Q-flex opens up new MRF capabilities

qflex300The new freeform raster capability of Q-flex broadens the range of MRF capabilities for high precision applications. Combined with our new C30 fluid, Q-flex “freeform raster mode” makes mid-spatial frequency corrections on spheres and aspheres better than previously achievable with any MRF system. This capability reduces the need to add costly, time consuming technologies to the process for high precision optics manufacturing.

 

  


 

 1) Q-flex Modularity Enables Rapid Configuration Changeover

mrf application 7 pict1

 Q-flex enables fast changeovers:

  • MRF Head changes in < 15 min
  • MRF FCM changes in < 15 min
  • Less downtime = higher throughput

 

Fast Changeovers enable:

  • Wider range of process options
  • Greater potential for process optimization

 

Which leads to:

  • More efficient production
  • Wider range of capabilities

Not possible on Q22-X/Y!

 

 

 


 

 2) Q-flex Enables Raster Polishing of Spheres and Aspheres

mrf application 7 pict2Polish almost any shape with Freeform Raster Polishing

  • Rotationally symmetric spheres & aspheres
  • Off-axis aspheres, toroids, true freeforms
  • Round, rect, hex, general aperture shapes
  • Maximum freeform surface slopes of:
  • ~90° in X-direction,
  • ~30-45° in Y-direction (depending on wheel)

 

Enhanced correction of fine features

  • Correct mid-spatial frequencies
  • Avoid/correct center artifacts

 

“Around the wheel” polishing creates “virtual C-axis”

  • Combined with B-axis allows tip and tilt in both X & Y-directions

 

Significantly more capability than Q22-Y machines!

 

 


  

 

 3.) Inducing Freeform Shape and Correcting MSF

 

mrf application 7 pict3Goals:

  • Start from a “standard” best-fit sphere
  • Induce mild “OAP-like” freeform shape (~13 λ PV)
  • Finish to extremely high precision: λ/30

 

Part details:

  • Size: ~150 mm Φ
  • Radius: ~210 mm (concave)
  • Material: soft optical glass

 

Q-flex 300 configuration:

  • Raster “free-form” polishing mode
  • 150mm wheel, 50mm wheel and 20mm wheel
  • D11 Fluid and C30 Fluid

 

Process Overview:

  • Use “ultra-fine” MRF to finish to extremely high precision, including reduction of mid-spatial frequency errors
  • Use “standard” MRF to reach high precision
  • Use “aggressive” MRF to induce freeform shape
  • Start from a best-fit sphere

 

Ion Beam Finishing (IBF) is often used for the “ultra-fine” finishing step, but is too slow to induce microns of freeform shape –
now MRF can do both!

 

 

 

 

 


   

4.) Multi-step process – all on 1 machine

  • mrf application 7 pict4Multi-step process, each tailored to a specific goal
  • Q-flex enabled ~15 minute changeovers utilizing 3 heads and 2 FCMs
  • Depending on precision needed, correction process could stop after any of above steps

2 hours = λ/2

or...  3 hours = λ/10 

or…. 6 hours = λ/30 !

 


    

5.) Final Results: FreeForm  Introduction on ~150mm Φ sphere

 


mrf application 7 pict5Final Results

  • 440x RMS improvement!
  • 360x PV improvement!

 

Cycle Time:

  • Total of only 6 hours!
  • Over 3 runs!

 

PV Error was improved from 12.18 waves to 0.034 waves!

Notes:

  1. Plots on same scale
  2. Piston, tilt & power removed
  3. 3 pixel by 3 pixel median filter applied
  4. Cropped to clear aperture

 

 

 


  

 6.) Mid-spatial Frequency Improvement

 

mrf application 7 pict6


   

7.) Summary

New features of the Q-flex platform were leveraged to create mild freeform to ultra-high precision and with ultra-low levels of mid-spatial frequencies

  • Rapid module changeovers enable your business to offer optics with a range of quality/cost options
  • Freeform raster capability opens up raster polishing for ultra-high precision spheres, aspheres, and freeforms

 

Mid-spatial frequencies as small as 1 mm are now correctable by MRF

  • Now the same machine can perform shape correction (microns of low-order removal) and mid-spatial frequency correction (nm of high-order removal) in a fast, production-oriented solution
  • Ion Beam Figuring (IBF) cannot do all this!

Two new features of the Q-flex platform enable powerful new MRF capabilities

Modularity of Polishing Wheels (MRF Heads) and Delivery System (MRF FCM) allows:

  • Rapid configuration changeover: Change wheels quickly and  Change fluids quickly

  • Multiple wheel orientations: Traditional (rotational polishing) and  Rotated 90º, which enables full freeform raster polishing

 

In this case study, we combine these new features to create a mild freeform optic with

  • Ultra-high precision

  • Ultra-low levels of mid-spatial frequencies