Automobile-gearbox

Die casting case for automobile gearbox

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Developing successful die-casting molds involves integrating various technologies such as materials, heat treatment, mold design, die casting, processing, assembly, production management, and quality control. Customized die-casting solutions are crucial, as the technology directly impacts part quality and post-production outcomes.

The automobile gearbox is a critical component of the transmission system, often featuring intricate structures that are challenging to manufacture. For such complex die-casted parts, a well-designed die-casting solution is essential for ensuring product quality. This article will detail a case study on Ford automobile gearboxes manufactured by Conovawell.

Die casting case for automobile gearbox

Material analysis for die-casted gearboxes:

The gearbox shell material is A380, known for its excellent fluidity, wear resistance, airtightness, and resistance to heat cracking. It offers a perfect balance of casting, mechanical, and thermal properties.

Its comprehensive casting properties make it ideal for manufacturing gearbox shells. The analysis of its chemical composition and mechanical properties below demonstrates its suitability:

Analysis of the early-stage problems of die-casted components:

The gearbox shell has dimensions of approximately 322mm x 321mm x 203mm, with a weight of around 7.6kg. Its structure features thin walls, with an average thickness of about 4mm, and includes numerous bosses, pits, reinforcing ribs, and bolt holes. The complex geometry can hinder proper metal flow during casting, leading to poor filling. After conducting CAE analysis and scientific calculations, we opted to use a 1600T die-casting machine for production. If there are any issues with the customer’s drawings, the CONOVAWELL team collaborates with the customer to make improvements and modifications before presenting the solution for review.

Optimizing the design of die-casting technology

The die-casting mold for gearbox shells operates in harsh conditions, requiring high performance and featuring a complex structure with significant variations in wall thickness. It must withstand high-pressure leakage testing, making it crucial to prevent and address defects such as cold insulation and air holes that can lead to leakage during casting. To tackle these issues, a comprehensive approach is necessary, including evaluating mold structure, parameter design, and CAE analysis, optimizing the die casting process, refining design elements, and validating reasonability through production testing.

Design of pouring system:

The pouring system design should prioritize achieving the shortest flow path possible. Melted metal from both sides should be fed synchronously, reaching the peak simultaneously, and expelled in parallel along with air and waste, without trapping air at the ends. According to the simulation analysis results, this pouring system represents an ideal solution. Please review the detailed CAE analysis report for further information.

Design of pouring system:

Die casting mold CAE

Design for die-casting mold:

This die-casted part, a car gearbox shell, operates in harsh conditions, enduring prolonged exposure to high temperatures, high pressure, humidity, cold, jolting, and dust. It boasts a relatively large size and intricate structure, demanding high air tightness. Consequently, designing, machining, and die casting must meet stringent requirements. For material selection, we opted for Uddeholm Tooling’s steel 8407 from Sweden, renowned for its exceptional resistance to plastic distortion, thermal wear, thermal impact cracking, and thermal fatigue cracking. Please review the detailed DFM analysis and 3D mold design for more information.

Design for die-casting mold

CONOVAWELL finalized the mold structure and fabricated the die-casting mold for the car gearbox shell based on the chosen die-casting processing solution and technological parameters. During the mold trial, we initially set the mold temperature to 210℃. As the temperature gradually increased and the mold achieved thermal balance, no obvious defects were detected on the product. Finally, we determined the relevant die-casting parameters through comprehensive analysis and calculation, taking into account the characteristics of both the mold and the part.

Design for die-casting mold:

Quality inspection for die-casted gearbox shell.

Based on CONOVAWELL’s extensive experience in similar projects, potential issues in die-casting production may arise, including:

  • Product distortion occurs in demolding caused by too large a holding force.
  • Pulling damage occurs inside shift shaft holes.
  • Cold insulation occurs at the end face or intersection of reinforcing ribs.
  • Cracks occur in small corners.

We conduct composition inspections of die-casting materials using a spectrometer to ensure they meet product requirements and avoid using incorrect or unqualified materials, which could result in failed die-cast products that do not meet automotive standards.

Surface inspection mainly involves visually examining die-casted parts for common defects such as:

  • Strain: Pull damage along the demolding direction caused by inadequate mold draft and metal stickiness, sometimes resulting in a strained surface.
  • Layer marks: Visible metal layers in the casted parts.
  • Water waves: Smooth stripes present on the surface of casted parts.
  • Cold insulation: Irregular, sunken line marks (penetrating and non-penetrating) with tiny and narrow shapes, sometimes with smooth edges and potential for breakage.
  • Cracking: Thermal fatigue in the mold cavity surface leading to network bulges and metal flash on the casted part surface.
  • Sunk: Smooth sunk marks appearing in thick areas of the casted parts.
  • Short-casting: Insufficient areas on the casted part surface, resulting in an unclear outline.
  • Flash, burr: Thin metal sheets, rough, or sharp edges occurring at the parting surface edges.

X-ray inspection of die casted parts (inspection of internal pores)

Exceeding standard hole sizes inside casted parts can directly impact the mechanical performance of the product. Therefore, it’s essential to determine the location and size of holes inside the product through X-ray inspection. For gearbox products, we conduct 100% X-ray inspection to ensure that each product meets the required standards.

X-ray inspection of die casted parts
X-ray inspection of die casted parts

Dimension inspection:

The dimensions of die-casted parts are primarily inspected using CMM (Coordinate Measuring Machine) and a profile projector. With specially designed inspection gauges, the CONOVAWELL QC department can accurately measure data to determine whether the part meets dimensional requirements.

Dimension inspection

Conclusion of Ford gearbox:

For Ford gearbox production, our pass rate exceeds 98% according to statistics. Our die-casted products demonstrate CONOVAWELL’s expertise in high-end, complex die-casting technology.

CONOVAWELL is equipped with over 10 die-casting machines, including a 3500T machine capable of producing large-sized die-casted products. Additionally, we possess more than 50 post-processing and inspection equipment. Furthermore, we continually enhance our manufacturing capacity each year.

The CONOVAWELL team is always available to assist you and ensure your products are perfected.

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