Air bearings –the high speed solution for FC blowers reliability/Long service life –maintenance-free bearing system 3. Clean air supply to FC –oil-free bearing system Clean air

Copyright 2015, GSI Group Ltd. Company Confidential

Westwind Air Bearings GSI Group Ltd

Air bearings – the high speed solution for FC blowers


For over 50 years, Westwind has been a world leader in air bearing technology. Westwind technology has been applied across a broad industry spectrum, from PCB drilling to pre-press image setting, working closely with OEMs to match solutions to application and business needs.

A division of GSI Inc, a leading provider of laser, medical and precision motion products

Westwind Air Bearings Division


UK Facility - Westwind Headquarters

Westwind’s headquarters and European center of design excellence is based in Poole, UK. This high-tech facility employs a local workforce of around 110 staff and is the source of new product development initiatives and manufacturing for selected product lines

China Facility

Located in the Suzhou Industrial Park in Jiangsu, the 5,000 square meter site features manufacturing space, office space, demonstration equipment and meeting rooms. This purpose-built facility is Westwind’s main site for manufacturing and provides work for over 200 employees. In addition, Westwind also has a sales and service center based in Shenzhen, China.

Westwind Air Bearings locations


World class facilities 15,000 spindles per year


What does an air bearing look like ?


High speed aerostatic bearing spindle

Water cooled body

Motor

Front radial bearingRear radial bearing

Axial bearingBack cap

Shaft


Bearing

aP

Pd

aP

Pd

Shaft

Ps

Aerostatic bearing technology

Jet

Shallow groove

Requires external pressure supply, typically 4 to 6 bar


Sealing area

Grooved areaa

P

Direction of shaft to drag gas into groove

Fig. 15.21 Axial bearing plate

P aP

W1

2W

Aerodynamic bearing technology

Waved/grooved radial bearing design Patent # EP 94916333.1

Shaft

High pressure zone

High pressure zone

High pressure zone

Lobe

Stabilizing groove

• Aerodynamic, or self acting, bearing design requiring no external air supply• Fixed shaft rotational axis allowing minimum radial movement (small tip clearance)• Ideal for low cost (low part count) design• Field proven technology with many thousands in operation (various applications)

Spiral groove axial bearing design


Manufacturing precision for an air bearing

Typical radial air bearing clearance : 12 microns

Typical tolerance on bearingdiameter: 1-2 microns


Air Bearing Advantages

• Very high rotational speed • Low vibration • High rotational accuracy• Low frictional drag/heat generation• High stiffness • Long lifetime• Zero contamination to process


General air bearing applications


PCB drilling/routing

6 station twin-spindle machine

Typical 6 spindle drilling machinePCB routing at 30k rpm

Drilling 6mm dia. at 20k rpm

Drilling 0.2mm dia. at 285k rpm


Hard material dicing at 40k rpm

Electrostatic rotary spraying at 60k rpm

Ion implantation under high vacuum

Glass grinding at 160k rpm

General AerostaticIndustrial Applications


Polygon laser scanning at 20k rpm

Micromachining aluminium at 160k rpm

Silicon wafer notch grinding at 160k rpm

300mm wafer back-grinding using twin shaft, 300kg spindle

General AerostaticIndustrial Applications


Fuel cell blowers/compressors


Specific benefits of using air bearings in fuel cell air blower/compressors

1. High efficiency: • low parasitic losses• small rotor tip clearance• low loss direct drive DC motor/drive unit

2. High reliability/Long service life – maintenance-free bearing system3. Clean air supply to FC – oil-free bearing system4. Compact size:

• small diameter, very high speed rotor• optimized bearing/shaft design• low mass materials

5. Low noise – non-contacting bearing system0

0.05

0.1

0.15

0.2

0 20000 40000 60000 80000

rotational speed rpm

oute

r dia

met

er m


Small aerodynamic bearing blowers• Flowrate: 2-10 gm/sec• Pressure ratio (max): 1.2• Speed range: 20,000 to 70,000 rpm• Motor power (max): 300 W• Lifetime stop/starts: > 400,000• Body dia. (min): 75mm• Mass (min): 1.75 Kg• Application: 1 to 2 kW microCHP FC


Small aerodynamic blower design

Impeller backplateImpeller casing

ImpellerAxial bearing Radial bearings

Shaft assembly

Housing

Motor stator

Impeller seal

Motor magnet


Typical performance of a small aerodynamic bearing blower

Typical 1.1 kW microCHP FC blower impeller performancewith speeds from 50,000 to 70,000 rpm

1

1.02

1.04

1.06

1.08

1.1

1.12

1.14

1.16

1.18

1.2

0 2 4 6 8 10 12

Mass flowrate (gm/sec)

Pres

sure

ratio 50,000 rpm

55,000 rpm60,000 rpm65,000 rpm70,000 rpm


New developmentsHigh power aerostatic and aerodynamic blowers for automotive/industrial applications

• To suit fuel cells between 10 kW and 90 kW• Pressure ratios to 2.5• Flowrates to 5000 l/min• Motor powers to 15 kW (peak)• Water cooled motors & bearings• 500,000 start/stops• Speeds to 120,000 rpm


Thank you for listening

Visit our stand – C34, Hall 27

Documents

Air bearings –the high speed solution for FC blowers reliability/Long service life –maintenance-free bearing system 3. Clean air supply to FC –oil-free bearing system Clean air