Plastic injection moulder upgrades tool room

It was as recently as 2012 that manual plus two-and-a-half-axis CNC milling gave way to full 3D machining of plastic injection moulds on a three-axis vertical machining centre at family-run tool maker and plastic injection-moulding specialist Plasticom Group. Since that time the tool room has undergone a transformation, with 2020 alone seeing investment of £250,000, mainly for the purchase of a Sodick die-sink EDM machine and a German-built Spinner three-axis machining centre from UK sales agent Whitehouse Machine Tools.

The arrival of the latter machine at the end of September 2020 coincided with the departure of a 25-year-old CNC milling machine. It fell to tool-room co-ordinator Ian Alexander to investigate the best replacement for machine. In total, he scrutinised three machines before selecting the Spinner due to the comprehensive specification of the standard version of the VC750.

Spinner’s VC750 machining centre includes linear scales, 22 bar through-spindle coolant, a swarf conveyor, Blum TC52 spindle probing, a 24-station BT40 tool magazine, a 12,000 rpm spindle, Siemens drives with up to 36 m/min feed rate and the latest Sinumerik 840D control with 24-inch Industry 4.0 multi-touch display. Alexander says that the equivalent package from other suppliers would have cost half as much again.

“The VC750 represented the best value for money by far, and the latest Siemens control is a real bonus,” he states. “It allows us to program cycles to produce complex forms directly at the machine, taking the load off our CADCAM department. We also like the rigid, cross-table, C-frame design, which results in superior cutting performance and component geometry. The ability to probe a part before it comes off the table and re-machine it if necessary is a big time-saver and makes us more competitive.

“The Spinner is between 30 and 70% quicker than our other VMC, depending on the type of component,” he continues. “I should say it halves cycle times on average due to faster axis movements, the extra rigidity – which allows heavier cuts to be taken without causing vibration – and the latest Siemens control. It offers so much more productive capacity that there will be a lot of spare time to take on additional subcontract machining, which at present accounts for only a few percent of turnover.”

Operating from a factory of nearly 20,000 sq ft in Ashford, Kent, Plasticom has long-standing, high-profile customers that include household names such as Stanley Black & Decker, Games Workshop, Qualcast and Swann-Morton, as well as a host of smaller firms that call on its services. The company was invited in March to be part of the UK Government’s Ventilator Challenge UK consortium, and staff worked long hours under considerable pressure to ship 15,000 plastic ventilator parts to McLaren Racing against a very challenging schedule.

The company is ISO13485 accredited and has a class 7 clean room for the assembly of medical devices. Plasticom Group’s plastic injection-moulding capacity utilises machines rated from 20 to 530 tonnes, including automation, and extends to twin-shot moulding and over-moulding. The manufacture of press tools, vacuum forming tools and die-casting tools also forms part of its remit, while other services include ultrasonic welding, blister and other packaging techniques, and laser welding and printing.

The 60-years-established company is owned by chairman Edwin Simmonds and his wife, Sonia, group finance director, who says: “More than four-fifths of the injection mould tools we make are used in-house to produce a wide range of parts for customers, a side of the business that accounts for a similar proportion of our turnover. Keeping the moulding section operating is therefore critically important, so we look to our machine-tool suppliers to provide prompt aftersales back-up.

“The service that we have received so far from Whitehouse has been excellent, both in terms of the technical input and the training,” she adds. “Our shop floor staff have had one week of tuition so far but no limit has been placed on the amount we will receive in the future, free of charge, which is unusual and a great reassurance.”

Alexander has adopted a policy of buying in bolsters from Meusburger to allow Plasticom to concentrate on the 3D milling and sparking of tools. A fixture sits permanently on the table of the Spinner VC750 so that operators can quickly clamp each new bolster prior to the machining of mould inserts within the 760 x 460 x 460 mm working envelope, which is large for the machine’s 2.6 x 1.7 m footprint.

He also advises that dimensional tolerances down to a few microns are routine and that the surface finish achieved is “fantastic”. In aluminium, as well as Stavax, a mirror finish is achievable using standard, mid-price, carbide end mills, requiring considerably less polishing overall.

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Quick on the uptake

Mills CNC, the exclusive distributor of Doosan machine tools in the UK and Ireland, has supplied Quick Machining Solutions, a precision subcontract specialist based on the outskirts of the New Forest, with a new vertical machining centre. The machine, a Doosan DNM 4500 three-axis machining centre, was installed at Quick Machining Solutions’ refurbished 7000 sq ft facility in September 2020.

Investing in a new machine tool during the pandemic, at a time when many manufacturers were “battening down the hatches” has helped Quick Machining Solutions meet growing demand for its machining capacity and capabilities.

Explains Wayne Harris, owner and managing director: “A number of component manufacturers closed down their operations and/or furloughed a significant number of staff in response to the pandemic. We felt that even in these uncertain times, we had an obligation to remain open while ensuring we did everything to keep our staff safe. We also used any spare time for training, maintenance and other improvements within the business.

“As a consequence of keeping our doors open we were able to pick up new work from a number of customers who were having difficulty sourcing their machined parts in the necessary timescale,” he continues. “This increase in demand, in addition to continually improving our machining capabilities, was the main catalyst behind the DNM 4500 investment.”

To ensure that the new machining centre would meet its immediate and future production requirements, the company drew up a checklist and investigated the market.

“We needed a high-performance three-axis machine with a compact footprint and a good-sized working envelope to handle a wide range of different-sized parts,” says Harris. “Also, we required a machine with a Heidenhain 640 control to integrate with our existing database of machines and programs.”

He adds: “We’d looked at purchasing a Doosan DNM 4500 at the start of the year but had postponed the decision, temporarily as it transpired. However, the increase in demand and the need for swift delivery, combined with a great purchase price, meant that the investment was given the go-ahead.”

Since being installed, the DNM 4500 has been used to machine a range of components for customers operating in the motorsport, film, leisure and industrial sensor sectors, to name but a few. These parts, machined in small-to-medium batch sizes and from materials that include aluminium, stainless steels, titanium and engineering plastics, often exhibit tight tolerances (down to a few microns in some instances) and surface finishes of Ra 0.1 µm.

The DNM 4500 machine supplied to Quick Machining Solutions is equipped with a direct-drive 12,000 rpm spindle, a 1000 x 450 mm work table, a 30-position ATC and a Heidenhain TNC 640 control. Further features include roller LM guideways and thermal error compensation to ensure high accuracies and repeatability over long machining runs.

Says Harris: “The DNM 4500 is versatile and a great all-round performer. We ordered the machine in September and in the same month it was delivered, installed and cutting metal.”

Founded in 2010, Quick Machining Solutions has achieved significant growth and success over the past 10 years. The company today employs eight members of staff, has substantially increased its turnover and, to win new business and secure its position within customer supply chains, has achieved ISO9001 accreditation. Its commitment to continuous improvement is further reflected in strategic and prudent investment in machine tools and ancillary technologies, as evidenced by its first Doosan machine acquisition around two years ago.

In November 2018 Quick Machining Solutions invested in a Doosan Lynx 2100LMA multi-axis turning centre with an integrated servo-driven bar feeder.

“To maintain our competitive edge we made the strategic decision to invest in a flexible, high-performance multi-tasking turning centre,” says Harris. “We were looking for a lathe that was fast, powerful and accurate, and we were specifically keen on acquiring a machine that was equipped with driven tooling to help us reduce set-up and part cycle times. A bar feeder was also required to help us improve productivity and facilitate ‘lights-out’ and unattended operations.”

Before taking any purchase decision, Quick Machining Solutions did its homework and researched the market. The results revealed that Doosan lathes were popular among component manufacturers and that, for small component production, the Lynx range came highly recommended.

On the basis of its findings, which also included visiting an existing Mills customer and Lynx lathe user, Quick Machining Solutions placed its order for a Lynx 2100LMA.

Says Harris: “The Lynx lathe is a real workhorse and, since its installation, hasn’t missed a beat. The performance and reliability of the Lynx lathe, and the ease of doing business with Mills, were major factors in us deciding to invest in the DNM 4500.”

Investing in new technology as well as its people, plant and manufacturing processes and systems, is definitely the “direction of travel” for the company moving forward. Other recent and planned investments to enhance its performance include: the recent purchase/integration of an MRP system to help improve productivity and operational efficiencies; investment in a new CMM to boost inspection capabilities; the roll out of a plan to generate solar energy; and the continuation of the firm’s in-house apprenticeship programme.

“We’re always looking to improve and innovate,” concludes Harris. “We’ve built a solid reputation in the market based on the quality of our machined components, the fast turnaround times we can achieve for customers and our competitive prices. In a relatively short space of time we’ve become a ‘go-to’ precision component manufacturer for customers operating in number of industries. Our investments in Doosan machine-tool technologies have been more than instrumental in helping us get to where we are.”

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MSC achieves six-figure savings for Sulzer

As a global specialist in fluid engineering technology such as pumping, agitation, mixing, separation and application technologies, Sulzer has a network of 180 manufacturing facilities and service centres across the globe. With more than 25 service and manufacturing facilities in the UK; a reliable and reputable supply chain is critical for this OEM and service provider, which is why Sulzer recently committed to a three-year contract with metalworking and MRO experts MSC Industrial Supply Co.

Driven by quality, innovation and continuous improvement, Sulzer witnessed indifferent levels of support from its previous integrator of consumable products and made the bold move to change its supplier during the pandemic. It was only a matter of weeks from signing the contract before MSC was identifying savings worth hundreds of thousands of pounds at Sulzer.

Notably, MSC identified the savings ‘virtually’, during the UK lockdown.

The initial phase of the contract is seeing MSC implement vending solutions into two of Sulzer’s largest UK manufacturing sites in Birmingham and Leeds, with bespoke solutions introduced gradually at Sulzer’s other UK sites.

MSC application engineer Stuart Wiezniak was tasked with identifying ‘cost-down’ improvements to meet and exceed MSC’s contractually agreed commitments. Using its manufacturing expertise, a choice of unbiased suppliers, hundreds of best practice reference points and the combined experience of 15-strong application engineering team, MSC identified productivity gains and cost-down savings that would shatter the contractually obliged target on just two machine tools at the Sulzer manufacturing site in Leeds.

During his initial and socially distanced site ‘walk-round’, Wiezniak was introduced to the machine shop and staff, where early conversations identified concerns over a new project that involved turning a 4 m long Inconel shaft for a new high-pressure pump product line used in heavy-engineering sectors such as offshore.

Currently turning hundreds of 3 to 4 m long Super Duplex shafts, the introduction of Inconel for a new product line raised concerns for Sulzer. However, with hundreds of shafts turned annually on lathes over 20 years old, Wiezniak had no concerns over the performance of the machines.

“The older machines have construction and rigidity that far outweighs most modern machine tools, so we had the perfect foundation for trialling MSC’s range of tools,” he says. “We selected a couple of premium carbide grades for Inconel machining, achieving marginal gains on the speeds, feeds and overall cycle times. To attain the ‘step change’ we really wanted, we had to look at ceramic tooling.”

With the extensive range of Japanese ceramic cutting tools from specialist NTK recently added to the MSC range, Sulzer adopted a paradigm shift in strategy. For Sulzer, the concern around switching to ceramic tooling was the potential for additional heat and distortion. Wiezniak thus identified the need to change the machine coolant, as well as the slide wipers on the lathe bed from nylon to steel to protect the machine bed from the increased swarf temperatures created by high-speed and feed turning.

“With the machine fully prepared for trials, we worked closely with NTK’s application engineer Glyn Shaw and Sulzer’s machine operator and programmer Jamie Fieldhouse; a genuine team effort.”

Despite the stable machine platform, the new coolant and the slide guarding, the trio of engineers realised that the steady rest on one lathe required relocation from an average distance of 1 m from the cutting tool, to 350 mm, to increase the rigidity and stability for ceramic tooling. Ceramic tooling is inherently more brittle and susceptible to vibration than its carbide counterparts.

An initial batch of five Inconel 625 shafts required machining from a raw 200 mm diameter by 4 m long billet, down to a range of stepped diameters from 100 to 180 mm. After the primary work of preparing the machine and devising the rough machining strategies, the trials began. When rough machining the shafts to just leave +2 mm for semi-finish turning, the best carbide turning results typically yielded a finish machining time of 14 hours and 1 minute. Cutting data included depths of cut from 1 to 3 mm, cutting speeds of 40 to 50 m/min and spindle speeds of 80 to 200 rpm. These times, like all other times recorded by MSC at Sulzer account for cutting time only and do not include the additional reductions in set-ups and tool changes.

Wiezniak says: “Upon the recommendation of Glyn, we selected NTK’s Bidemic series of inserts and, in particular, the JX1 grade with a round RNMG12 insert geometry. This was because the Bidemic range offers better wear and notching resistance compared to whisker ceramic grades that are used widely in the industry.

“The NTK trials started at a cutting speed of 250 m/min, but we found the optimal speed for this job at 370 m/min, a massive increase over the 40 to 50 m/min we could achieve with carbide,” he continues. “We also increased the spindle speed from 80 to 200 rpm to over 740 to 1000 rpm, depending upon the diameter being turned.

“Cutting with an average depth of 1.5 to 2 mm, we reduced the rough machining time on the five Inconel 625 shafts from 14 hours, to just 2 hours and 4 minutes per shaft. This yielded a material removal rate (MMR) of 222 cm³/min, up from the previous rate of 30 cm³/min. An unexpected benefit was the improved concentricity after releasing the steady rest. With carbide tools, the rollers were showing a run-out of up to ±1 mm, yet with the ceramic inserts, which only increased workpiece temperature by 9°C during machining, the runout was consistently between ±0.15 to 0.20 mm.”

Aside from a nominal annual tooling cost increase of less than £1000, the six-figure financial savings justify the tool cost increase.

“From discussions with Sulzer, they have already identified more than 170 forward orders for the next 12 months for this particular pump,” says Wiezniak. “Based on our CAM and cutting-tool data, we project that we will reduce annual machining costs by 85%, reduce machining times by 85% and reduce the cost per part by 8%. To qualify this, total cutting hours will fall from 2380 per annum to less than 350, and this doesn’t include set-up and tool change reductions. This will yield a significant six-figure financial saving for Sulzer on the production of forward order Inconel 625 shafts and the respective pumps.”

With the groundwork and trials already successfully implemented on the Inconel parts, the cutting data has also been adapted for Sulzer’s large-bed turning centre that presently has more than 100 Super Duplex shafts scheduled for production.

“Although Super Duplex has a somewhat different and softer composition than Inconel, it is still an extremely difficult material to machine,” says Wiezniak. “We have already started work on this and are fully confident that we’ll replicate the ‘seven times’ overall cycle time reduction from the Inconel parts, doubling our already fantastic results.”

Indeed, MSC has already identified further and potentially equally impressive savings on the same shafts on a third machine. With the rough-turned shafts finished to +0.3 to +0.5 mm, the final process of grinding takes place on an 8-tonne Churchill BX cylindrical grinding centre.

Explains Wiezniak: “While we are optimising the turning process to minimise stock for finish grinding, we have identified potentially huge savings when grinding the Inconel shafts. By introducing new grinding wheel technology with the help of Kim Dean from Tyrolit, we can double the depth of cut from the existing 0.05 mm, to 0.1 mm, effectively halving the 36-hour cycle time. But taking this even further, we’ve also identified cycle-time savings from slashing non-grinding times with the introduction of a secondary wheel dressing unit to reduce wheel traversing distances and dressing times.”

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Second pair of VMCs at RDMS

Rapid Design Manufacturing Solutions (RDMS), a manufacturer of plastic injection production and rapid mould tools, has invested in a second pair of high-precision, three-axis vertical machining centres from Roeders. Sole UK agent Hurco Europe supplied the machines to the toolmaker’s Oldham factory in autumn 2020.

Established in 1998 and run by co-owners Neil Richardson and Paul Ryan, RDMS works closely with its customers to provide high-end, multi-cavity tools. The tools, weighing up to 2 tonnes, are supplied in short lead-times and at competitive prices. Some of the more challenging applications involve in-mould labelling and multi-shot tool production.

Medical work features significantly, including providing assistance to suppliers of hospital and laboratory equipment in the current pandemic. In addition, the firm manufactures injection moulds for producing interior trim that ends up in, for example, Mercedes, BMW, Audi, Porsche, JLR and Nissan cars. The white goods and electronics sectors are also regular recipients of the company’s tools.

A particular specialism at Oldham is the machining of two-shot tooling, used to produce complex parts from two different materials, without the need for assembly, by over-moulding plastic around a preformed plastic or metal insert, often in high volumes. Extreme accuracy and repeatability of machining is required when producing this type of tool, and is the reason that RDMS selected Roeders machining centres right from the start.

Says Ryan: “We need to hold tolerances of less than 10 µm on nearly every tool we produce and these German high-speed machines have always allowed us to do that. Soon after we started out over 20 years ago, we bought a 42,000 rpm Roeders 600p VMC networked to a Mitutoyo CMM and linked to an Erowa cell housing 360 mm square pallets [16 in total].

“A manual handling device speeded transfer of zero-point pallets within the cell, often 24/7, resulting in a high level of productivity as we were able to pre-set the pallets offline and load them accurately on to the machine table,” he continues. “It also increased machining precision, as we could adjust the offsets in the control according to the CMM measurements on the last part.”

To increase capacity both in terms of throughput and workpiece size, a couple of years later the toolmaker purchased a larger, stand-alone Roeders RP800 with 800 x 600 x 400 mm working volume, 30,000 rpm high-torque spindle and up to 60 m/min feed rates.

Even today, a polisher only needs to go over the machining marks on a mould produced on either machine; there is no need to revise the mould’s form. RDMS shows customers a part-to-CAD comparison to prove the fidelity of the machined shape to the design.

“A two-shot mould from China that a company was recently sourcing had ripples in the surface that their polisher had trouble removing,” explains Richardson. “We remade the tool by high-speed machining alone, without the need for any sparking, and eliminated all of the difficulties. It was an important issue for the user, as the cosmetic appearance of plastic components is increasingly important these days, added to which inaccuracies in a multi-shot mould can cause stresses and cracks in the parts it produces.”

The feature of equipment from Roeders that originally clinched its selection by the toolmaker, after four different machining centres had been trialled, was the ability of the machines to scan across the shut face, down into the mould features and then back up to the shut face in one continuous path, producing razor sharp edges at the transitions.

According to Richardson, if lower quality machines try to achieve a similar result, edge quality is lower and definition is lost in the moulded part. Modern inspection techniques can easily identify such imperfections. The solution is to machine the shut face first in its entirety and then the mould features, but that takes longer, requires more job management and lowers profitability.

To cope with an increasing order book and reinstate the high milling accuracy originally obtained with the 20-year-old Roeders machines, the two early models have now been supplemented by a pair of more modern, three-axis, high-speed machining centres from the same manufacturer. It leaves the 600p machine free to produce nearly all of the graphite electrodes in use at the factory, as well as mould tools. The RP800 also continues to run.
RDMS’ new RXP500 has a 500 x 455 x 240 mm machining envelope and 60,000 rpm spindle, while the new RXP801 offers 800 x 635 x 400 mm and 42,000 rpm. Both machines have spindle growth compensation and the former is fitted out with an interface for the future addition of an Erowa 120-pallet cell. For now, however, the new machining centres are side by side, with the manual handling device and CMM relocated to serve both machines.

All machining centres on-site are vertical-spindle models from Hurco, not only the Roeders but several own-brand, three-axis models fitted with the WinMax twin-screen control system. In addition to two Hurco BMC30s and the same number of BMC2416s, there is a pair of VMX42i machining centres, the second of which arrived in 2018.

Typical uses include manufacturing bolsters, ejector plates, back plates and other less high-precision work. However, it is notable that the latest Hurco VMX42i has linear scales rather than rotary encoder feedback of axis position to the control, making it sufficiently accurate for the finish-machining of dies.

Richardson concludes: “The future is more automation, to enable us to remain competitive on price and keep lead-times short, this being one of our USPs over competitors, especially those overseas. The other pillar of our work is continued use of top-quality Roeders machines, as they allow us to deliver perfect moulds, first time. That is essential, as it’s very expensive to take a tool out of commission for adjustment. The service we receive is excellent, not only from Hurco but direct from the German factory, which is linked to all four machines for remote monitoring and troubleshooting.”

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The colour of success at Cutting Blue

Mills CNC, the exclusive distributor of Doosan machine tools in the UK and Ireland, has recently supplied Birmingham-based Cutting Blue Ltd, the newly-created manufacturing arm of engineering consultancy and training specialist, Cutting Blue Solutions Ltd, with a new Doosan vertical machining centre.
The machine, a large-capacity DNM 6700, was delivered and installed at the company’s 2000 sq ft facility in Saltley in September 2020 where it is being used to machine (in mainly small batch sizes at this moment in time) high-precision and high-value components for a range of customers operating in the motorsport and general engineering sectors – to name but a few.

The creation of Cutting Blue Ltd is the brainchild of owner and managing director, Piotr Parobczy. Having started his working life, first as a machine tool setter and then as a CADCAM programmer, Parobczy used this knowledge and experience, gained from working in a number of different manufacturing environments, to develop and hone a range of specific engineering consultancy skills.

The acquisition of these skills ultimately enabled him to start, and secure, work as a contractor where over the years he was responsible for the design and implementation of innovative and high-value projects for a number of UK- and internationally-based customers.

Following on from this success, and having built up an impressive track record Parobczy, in 2017, set up Cutting Blue Ltd, an engineering service company providing specialist training and consultancy services to blue-chip and progressive manufacturing companies.

Says Parobczy: “Cutting Blue Ltd began its life as an engineering consultancy. However, even back then it was always my ambition and intention to create a manufacturing company – when the time was right.”

That time, as it transpired, was in spring 2020.
“The pandemic had a detrimental effect on the availability of contract work and this proved to be the catalyst I was waiting for,” he says. “As the creation of a manufacturing company was a long held ambition of mine, I wasn’t starting such an undertaking from scratch. To a large extent, much of the preparatory work and planning had already been done.”

These plans covered all aspects of the business, including the location of the new company, the services it would provide, typical customer profiles and so on.

Continues Parobczy: “I chose Birmingham due of its central location and because I knew the area well. From my background and experience the company would not be a ‘jack of all trades’ operation, but instead would offer specialist, high-precision milling services to customers typically operating in the high-end motorsport, automotive and aerospace sectors.”

To realise its ambitions and objectives, Cutting Blue needed access to advanced machine tool technologies and made the decision, from a reliability perspective and to provide a clear statement of intent, to invest in a new rather than a used machining centre. Cutting Blue subsequently approached a number of machine-tool manufacturers with its requirements.

“Several companies I approached sent in literature but didn’t follow things up,” says Parobczy. “I got a different reception and reaction from Mills CNC who, from the outset, adopted a more proactive and partner-led approach. They took time to understand the business and the type of work that would be undertaken, and worked collaboratively with me to identify the optimum machine-tool solution.”

Understanding the type and size of components, the typical materials to be machined (i.e. aluminium, steel, stainless, titanium and engineering plastics), the typical part accuracies and surface finishes that would be required, and the volumes/batch sizes to be machined – resulted in the identification, selection and ordering of a Doosan DNM 6700 – a large-capacity vertical machining centre.

The Fanuc-controlled DNM 6700 installed at Cutting Blue’s facility is a highly-rigid machine that delivers speed, high accuracy and unrivalled process reliability. Equipped with an 18.5 kW/12,000 rpm directly-coupled high-speed spindle, the machine also features a 1500 x 670 mm work table with a 1300 kg maximum table load, a 30-position ATC, roller LM guideways in all axes and thermal error compensation routines. In addition, the machine houses a Blum TC50 workpiece touch probe and Blum ZX Speed IR tool-setting probe.

Concludes Parobczy: “I was already familiar with Doosan machine tools and knew that they were reliable, represented great value and delivered excellent cutting performance. The DNM 6700, with its large work table, will provide much-needed capacity, capability and flexibility now and in the future, enabling us to machine large or multiple smaller parts in one set-up. Although still early days I’m delighted with the DNM 6700 and am already looking at investing in second Doosan machine.”

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