The Intercity Express of the German state railway Deutsche Bahn (DB) is a continental European system of high-speed trains renowned for their comfort and reliability. Occasionally things go wrong, however, as happened last year when two rail carriages needed repair.

Both required a new secondary roll stop, a heavy steel component bolted to the underside of each passenger car that limits lateral play on tight curves to ensure safe cornering.

Secondary roll stops are safety-critical parts with a method of manufacture which rail engineers are reluctant to change. Nevertheless, DB was forced to do just that, as the component is not a regular service item but an accident repair part and therefore not normally held in stock. Two were needed quickly, although the usual supplier was quoting 10 months to deliver the castings, after which they still had to be machined by the usual subtractive process. Moreover, the quote was for a minimum order quantity of four castings.

Florens Lichte, DB’s head of additive manufacturing, says: “Apart from the extended lead-time for delivery, we would also have had to pay serious money for the initial tooling. None of this was an option for us. We needed to reduce the downtime of the railcars drastically to get them back into service quickly and economically. So we decided to 3D print the components using the WAAM process.

“A co-operation was set up with Gefertec, which manufactured the parts at its headquarters near Berlin,” he continues. “We were able to reduce the lead-time by five months, added to which the overall cost was 30% lower.”

Tobias Kruemberg, CEO of Gefertec, which is represented in the UK by Kingsbury, adds: “Our company produces WAAM three- and five-axis CNC metal 3D-printing systems, alongside a subcontract manufacturing service. The benefit of our technology is that many kilograms of metal can be deposited in a relatively short time. When DB came to us, we saw the additive manufacture of their secondary roll stops as ideal for our technology. It’s perfect for the rapid production of high-value metal parts in small quantities at reduced cost, so this application amounted to a sound business case.”

The two components were duly produced on an arc405 five-axis WAAM machine in a cycle time of 36 hours each. The raw material is standard welding coil that does not require the safety precautions associated with powder-bed layer-by-layer fusion technology. In this case, 1.2 mm diameter SW 100S NiMoCr wire was used to produce two high-tensile, fine-grain structures each measuring 250 x 216 x 312 mm and weighing 36.3 kg.

It is at this point that detail on the finalisation of the original project is lacking. So Richard Kingsbury, managing director of Kingsbury, decided to produce a video recreating the manufacturing process in its entirety, including interviews with the decision-makers involved.

He says: “When Gefertec described this application to me I found it so compelling that I wanted to document the project. It brought home to me how additive manufacturing is progressing year-on-year into an ever more practical, low-cost alternative to subtractive machining. So, on behalf of Gefertec, and in co-operation with another of our principals, machining centre manufacturer Hermle, as well as 3D metrology equipment supplier GOM UK, we’ve produced a video detailing the whole process.”

Kevin Hawley, director of GOM UK says: “We became involved in this reconstruction when a 3D-printed sample component identical to the DB secondary roll stop arrived from Gefertec. So that the subsequent machining could be optimised, we created scan data from the part by first taking the CAD model and putting it into our virtual measuring room software.”

The part was scanned in about one hour on the rotary table of a GOM ATOS ScanBox optical 3D measuring machine. When complete, it was possible to understand the part geometry and compare it with the CAD model to detect if there were any deviations. It was then an easy matter to ensure that the 3D-welded, near-net-shape component could be cleaned up satisfactorily when machined.

Dan Castles, business development manager – automated solutions at Kingsbury, says: “We took delivery of the 3D-printed component and the STL data file from GOM. The file was loaded into our CAM system to help us prepare a program for the machining process, which was completed on a Hermle C 650 five-axis vertical machining centre. It was more accurate to do it this way, using actual scan data rather than the theoretical CAD model, as the tool paths could be optimised to the exact form of the welded part.”

The procedure avoided air cuts and no safety passes were needed, as there was no chance of overloading the spindle by taking a heavy cut. It ensured that the part was machined back to net shape in one hit, in a cycle time of around seven hours. The machining time was considerably shorter than would have been required on the original casting and vastly less than trying to mill the part from billet.

Kingsbury concludes: “At the outset, because this is a safety-critical component, there was a lot of investigation, development and design of processes at DB before they could realise the completed part. What was originally a 10-month lead-time for castings was halved once the WAAM route was taken, but in reality we showed during our reconstruction that the process can be condensed into a matter of days, despite having to work with COVID-19 restrictions.

“If a current manufacturing process involves a lengthy lead-time of hard-to-machine material, be it cast, forged or billet, an economical Gefertec solution may be a viable commercial alternative to subtractive machining.”

The video is available at
https://kingsburyuk.com/3DMP

An engineer-to-order specialist, producing high-end tooling for the aerospace industry, has switched from its former parent company’s made-to-stock business management system, to the WorkPlan MES solution, describing it as the “perfect fit”.

API Design & Build is the new trading name of a company recently acquired by the Ansuka Ltd Group. All employees of the former company, KTL Tooling, have transferred to API, along with its assets and order book, and will be working from the same premises in Burnley, with the same processes and protocols.

Originally, KTL Tooling was part of a US-owned composites manufacturing corporation, and had to use the group-wide ERP system, which general manager Danny Hough says was far from ideal for its bespoke work: “It was a made-to-stock system, highly customised for the composites business, and as we’re a bespoke tooling company it was never a good fit.”

The bulk of the company’s production is high-end aerospace tooling, composite mould tools, assembly fixtures and drill templates, for both military and commercial applications. Customers include BAE Systems, Rolls Royce, Airbus and Boeing.

A lot of KTL’s history involves tooling for exterior panels – what Hough describes as the skin of the aircraft, and structural components such as ribs and wing spars.

“Historically these have been produced from aluminium alloys, but much progress has been made in converting these types of parts into composites,” he says.

The company uses a large Hexagon CMM, operating in an XYZ envelope of 6 x 3 x 2 m, which ensures that the process of guaranteeing a completely accurate final mould tool, is kept in-house.

“We’d never release a tool without a full report to the customer generated by a CMM,” says Hough. “So, if we didn’t have it, we’d have to subcontract the metrology operation out, and there’d be a cost implication. It makes us more competitive to have the CMM in-house; it’s more efficient, cost-effective, and provides full control.”

The CMM is installed on a purpose-built concrete base to reduce vibrations, in a temperature-controlled booth, and is listed on WorkPlan as a resource for capacity planning scheduling. Process times vary depending on the number of points being measured, and Hough says there is often a queue of parts waiting to go into the inspection booth: “WorkPlan gives us full visibility of the work going through the CMM, meaning we can make informed decisions on the implications of certain items queueing.”

A number of API Design & Build’s tools are particularly complex, or large – the company recently tendered on a single carbon component that was almost the full-wing structure for a small aircraft, 13 m long by 1.5 m wide. Many other jobs can involve up to 300 sub-assemblies, so Hough says it is no wonder the company’s old ERP system was causing issues, simply because of the number of processes required to load jobs, and in the way it operated.

“Everything had to be made and transacted through stock, and there was no link between the purchase order we’d placed, which was ultimately going into stock and then being called off by the job,” he explains. “It meant we couldn’t keep track of costs on a project until many of the sub-levels were transacted towards the end. So we genuinely didn’t know if we were making money on a job or not.”

All this changed when API Design & Build invested in WorkPlan.

“As we’re now placing those purchase orders directly against the job, even before the order is committed or delivered to us, we see the cost,” says Hough. “From day one of an order going into WorkPlan we start the manufacturing plan around it. It shows times and operations, which are then multiplied by our rates for each section. We constantly see the cost building up, and it creates a budget for us to work to.”

He describes the software’s purchase-to-order aspect as being “absolutely vital” by providing full control over processing the company’s large tools and sub-assemblies through the shop floor. Each job is entered by the commercial team as an order and, once approved, the planning department adds materials and operations before it goes to production.

The ‘Purchasing and Stock Management’ function is another major benefit, meaning the company’s buyer can easily bring up the material list for a job, then group materials together. He or she can then send everything to the supplier as one purchase order, or a multiple line PO, instead of requiring individual purchase orders.

Hough concludes by saying: “WorkPlan’s flexibility means API Design & Build now has a complete overview of where each project is in real time. Previously we had to draw up project and costing reports on Excel and presentation files.”

For further information www.workplan.com

Moorland Toolmaking in Batley, West Yorkshire has been a user of Hurco machining centres since 1985. The company was first attracted by the supplier’s Ultimax twin-screen control fitted to a KMB1x knee-type mill, on which a program could be created conversationally at one screen while a graphic of the part was automatically generated on the other.

Tool-room manager David Gibson recalls: “Its ease of use was perfect for a tool-making environment, where one-offs are the norm. Some 35 years on, we now operate 10 Hurco three-axis CNC machining centres due to their reliability, good performance and competitive price. All of them feature a similar control, although now the software – WinMax – is Windows-based and much updated in functionality.”

He points in particular to the patented Ultimotion feature with up to 10,000 blocks of dynamic variable look-ahead, which automatically determines the optimal trajectory for the cutter around the workpiece. This feature keeps the programmed feed rate consistent and increases speed when machining around corners, reducing cycle times and improving surface finish. According to Hurco, Ultimotion is better than the smoothing features offered by CADCAM software and improves upon CAM output by providing better machine kinematics.

Even today, with mould tools being considerably more complex than in the past, the tool-making and refurbishment specialist’s operators still write 30% of programs at the control, mainly the simpler ones for producing bolsters and plates. The remainder are prepared offline in Autodesk CAM from customers’ CAD models.

Moorland Toolmaking’s largest Hurco machine is a VMX64Ti with a 1625 x 864 x 762 mm working volume. In March 2020, the toolmaker invested in a slightly smaller BX50i double-column, bridge-type machining centre with a 1350 x 950 x 600 mm envelope for producing tools weighing up to 2.5 tonnes to even higher accuracy.

The BX50i is also used for producing other large components subcontracted out to the firm, a part of the business that currently accounts for 10% of turnover and involves not only milling but also turning, spark erosion, wire erosion and deep-hole drilling. On the tool-making side, which accounts for the other 90%, around two-thirds of output goes to trade moulders serving the automotive industry, and the rest to sectors such as white goods and garden wares.

Moorland Toolmaking’s new, 13-tonne machine represents a step up in accuracy and performance compared with the other prismatic machining equipment in the 16,000 sq ft Batley factory. The HSK-63A spindle speed is 18,000 rpm, up 50% on the previous maximum on site; scales rather than encoders provide feedback of linear axis positions; and thermal compensation measures have been incorporated throughout the machine.

Gibson says: “We saw the BX50i on the Hurco stand at the last MACH show and were impressed at its robust construction. Since the machine was installed, we’ve been holding dimensional tolerances of better than ± 25 µm and we expect that level of precision to be long-term.

“We also find that moulds coming off the machine have a better surface finish which typically needs 30% less polishing,” he adds. “It’s a big saving, especially on large tools that can take up to a month to machine and then a further week to hand finish.”

Gibson says that the higher spindle speed is a further advantage, as smaller diameter cutters can be used so fewer features need to be sparked out, saving the time and cost involved in transferring tools to a die-sink EDM machine and of making copper and graphite electrodes on the other Hurcos. In any case, milled features like deep ribs are quicker and easier to polish than if they are sparked, as the latter operation leaves a hard recast layer.

Despite being a satisfied, long-time Hurco machine user, Moorland Toolmaking considered two bridge-type machining centres offered by other potential sources. What really swung the decision in favour of the incumbent supplier was the generous 950 mm Y-axis travel on the BX50i, 150 mm more than was available on other machines of equivalent footprint (approximately 4.5 sq m).

Consequently, the table will accommodate a 1-m wide workpiece, extending the size of component that can be produced in one hit rather than having to reposition it on the table. The table also extends the size of part that can be tackled in two hits.

“The BX50i was delivered the day the country was locked down due to COVID-19,” says Gibson. “Hurco engineers did a great job installing the machine in difficult circumstances, with some of their staff on furlough. Since then the machine has run faultlessly during the day and we have full confidence in taking advantage of extensive lights-out running for finishing our moulds through the night, which we do frequently.”

For further information www.hurco.co.uk

Mills CNC, the exclusive distributor of Doosan machines in the UK and Ireland, has supplied 17D Ltd, a family-owned miniature railway manufacturing specialist based in Matlock, with a new Doosan vertical machining centre.

The machine – a compact, high-performance DNM 4500 – was installed at 17D’s 2500 sq ft facility in July 2020, and is being used to produce a range of precision components. These parts include live steam locomotive parts (such as valve gears and cylinders), chassis components, axles, bogies, couplings, buffers and wheels. Workpiece materials extend from aluminium, through to cast iron and carbon steel.

17D, which was established in 2010, manufactures a range of scaled working models of locomotives, carriages and wagons for three miniature railway gauge systems: 5”, 7¼” and 10¼”. The company’s locomotives for the 5” gauge are produced to a scale of one-twelfth, at around 6 ft long, rising to approximately 12 ft for the 10¼” gauge.

In addition to designing and manufacturing miniature locomotives and associated rolling stock, the company devotes significant time and resources to producing and supplying high-quality, cost-competitive and quick-turnaround parts and spares. These components are destined for a myriad of UK and internationally-based customers that include hobbyists and private collectors, through to clubs and commercial organisations.

The company has a strong reputation in the markets it serves and is highly regarded. To maintain its market position and competitive edge, 17D invests regularly in plant, equipment, processes and systems. The company’s commitment to continuous improvement, combined with a dramatic and sudden upsurge in demand for its machined parts, were the driving forces behind 17D’s new DNM 4500 machine-tool investment.

Explains partner Tristan Dengate: “Business had been growing incrementally, but the onset of the COVID-19 pandemic resulted in a sharp and dramatic increase in demand from hobbyists who, having been furloughed as part of the lockdown, had time on their hands.

“This increase in demand was putting a strain on our existing machine tools so, to ensure we could meet customer expectations, we made the decision to strengthen our capabilities and invest.”

17D has a variety of CNC and manual machines at its disposal and, in November 2019, further strengthened its turning operations by investing in a pre-owned 51 mm bar capacity Doosan Lynx 220LM lathe equipped with 6” chuck, C axis and driven tools.

“The arrival of the Lynx lathe had an immediate and positive effect, helping us to reduce part cycle times, eliminate production bottlenecks and improve lead time fulfilment,” explains Dengate. “Although the machine is a few years old, it still delivers exceptional performance and hasn’t missed a beat since installation.”

The machine’s arrival and subsequent performance also ‘converted’ 17D into becoming advocates of Doosan machine tools.

“The increase in demand for machined parts, which started at the onset of the pandemic in April, was putting pressure on our milling resources,” says Dengate. “We needed additional milling capacity and capabilities, and we needed them fast. Our experience with the Lynx 220LM helped narrow down our choice: put simply, we wanted a Doosan.”

17D drew up a list of key requirements, investigated the market and approached Mills CNC.

“We needed a versatile, high-performance machining centre – one that could deliver accuracy and high metal-removal rates, combined with an ability to produce intricate part details and features, and achieve super-fine surface finishes,” states Dengate.

To help reduce part cycle times, the machine also needed the ability to cope with high speeds and feeds, and aggressive depths of cut. The company had narrowed down its choice to a DNM 4500 machining centre and, with funding in place via an EU grant, placed the machine order with Mills CNC.

Says Dengate: “We ordered the machine on a Monday and it was delivered and installed by the end of that week.”

The DNM 4500 is a high-speed, rigid and versatile three-axis vertical machining centre that is suitable for a range of applications. Standard features include a large working envelope (800 x 450 x 510 mm), a direct-coupled spindle (18.5 kW/8000 rpm), roller LM guideways and an on-board thermal error compensation system.

Among further features are fast rapid-traverse rates (36/26/30 m/min in the X, Y and Z axes respectively), a large work table (1000 x 450 mm with 600 kg maximum table load) and a 30-position ATC. The machine supplied to 17D was equipped with a Fanuc i control, but it can also be specified with either a Siemens 828D or Heidenhain TNC 620 CNC.

Concludes Dengate: “The DNM 4500 is a great addition to our operation. We’re confident that the machine will be more than instrumental in helping us to further grow our business, not just with our miniature railway customers, but with customers from other sectors looking for a proven, high-quality subcontract machining specialist.”

For further information www.millscnc.co.uk

Established in 1989, Mildenhall-based subcontractor CTPE focuses on the medium to large volume production of high-precision components for the scientific, medical, electronics and defence sectors.

The company uses a number of three- to five-axis vertical machining centres, as well as fixed- and sliding-head CNC lathes.

To expand its prismatic machining capacity, in July 2020 CTPE invested in its first-ever horizontal machining centre, a four-axis Averex HS-450i with nominal half-metre cube working volume from Whitehouse Machine Tools, the sole sales agent for the Taiwanese HMC manufacturer in the UK and Ireland.

What prompted the purchase of the twin-pallet, 40-taper machine was an uplift from 150 to 350 per week of a particular 6061 aluminium, two-part enclosure. The enclosure is needed by CTPE’s largest customer, a medical sector OEM, for the production of critical care diagnostic equipment.

There is no problem completely machining the required quantity of covers three at a time in two hits on a Japanese-built Brother Speedio S1000X1 30-taper VMC, installed at Mildenhall last April by Whitehouse Machine Tools. Neither is there an issue completing Op2 on the matching housing using the same machine, which has now been fitted with an angle head to make the cycle even faster.
However, Op1 on the housing was proving too time-consuming on a three-axis VMC to meet the increased order level and was causing a permanent bottleneck, despite the running hours having been extended from 10 to 14 per day.

Alex Taylor, director of CTPE and son of the founder, Chris, decided that an HMC would best suit the higher production volume. The second pallet allows the next parts to be fixtured while the previous parts are being machined – automatic pallet change takes just five seconds. Dual augers remove chips that have fallen from a cube fixture, so there is no manual intervention except to empty the swarf bin after every couple of pallet changes.

In contrast, the spindle on the fixed-table VMC was idle for 25 minutes after each cycle for accumulated swarf to be cleared and the next parts clamped for machining. A further problem was that the re-cutting of chips which collected within the component risked damaging the solid-carbide tools.

An HMC eliminates that difficulty and is more robustly built than a VMC so vibration is lower, meaning that cutters last longer. The most significant benefit, however, is that four aluminium billets can be fixtured on a cube for Op1, so 24 housings are machined in a cycle time of 160 minutes. Formerly, on the VMC, only two billets could be fixtured for machining a total of 12 components and the program ran for 135 minutes. The figures equate to a production time saving of 40%, considerably reducing manufacturing cost per part for this operation, particularly as there is now minimal operator intervention.

Three potential HMC suppliers were reviewed by Alex and Chris before they made their decision. The Averex machine was chosen as it offered high quality at an affordable price and, unusually, the possibility to retrofit a pallet pool that adds a further four pallets to the existing two, making a total of six. Its tool magazine is also extendable from 80 through 120 to 220 pockets.

“The flexibility of being able to expand the machining cell on-site at an affordable price was very attractive,” says Alex. “We will almost certainly opt to do it in the next couple of years and take advantage of unattended machining to lower piece part cost when producing anything from large batches through small-lot multi-part runs to ones and twos. The other advantage of this route to automation is that it avoids the expense of buying another machine and saves space on the shop floor.

“We favoured the build quality of this 13-tonne machine,” he adds. “Although assembled in Taiwan, it includes thermal control of ball-screw nuts, thrust bearings, Y-axis servo mounting and spindle cartridge. The machine has hand-scraped surfaces for mounting the ball-screw bearing blocks and roller bearing slide ways, and it incorporates Japanese-made components, including the BIG Plus spindle, ball screws, heavy-duty roller guideways, rotary table and the tapered cones for pallet location.”

CTPE’s new HS-450i is also fast. The machine has a 15,000 rpm/22 kW direct-drive spindle, one-second servo-driven tool change, and 1g linear acceleration to 60 m/min cutting feed around the 640 x 610 x 680 mm working volume, all of which ensure minimal idle times. Maximum workpiece size is 750 mm diameter by 1000 mm high, while control is via a Fanuc 31i Nano CNC.

Whitehouse Machine Tools’ applications engineering department helped CTPE to configure the machine to suit the subcontractor’s requirements, including advising on the work holding and modifying and improving the Op1 part program that previously ran on the VMC. The HMC was therefore ready to enter full production within a few days of arrival.

In August 2020, the supplier was called upon again to convert the Op1 cover program from the Speedio to run on the Averex. This switch gives CTPE the flexibility to execute the first operation on both enclosure parts on the two HMC pallets respectively, while the customer’s call-off rate temporarily decreases before rising again in the winter.

For further information www.wmtcnc.com