Custom PEI (Ultem) CNC Machining Services | XML Precision Hardware Manufacturing

Searching for a high-performance thermoplastic with exceptional thermal, electrical, and mechanical properties? XML provides top-tier PEI (Polyetherimide, commonly known as Ultem™) CNC machining services. Valued for its high continuous operating temperature, inherent flame resistance, and unmatched dielectric strength, PEI is the ideal material for aerospace electrical connectors, medical surgical instruments, and high-frequency semiconductor equipment. From rapid prototyping to high-volume manufacturing, XML delivers highly precise, all-around manufacturing solutions. Get a free quote today!

Why Choose PEI (Ultem) for Your Critical CNC Machining Needs?

PEI (Polyetherimide), widely recognized by the SABIC trade name Ultem™, is an advanced, amorphous high-performance polymer. Known for its distinct translucent amber tint (in its unfilled grade, Ultem 1000), it serves as a crucial bridge between standard engineering plastics and ultra-expensive materials like PEEK.

When your project demands severe environmental endurance without the extreme cost of PEEK, PEI delivers:

Unmatched Electrical Insulation: Offers one of the highest dielectric strengths of any commercially available thermoplastic, making it the premier choice for high-frequency electronics and microwave insulators.
Exceptional Heat Resistance: Maintains structural integrity and stiffness in continuous high-temperature environments up to 170°C (340°F).
Inherent Flame Retardancy: Naturally self-extinguishing with a UL94 V-0 rating, producing exceptionally low smoke and toxicity during combustion—a strict requirement for aerospace interiors.
Medical-Grade Autoclave Resistance: Highly resistant to environmental stress cracking and repeated autoclave sterilization cycles, perfect for reusable medical and surgical devices.

Partnering with XML ensures your expensive PEI raw materials are machined with the utmost care, utilizing advanced stress-relieving techniques to prevent cracking and guarantee absolute dimensional stability.

PEI (Ultem) Technical Specifications & Machining Parameters

Mechanical & Thermal Properties	Metric Value	Imperial Value	Test Standard
Density (Specific Gravity)	1.27 g/cm³	0.046 lbs/in³	ASTM D792
Tensile Strength (Yield)	105 – 110 MPa	15,200 – 16,000 psi	ASTM D638
Flexural Modulus	3.3 – 3.5 GPa	480,000 – 500,000 psi	ASTM D790
Dielectric Strength	33 kV/mm	830 V/mil	ASTM D149
Max Continuous Temp	170°C	340°F	UL 746B
Glass Transition Temp (Tg)	217°C	423°F	ASTM D3418
Flammability Rating	UL94 V-0 (Inherent)	UL94 V-0	UL 94

Machining Parameters	Technical Specifications
Standard Tolerances	±0.02 mm to ±0.05 mm (Highly stable and precise)
Mandatory Annealing	Essential stress-relieving thermal cycles before and after machining to prevent micro-cracking and ensure long-term stability.
As-Machined Surface Finish	Ra 0.8 – Ra 1.6 μm (Smooth, polished-like finish retaining its amber transparency)
Cutting Strategy	High cutting speeds, low feed rates, and small depths of cut to minimize aggressive cutting pressure and heat generation.
Tooling Specifics	Polycrystalline Diamond (PCD) or razor-sharp uncoated carbide tools with positive rake angles to shear the material cleanly.
Coolant / Thermal Control	Dry machining with pressurized air cooling is highly recommended. PEI is sensitive to alkaline and oil-based coolants which can cause instant environmental stress cracking.
Supported Operations	3, 4 & 5-Axis CNC Milling, Precision CNC Turning, Swiss Machining, Micro-Drilling for electrical contacts.

Extensive Industry Applications of PEI (Ultem) Parts

Aerospace

Thanks to its supreme flame retardancy and low smoke toxicity, PEI is mandatory in many aircraft applications. We CNC machine lightweight cabin interior components, oxygen system valves, and high-performance electrical connectors that meet strict FAA regulations.

Medical Devices

Able to withstand thousands of steam autoclave cycles, PEI is a cornerstone of the medical industry. We manufacture biocompatible reusable surgical instrument handles, sterilization trays, and dental device components that remain structurally sound over time.

Robotics & Automation

Its outstanding dielectric properties make it the perfect insulator. We specialize in manufacturing high-precision semiconductor test sockets, high-frequency microwave insulators, and printed circuit board (PCB) mounting brackets for advanced electronics.

Automotive

Replacing heavy metal components in high-heat engine environments requires tough materials. We precision-machine high-temperature automotive sensors, ignition system insulators, and thermostat housings that resist heat and automotive fluids.