تصنيع المغسلة الحرارية ذات التهوية الفولاذية

A heat sink is a component used for thermal management. They prevent heat-generating components of a machine from overheating. High-performing heat sink manufacturing can be made with copper, aluminum, and steel.

Ventilated steel heat sink machining is the process of perforating the steel sheet to allow airflow through the metal, thereby improving heat transfer by convection. Stainless steel heat sinks are mostly used in demanding environments, including:

• High temperature environments – Stainless steel handles higher temperatures better than aluminum without compromising structural integrity.
• Environments with corrosive materials – When chemicals or moisture in an environment can damage aluminum, stainless steel can be used as an alternative.
• Industrial power electronics – Stainless steel heat sink is used in high-power applications like DC-DC bricks, motor controllers, and electrical welders, which run hot during operation.
• Structural role – Stainless steel heat sink can also serve the dual role of cooling and being a structural component of the casing.

متطلبات العميل

A heat sink manufacturer approached First Mold for heat sink rapid prototyping. The client clarified that the material for the project was steel because it was supposed to play a structural role, in addition to cooling.

During the first discussion to review the project blueprint, the client explained that the tolerance of the heat sink prototyping should be no more than 0.01 mm. According to them, the project was for a high-performance application.

“The high tolerance is necessary for maximum thermal efficiency, consistent performance across batches, and reliable structural mounting,” the client explained.

After the discussions, First Mold’s Project Manager, Bowen Huang, took the client around the factory to showcase some of the advanced machinery, reassuring them of First Mold’s capability to effectively handle the project.

“We have some of the most advanced 5-axis CNC machines in the industry for rapid prototyping,” Huang said. “Our team of engineers has over one hundred years of collective experience in CNC machining. It is always a delight to take on projects that help us showcase our wealth of experience.”

التحديات والحلول

Heat sink machining using steel presents unique challenges, primarily because of the nature of the material. Steel has poor thermal conductivity and a high work-hardening rate, which makes it harder to machine. Some of the key challenges of steel heat sink manufacturing include:

• Excessive tool wear: Steel is abrasive and hard, which accelerates tool wear. Excessive tool wear will increase tool cost and downtime between changing tools. This can lengthen machining time.
• Vibration can affect structural stability: The high cutting force can lead to vibration, which may lead to deformation of thin, delicate structures and poor surface finish.
• Warping from high thermal stress: Steel retains heat rather than dissipating it during cutting. If not properly cooled, this heat concentration can lead to warping of the workpiece.
• Difficulty with chip management: Steel machining produces significant hot chip volumes. If not properly controlled, it can damage tools and lead to a poor surface finish.

For successful steel heat sink machining, First Mold engineers had to find ways to overcome these unique challenges.

Overcoming Work Hardening and Low Thermal Conductivity of Steel

Steel’s high toughness and strength require an elevated cutting force to machine. However, increasing the cutting force can lead to vibration. Apart from vibration, the surface can harden rapidly during cutting, making subsequent cuts more difficult. This can wear the cutting tool faster.

The low thermal conductivity of steel also means that during the heat sink manufacturing using CNC machining, the heat generated at the cutting surface is not dissipated or carried away by the chippings. It concentrates around the tip of the cutting tool, accelerating its wear and failure.

The 5-axis CNC machine used by First Mold is specially fitted with four nozzle coolant systems that jet coolant at high pressure (1,000+ psi) onto the cutting surface. These coolant systems are not only effective in dissipating the heat generated by the cutting tip, but they also break and remove chips to prevent deformation to the surface of the heat sink prototype.

Machining Curved Steel Heat Sink Prototype Surface

The client’s curved heat sink blueprint posed a special machining challenge. Flat surfaces allow for simple toolpaths, but a curved surface will require special toolpaths. Key challenges of machining curved steel include:

• Complex CAM programming: Heat sink manufacturing using curved steel requires the use of sophisticated software to control tool orientation and feed rates along changing contours.
• The need for a multi-axis machine: Curved surfaces need complex, multi-motion with precise finishing passes. First Mold’s 5-axis CNC machine helps to eliminate constant, manual repositioning of the workpiece, which can introduce errors.

The team of First Mold engineers used trochoidal milling, a strategy where the high-speed CNC machine uses a circular, spiraling toolpath to cut slots. By maintaining radial engagement and high axial depth, this motion reduces cutting forces, heat, and vibration. This allows for faster material removal and extended tool life. This technique also helps to speed up the heat sink prototyping time.

Optimizing Heat Sink Machining Efficiency

The combination of high material toughness, low speed, and specialized tooling makes the machining process of steel slow and time-consuming.

To overcome these shortfalls, First Mold’s team of engineers implemented design for manufacturability (DFM) principles. For example, we used coated tools with high heat resistance and positive rake angles to reduce cutting forces.

The fin thickness was slightly increased, and the fin depth was limited to enhance rigidity during machining. Also, the team deployed specialized toolpaths in the CAM programming and used rigid machines to minimize vibrations and distortions.

The Importance of Maintaining 0.01mm Tolerance for the Heat Sink Manufacturing Project

During the heat sink machining, First Mold engineers paid extra attention to the CAM programming to achieve the 0.01mm tolerance requirement. Achieving the desired tolerance was crucial for several reasons, including:

• Precision mounting: Achieving the right precision leads to perfect alignment between the screws and holes on the mounting surfaces. This prevents structural stress on the components.
• Enhance structural integrity: A tolerance of 0.01mm allows the heat sink prototype to also act as structural support. Because of the strength of steel, it can be used in high-pressure, high-temperature, and high-vibration environments without undermining thermal performance.
• Consistent performance across batches: For high-volume heat sink manufacturing, maintaining a 0.01mm tolerance ensures that every product performs identically. This is crucial for specialized industries like medical imaging and aerospace.

ما الذي اكتسبه العميل من حلول شركة فيرست مولدز

The heat sink prototyping using steel was delivered a week ahead of schedule, which the client greatly appreciated. By using an innovative machining technique, First Mold was able to machine the prototype at a budget that was better than the quote provided by other machinists the client had previously met.

“We kept our timeline expectations moderate based on our previous experiences,” the client said, after inspecting the accuracy of the heat sink prototype to the blueprint. “We weren’t expecting to receive the prototype for another week”.

By partnering with First Mold, the client secured a trusted supplier that will assist them in scaling on demand when the need arises. “We are always committed to putting the success and happiness of our clients first,” Huang said.  

الأسئلة الشائعة

كان هذا العميل داعمًا جدًا لجهودنا الترويجية لدرجة أنه اقترح علينا عرض فيديو لعملية التفريز باستخدام الحاسب الآلي لقطعة العمل.