Founded in 1976 — and both owned and managed by Eric Charlesworth — Meltham Carbide Precision is a manufacturer of plug gauges and components such as punches, mould and core pins, and blank carbide rods for the cutting-tool industry.
The company has a broad customer base in a range of industries that include Formula 1, aerospace, tool-making, fasteners, medical and cutting tools.
Its capabilities are focused on centreless grinding, surface grinding and cylindrical grinding in a variety of materials, including steel, carbide and ceramic; and while the largest market for Meltham is the UK, the company also exports world-wide.
Mr Charlesworth recognised the need for grinding to a higher level of precision and reducing manufacturing times — in particular, removing the need to transfer parts across several machines to arrive at the finished result.
He began looking for a machine capable of producing large batches of precision parts in a single automatic operation, while being able to run unmanned all night and produce special tools in small batches during the day.
Because the purchase of the required machine would be the largest single investment ever made by Meltham, investigations were carried out over several months; these included visiting MACH 2018
, where Mr Charlesworth and his colleague Peter Nash saw a Rollomatic ShapeSmart NP3+ grinding machine on the stand of Gloucester-based Advanced Grinding Solutions (www.advancedgrindingsolutions.com
) — the sole UK agent for Rollomatic.
Having seen a demonstration, they noted the machine’s ‘pinch and peel’ grinding method, which ensures that the grinding operation is always carried out immediately adjacent to where the component is supported.
This allows parts with lengths of up to 400-times the part diameter to be ground without deflection, with diameters controlled to under 0.002mm across large batches of parts.
The Rollomatic Shape-Smart NP3+ was installed in January this year.
Flexibility and precision
Explaining his machine choice, Mr Charles-worth said the Swiss-made Rollomatic machine is the only one of its type that gives him the flexibility, degree of high precision and mirror-like surface finish needed while producing his components in one automatic operation.
“While other machines are available, most do not offer the ability to both rough- and finish-grind in one operation, and in the case of the Rollomatic both at the same time if needed.”
Highlighting an example of how the machine has improved manufacturing efficiency at Meltham, Mr Charlesworth refers to a set of 10 carbide punches nominally 6.35mm in diameter x 110mm long with a point radius and three different diameters with 5µm tolerances.
“This job would have taken us a full day to manufacture previously; with the Rollomatic, we need just 15min for set-up and about 2hr of grinding time.
“Moreover, the surface finish is much better, and the lengths and diameters are all well within tolerance.”
The Rollomatic machine installed at Meltham’s works accommodates parts from 0.025 to 25mm in diameter, with the automatic loading of up to 1,000 parts from pallets via a fully integrated three-axis robot loader.
The multi-axis ShapeSmart NP3+ allows stepped diameters, angles, tapers and chamfers to be ground with ease.
Furthermore, the machine’s software, in conjunction with the rough- and finish-grinding wheels, allows users to specify multi-pass grinding operations for roughing and/or finishing, thereby achieving high levels of accuracy while producing superior surface finishes on tapers and radii.
Even the longest tools are produced with run-out concentricity of less than 0.001mm.
Renishaw and Marposs gauges are used for part positioning and for the post-process automatic gauging of ground diameters, along with automatic feedback to the Rollomatic machine’s Fanuc control.
This ability to automatically gauge parts upon loading and again after grinding was important to Meltham, as it has allowed them to introduce unmanned production overnight, knowing that parts are machined to specification without the need of operator intervention; and if the gauge detects any unwanted change in quality, it will stop the machine, thereby ensuring that no batch work is scrapped.
Indeed, Mr Charlesworth says that the key advantage of the Rollomatic is its ‘lights out’ feature.
He also highlights the three-years parts and labour warranty that comes as standard — plus free software updates for the life of the machine.
“The Rollomatic machine has simply transformed our production.
“We previously had to manufacture punches using three separate machines, and we were constantly having to re-set those to get the job within tolerance, with parallelism and roundness being particularly difficult to achieve.
“With the Rollomatic, we have one simple set-up, parts are made perfectly round and parallel, and the surface finish is excellent — and radii are ground to precisely the correct size.”
Chris Boraston, Advanced Grinding Solutions’ managing director, said: “With more rotary tools of all kinds being manufactured on Rollomatics here in the UK and in Ireland than on any other make of grinding machine, they are one of the leaders in their field.
“In the last year, we have been able to add a number of new customers that have become Rollomatic end users for the first time, and this is especially pleasing.
“The Rollomatic NP3 and NP5 machines — newly designated NP50 — are the firm favourites for tool-manufacturing companies.
“It is good to see other specialist makers of tools and punches investing in these machines to increase the precision of their parts and to drastically reduce their cycle times.”