# D35.1 UHV Stepper Motor

> 1.8°, two phase hybrid stepper motors (1 x 10-10 mBar)

Canonical product page: [https://arunmicro.com/products/D35-1_UHV_Compatible_Stepper_Motor/](https://arunmicro.com/products/D35-1_UHV_Compatible_Stepper_Motor/)

75 mNm, NEMA 14

## Product details

- Product code: `d35.1`
- Category: [UHV Stepper Motors](https://arunmicro.com/products/category/motors/)
- Made in the UK
- UK-based support

## Best for

Compact ultra-high-vacuum motion applications requiring more torque than the D28.1 while retaining a relatively small motor package.

The D35.1 is a NEMA 14 UHV stepper motor with 75 mNm holding torque. It is intended for low-speed, precision in-vacuum positioning and manipulation.

Choose the D35.1 when 55 mNm from the smaller D28.1 is insufficient but the substantially higher torque of a NEMA 17 D42 motor is not required.

Suitable for UHV systems operating below 1 × 10⁻¹⁰ mbar. Standard specification includes a 1.8° step angle, operating temperature range of -65 °C to +190 °C and bakeout capability to 200 °C. Cryogenic, dry-lubricated hybrid-bearing, radiation-hardened, PT100 and custom-shaft configurations are available.

## Not suitable when

Do not select the D35.1 where more than 75 mNm holding torque is required; consider the D42.1, D42.2, D42.3 or D57.1 depending on the torque requirement.

Where installation space is extremely restricted and 55 mNm is sufficient, consider the smaller NEMA 11 D28.1 instead.

The standard D35.1 is not suitable for operation below -65 °C; select the D35.1-C cryogenic version for operation down to -196 °C.

Applications involving unusually high speed, high duty cycle, significant axial or radial loads, special shaft geometry or unusual environmental conditions should be reviewed with AML.

## Selection guidance

Select the D35.1 when 75 mNm holding torque is sufficient and a compact NEMA 14 motor is preferred.

For lower torque and minimum size, consider:
- D28.1: 55 mNm, NEMA 11

For higher torque, consider:
- D42.1: 250 mNm, NEMA 17
- D42.2: 450 mNm, NEMA 17
- D42.3: 550 mNm, NEMA 17
- D57.1: 1,000 mNm, NEMA 23

Motor selection should consider required torque at operating speed, duty cycle, motor temperature, mechanical loading and vacuum environment rather than holding torque alone.

## Compatibility and prerequisites

The D35.1 is a two-phase bipolar hybrid stepper motor designed for installation inside an ultra-high-vacuum system.

A compatible bipolar stepper motor drive is required. AML SMD3 and SMD4 drives are designed for use with AML D-series vacuum stepper motors.

The embedded motor temperature sensor should be used for motor protection because convection cooling is absent in vacuum. Standard motors use an embedded Type K thermocouple; a PT100 temperature sensor is available as an option.

Confirm that the mounting arrangement, shaft coupling, axial and radial loads, vacuum-compatible cabling, electrical feedthrough and motor drive are suitable for the application.

## Ordering guidance

Standard order code: D35.1 — 75 mNm UHV stepper motor.

Available configurations include:
- D35.1-C — cryogenic version, -196 °C to +190 °C
- D35.1-H — dry-lubricated hybrid ceramic bearings
- D35.1-P — PT100 temperature sensor instead of the standard thermocouple
- D35.1-R — gamma-radiation-hardened version, rated to 1 × 10⁶ Gy
- D35.1-X — custom shaft modification

Before requesting a quotation, provide the required quantity and identify any cryogenic, bearing, radiation, temperature-sensor, shaft, connector or cabling requirements.

For custom shaft configurations, provide AML with a dimensional drawing or sketch.

If motor suitability is uncertain, provide the required operating pressure, temperature range, torque or load requirement, operating speed, duty cycle and mechanical interface.

## Order codes

| Order code | Description | Price |
| --- | --- | --- |
| D35.1 | 75 mNm UHV stepper motor | £779.00 |
| D35.1-C | D35.1, Cryogenic -196 °C to +190 °C | £872.00 |
| D35.1-H | D35.1, Dry lubricated hybrid ceramic bearings | £872.00 |
| D35.1-P | D35.1 with PT100 temperature sensor in lieu of thermocouple | £838.00 |
| D35.1-R | D35.1, Gamma radiation hardened | £872.00 |
| D35.1-X | D35.1 with shaft modification | Price on request. Contact AML for a quotation. |

## Overview

- Suitable for use below 1 x 10-10 mBar (7.5 x 10-11 Torr)

- Continuous running in vacuum at high torque and step rates with AML drive

- Bakeable to 200 °C

- Step angle of 1.8°

- Step angle tolerance of ±5%

- Operational temperature range -65 °C to +190 °C

- Embedded thermocouple or PT100 sensor

- Open construction with all internal spaces vented

- Cryogenic extended operating temperature option available, range -196 °C to +190 °C

- Gamma radiation hard versions available 1 x 106 Gy

- Standard motors are fitted with open stainless steel bearings, lubricated with NyeTorr® 6300 ultra low outgassing UHV grease 

- Hybrid silicone nitride ceramic bearings option available, dry lubricated with tungsten disulfide

- Custom shaft modifications available

## Documentation and downloads

- [Application of UHV Stepper Motors](https://arunmicro.com/documentation/APN_Application_Notes_for_UHV_Stepper_Motors.pdf)
- [Axial & Radial Loads](https://bookstack.vps-da8d40f3.arunmicro.com/books/axial-and-radial-loads-on-aml-stepper-motor-bearings)
- [Datasheet](https://arunmicro.com/documentation/Datasheet_AML_UHV_Compatible_Stepper_Motor.pdf)
- [Magnetic Leakage Fields](https://arunmicro.com/documentation/APN_Magnetic_Leakage_Fields.pdf)
- [Material Content](https://arunmicro.com/documentation/APN_Material_Content_of_AML_UHV_Stepper_Motors.pdf)
- [Operating Instructions](https://bookstack.vps-da8d40f3.arunmicro.com/books/d-series-uhv-stepper-motor-user-manual)
- [RoHS](https://arunmicro.com/documentation/CE_AML_UHV_Stepper_Motors.pdf)
- [Vacuum Performance](https://arunmicro.com/documentation/APN_Vacuum_Performance_of_AML_UHV_Stepper_Motors.pdf)
- [CAD Models (.STEP)](https://arunmicro.com/downloads/CAD_VCSM.zip)

## Related products

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- [D42.1 UHV Stepper Motor](https://arunmicro.com/products/D42-1_UHV_Compatible_Stepper_Motor/): 250 mNm, NEMA 17
- [SMD4 Stepper Motor Drive](https://arunmicro.com/products/smd4-stepper-motor-drive/): Stepper motor drive optimised for use with AML UHV-compatible motors. Features advanced connectivity with USB, Ethernet and RS232/485 interfaces. Optional encoder module for incremental and absolute encoders
- [SMD3 Stepper Motor Drive](https://arunmicro.com/products/smd3-stepper-motor-drive/): Stepper motor drive optimised for use with AML UHV-compatible motors. Four operating modes including USB remote from a host PC and opto-isolated step and direction inputs. Continuous monitoring of motor temperature is provided with automatic shutdown to prevent motor damage.
- [MLF18F](https://arunmicro.com/products/electrical-feedthrough/): MLF18F 18-way feedthrough on a DN40 CF flange (70 mm OD). Individual glass compression seals and bakeable to 250°C.
- [MLF18 UHV Connectors](https://arunmicro.com/products/vacuum-side-connector/): UHV, 18-way Vacuum-Side Connectors.