Description

Product Introduction

This custom CNC machined PEEK U-Shaped fixture is engineered specifically for the delicate handling, positioning, and nesting of cylindrical or thin-plate precision components. Featuring a U-shaped open structure with internal locating notches, dual precision pin holes, and two counterbored mounting holes, this fixture ensures accurate, vibration-free, and scratch-free placement of workpieces.

While it is the industry standard for semiconductor wafer gripping and positioning (as a Wafer Nest) due to PEEK’s ultra-low outgassing properties, this versatile automation component is equally ideal for medical catheter positioning, sensor housing fixation, and high-end optical lens assembly.

CNC Machining Services & Specifications Table

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Application Scenarios (Where is it used?)

Thanks to its U-shaped open nest design, this part serves critical functions across three high-end sectors:

1. Semiconductor & Wafer Handling (Primary): Used as a Wafer Positioning Nest / End Effector Gripper to hold 4-inch, 6-inch, 8-inch, or 12-inch silicon wafers during transport, etching, or inspection inside vacuum chambers.

2. Medical Device Automation: Utilized as a Catheter Syringe Clamping Jig or Sensor Probe Fixation Bracket in automated IV pumps, diagnostic analyzers, and assembly lines for medical tubes.

3. 3C & Optical Precision Assembly: Used as an Assembly Alignment Block to temporarily secure cylindrical motor housings, lens barrels, and connectors before soldering or press-fitting.

Material Analysis: Why PEEK over Metal or POM?

The choice of PEEK (Polyether Ether Ketone) is not accidental; it is a technical mandate for high-end automated equipment.

• Ultra-Low Outgassing & Cleanliness: Unlike POM (Delrin) or Nylon, PEEK does not release volatile gases or particles in vacuum environments, making it essential for semiconductor cleanrooms (Class 100).

• Non-Abrasive & Scratch-Free: It will never scratch delicate silicon wafers, optical lenses, or medical coatings, whereas aluminum or stainless steel jaws cause micro-scratches that lead to defect rates.

• High Temperature & Chemical Resistance: Resistant to sustained 260°C (500°F) heat and harsh chemical cleaning agents (ACID, IPA) used in semiconductor and pharmaceutical cleaning processes.

• Excellent Mechanical Strength: Offers high stiffness and creep resistance even at elevated temperatures, ensuring the U-shaped arms do not bend or fatigue over millions of robotic actuation cycles.

Tolerance Capabilities

Achieving extreme precision on plastic materials is harder than on metals. Our facility guarantees:

• Pin-hole positioning: Down to ±0.005mm to ensure absolute mating with the automation base plate without any play.

• U-Shape Arm Parallelism: Down to 0.02mm over a 100mm span, preventing wafer tilting or glass breakage.

• Inner Arc Radius: Customizable to exact radii (e.g., R50, R100, R150) with tolerance ±0.01mm to perfectly wrap around cylindrical workpieces.

Manufacturing Difficulties (Why choose a pro?)

Machining PEEK into a U-shape is technically challenging. Our engineers must overcome:

1. Thermal Deformation during Machining: PEEK has a high coefficient of thermal expansion. If the coolant is not properly managed, the long U-shaped arms will warp or vibrate during milling (chatter marks).

2. Stress Relief: PEEK rods carry internal residual stress. We implement a pre-machining annealing treatment (Stress Relieving) to unlock internal stress, ensuring the final U-shape remains straight after unclamping from the CNC fixture.

3. Deburring the Inner Cutouts: The inner groove and locating notches have sharp edges when machined. We utilize manual ceramic deburring + CBN polishing to achieve a mirror-smooth inner wall (Ra < 0.4 μm), completely eliminating burrs that might shed particles.

Frequently Asked Questions (FAQ)

Q1: Can this U-shaped fixture be autoclaved for medical use?
A: Yes, PEEK is fully steam autoclavable (up to 134°C) and compatible with EtO sterilization, making it perfect for medical automation applications.

Q2: How do the two smaller holes function on the base?
A: Those are precision dowel pin holes. In automation engineering, they serve as a mechanical “foolproof” positioning mechanism. They ensure the fixture aligns perfectly with the pneumatic slide or robotic arm every single time, maintaining repeatability within 0.01mm.

Q3: What is the difference between CNC machining and injection molding for this part?
A: This part is exclusively CNC machined. Semiconductors and medical instruments require high-performance virgin PEEK without flow lines or weld marks. CNC allows us to make small-batch customizations (e.g., changing inner diameter for a different wafer size) without expensive injection molds.

Q4: Is this PEEK electrically conductive?
A: Standard PEEK is an excellent electrical insulator. If anti-static (ESD) properties are required for your semiconductor environment, we can infuse it with carbon fiber, or recommend a black anti-static PEEK alternative.

Real-World Case Study (Actual Case)

Client: A leading Semiconductor Equipment Manufacturer in the USA.
Challenge: The client was using standard aluminum alloy wafer grippers. The metal particles generated from friction were causing short circuits on the chips. They needed a non-metallic, heat-resistant, U-shaped positioning fixture with precise alignment holes, specifically for 12-inch wafers in a 200°C rapid thermal processing (RTP) machine.
Our Solution:
We reverse-engineered their design and recommended Virgin Natural PEEK (unfilled). Our CNC team machined the U-shaped fixture on a 5-axis machine to guarantee a perfectly smooth inner arc. We added stress-relieving steps to ensure the two arms remained perfectly parallel even after high-temperature cycles.
Result: The PEEK fixture reduced the particle contamination yield loss by 98% and successfully withstood over 5 million robotic pick-and-place cycles without cracking or warping, increasing the client’s semiconductor fab production efficiency.