This guide uses a real project. You will see the challenges, the full process, the real cost, and the quality checks. By the end, you will know what it takes to make a flagship phone frame.

1. Project Background and Challenge: Full-Process Machining of a Flagship Phone Upper Frame

2. Our Engineering Team's Full-Process Solution

3. Real Cost Breakdown and Quoting Logic for Phone Housing CNC Machining

4. Your End-to-End Service Process: Seven Steps to a Perfect Phone Housing

5. Why Choose DongGuan YiTai as Your Mass Production Partner for Phone Housings

6. Expert Insight: Thin Walls Need a Gentle Touch

7. Frequently Asked Questions (FAQ)

1. Project Background and Challenge: Full-Process Machining of a Flagship Phone Upper Frame

A client needed a 6061 aluminum plate machined into a one‑piece middle frame. The wall thickness was only 1.2mm. The flatness requirement was 0.08mm over the whole 150mm x 70mm area. The surface needed fine sandblasting and anodizing. No color difference allowed.

Three Technical Challenges            

• Thin‑wall vibration: 1.2mm walls chatter during milling. The cutter pushes the wall. The wall springs back. The thickness becomes uneven.

• Micro‑porous surface for nano‑molding: Before plastic injection, the aluminum surface must have tiny pores. This is done by chemical etching or special blasting. The pore size and density must be controlled.

• No color difference after anodizing: Anodizing can show slight shade differences on the same part. The customer required ΔE < 0.8 between any two points.

2. Our Engineering Team's Full-Process Solution

We designed a six‑step process.

1. Rough milling – Remove most material. Leave 0.3mm stock.

2. Stress‑relief annealing – Heat the part to remove cutting stress. This stops warping.

3. Finish milling – Cut to final dimensions. Use vacuum fixture to hold the part flat.

4. Sandblasting – Fine glass bead at low pressure. Creates uniform matte surface.

5. Anodizing – Clear or custom color. Control temperature and current for even coating.

6. Laser engraving – Add logos and text.

Key Process Controls

• Vacuum chuck fixture: The thin frame is sucked down onto a flat plate. No clamping force that could bend it.

• Diamond tools for chamfering: For the high‑light edges that reflect light. Diamond tools keep the angle sharp and the surface smooth.

• In‑process probing: The machine measures key holes after cutting. If a hole is off, the program adjusts for the next part.

Project Results (First trial batch of 2,000 pieces)

3. Real Cost Breakdown and Quoting Logic for Phone Housing CNC Machining

The cost of a phone frame comes from several factors.

Cost Factor Breakdown (for a typical 6.5‑inch frame)

Batch Price Reference (USD per piece, approximate)

Our pricing principle: No hidden programming fees for prototypes. Volume discounts apply from 1,000 pieces. We can sign a yearly agreement to lock prices for 6–12 months.

4. Your End-to-End Service Process: Seven Steps to a Perfect Phone Housing

We follow a strict seven‑step process.

1. Drawing & DFM report (within 24 hours) – We check thin‑wall feasibility, undercut avoidance, and anodizing masking needs.

2. Sample approval – We machine samples using production methods. Full dimension report + appearance sample signed off by client.

3. Material & stress relief – We buy certified 6061 plate. We perform stress‑relief annealing in‑house.

4. Precision CNC milling – Multi‑side fixturing. On‑machine probe checks critical holes and depths.

5. Sandblasting & anodizing – Our certified partner does the surface work. We measure L*a*b values to control color difference.

6. Full inspection & packaging – Automatic vision system checks all dimensions. Manual visual check for scratches. Special foam trays prevent scratches during shipping.

7. Documentation & support – Material certificate, CMM report, CPK data, and photos of the actual parts. We handle assembly issues fast.

5. Why Choose DongGuan YiTai as Your Mass Production Partner for Phone Housings

We have the right equipment and the right attitude.

Core Equipment

• High‑speed CNC milling centers (20,000–30,000 RPM)

• Vacuum fixtures for thin parts

• Renishaw probe systems for on‑machine measurement

Quality Commitment

• Batch CPK ≥ 1.33 for all critical dimensions

• Appearance matches client‑approved sample (visual judgment under specified light)

• On‑time delivery rate ≥ 98%

Flexible Manufacturing

We accept orders from 50 pieces (trial run) to 100,000 pieces per month. No minimum too small. No volume too large.

6. Expert Insight: Thin Walls Need a Gentle Touch

“Phone frames are the most difficult aluminum parts I have ever machined. 1.2mm walls are like paper. If you clamp too hard, you bend the part before cutting. If you cut too fast, the wall chatters. The surface looks wavy. The trick is three things: a vacuum fixture, sharp tools, and light finishing passes. Also, do not skip stress relief. Without it, the part will twist after anodizing. The flatness will fail. You cannot fix that later.”
— Lead CNC Engineer, DongGuan YiTai Electronic Technologies

7. Frequently Asked Questions (FAQ)

Q: Can you make phone housings from stainless steel instead of aluminum?
A: Yes, but stainless is heavier and harder to machine. Cost is higher. Surface finishing is also harder (thinner anodizing). Most phones use aluminum 6061 or 7075 for the best balance of strength, weight, and cost.

Q: What is the typical flatness requirement for a phone middle frame?
A: For flagship phones, 0.08mm or better over the entire frame. For mid‑range phones, 0.10–0.12mm is acceptable. The screen and back glass must seal without gaps.

Q: How do you control color difference in anodizing?
A: We control the anodizing bath temperature, current density, and time. We also use a colorimeter to measure L*a*b values on every batch. The difference (ΔE) between the sample and the production part must be under 1.0. For critical clients, under 0.8.

Q: What is the lead time for a prototype phone frame?
A: For a single prototype, about 7–10 working days after drawing approval. For a small batch (50 pieces), 3 weeks. We need time for programming, making the vacuum fixture, and setting up the anodizing line.

Q: Do you also do the nano‑molding preparation for antenna lines?
A: Yes. We can do the T‑treatment (chemical etching) that creates micro‑pores for plastic injection. We coordinate with our injection molding partner to ensure the plastic bonds well.

Q: How do you ensure no scratches after anodizing?
A: We use soft silicone or foam inserts in trays. Each part has its own slot. We also use clean gloves for handling. Packing is done in a clean environment. A single scratch can reject a $12 frame.

DongGuan YiTai Electronic Technologies Co.,Ltd

DongGuan YiTai Electronic Technologies Co.,Ltd is a manufacturing service provider located in Dongguan, China.

YiTai specialized in CNC turning machining and sheet metal fabrication mainly. As a member of Hung Mou Group, we focus on the overseas marketing development. And based on our parent company’s manufacturing capability and resources, YiTai also expended machining services such as die casting, injection molding, aluminum profile extrusion, 3D printing, which are committed to providing customers with one-stop purchasing services and experience.

 CNC MACHINING , CNC MILLING , CNC TURNING , SHEETMETAL , FASTENER , OTHERS