Spherical/Ball Lapping & Polishing

Current buffing processes used to polish spherical balls and cups can detrimentally effect the roundness. Current machines used to polish spherical balls and cups have between 10-20% failure rate. The machine and process developed at Kemet International produces a mirror polish, holds geometry and can correct these failures while maintaining roundness down to 2 microns. The whole process takes less than 9 minutes. The machine can process parts from 12mm to 75mm diameter. With special modifications, parts up to 100mm diameter can be polished.

The system can be used on most materials including ceramic, natural metals and alloyed metals. Applications include:

spherical lapping and spherical polishing

ball lapping

Material that can be polished include:

  • Cobalt Chrome
  • Stellite
  • Ceramic
  • Other materials may be possible

There are only 2 steps to obtain a mirror polish starting with a machine ground spherical ball or cup. These are lapping stage and polishing Stage


  • Able to process all common materials including Stellite, Ceramic and Cobalt Chrome.
  • Simple fixture designs to accommodate all styles of product.
  • All critical parts manufactured from stainless steel.
  • Modular design to enable easy configuration of manufacturing cell (Eg 2 x polishing stations or 2 x lapping stations).
  • Dedicated approved consumable formulations to give consistent repeatability.
  • Built in cleaning option between stages.

KemiSphere II - Bench Top Spherical/Ball Polishing Machine

The KemiSphere II is a small single station spherical lapping and polishing machine ideal for either matching 2 spherical forms together or, with appropriate tooling, it has the ability to lap and polish spherical forms to better than 5μm roundness with a mirror finish. It’s a perfect replacement for jobs currently hand lapped together, and its bench top design makes it a useful addition to any workshop involved in spherical lapping.

  • 3 motors with independent variable speed control
  • Siemens PLC and HMI
  • Pressure application system
  • Benchtop machine
  • Process parts up to 100mmø
  • Programmable sweep start and finish point
  • Single button process start
  • Manual and jog facility for simple machine setting
  • CE marked
  • 230V single phase (110V available)
  • Fully guarded with interlocks
  • Dimensions: 906 x 1055 x 549mm
  • Product Code: 359316
spherical ball polishing

Square Polishing Pads for the KemiSphere

The Sphericloth Polishing Squares incorporate new unique flock length technology. This technology allows a far greater flow of polish to the pad increasing dramatically the amount of polish at the surface during the polishing cycle. When this increase in polish is combined with the enhanced polishing action of the new flock design you are left with an outstanding example of a polished surface.

Type Description 127 x 127mm
Sphericloth-A For general purpose, single use spherical polishing pads. 341998
Sphericloth-B 341966
NLH For high gloss spherical polishing 341276

Why Should you choose a Kemet Spherical Polishing system?

  • Proven and established technology.
  • No more buffing by hand.
  • Able to correct failures produced by other Spherical polishing machines.
  • Superior mirror polish is achieved.
  • Kemet machines hold geometry and achieve roundness better than 2 Microns.
  • Able to process common materials such as Stellite, Ceramic and Cobalt Chrome.

Ball Polishing Case Studies

Test Requirements: To polish modular heads
Component/Material: Ground heads

Process Breakdown
Stage Plate/cloth type Abrasive type/grade Process time
1 Cast Iron 9 micron SiC/W3 slurry 8 minutes
2 NLH cloth 1 micron diamond compound 4 minutes

The ground components all lapped within the standard 8 minute cycle, and polished in 4 minutes using the Kemet Spherical Polishing Machine. The Kemet spherical polisher is ideal for all engineering workshops where polishing and surface finish on a range of components are of prime importance.

small ball grinding

Test Requirements: To lap 2” Flow Control Ball Valve ready for Chrome Coating (Ra better than 0.4 µm). Roundness better than 10 µm
Component/Material: 2” Non plated Semi Spheres.

Process Breakdown
Stage Matching Abrasive type/grade Process time
1 Rotary control valve Silicon carbide 22 micron 20-35 Minutes

Parts were lapped on the Kemet Spherical Lapping Machine and checked every 10 minutes on a roundness machine until roundness was better than 10 µm. (parts turned before lapping to 40 µm)

ball valve polishing