Coborn Engineering, which designs and manufactures specialised CNC grinding, polishing and lapping machines for the diamond tooling and gemstone industries, is taking advantage of Kaydon bearings from R.A. Rodriguez (U.K.) Limited to help boost the performance of its industry-leading Planetary Grinding (PG) Series machines. In this extremely high-precision application, Kaydon bearings are an essential element of the machine, allowing users to process diamond cutting tools to radius form waviness levels of 50 nm (0.00005 mm).
For almost 80 years, Romford-based Coborn Engineering has been actively involved in many aspects of machine tool design and manufacture. Established in 1942 the company initially produced high–precision spindle and balancing machines. However, by the 1960s, activity had diversified into planetary grinding machines for the gem and single-crystal diamond (SCD) industries, and by the late 1970s into reciprocating grinding machines for polycrystalline diamond.
The latest version of Coborn’s PG Series the PG6, is an automatic, ultra-high precision grinding machine for processing natural or synthetic SCD tools. Coborn’s PG6 is a world-first engineering solution that relies on high–quality bearings for the precision manufacture of controlled waviness and complex geometry tools.
“We selected Kaydon bearings from R.A. Rodriguez (U.K.) Limited because they give us the precision needed by PG machine users, who typically want to process synthetic and natural diamond tooling to levels better than 50 nm,” explains Robert Bullman, Sales Manager at Coborn.
To verify performance, Coborn can perform a TRC [tool radius check], which is essentially a microscope with image analysis software to measure tool radius and radius waviness.
“The system generates custom-designed QC graphical data sheets that we can then supply with the associated tool,” explains Mr Bullman. “Our PG Series machines generate waviness values of sub 50 nm, which is market leading. The bearings are a key part of the machine, allowing users to process diamond tooling to these accuracies.”
Coborn’s PG6 also features a closed loop nano-stop for more accurate finishing of the radius form, while the high–resolution PoE camera works in conjunction with an improved optical lens system to enable tool measurements and geometry validation.
The company currently manufactures around 20 PG Series machines every year, although this number is now rising as global economies pick up following the Covid-19 pandemic. Coborn exports around 90% of its machines overseas, including many to China, the USA and Germany. The company is the only market player offering a commercially built, off-the-shelf machine for the single-crystal diamond tool industry.All Coborn PG6 machines feature the same Kaydon bearing set.
R.A. Rodriguez (U.K.) Limited supplies Coborn with Kaydon KD series high-precision, angular contact, preloaded bearings in duplex (back-to-back) configuration. Each Coborn PG machine requires a pair of these 7-inch diameter bearings. The company has been a customer of R.A. Rodriguez (U.K.) Limited for the past 22 years and has been using Kaydon KD series bearings since 2013.
Concludes Mr Bullman: “We are a very well established customer of R.A. Rodriguez (U.K.) Limited and appreciate their high–quality products and the support offered over the years, which continues to this day.”