Glendower Cutting Tools Ltd has been in Leicester since 1972, where the company was started by Jim Doherty with just a few manual grinding machines. Over the years it has moved several times and is now operating in a modern factory unit in Thurmaston. The company also remains under family ownership, with Mr Doherty’s daughter Cynthia Sanders supported by a management team headed up by his grandson Justin Sanders.
While Glendower offers a vast array of standard inserts and tooling, the company also manufactures its own special inserts. From the initial design concept to the final product, great attention is made to making special inserts to the highest standards — hence the company’s philosophy of having complete in-house control over all manufacturing processes.
This control even extends to pressing and sintering its own carbide inserts with a 12.5-tonne insert press and vacuum furnace. Moreover, even the dies and punches that are needed are designed and manufactured in-house.
Staff retention has always been very important to Glendower and most of those working there are long-serving highly-skilled engineers who can master many processes, including pressing, sintering, brazing, milling, lapping, and grinding, the latter being undertaken on a variety of three-axis and four-axis machines — and more recently with six axes, following the purchase of a Rollomatic 630 XW six-axis CNC tool-grinding machine from Coventry-based
Advanced Grinding Solutions Ltd, the agent for Rollomatic in the UK and Ireland.
Dave Chattaway, Glendower’s chief engineer, who has been with the company for some 47 years, says the Swiss-made Rollomatic machine is boosting insert production, adding that he can now program all special insert geometry from his office. “The machine is currently busy producing special inserts in low batches of 10s, 20s and 30s. However, with production rising to over 40,000 inserts per month it will not be long before the Rollomatic’s automatic part loader is used on larger batches of 1,000 inserts or more.
“The sixth axis on the Rollomatic allows me to create very special forms that are not possible on machines with fewer axes; the machine also allows for one-hit production in a single setup — saving a lot of time and bringing a higher accuracy than is possible when grinding special forms on two or three separate machines. Moreover, the ability to quickly program and then manufacture the small batch work has really shortened lead time through the shopfloor by eliminating work-in-progress on multiple machines.”
Export marketsToday, Glendower is even exporting inserts to customers in countries such as Taiwan, which has many insert manufacturers of its own. However, many customers there keep returning to Glendower for special-geometry high-quality inserts — particularly now that the Rollomatic enables the company to manufacture inserts that others simply cannot make.
Mr Chattaway added: “The Rollomatic 630XW machine is designed for grinding many kinds of cutting tools with complex geometries, with its sixth A axis — unique within the industry — providing an improved accuracy on ball-nose end mills or corner radii; and being able to incline the grinding wheels by up to 45deg avoids collisions, allows for easier programming, and allows the grinding — in a single operation — of demanding and highly precise geometric forms, such as those found on special inserts. Moreover, unlike dedicated insert grinders, the Rollomatic has the flexibility to quickly change over to grinding cylindrical cutting tools within minutes.”
The Rollomatic 630XW, which can grind tools from 0.1mm to 20mm in diameter (3.9mm to 25.4mm IC — inscribed circle — diameter on inserts), has a high-speed multi-pallet pick and place loader with positions for up to 1,360 tools as standard. Also standard is a six-position grinding wheel changer that accommodates up to 24 wheels.
Moreover, the synchronous grinding spindle motor provides constant rotation speed and torque regardless of the load on the motor; this capability, combined with the latest linear motor technology, provides benefits such as an enhanced surface finish.
For grinding Glendower’s inserts, the Rollomatic was specified with the option of a retractable grinding wheel dressing unit with an in-built Dittel acoustic sensor. The machine is also equipped with a touch probe and software that determines the exact location of the insert blank after clamping, thereby ensuring that the tool geometry is ground according to the virtual centerline of the blank and that a run-out of just 2µm can be easily achieved; and like all Rollomatic grinding machines it comes with a three-year parts and labour warranty and also free-of-charge software and software updates for life.
Complex formsChris Boraston, Advanced Grinding Solutions’ managing director, said: “Cutting tool inserts are not easy to grind. There is an almost infinite number of different and ever more complex forms to deal with, and many of them have very tight tolerances, require perfect and tiny radii — and fine mirror-like surface finishes. In the UK you can count the number of dedicated insert manufacturers on one hand, and insert grinding is very much a highly specialised field with most UK companies buying these tools in from abroad.
“Glendower is competing globally when it comes to the manufacture of cutting tool inserts, as it exports worldwide into other markets. Moreover, there are many considerations that need to be understood when offering grinding solutions for inserts; not only does the software used need to be extremely powerful and versatile to cope with the huge variety of forms, the clamping of inserts can also be challenging.
“Rollomatic has developed efficient clamping devices for all types of inserts, including: beak-type jaws for holding dog-bone-form inserts; a claw clamping device for milling inserts; a flat clamping system for profiled inserts; and a cylindrical arbor holder for holding inserts that have a hole in the center.
“Glendower needed all of these holding devices and challenged Rollomatic at every level during the test and trial phase whereby Rollomatic successfully ground several different inserts for the company’s approval. We enjoyed working with Glendower to help make the company’s investment in the latest grinding technology the success that it is proving to be.”