Professional Instruments Company
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4R Blockhead

Our standard universal spindle with a round stator. One of our most popular models, and typically the best place to start.

1 µin25 nmSynchronous error, radial and axial
0.45 lb/µin80 N/µmRadial stiffness
1.25 in32 mmAperture
7,500 rpmRated speed

Overview

Since 1965, Professional Instruments has offered the Blockhead family of air bearing spindles for the most demanding rotary applications. Designed for universal integration, their combination of accuracy and stiffness makes Blockheads the first choice for applications from optics manufacturing to metrology.

The 4R features stainless steel construction in our medium package size. Its porting allows biasing and pneumo-lock modes, preferably configured at the factory but convertible in the field. Inlet air can come through the standard air fittings or through porting in the mounting face.

A motor, encoder, chucks and housings can be added to suit your requirements.

Features

  • 400 series stainless steel
  • Horizontal or vertical orientation
  • Nanometer-level error motion
  • 4.07 in103 mm height
  • 5.625 in143 mm diameter stator
  • 1.25 in32 mm diameter aperture

Applications

  • Precision manufacturing and metrology
  • Single point diamond turning
  • Synchrotron instrumentation
  • HDD writing and testing
  • Wafer inspection

Specifications

At 100 psi (0.7 MPa) supply pressure. Switch between inch and metric units in the bar above.

Load capacity

UltimateWorking
Radial70 lb30 kg35 lb15 kg
Axial270 lb120 kg135 lb60 kg
Tilt270 lb·in30 N·m135 lb·in15 N·m

Stiffness

Radial0.45 lb/µin80 N/µm
Axial1.3 lb/µin230 N/µm
Tilt2.7 lb·in/µrad0.3 N·m/µrad

Synchronous error

Radial1 µin25 nm
Axial1 µin25 nm
Tilt0.1 µrad

Physical and air

Air consumption0.7 SCFM20 SLPM
Rotor inertia0.05 lb·in·sec²0.005 kg·m²
Rotor weight7.7 lb3.5 kg
Total weight18 lb8.2 kg
Rated speed7,500 rpm125 Hz

Drawing and downloads

Dimensions in inches. The brochure includes the full drawing with tolerances and notes.

Dimensioned drawing of the 4R Blockhead: end and side views with mounting holes, ports, stator pilot and overall length

Options

Configured at the factory to your requirements.

Motor and encoder

An optional motor and encoder, matched to the application.

Chucks and housings

Optional chucks and housings to hold the work and mount the spindle.

Biasing and pneumo-lock

Pneumo-lock fixes the rotor in position without introducing rotational error.

Air inlet

Through the standard air fittings, or through porting in the mounting face.

Request a quote for the 4R Blockhead.

Tell us about your application and the quantity you need.

(952) 933-1222sales@airbearings.com