“It’s about optimum tension’. Using the right cutting wheel reduces splintering in processing, which means that in toughened, heat strengthened and heat soaked glass, you can cut failures, remakes and the costs that go with that, significantly”, says Dave Broxton, Managing Director, Bohle. "Cutting wheels are small but can have a disproportionately big impact on your productivity, particularly in IGU manufacture”, he continues.
While it has grown since its beginnings in the 1920s to offer an extensive range of glass processing consumables and hardware, Bohle’s origins are firmly rooted in glass cutting. This is founded on its iconic Silberschnitt cutting wheel range, which has evolved over almost a century from simple hand held tools to high-tech automatic cutting wheel designs. This includes the development of products in partnership with the leading glass machinery companies including Glaston Bavelloni, Bottero, Bystronic, Benteler, CMS Brembana, Grenzebach, Hegla, Intermac, Macotec and Lisec. With its own research laboratories and a rigorous research and development programme, it’s this partnership approach which has allowed Bohle to deliver a step-change in cutting-wheel technologies.
“Get it wrong and your edge-quality can drop off a cliff”, says Broxton, “that leads to splintering and weakness in the glass, which are exposed the minute you try and toughen it. That has significant ramifications for IGU manufactures where toughened glass has become the mainstay of production. These are even greater, because of the focus in IGU on high volume and automation of manufacture combined with acute pressure on margin. What toughened, heat strengthened and heat soaked glass are singularly reliant on is edge quality”, he adds.
If it’s the ‘little things that count’, Bohle has brought exacting precision to cutting wheel manufacture on a molecular level. To this end Bohle’s cutting wheel manufacturing facility is cutting edge, using specially developed robotics technologies to manufacture each cutting wheel with exacting precision. This includes hone processing (an abrasive process which improves geometry at an almost molecular level) of holes , and ultra-fine polishing and lapping.
This technology is in the literal and metaphorical sense, ‘cutting-edge’. These developmental principles are enshrined in its Silberschnitt Cutmaster Platinum Range. It’s been developed by Bohle to maximise edge quality, featuring a specially developed micro-structure. “It works using a series of microscopic ridges which transfer tension into the glass at the same time as minimising the transfer of the cutting force during the cut, reducing damage to edges and making failure in toughening less likely”, says Broxton.
In use the Cutmaster Platinum cutting wheel penetrates as notches into the glass compared to standard wheels which score the glass along their whole circumference. As a result, micro-openings of the fissure are produced precisely in the cutting direction. Accompanying cracks and damages deviating from the score line are effectively avoided and edge damage is minimized.
Broxton continues: “Bohle also offers standard carbide wheels and we also manufacture a polycrystalline diamond (PCD) range. These are ideal for use in IGU manufacture as a high volume and high demand use, offering an exceptional service life, while almost eliminating dusting and splintering, making them ideal for use in cutting ahead of toughening.”
This is according to Broxton a key advantage of PCD. Using diamond-based technologies, PCD cutting wheels offer an exceptionally long service life, while delivering consistently high cutting quality throughout their entire service life and developed for specific applications.
To deliver even better edge quality Bohle also offers a specially developed range of PCD wheel holders and axles, which guarantee smooth operation at high speeds and easy change over if required.
Bohle also supplies a range of cutting fluids, which have been designed to deliver a ‘softer’ break maximising edge quality. This again, encompasses different options for different glass-types, coatings and thicknesses. “For the IGU sector we tend to sell Acecut 5503 in the greatest volume. It’s been developed as a standard product for cutting insulated low-E glass up to 10mm thick”, says Broxton.
He continues: “Markets are invariably competitive but competition in IGU is increasingly off the scale with the growing influence of a handful of big manufacturers putting pressure on prices and driving consolidation. We’re at the point in IGU manufacture where each and every incremental efficiency gain counts. Automation of process, increased efficiencies and the delivery of higher volumes is key. The cutting wheel is a very small but at the same time very ‘big’ part of the delivery of those efficiencies and with it, competitivity in a highly competitive commercial environment.”