PI / Polyimide Machined Parts

A Guide to PI - CNC Milled & Turned Parts: Properties, Applications and Design Considerations

What is PI?

Polyimides (PI or often referred to as the brand name Vespel®) are a family of some of the most heat and fire resistant polymers in existence. Low wear rates combined with the ability to work under unlubricated conditions and high pV-rates makes it the ideal material for challenging friction and wear applications, extending lifetime and reducing maintenance costs.

There are many different grades of PI/Polyimide, all with varying characteristics. A comparison of the technical properties can be found in the tab below.

Main Attributes of PI:

High strength
Outstanding wear resistance
High dimensional stability, even up to 260°C
Long term thermal stability 300°C
Excellent thermal and electrical insulation
Good machinability
Flame retardant
Creep resistant
Good chemical resistance
Resistance to high energy radiation
Excellent machinability

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Detailed information about PI for designers including UK stock sizes and technical properties can be found in the tabs below. Please note: this information is provided as a guide only. All information is based on our present knowledge and is given in good faith. No liability will be accepted by Penta Precision in respect of any action taken by any third party in reliance thereon.

Similar or obsolete designation and trade names

You may also see PI referred to as:

Vespel®
TECASINT® (1000, 2000, 4000, 5000 and 8000 series)
Duratron®
Meldin®
Plavis®
Sintimid®
Kapton®
Cirlex®
Imidez®

PI Components, Applications & Industries

Here are some examples of the industries and components for which PI is appropriate. This is by no means an exhaustive list. Please do get in touch if you are considering using PI and we can talk through your project with you.

Typical Components & Applications:

Valve and pump seats
Wear parts
Fixtures
Washers, bushings, bearings

Industry Examples:

Aerospace

Nuclear

Automotive

Military / Defence

Mechanical engineering

Electrical / Electronics

Food technology

Vacuum technology

PI Machining Service

Penta Precision provides highly accurate machined parts in PI. Customers turn to us when they have had quality and delivery issues with their existing suppliers and need a reliable precision machining partner.

Penta Precision provides the following PI services:

CNC milling – prototypes & large batch runs
CNC turning – prototypes & large batch runs
Insert installation
Part marking
Manual milling
Manual turning
Machining design advice
Machining drawing service

Reasons to Choose Penta:

ISO 9001:2015 quality assurance
Consistent high quality machined parts
Reliable delivery dates - our track record speaks volumes
Exceptional customer service and communication
Machining design advice
Extensive experience in our field

What Makes Penta Different?

We are committed to delivering an exemplary service to our customers. One significant way in which we achieve this is through
the implementation of our ‘3 Cs’:

We Communicate well
We take Care at each stage
Our service is Consistent

See our ‘Proven Process’ page to find out more

We are regularly machining PI for customers all over the UK. Our customers depend on our machining expertise as well as our outstanding delivery performance, to machine the highest quality parts. Contact us to discuss how we can help you with your PI machining requirements.

Mechanical Properties	1011 (natural)	1021 (black)	1031 (black)	1061 (black)	2011 (natural)	2021 (black)	2031 (black)	2061 (black)	2391 (black)	4011 (natural)	4021 (black)	4111 (natural)	4121 (black)	5051 (grey-green)	8001 (yellow-brown)	8061 (yellow-brown)	Parameter	Norm
Modulus of Elasticity (tensile test)	3600 MPa	4000 MPa			370 MPa	4400 MPa	6300 MPa	3900 MPa	4400 MPa	4000 MPa	4943 MPa	6300 MPa	6600 MPa	5800 MPa			1mm/min, 23°C	DIN EN ISO 527-1
Tensile Strength	116 MPa	97 MPa	65 MPa	77 MPa	118 MPa	101 MPa	65 MPa	63 MPa	95 MPa	130 MPa	93 MPa	100 MPa	34 MPa	94 MPa	15 MPa	13 MPa	50mm/min, 23°C	DIN EN ISO 527-1
Elongation at Break	3.8%	2.8%	2.2%	2.9%	4.5%	3.7%	2.1%	2.7%	2.9%	4.5%	3%	1.7%	0.5%	3.4%	200%	4%	50mm/min, 23°C	DIN EN ISO 527-1
Elongation at Break	6%	4.5%	1.4%	3.6%	6.1%	4.6%	2.2%	3.3%	3.6%	6.0%							50mm/min, 23°C	DIN EN ISO 178
Elongation at Break											3.4%	2.5%	1.8%	3.1%			10mm/min, 23°C	DIN EN ISO 178
Flexural Strength	170 MPa	150 MPa	88 MPa	120 MPa	177 MPa	145 MPa	87.5 MPa	89 MPa	137 MPa	180 MPa	131 MPa	160 MPa	113 MPa	163 MPa		29MPa	10mm/min, 23°C	DIN EN ISO 178
Modulus of Elasticity (flexural test)	3700 MPa	4000 MPa			3600 MPa	4300 MPa	5200 MPa	3490 MPa	4136 MPa	4300 MPa	4200 MPa	6100 MPa	6100 MPa	6625 MPa			2mm/min, 23°C	DIN EN ISO 178
Compression Strength	500 MPa	210 MPa	180 MPa	227 MPa	486 MPa	300 MPa	131 MPa	164 MPa	252 MPa	40 MPa	208 MPa	250 MPa	200 MPa	260 MPa		60MPa	10mm/min, 23°C	EN ISO 604
Compression Strength	190 MPa	175 MPa			170 MPa	160 MPa	124 MPa	142 MPa	180 MPa	185 MPa	163 MPa	250 MPa	183 MPa				10mm/min, 10% strain, 23°C	EN ISO 604
Compressive Strain at Break	45%	20.1%			58%	43%	12.5%	16.4%	35.6%		36%	25%	15%	72%			10mm/min, 10% strain, 23°C	EN ISO 604
Compression Modulus	2000 MPa	1880 MPa			1713 MPa	1900 MPa	2027 MPa	1748 MPa	2200 MPa	2100 MPa	2067 MPa	2500 MPa	2200 MPa	2590 MPa			1mm/min, 23°C	EN ISO 604
Impact Strength (Charpy)	75.8 kJ/m²	35.1 kJ/m²	16.5 kJ/m²	25.8 kJ/m²	87.9 kJ/m²	36.7 kJ/m²	14.2 kJ/m²	19.4 kJ/m²		87 kJ/m²	24.4 kJ/m²	24 kJ/m²	11 kJ/m²	27.3 kJ/m²		5.4 kJ/m²	max. 7.5J, 23°C	DIN EN ISO 179-1eU
Notched Impact Strength (Charpy)	5 kJ/m²	4.8 kJ/m²	3.6 kJ/m²	3.9 kJ/m²	9.3 kJ/m²	2.9 kJ/m²	3.3 kJ/m²	3.2 kJ/m²		9.6 kJ/m²	4.8 kJ/m²	1.1 kJ/m²	1.4 kJ/m²	5.1 kJ/m²		2.5 kJ/m2	max. 7.5J, 23°C	DIN EN ISO 179-1eA
Shore Hardness	90D	88D	85D	85D	90D	87D	84D	84D	90D	88D	86D	90D	87D	92D	65D	70D	Shore D, 23°C	DIN 53505

Mechanical Properties

1011 (natural)

1021 (black)

1031 (black)

1061 (black)

2011 (natural)

2021 (black)

2031 (black)

2061 (black)

2391 (black)

4011 (natural)

4021 (black)

4111 (natural)

4121 (black)

5051 (grey-green)

8001 (yellow-brown)

8061 (yellow-brown)

Parameter

Norm

Modulus of Elasticity (tensile test)

3600 MPa

4000
MPa

370
MPa

4400
MPa

6300
MPa

3900
MPa

4400
MPa

4000
MPa

4943
MPa

6300
MPa

6600
MPa

5800
MPa

1mm/min,
23°C

DIN EN ISO 527-1

Tensile Strength

116
MPa

97
MPa

65
MPa

77
MPa

118
MPa

101
MPa

65
MPa

63
MPa

95
MPa

130
MPa

93
MPa

100
MPa

34
MPa

94
MPa

15
MPa

13
MPa

50mm/min,
23°C

DIN EN ISO 527-1

Elongation at Break

3.8%

2.8%

2.2%

2.9%

4.5%

3.7%

2.1%

2.7%

2.9%

4.5%

1.7%

0.5%

3.4%

200%

50mm/min,
23°C

DIN EN ISO 527-1

Elongation at Break

4.5%

1.4%

3.6%

6.1%

4.6%

2.2%

3.3%

3.6%

6.0%

50mm/min,
23°C

DIN EN ISO 178

Elongation at Break

3.4%

2.5%

1.8%

3.1%

10mm/min,
23°C

DIN EN ISO 178

Flexural Strength

170 MPa

150
MPa

88
MPa

120
MPa

177
MPa

145
MPa

87.5
MPa

89
MPa

137
MPa

180
MPa

131
MPa

160
MPa

113
MPa

163
MPa

29MPa

10mm/min,
23°C

DIN EN ISO 178

Modulus of Elasticity (flexural test)

3700 MPa

4000
MPa

3600
MPa

4300
MPa

5200
MPa

3490
MPa

4136
MPa

4300
MPa

4200
MPa

6100
MPa

6625
MPa

2mm/min,
23°C

DIN EN ISO 178

Compression Strength

500 MPa

210
MPa

180
MPa

227
MPa

486
MPa

300
MPa

131
MPa

164
MPa

252
MPa

40
MPa

208
MPa

250
MPa

200
MPa

260
MPa

60MPa

10mm/min,
23°C

EN ISO 604

Compression Strength

190 MPa

175
MPa

170
MPa

160
MPa

124
MPa

142
MPa

180
MPa

185
MPa

163
MPa

250
MPa

183
MPa

10mm/min, 10% strain, 23°C

EN ISO 604

Compressive Strain at Break

45%

20.1%

58%

43%

12.5%

16.4%

35.6%

36%

25%

15%

72%

10mm/min, 10% strain, 23°C

EN ISO 604

Compression Modulus

2000 MPa

1880
MPa

1713
MPa

1900
MPa

2027
MPa

1748
MPa

2200
MPa

2100
MPa

2067
MPa

2500
MPa

2200
MPa

2590
MPa

1mm/min,
23°C

EN ISO 604

Impact Strength (Charpy)

75.8 kJ/m²

35.1
kJ/m²

16.5
kJ/m²

25.8
kJ/m²

87.9
kJ/m²

36.7
kJ/m²

14.2
kJ/m²

19.4
kJ/m²

87
kJ/m²

24.4
kJ/m²

24
kJ/m²

11
kJ/m²

27.3
kJ/m²

5.4
kJ/m²

max. 7.5J, 23°C

DIN EN ISO 179-1eU

Notched Impact Strength (Charpy)

5
kJ/m²

4.8
kJ/m²

3.6
kJ/m²

3.9
kJ/m²

9.3
kJ/m²

2.9
kJ/m²

3.3
kJ/m²

3.2
kJ/m²

9.6
kJ/m²

4.8
kJ/m²

1.1
kJ/m²

1.4
kJ/m²

5.1
kJ/m²

2.5
kJ/m2

max. 7.5J, 23°C

DIN EN ISO 179-1eA

Shore Hardness

90D

88D

85D

90D

87D

84D

90D

88D

86D

90D

87D

92D

65D

70D

Shore D, 23°C

DIN 53505

Thermal Properties

1011 (natural)

1021 (black)

1031 (black)

1061 (black)

2011 (natural)

2021 (black)

2031 (black)

2061 (black)

2391 (black)

4011 (natural)

4021 (black)

4111 (natural)

4121 (black)

5051 (grey-green)

8001 (yellow-brown)

8061 (yellow-brown)

Parameter

Norm

Notes

Glass Transition Temperature

368°C

330°C

370°C

260°C

340°C

- 20°C

20°C

DMA, maximum loss factor tan d / DIN EN ISO 11357

Heat Distortion Temperature

368°C

300°C

319°C

335°C

325°C

360°C

470°C

1.85
MPa

DIN 53 461

Service Temperature

250°C

270°C

long
term

Found in public sources, individual testing regarding application is mandatory

Service Temperature

300°C

short
term

Found in public sources, individual testing regarding application is mandatory

Thermal Expansion (CLTE)

4.3 10-5*1/K

4.5 10-5*1/K

4.7 10-5*1/K

5.6 10-5*1/K

5.4 10-5*1/K

5.2 10-5*1/K

5.0 10-5*1/K

50-
200°C

DIN 53 752

Thermal expansion XY/Z axis

Thermal Expansion (CLTE)

5.3 10-5*1/K

5.1 10-5*1/K

5.44.3 10-5*1/K

5.7 10-5*1/K

7.6 10-5*1/K

7.3 10-5*1/K

6.9 10-5*1/K

6.6 10-5*1/K

200-300°C

DIN 53 752

Thermal expansion XY/Z axis

Thermal Expansion (CLTE)

11.2 10-5*1/K

10.5 10-5*1/K

300-350°C

DIN 53 752

Thermal expansion XY/Z axis

Thermal Expansion (CLTE)

9.9 10-5*1/K

9.7 10-5*1/K

300-400°C

DIN 53 752

Thermal expansion XY/Z axis

Specific Heat

1.04 J/(g*K)

1.13 J/(g*K)

0.925 J/(g*K)

1.04 J/(g*K)

1.20 J/(g*K)

1 J/(g*K)

Thermal Conductivity

0.22 W/(k*m)

0.53 W/(k*m)

0.22 W/(k*m)

0.4 W/(k*m)

0.35 W/(k*m)

0.4 W/(k*m)

0.25 W(k*m)

40°C

ISO 8302

Electrical Properties

1011 (natural)

1021 (black)

1031 (black)

1061 (black)

2011 (natural)

2021 (black)

2031 (black)

2061 (black)

2391 (black)

4011 (natural)

4021 (black)

4111 (natural)

4121 (black)

5051 (grey-green)

8001 (yellow-brown)

8061 (yellow-brown)

Parameter

Norm

Specific Surface Resistance

10¹⁶ O

10¹⁵O

10¹⁶ O

10¹⁴

23°C

DIN IEC 60093 / ASTM D 257

Specific Volume Resistance

10¹⁷ O*cm

10¹⁵
O*cm

10¹⁶ O*cm

>10¹⁴
O*cm

10¹⁸ O*cm

10¹⁷O*cm

23°C

DIN IEC 60093 / ASTM D 257

Dielectric Constant

4.2

3.59

1 kHz, 23°C

DIN IEC 60250 / ASTM D 150

Dielectric Constant

4.1

2.3

10 kHz, 23°C

DIN IEC 60250

Dielectric Constant

4.1

100 kHz, 23°C

DIN IEC 60250

Dielectric Constant

3.5

50 Hz, 23°C

DIN IEC 60250

Dielectric Constant

3.7

1 MHz, 23°C

ASTM D 150

Dielectric Constant

3.1

27 MHz, 23°C

DIN IEC 60250

Dielectric Constant

4.2

100 Hz, 23°C

DIN IEC 60250

Electric Strength DC

20 kV*mm-1

21.8
kV*mm-1

18 kV*mm-1

22.7 kV*mm-1

23°C

ISO 60243-1 / ASTM D 149

Dielectric Loss Factor

1*10^-3

50 Hz, 23°C

DIN 53483-1 / ASTM D 150

Dielectric Loss Factor

1*10^-3

1 kHz, 23°C

Dielectric Loss Factor

0.0013

1 MHz, 23°C

ASTM D 150

Dielectric Loss Factor

3*10^-3

27 MHz, 23°C

DIN 53483-1

Other Properties	1011 (natural)	1021 (black)	1031 (black)	1061 (black)	2011 (natural)	2021 (black)	2031 (black)	2061 (black)	2391 (black)	4011 (natural)	4021 (black)	4111 (natural)	4121 (black)	5051 (grey-green)	8001 (yellow-brown)	8061 (yellow-brown)	Parameter	Norm	Notes
Water Absorption	1.08%	0.51%	0.42%		0.47%	0.44%	1.2%	0.35%	0.53%	0.16%	0.08%	0.08%	0.08%	0.53%	0.70%	1.12%	24 h in water, 23°C	DIN EN ISO 62
Water Absorption	3.29%	1.57%			1.65%	1.55%	2.18%	1.5%	1.58%	0.6%	0.53%	0.2%	0.38%				24 h in water, 80°C	DIN EN ISO 62
Flammability (UL94)	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	V0	Corresponding to	DIN IEC 60695-11-10	Corresponding means no listing at UL (yellow card). The information might be taken from resin, stock shape or estimation. Individual testing regarding application conditions is mandatory.
Oxygen Index										49%		53%						EN ISO 4589-2
Density	1.34 g/cm³	1.42 g/cm³	1.57 g/cm³	1.48 g/cm³	1.38 g/cm³	1.45 g/cm³	1.59 g/cm³	1.52 g/cm³	1.54 g/cm³	1.41 g/cm³	1.49 g/cm³	1.46 g/cm³	1.53 g/cm³	1.57 g/cm³	1.88 g/cm³	1.68 g/cm³

Other Properties

1011 (natural)

1021 (black)

1031 (black)

1061 (black)

2011 (natural)

2021 (black)

2031 (black)

2061 (black)

2391 (black)

4011 (natural)

4021 (black)

4111 (natural)

4121 (black)

5051 (grey-green)

8001 (yellow-brown)

8061 (yellow-brown)

Parameter

Norm

Notes

Water Absorption

1.08%

0.51%

0.42%

0.47%

0.44%

1.2%

0.35%

0.53%

0.16%

0.08%

0.53%

0.70%

1.12%

24 h in
water,
23°C

DIN EN ISO 62

Water Absorption

3.29%

1.57%

1.65%

1.55%

2.18%

1.5%

1.58%

0.6%

0.53%

0.2%

0.38%

24 h in
water,
80°C

DIN EN ISO 62

Flammability (UL94)

Corresponding
to

DIN IEC 60695-11-10

Corresponding means no
listing at UL (yellow card).
The information might be
taken from resin, stock shape
or estimation. Individual
testing regarding application
conditions is mandatory.

Oxygen Index

49%

53%

EN ISO 4589-2

Density

1.34 g/cm³

1.42 g/cm³

1.57 g/cm³

1.48 g/cm³

1.38 g/cm³

1.45 g/cm³

1.59 g/cm³

1.52
g/cm³

1.54
g/cm³

1.41 g/cm³

1.49 g/cm³

1.46 g/cm³

1.53
g/cm³

1.57 g/cm³

1.88 g/cm³

1.68 g/cm³

PI / Polyimide Machined Parts

A Guide to PI - CNC Milled & Turned Parts: Properties, Applications and Design Considerations

What is PI?

Main Attributes of PI:

GET A QUOTE

Similar or obsolete designation and trade names

PI Components, Applications & Industries

Typical Components & Applications:

Industry Examples:

PI Machining Service

Reasons to Choose Penta:

What Makes Penta Different?

CNC Machining PI - Notes for Designers

PI Machining Characteristics

PI UK Stock Sizes

TECASINT 1011 natural (unfilled) stock sizes

PI Rod

PI Plate

PI/Polyimide Technical Properties

TECASINT PI Properties