Remain-Core Molding

Remain Core Molding technology, which is the combination of blow molding and injection molding, was pioneered by EXCELL.
A traditional metal intake manifold such as aluminum is replaced to plastic by using Remain Core technology. Excell was the first company to mass produce a plastic intake manifold in Japan.

Remain Core Molding Process

The inner core is formed by blow molding with functional parts, such as a flange, being formed by low-pressure injection molding around the blow molded inner core.
The blow molded core has a non-reinforced nylon layer which reduces inner air flow resistance. The mechanical strength is maintained by molding glass fiber reinforced nylon around this inner core.

45% GF reinforced Nylon 6 / 30% GF reinforced Nylon 6 / Non-reinforced Nylon
Inner Core: Blow Molding (air path forming) / Outer layer: Low-pressure Injection Molding (adding function and rigidity)

Manufacturing Process of Remain-Core

Blow Molding → Low-pressure Injection Molding → Cutting Work → Assembly Process
As seen above, highly functional products are produced in a very simple manufacturing process.

Blow Molding Low-pressure Injection Molding Cutting Work Assembly Process

Intake Manifold by Remain-Core Molding Process 01

Weight Reduction, Noise Reduction, Cost Reduction, High Reliability.

30% of weight is reduced by replacing metal parts to plastic.
Remain-Core method is formed with multiple layer of plastics therefore high noise reduction performance is achieved by plastic materials and their combination.
Its sound transmission loss quality is the same as aluminum.
Strength and reliability are high because outer part of Blow Molded product is completely covered by Injection Molding layer.

Intake Manifold (Blow + Low-pressure Injection Molding) 3 layers (PA6+PA6-GF30%+PA6-GF45%) SUBARU: SAMBER DIAS (lightweight truck) Intake Manifold (Blow + Low-pressure Injection Molding) 3 layers (PA6+PA6-GF30%+PA6-GF45%) SUBARU: SAMBER DIAS (lightweight truck)
Intake Manifold (Blow + Low-pressure Injection Molding) 3 layers (PA6+PA6-GF30%+PA6-GF45%) SUBARU: SAMBER DIAS (lightweight truck)

Intake Manifold by Remain-Core Molding Process 02

Design based on commercial production experience with heavy duty engines using super chargers, this application has been adopted for commercial vehicle.
The complicated intake manifold of horizontally opposed engine is replaced to plastic by Remain-Core molding.

[1] Blow Molded Inner Core/ [2] Injection Molded Part [3] Fitting harnesses and other parts / [4] Mount onto SUBARU LEGACY