CUSTOM LAPPING AND POLISHING

Applications

Although a large part of our business is aimed at optical applications such as laser quality mirrors, we can also help many of our customers with extremely accurate metal parts for other uses. Our precision lapped or polished surfaces are used for many applications including semiconductor inspection equipment, precision mating surfaces for seals and alignment aids for scientific instruments.

If you have a need for extreme precision please send us an enquiry. We welcome the challenge of developing process methods for lapping and polishing new materials. We have supplied lapped and polished parts for fibre optic connectors, medical implants, Formula 1 racing, nuclear installations and the food industry.

Specifications

Our double sided lapping and double sided polishing equipment can generate parts with variations in edge thickness of just 1 micron. Similar specifications are available on polished ceramics, alloys and CVD materials.

Over 25 years we have lapped and polished many different materials such as: Stainless Steel, Tungsten, Graphite, Bronze, Brass, Titanium, Ceramics, Mild Steel, Nickel, Arcap Alloy, Graphite, Electroless Nickel and Crystals.

  • Typical flatness achieved is 0.5 micron or better on lapped parts up to 270mm diameter.
  • Interferometric test results can be provided with 0.05 microns accuracy.
  • Polished metal mirror surfaces have the surface smoothness and low scatter normally specified for UV optics.

Many optical designers and specifiers are aware of the importance of surface quality and specify surface roughness as Ra (an average roughness) or Rrms (a root mean square). By both measurements Laser Beam Products offer the smoothest optical mirror surfaces available.

Ra Rrms Laser Damage Threshold
Laser Beam Products 1-3nm >5nm <40Jcm2 80ns pulse
Diamond Machined 2-25nm 7-35nm >10Jcm2 80ns pulse

Chemical Polishing

Laser Beam Products have taken the techniques used in semiconductor polishing and developed them for the chemical polishing of metals. The material removal is entirely chemical, there is no mechanical abrasive action, leaving a flaw free, ultra smooth mirror surface of sub nanometer surface roughness. Because no abrasive is used, there are no embedded particles in the surface to act as absorbing sites.

Laser optics require exceptional surface quality for low scatter and high laser damage threshold. Our polished metal surface quality is far superior to anything even the very best diamond machining can offer. Where surface quality is important, many diamond machined optics have to be "post polished" to improve the surface quality.

With polished surfaces there are no cutting arcs, target patterns or chatter marks that are so easily visible on the surface of a diamond machined mirror.

Diamond machined surface showing roughness
Diamond machined surface showing roughness

Improved surface smoothness after polishing
Improved surface smoothness after polishing

Surface scatter and diffraction reduced by polishing
Surface scatter and diffraction reduced by polishing


Fly cutting arcs from diamond machining of Copper mirror

These unwanted surface faults can initiate laser damage and cause diffraction of the laser beam. In some cases the diffraction and scatter of diamond machined optics is so great that a red alignment beam can be completely lost after reflecting off a few mirrors. Sometimes on diamond turned concave or convex mirrors a spike of metal can be left in the centre of the spherical mirror due to poor proof of centre during machining.

Plating and Coating

We have our own custom made electroless nickel plating equipment, we do not sub contract this operation. We monitor and control the plating process quality and just as crucially the substrate preparation for plating, in laboratory conditions. Our electroless nickel plated parts are bright, stain free and low in porosity.

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