Custom Mobile Phone Middle Chassis Parts at WayKen

Explore how CNC machining helps mobile phone prototyping. Take a case study about the considerations, challenges, and solutions for making aluminum middle chassis parts.

At a Glance of the Project

IndustryConsumer Electronics
ProductMobile phone aluminum panel
ChallengesDeformation, tiny threaded holes
TechnologyCNC Machining
Surface finishAnodizing with matte surface
Quantity5 Sets
Lead Time7 Business days

About Project and Product

CNC machining is widely used across various industries, including consumer electronics, aerospace, medical, automotive, and more.

Recently, our customer approached a smartphone design, seeking WayKen’s expertise for a processing solution. The design includes dozens of parts such as the front case, back cover, middle chassis, and various small buttons like the power and volume buttons.

In the early stages, WayKen engaged in comprehensive and in-depth discussions with our customers regarding material selection, processing methods, and post-finishing techniques for each part. After thoroughly understanding their needs, the WayKen team developed a tailored production plan to successfully meet the customer’s requirements.

In this case study, we chose one of the typical parts – the middle chassis to share with you.

Consider Material Selection

Due to the small size of mobile phones, lighter and thinner material is a point that users have been pursuing, this part needs to be considered lightweight material. Among many metal materials, aluminum alloy has always played the leading role in making the middle chassis of mobile phones. Aluminum alloy has a low density and is lightweight, which is suitable for manufacturing mobile phone components.

At the same time, aluminum alloy has high strength to meet the requirements of anti-fall for mobile phone parts. Therefore, this middle chassis is chosen to be made with AL7075.

CNC middle chassis

Analyzing Machining Keypoints

There are 3 key points that should be considered during production.

Thin Wall and Deformation

The mass production of aluminum alloy middle chassis is mostly manufactured by the die-casting process. However, for middle chassis parts that are in the prototype verification stage, CNC machining is a more suitable process.

As shown in the picture below, the entire chassis part is thin and relatively large, with the thinnest section measuring only 0.4mm. We must exercise great care while processing this area to prevent any punctures. Additionally, this part must be machined from a single piece of material and include several hollow structures. The extensive material removal makes it susceptible to deformation during processing.

To minimize deformation, we made a processing route that involves rough machining the front side first, followed by the back. After roughing is complete, we perform fine machining on both the front and back. We also customized a vacuum fixture for this part to hold it from below, reducing the impact of external forces during processing and further minimizing deformation.

phone chassis thick wall

Ensuring Assembly with Other Parts

The middle chassis features a series of complex structures important for assembling various electronic components. These structures must be precisely machined to the specified dimensions, with no structural defects allowed.

As shown in the picture below, the sharp corners and grooves are designed for installing modules such as cameras, which must align accurately with other parts. During processing, it is essential to maintain these structural features. However, the cutting tools used in CNC machining have geometric limitations, which means that some radii will inevitably remain.

So how to ensure that these structures can be accurately processed, we could use EDM (electric discharge machining). Although EDM is more expensive and results in a rougher surface finish, it could address the geometric limitations of CNC cutting tools to keep structural features. As for the rougher surface finish, WayKen employed manual corner cleaning, performed by our professional craftsmen who have over ten years of experience.

sharp corners in the middle chassis

Tiny Thread Holes

As shown in the drawing, in addition to several through holes, there are many M1.2 threaded holes on the backside. These threaded holes are very small and must be precisely positioned. Normally, we tap these holes for prototypes, but tapping can result in slight deviations and imprecise positioning. Standard milling tools are not suitable due to their larger diameters.

tiny holes of phone chassis in the drawing

To ensure the accurate positioning and stability of the M1.2 threaded holes, we used customized milling tools. This allows us to maintain a positional accuracy of 0.1 mm. Additionally, since this part requires anodizing, the threaded holes must be covered before the oxidation process.

Get Start With WayKen for Your Projects

CNC machining services are a matching solution for verifying the design in the pilot stage for mobile phones. Through reasonable process and fixture design, it can effectively reduce the amount of deformation and ensure the structure and performance of the product. The customer was very satisfied with the final result. WayKen will continue to work hard to provide professional one-on-one customized processing solutions to our customers. We hope that our solutions can also inspire your projects.

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