introduced leakage testing for each and every product before dispatching it to the customers. Thus, we applied rigorous quality checks to avoid passing faulty and defective products to the customer.

Benefits of Resolving Shrinkage Porosity

There are many benefits we observed after resolving the issues of shrinkage porosity:

  • Less product rejections
  • Shorten delivery time
  • Improved quality
  • Scrap reduction
  • Improved material and energy consumption
  • Higher customer satisfaction

Results and Conclusion

After implementing all the above-recommended solutions developed by our experts, the number of rejections and defects in manifolds has become defect-free. Our team embraced this challenge as an opportunity for improvement. We stepped in with speed, engineering creativity, and an innovative mind in this issue with the aim of producing high-quality and defect-free aluminum manifolds.

Contact our Engineering Team to learn more about our diverse manufacturing and engineering service and how we can help on your projects.

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Omnidex Castings – Your one-stop Metal Casting solutions provider of choice

Omnidex Castings, a member of The Omnidex Group and ISO 9001-2015 credited, has developed into one of the leading single-source providers of precision castings and machined parts. We supply sand castings, investment castings, and gravity die-cast elements to a broad range of industries and applications across the globe. With over 18 years of experience in the field, we are confident in our expertise in product design and engineering, manufacturing, component sourcing, product assembly, quality control and more.

Our supply chain includes China and Vietnam casting foundries and warehousing facilities as well as 200+ fully-managed, quality-assured partnerships in the SE Asia region.

Our Metal Casting Specialties:

  • Iron, steel or aluminium
  • 100 g to 15,000 kg
  • Non-ferrous metals
  • 100 g to 50 kg
  • Non-ferrous metals
  • 100 g to 100 kg
  • Any metal
  • 10 g to 100 kg
  • Any metal
  • 100 g to 5,000 kg
  • Any metal
  • 100 g to 20 kg

Advantages of Our Casting Services:

  1. Our one-stop customized solutions: designed and managed to meet the needs of every client
  2. Quality assured: Porosity-free Casting
  3. Expertise and experience to cast a range of ferrous & non-ferrous metals
  4. Cost-effective implementation & production.

Discover more about each pillar service Omnidex Group  offers and how we excel at these key Manufacturing Processes:

We Are Always Ready To Help With Your Latest Project.
To discuss your requirements, call a member of Omnidex’s team on +44 (0) 1383 277077, send us a message here or email

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