Product Introduction

It's an exhauste manifold used in automotive exhaust system, special as race parts.  The exhaust manifold is a critical component in internal combustion engines, responsible for distributing air from the throttle body to each cylinder for combustion.

Exhaust manifold consists of a main plenum and branches, with the number of runners matching the number of cylinders. Commonly made of aluminum, cast iron, or lightweight engineering plastics. This exhaust manifold is casted whole complete by precision casting, or called investment casting, it is totally casted without any welding, not different than welding style manifold, so it is much safe, much durable, each weight in around 3.8kgs. Blows are the intake manifold 3D drawings:

 intake manifold 3D drawings-1

intake manifold 3D drawings-2

intake manifold 3D drawings-3

Material and process:

Stainless steel 304 is pretty popular material option to exhaust manifold, which has nickel composition more than 8%, and Cr more than 18%. Silica sol casting is the best solution for the casting , it is much precise than water glass casting. However this manifold is much hard to work than our another product -downpipe, regarding the complex structurer. 

Water-soluble core is necessary for this item when make the wax pattern. It is a kind of core material that can be dissolved in water. It is mainly used in manufacturing processes such as casting, injection molding, and composite material production to form the internal cavities or complex structures of products.  

In the manufacturing process, the water - soluble core is placed in the mold cavity first. Then, the molten wax is poured into the mold to form the outer shell of the product. After the product is formed, the water - soluble core is dissolved and removed by immersing the product in water, leaving behind the designed internal cavity or structure. The wax pattern is finished as following:

This green color wax is medium temperature wax, it is a crucial material in investment casting, with a melting point typically ranging from 50-80°C. It bridges the gap between low-temperature wax (40-50°C) and high-temperature wax (80-120°C), offering a balance of moldability, strength, and dimensional stability for precision casting applications.

After finishing the wax pattern, we begin to make the castings. Individual wax patterns are welded to wax runners trunk, forming a wax tree that allows metal to flow into multiple patterns. The wax tree is dipped into silica sol slurry and refractory sand to make shell. The molten metal is poured into the preheated shell and solidifies as it cools. The casting is separated from the wax tree using saws or grinders. Surface burrs and flash are removed via sandblasting, grinding.

This product has multiple cavities and a curved structure. During the demolding and sand removal processes, many difficulties were encountered. However, we overcame them all and produced a smooth and perfect product. Here is the rough silica sol casting part in stainless steel 304.

Finally, the castings were sent to CNC milling the flange surface on the ends and shot blasted.

Packing：

These products are wrapped in bubble wrap to protect them from bumps and scratches, and finally packed in wooden crates for shipping. The bubble wrap creates a cushioning layer that absorbs shocks during transit, while the wooden crates provide robust structural support, ensuring the goods remain intact from workshop to delivery. This dual-layer packaging approach balances impact resistance with transport durability.

Ningbo Joyo Metal Products Co.,Ltd. continuously overcomes difficulties, we challenge ourselves, and finally complete this batch of products with outstanding performance.

This process not only tests our technical capabilities but also strengthens our resolve to tackle complex tasks. Each obstacle becomes an opportunity to refine craftsmanship, optimize processes, and ensure every product meets the highest standards.