Core Challenges 1

*Material Barriers: foreign common rail units used high-purity specialty steel, with no equivalent standardized material available domestically;
* Fuel pipe processing challenges:
1. Intersecting eccentric hole machining: Required surface finish of 3.2μm, hole spacing tolerance of ±0.3mm, length of 4000–12000mm, and axial hole twist relative to center hole ≤±15°;
2. Traditional process flaw: "Sequential drilling" caused precision loss due to tool deflection;

Core Challenges 2

* Servo Pipe Machining Challenges: Precision boring and polishing of ultra-long slender pipes (12 meters);
* Low Pass Rate for Valve Body: only 30% first-pass rate in international assembly case;
*Testing Dependency: Testing had to be conducted in Switzerland, resulting in long cycles, high costs, and production discontinuity.

Technological Breakthroughs

1. Material localization breakthrough: Develop domestic alternative materials through electroslag remelting, pre-furnace refining, forging and heat treatment and tempering process; performance and NDT indexes exceeded foreign standards and were certified by customers and classification societies.
2. Fuel pipe process innovation and servo tube precision machining: developed a special guide device for peanut holes to solve the problem of letting the knife; optimize the process to ensure that the hole distance of ± 0.3mm, twist ≤ ± 15 °, and other core accuracy; developed an ultra-long servo tube bore polishing device to achieve high-precision polishing of the 12-meter fuel pipe.
3. High-efficiency assembly of the valve body: the use of special cutting tools, combined with 10 years of experience in diesel parts processing; the introduction of joint surface matching research process, an assembly qualification rate increased to more than 90%, significantly reducing rework costs.