Insert grinding at Glendower – when five axes isn’t enough

Glendower’s 6-axis Rollomatic tool grinding machine
Glendower’s 6-axis Rollomatic tool grinding machine

Glendower Cutting Tools, which recently celebrated its 50th anniversary, has recently invested in a Rollomatic 630XW 6-axis CNC tool grinding machine that is now busy boosting the production of cutting tool inserts. PES reports.

Glendower Cutting Tools, a specialist insert manufacturer, has been located in Leicester since 1972 when Jim Doherty started the business with just a few manual grinding machines. Over the years the company has moved several times and is now located in a modern factory unit in Thurmaston and remains under family ownership with Jim Doherty’s daughter Cynthia Sanders, supported by Glendower’s management team headed up by his grandson Justin Sanders.

While offering a vast array of standard inserts and tooling, Glendower also manufactures its own special inserts. From the initial design concept to final product, great attention is paid to manufacturing special inserts to the finest possible qualities.

Glendower’s philosophy is to have complete in-house control over all manufacturing processes and that extends, for example, to pressing and sintering carbide inserts with its own 12.5 ton insert press and vacuum furnace. 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 very long serving and highly skilled employees who are able to master many different processes including pressing, sintering, brazing, milling, lapping, and of course grinding on a variety of 3-axis, 4-axis and now, with the introduction of the Rollomatic, 6-axis CNC tool grinding machines.

Inserts ground on the Rollomatic 630XW
Inserts ground on the Rollomatic 630XW

Six axes and single setups

Dave Chattaway, Glendower’s chief engineer, who joined Glendower some 47 years ago, is especially pleased with the introduction of the latest grinding technology in terms of enhanced insert production. He welcomes the ability to programme 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. Mr Chattaway states that the sixth axis on the Rollomatic allows him to create special forms that are not possible on machines with less axes. It facilitates one-hit production in a single set-up which saves a lot of time and brings higher accuracies than is possible when grinding special forms on two or three separate machines. The ability to quickly programme and then manufacture small batch work has significantly sped up lead-times through the shopfloor and work in progress on multiple machines.

Today Glendower is exporting inserts to businesses in countries such as Taiwan which, although far from being short of having many local insert manufacturers of its own, prefer to keep coming back to Glendower for the special geometry and high quality of inserts that it can provide. The investment in the Rollomatic grinding machine will further enable Glendower to manufacture inserts that others simply cannot do.

The Rollomatic 630XW is designed for grinding many kinds of cutting tools with more complex geometry where its additional sixth A-axis, said to be unique within the industry, provides improved accuracy on ball nose end mills or corner radii with a possibility to incline the grinding wheels by up to 45°.

This avoids collisions, allows for easier programming and ensures demanding and highly precise geometric forms, such as those found on special inserts, can be machined in a single operation. Unlike dedicated insert grinders, the Rollomatic has the flexibility and ability to quickly change over to grinding cylindrical cutting tools within minutes; something that is not possible on dedicated machinery.

The machine has a general working range of grinding tools from 0.1mm to 20mm in diameter, (3.9mm to 25.4mm inscribed circle (IC) diameter on inserts), has a high-speed multi-pallet pick and place loader with positions for up to 1,360 tools as standard, and, also as standard, a six position grinding wheel changer holding up to 24 wheels.

The ultra-efficient synchronous grinding spindle motor provides constant rotation speed and torque regardless of the load on the motor and this, combined with the latest linear motor technology, provides benefits such as an enhanced surface finish.

For grinding Glendower’s inserts, the machine was specified with the optional retractable grinding wheel dressing unit with an in-built Dittel acoustic sensor. The machine is also equipped with a touch probe that determines the exact location of the insert blank after clamping so that the software can grind the tool geometry according to the virtual centreline of the blank which ensures a run-out of just 2µm can easily be achieved.

Quick change clamping devices for insert manufacture
Quick change clamping devices for insert manufacture

Additional benefits

Like all Rollomatic grinding machines, the 630XW comes with a three year parts and labour warranty that is provided at no additional cost, and also free of charge software and software updates for life.

Chris Boraston, managing director at Advanced Grinding Solutions, the agent for Rollomatic in the UK and Eire comments: “Cutting tool inserts are not easy to grind. There is an almost infinite number of different and ever more complex forms to deal with. Many have very tight tolerances with ultra small radii and a requirement for 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 the majority of UK companies buying these tools in from overseas.

“Glendower is competing head on with anyone globally when it comes to the manufacture of cutting tool inserts as it exports worldwide into other markets itself. There are many considerations that need to be understood when offering grinding solutions for inserts; not only does the software need to be extremely powerful and versatile to cope with the huge variety of forms, but the clamping of inserts can also be challenging.

“Rollomatic has developed really excellent 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 centre,” he adds.

“Glendower needed all of these holding devices and challenged Rollomatic at every level during the test and trial phase when Rollomatic successfully ground a number of different inserts for their approval. We all very much enjoyed the challenge and working with Glendower to help make this investment in the latest grinding technology the success that its being proven to be.”

Advanced Grinding Solutions
www.advancedgrindingsolutions.co.uk

Glendower Cutting Tools
www.glendower.co.uk

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