Ultem Machining Services

DEK's Ultem machining service turns Ultem 1000 and 30% glass-filled Ultem 2300 into test sockets, sterilization trays and aircraft brackets, holding ±0.01 mm with prototypes in 3–5 days. Every part is annealed to prevent cracking and runs beside your metal parts.

Get A Quote View All Plastics

±0.01 mm
Typical Tolerance
170 °C
Continuous Service
3–5 days
Prototype Lead Time

Transparent amber plastic part with internal microchannels and threaded features

ISO 9001:2015 Certified AS9100D and ISO 13485 certified

What Makes Ultem Ideal for High-Heat Parts?

Ultem is polyetherimide (PEI), an amber, amorphous high-performance plastic that keeps 105 MPa tensile strength at room temperature, works continuously at 170 °C and passes UL 94 V-0 without additives. Its thermal expansion is the lowest of the unfilled engineering plastics.

It is also notch-sensitive and holds residual stress from extrusion, so PEI machining needs annealing and a disciplined process. We run it on the same 3-, 4- and 5-axis mills as metal parts, as part of our plastic CNC machining services.

ISO 9001:2015, ISO 13485 and AS9100D
Engineer-reviewed quotes within 6 hours
IQC, IPQC, FAI and OQC on CMM
Batches from 1 to 10,000+ pieces

Two amber PEI machined enclosures on white

Ultem Grades We Machine

Three PEI families cover most Ultem drawings: unfilled for versatility, glass-filled for stiffness, healthcare grades for sterilization.

Ultem 1000
105 MPa tensile, 170 °C
Unfilled grade for insulators, medical trays and amber sight glasses; Ultem 1000 machining runs on standard carbide.
Ultem 2300
30% glass-filled, 160 MPa
For test sockets and aerospace brackets needing stiffness and creep resistance; Ultem 2300 machining needs diamond tooling.
Ultem 1010 / HU1000
ISO 10993 biocompatible
Healthcare grades for parts that see repeated steam sterilization; they cost more as stock than standard Ultem 1000.

CNC milling Ultem PEI block with end mill cutting

±0.005 mm
Socket cavities and bores
±0.02 mm
Long glass-filled sections
Ra 0.8–1.6
As-machined finish (µm)
56 µm/m·K
Ultem 1000 expansion

Ultem CNC Machining Capabilities

We machine PEI on the same 3-, 4- and 5-axis mills as metal, with sharp carbide or diamond tooling and annealing between roughing and finishing.

1

CNC Milling

3-, 4- and 5-axis CNC milling for test sockets, manifolds, brackets, sterilization trays and insulator plates, with fixturing for thin-walled trays.
2

CNC & Swiss Turning

CNC turning for bushings, bobbins, connector bodies and sight glasses; Swiss turning for pins and probes under 20 mm.
3

Micro Milling

Micro milling of pogo-pin arrays and socket cavities at 0.3–0.6 mm pitch, holding ±0.005 mm positional accuracy.
4

Drilling & Tapping

Drilling, reaming and tapping with sharp carbide; PEI threads rarely need inserts. Ultrasonic cleaning follows for semiconductor and medical parts.

Design & Machining Tips for Ultem

What our engineers check on every Ultem drawing to prevent cracking, tool wear and tolerance drift in service.

1

Anneal Before Finishing

Extruded PEI rod and plate carry high residual stress. We anneal at 150–160 °C for one hour per 3 mm thickness, rough, anneal again, then finish, so parts do not crack at holes weeks later.
2

Tool Wear on Glass-Filled Grades

Ultem 2300 abrades carbide roughly five times faster than unfilled stock. We run PCD or diamond-coated end mills, replace tools on schedule and re-measure critical bores mid-batch.
3

Thermal Expansion

56 µm/m·K is about 2.5 times aluminum: a 100 mm Ultem socket base grows 0.06 mm more than its aluminum frame over 10 °C. Tolerance hot-test pin fields at operating temperature.
4

Sharp Corners & Notches

Notch sensitivity is PEI’s main weakness. Specify internal radii of at least 0.5 mm, 0.3 mm chamfers on edges, and never a sharp thread run-out under load.
5

Minimum Wall Thickness

Keep walls at 1.0 mm minimum for unfilled Ultem and 1.5 mm for glass-filled; thinner walls in Ultem 2300 chip at the fiber ends.
6

Coolant & Cleaning

Avoid chlorinated solvents and strong alkalis during machining and cleaning; water-based coolant is safe. On drawings, call out only the datums and fits that matter.

Ultem 1000 and Ultem 2300 Grade Pages

Grade sheets for unfilled Ultem 1000 and 30% glass-filled Ultem 2300, side by side: 105 MPa vs 160 MPa tensile, 1.27 vs 1.51 g/cm³ density.

When to Choose Ultem vs PEEK, PPSU or Polycarbonate

Ultem sits between polycarbonate and PEEK on heat and cost; where weight or insulation matter it also replaces stainless steel at a sixth of the density.

Criteria	This MaterialUltem	PEEK	PPSU	Polycarbonate
Choose it for	Sockets, trays	Chemicals	Surgical handles	Tough, clear
Max temp	170 °C	250 °C	–	120 °C
Cost	Baseline	About twice	Higher	A fifth
Stiffness	Stiffer	Lower	Lower	–
Impact	Lower	–	Far better	Tougher
Steam cycles	Hundreds	–	More	–
Flame rating	UL 94 V-0	–	–	–

Where Ultem Parts Are Used

Ultem parts go where heat, flame rating and sterilization rule out cheaper plastics, and usually bolt to machined metal made in the same order.

Finishing Options for Ultem Parts

Every finish is applied after CNC machining. Anodizing and plating do not apply to PEI, so options focus on texture, clarity and marking.

Surface Finishes

As-machined
Bead blasting
Painting
Vapor polishing
Laser marking

Need a finish not listed? Ask our engineers for a review

Ultem Machining FAQ

Answers on machinability, grades, sterilization and tolerances for PEI parts.

Is Ultem hard to machine?

It machines well with sharp carbide tools and moderate feeds, but it is notch-sensitive and carries residual stress from extrusion. Without annealing before and after roughing, PEI parts crack at holes and corners. Glass-filled Ultem 2300 adds tool wear that shops without diamond tooling underestimate.

What is the difference between Ultem 1000 and Ultem 2300?

Ultem 1000 is unfilled: transparent amber, 105 MPa tensile, easier to machine and better for thin features. Ultem 2300 has 30% glass fiber: opaque, 160 MPa, stiffer and more stable, the standard for test sockets and brackets, but abrasive and more brittle at thin edges.

Can Ultem be autoclaved?

Yes. Unfilled Ultem 1000 and the healthcare grades withstand hundreds of steam sterilization cycles at 134 °C with little loss of strength, and PEI is ISO 10993 biocompatible in the appropriate grades. PPSU survives even more cycles if impact resistance is the priority.

What tolerance can you hold in Ultem CNC machining?

±0.01 mm typical on Ultem 1000, ±0.005 mm on socket cavities and short turned diameters, and ±0.02 mm across long glass-filled sections. Parts are annealed and inspected at 23 °C so the numbers repeat in your assembly.