Rapid expansion at anodising centre

BCW Treatments in Burnley is an aluminium anodising facility that opened in early 2015 to provide a full service to companies using the subcontract machining services of BCW Manufacturing Group’s machine shops on the same industrial estate. Anodising is carried out in a Galvatek automated finishing line supplied by Turbex, which was deemed to be the best all-round package of three alternatives considered. Currently, an average of 2600 sq m of product per week are finished across more than 240 part lines.

One of BCW’s automotive contracts involves the production of aluminium components, mainly from A365 castings, 6060 extrusion, superplastic 5083, and 5754 sheet for a premium automotive customer in the UK specialising in manufacturing luxury sports cars and grand tourers.
More recently, the subcontractor has received further business from another prestigious UK automotive customer that produces high performance 4×4 and special operations vehicles. The work will start at the end of 2018 and entail the installation in an adjacent factory of a line for passivating components as a corrosion-resistant pre-treatment.
Enquiries have also been received for finishing lightweight components for aircraft, such as cabin seating, and for electric cars, hybrids, amphibious vehicles and trucks. Consequently, by the end of the decade, the firm is destined to become a major force in component finishing in the north of England.
Dr Andrew Wilson, managing director of BCW Treatments, says: “Although more than a century old, modern anodising is an exacting discipline requiring extremely close control to achieve the highest quality and, even more importantly, the correct film properties.

“Some manufacturers’ car parts are adhered rather than welded, and a nominal thickness of the anodic layer of 2-10 µm is required, above which there is a risk of components pulling apart under stress. A tolerance band of 4-6 µm is achieved using the Turbex line, so precise is the process.”
An ERP system drives the finishing process in Burnley, raising each manufacturing order and triggering the issue of material. The line’s control system learns which aluminium products are mounted on which universal or part-specific jig by scanning the manufacturing order. Once the part number is known, the correct program is automatically selected.
There are four load/unload stations at one end of the line, where components are loaded on to flight bars that progress to a buffer station from where they are picked up by one of two overhead transporters and dipped into 15 tanks sequentially. Up to five jobs can be processed simultaneously in the line.
Automatic dosing stations are provided for metered dosing of chemicals into several of the tanks, the quantity being worked out automatically according to the amount of surface area to be anodised on each flight bar. The working environment is clean and fume-free, as each tank is hermetically sealed and the lid is not opened until a transporter is directly above it. Positive pressure pulls the fumes through the handling system and extracts them to a scrubbing unit.
After processing, flight bars are returned to four load/unload stations adjacent to the loading area and the test pieces are taken away for analysis, which includes pull and shear tests after adhesive has been applied. Following each successful test, the ERP system is advised that the components are ready to deliver to the customer.
As a conveyor is not involved in transporting flight bars around the system, the anodising process starts in the centre of the line and progresses away from the load/unload stations. Alkaline degreasing takes up to one hour in the first tank for the most soiled castings and the solution is rinsed off in water in the next two tanks, the water being recycled between the second and third stage.

Tank 4 is a chemical etch using sodium hydroxide to remove pre-existing aluminium oxide from the surface of components. Immersion time is controlled to avoid unduly changing of the geometry of the components. It also precludes the need to plug holes, resulting in a cost saving and eliminating the risk of parts being returned by the customer if plugs are inadvertently left in at the time of delivery.
An eco-rinse cycle in water is performed in the next three tanks, again with recycling between the stages. The following process, which takes place at the far end of the line in tank 8, is the removal in a mix of nitric acid and hydrofluoric acid of alloying elements on the surface of components, especially of castings, that remain after chemical etching. Two further eco-rinse immersions in tanks 9 and 10 bring the pre-treatment to a close, by which time the components have travelled back past the centre tank towards the load/unload stations.
The actual anodising stage of the process is in tank 11, which contains sulphuric acid, and lasts between eight and 10 minutes, during which time a nominal 4-6 µm film thickness is deposited. An ecological feature of the equipment is continuous dosing of the acid, instead of recycling the fluid when the aluminium content reaches say 20 g/l. Avoidance of waste is made possible by employing a pump to recirculate the fluid through a retardation unit, where the aluminium is filtered out.
A clean rinse in three successive tanks containing deionised water, which is produced locally in the line, ends with an ultra-clean rinse to ensure that conductivity requirements are met.
The last stage, prior to the flight bar being taken back to the unload station, is hydrothermal sealing at 96°C in a proprietary chemical blend. Reserved for high-end applications and involving 30 µm particulate filtration, the process seals microscopically small pores created on the surface of components as a result of dielectric breakdown during anodising.
For further information www.turbex.co.uk

Probes automate metrology equipment production

The production of hand-held measuring equipment often means large batch runs and high demands on product accuracy. In this context, the selected manufacturing technology is faced with the challenging task of working at speed and with a high degree of precision. With this in mind, the solution chosen by Helios-Preisser in Germany is aided by Blum touch probes, which are used in the company’s machining centres for integrating continuous measurements into the process.

In 2008, Helios-Preisser, a manufacturer of hand-held measuring equipment for professional use, became aware that the capacity of its three machining centres was no longer sufficient. The company was operating around the clock in three shifts to manufacture its micrometers, vernier calipers, dial gauges, and marking and measuring instruments. Due to its positive experience with the company’s existing machine tools, Gammertingen-based Helios-Preisser opted to continue relying on machine tools from Heller fitted with Blum Novotest measuring systems.
A 14-m long pallet magazine connects the company’s machining centres, which are supplied with clamped workpieces by a robot. Helios-Preisser employees already had many years of positive experience with Blum touch probes in the company’s previous Heller machining centres, which still operate with great reliability. As a result, a new Heller four-axis machine was also specified with a Blum measuring probe.
Only the company’s five-axis machining centre used a probe from another manufacturer, a fact that did not meet with great approval at Helios-Preisser. “Where possible, I endeavour to make regional purchases. In Blum, we have found a partner that can offer us high-quality products and corresponding service from a close distance – we like to have just one point of contact,” emphasises CEO Siegfried Lorch. “In addition, we have been extremely satisfied with the Blum touch probes for many years.” As a result, a Blum probe has since been fitted to the five-axis machining centre.

With 120 employees, Helios-Preisser uses TC50 and TC60 touch probes from Blum. The former transmit data via infrared, the latter via radio technology. Each touch probe is fitted on a tool holder and can be substituted if necessary in order to execute measuring tasks before, during and after machining. The infrared system can be used when line-of-sight can be guaranteed between the touch probe and receiver. A measuring system with radio transmission is installed on the five-axis machining centre, which reliably transmits the signals from the touch probe to the receiver – even when the line-of-sight is disrupted by the large swivel head.
Blum touch probes are used for a whole range of tasks at Helios-Preisser. For example, they check whether the workpieces are clamped correctly prior to the commencement of machining. “We also use the probe to measure the result of machining,” says Tobias Weber, foreman of the milling shop. “After casting, the dimensions of cast blanks are often very different, which is why, prior to machining, the position of the blank is captured using the probe, with compensation values for the NC program transmitted to the machine controller. Thanks to the Blum touch probes, we have been able to reduce the rejection rate for these components from 10% to 1-2%.”
Another example is the tailstocks of the company’s bench metrology centres. Here, a hole must be positioned accurately to 0.01 mm for a channel on the same part. Previously, there had always been fluctuations, often due to the temperature response of the machine. If the dimension was correct in the morning with a cold machine and shop floor, by noon, with a hot machine and warm weather, the dimension would be out of tolerance. The channel is now machined and measured before finally being drilled using the measurement data. This strategy enables the desired precision to be reliably achieved regardless of temperature.

The large volumes manufactured in Gammertingen require short cycle times, so measurement must not take too long. Blum touch probes are designed for maximum measuring speed and are not sensitive to coolant, which is simply pushed away by the high measuring pressure. Measurements can also be taken directly after machining.
“The touch probe is moved at a top speed of 60 m/min until close to the component; touching then takes place at up to 3 m/min – so not much time is lost,” reports Weber. “After machining, we check almost all fits using the Blum touch probe.
“Our manufacturing process has now become so precise that we no longer have to grind many parts. Previously, numerous components were milled with an allowance and then ground to the finished size in order to achieve the required precision for our measuring equipment.”
If a machine determines that a tolerance has not been held, the pallet is automatically removed and placed in the company’s pallet store with an inspection record. The next morning it can be inspected to determine where the fault is and, in the meantime, the machine can continue to process further pallets.
With respect to unmanned production, the touch probes from Blum have completely proven themselves at Helios-Preisser. “Overnight, and often for parts of the weekend, the machines run unmanned,” confirms Weber. “We only operate one shift, but we produce more than we did previously in three shifts.”
Lorch concludes: “The systems run reliably during unmanned operation, which relieves the pressure on us and makes it possible to manufacture the required volumes without needing a night shift. Blum probes are essential to unmanned operations, especially as we are also very satisfied with the service offered by the company.”
For further information www.blum-novotest.com

RD Castings installs two more Brother machines

Zinc and aluminium high-pressure die-casting specialist, RD Castings, has used Japanese-built, high-speed, twin-pallet machining centres from Brother since 1989, and currently has nine of them adding value to its products in two machine shops in Mildenhall. Since the mid-90s, the 30-taper machines have replaced manual milling, drilling and tapping, which was both labour intensive and subject to quality variation.

Running the company are siblings Anthony and Michael Pateman, who were interested when Brother’s UK agent, Whitehouse Machine Tools, suggested they see a demonstration of the new ISO control with 12” colour LCD screen, the CNC-C00, a significantly faster and more user-friendly CNC system fitted to its latest machines.
After they visited the agent’s Kenilworth showroom and technical centre, they came away not only with up-to-date information on the new control’s capabilities, but also having ordered another Brother machining centre, a Speedio R650X1 with Nikken rotary 4th axis. It was not their intention before the visit, but the machine was so productive and such a good fit for RD Castings’ needs that they placed the order on the day and invested in a second identical model within six months.
Numerous facets make the machine particularly applicable to machining light castings, one being its outstanding speed. Workpiece changeover is completed entirely within the 3.4-second rotation of the twin-pallet ‘Quick Table’, while the 21-pocket magazine’s 0.9 second tool-change time, 50 m/min rapids in X Y and Z, and rotation of the 4th CNC axis, are carried out simultaneously.
The first tool is ready to cut the next component immediately it arrives in the machining area, and little time is wasted on each subsequent exchange of the cutter due to the rapid tool-to-tool time and spindle acceleration from zero to 16,000 rpm in 150 ms, with similarly fast stop time.
“The speed of tool change on the R650X1 mirrors that of our Brother 324N and R2A models, where the tool carousel encircles and travels with the spindle, which does not have to move away to pick up a new cutter as on the Brother TC32A and 32B machining centres that we also have on-site,” explains Michael Pateman. “It results in very high productivity that is enhanced by faster processing of existing programs in the new CNC-C00 control. For example, we recently reduced a 3.5-minute cycle by 20 seconds with no change to the original program. If we are machining say 20,000-off parts annually, the saving runs into thousands of pounds.”

Anthony Pateman pointed out another advantage of the R650X1; the generous axis travels of 650 x 400 x 305 mm in X, Y and Z. The table accepts RD Castings’ 500 x 350 mm base plates on the trunnion fitted to both machines, allowing multiple components to be fixtured for two- and three-axis machining, relieving the load on the 324Ns and R2As, which are always filled with work.
He adds: “There is a trend towards larger castings these days and we have just installed a 500-tonne casting machine to meet the requirement. In order to perform machining, the ability of the R650X1 to swing our 400 mm diameter parts in the rotary axis means that we are often able to finish these bigger castings in one hit and save on a second set-up operation, which hugely decreases the cost of production.”
To underline this comment, he points to a casting of about the size that used to need a second operation but is now machined in one four-axis process, saving 70p per part.
Simon Hale, CNC machine shop manager, stated that the productivity of another part – an aluminium die cast housing for the rail industry – has been nearly doubled using the larger machine compared with the other Brother models featuring similar tool carousels. Some 17 castings per hour were drilled and tapped using 12 tools on the latter machines, whereas with a trunnion fixture on an R650X1, 32 parts per hour come off the machine after each pallet rotation. Furthermore, just eight tools are needed.
The increase in output is partly because, by routing coolant at the uprated 30-bar pressure on RD Castings’ latest machines through an indexable-insert drill rather than employing a twist drill, it is possible to produce larger holes above 18 mm diameter in one spindle movement, rather than having to spot and then peck drill the holes multiple times.
Michael Pateman asserts that manufacturing costs are increasing in Asia while the lower pre-Brexit value of the pound is helping UK competitiveness.

He sums up: “By employing ultra-high speed machining techniques on 30-taper rather than 40-taper machines, with extensive use of PCD inserts clamped in dynamically balanced tool holders, the cost of producing a casting is now about the same in Mildenhall as it is in China – and we are winning back business as a result.
“The latest Brother Speedios with their larger working envelope have added considerable versatility to our shop floor, as they can economically machine anything from the simplest, smallest casting up to the largest and most complex. Productivity is also up due to the faster control and by allowing more flexible production planning.
“All of our Brother machines work flat out eight hours a day and their speed, accuracy and reliability are fantastic. Coupled with the high level of support from Whitehouse, it has been an unbeatable package for us.”
For further information www.wmtcnc.com

Doosan machine makes sound investment

Mills CNC, the sole distributor of Doosan machine tools in the UK and Ireland, has recently supplied a new Doosan VC630 5AX five-axis machining centre, equipped with a Heidenhain control, to hi-fi design and manufacturing specialist, Linn Products.
The machine has been installed at the company’s factory in Glasgow and is being used to produce a range of precision parts for Linn’s music systems. These components include machined-from-solid aluminium enclosures that comprise a lid and base for the company’s range-topping Klimax systems.

Prior to investing in the VC630 5AX, the machining of these enclosures was subcontracted, and while this situation was satisfactory it had its drawbacks and was always considered to be temporary. The arrangement was superseded by Linn’s desire to become more self-sufficient and vertically integrated, with the decision taken to commence machining the Klimax metalwork in-house.
Explains Fraser Crown, Linn Products’ operations architect: “The more of our manufacturing processes we can bring in-house, the better able we are to manage, control, optimise and ultimately improve them. Linn does not mass produce products; every product we manufacture is built to order. This can potentially cause scheduling and delivery fulfilment issues when relying on subcontractors who, quite naturally, prefer to handle larger and more predictable batch-type work.
“As part of our commitment to continuous improvement, it was a natural progression for us to look at bringing machining processes in-house, such as those employed to manufacture our enclosures,” he adds.
To enable Linn to manufacture all its Klimax metalwork in-house, the company needed to acquire additional machining capability. Linn is certainly no stranger to CNC machining and, some years earlier invested in a three-axis Doosan DNM650 vertical machining centre from Mills to manufacture a range of parts. Since being installed, the machine, according to Crown, “hasn’t missed a beat” and is working near peak production.
With regard to its next investment, three key questions initially confronted Linn: what type of machine tool would best produce the enclosures; which manufacturer would be able to supply the machine, and what support could they provide; and how quickly could Linn develop a reliable and repeatable machining process?

Linn’s ‘milled from solid’ enclosures feature in both the Klimax DS and Klimax DSM streamers, the Klimax amplifier, Klimax Exakt, and the Radikal power supply for the Klimax LP12 turntable. The enclosures are machined (internally and externally) from individual solid aluminium billets. Internally machined features include a number of separate and isolated chambers (divided by walls) where audio/electronic circuitry and power supply units are housed separately. The back of the enclosures contain a variation of machined holes for output and input connectors and ports.
All exterior faces of the enclosure are machined to a mirror-like finish, with the top and bottom being finished using a large diameter fly-cutter (cutting) tool that is able to face mill the entire surface in one pass to produce a uniform finish. “Surface finish imperfections, however small, are not acceptable as they would show up after the enclosures have been anodised,” states Crown.
To meet Linn’s manufacturing imperatives and quality standards, the company researched the market to identify the types of machining centres available.
“We wanted the machine to meet our immediate and future requirements, which is why we looked at large-capacity five-axis vertical and horizontal machining centres,” says Crown. “Although we do not machine parts in high volumes, flexibility, reduced set-up and cycle times, which are key advantages of five-axis machine tool technology, are important to us.
“We ultimately decided on a vertical machine with full five-axis simultaneous machining capability because it enables each side of the billet to be produced continuously without the need to remount the job,” he continues. “As a result, we negate any incremental dimensional inaccuracies and poor finish quality. We believe it will provide us with far more flexibility going forward. Furthermore, for certain machined features, most notably where the front panel display is located on the enclosure lid, we knew that using five-axis simultaneous machining capabilities would enable features to be machined reliably and accurately. In reality, the seamless five-axis movement which creates the ‘Klimax smile’ is dimensionally perfect, has a faultless finish and it is a joy to watch being machined.”

Linn already had a good relationship with Mills CNC following its investment in the Doosan DNM650 vertical machining centre five years ago. Discussing its latest requirements with Mills’ sales and technical staff, Linn decided to invest in a large-capacity VC630 5AX machine with Heidenhain CNC.
Owning a large-capacity machine means that Linn can produce a wide range of components – big and small. The decision to opt for the Heidenhain control (favoured by many mould tool and die makers) was taken for its ease of use and on-board functionality – especially its ability to help machine complex 3D surfaces and curved contours. The VC 630 5AX has a large working envelope (650 x 765 x 520 mm in XYZ), and a 32 kW/12,000 rpm direct-drive spindle.
Bringing any machining process in-house means there is an inevitable learning curve. Add to that the need to get to grips with the Heidenhain control (Linn’s Doosan DNM650 machine is equipped with a Fanuc control), and the curve becomes naturally steeper. However, the skill and experience of Linn’s operators and programmers, combined with technical and applications support (including training) provided by Mills CNC, has helped the company develop a secure and reliable machining process for its enclosures. Further refinement to fully optimise the process is ongoing and part and parcel of Linn’s continuous improvement ethos.
Concludes Crown: “The new machine is working well and we have found that having five-axis machining capability in-house makes us more productive and flexible. We are also able to respond, from a machining perspective, much more efficiently and effectively with regard to product design upgrades and modifications.”
For further information www.millscnc.co.uk

Gantry machining centre moulds future at TRP

Consistency of manufacturing cycles enabling extended unmanned running, while maintaining accuracy and precise levels of surface finish and repeatability, are critical to elastomeric rubber seal, gasket and moulding specialist TRP Sealing Systems’ production at its Hereford headquarters. The company has been able to maintain high levels of overall productivity during the past three years following the establishment of its own toolroom and the installation of a Wele large bridge-type (LB series) LB421 gantry machining centre.

Supplied by 2D CNC Machinery, the investment was critical in order to bring often very complex mould production and refurbishment operations in-house as front line support to its seal moulding and gasket manufacturing. Here, rubber mouldings weighing up to 5 kg are produced in ‘made-to-order’ batches of up to 250,000 a year from mould tools that can vary in size between 300 mm square to 3900 x 1700 mm. These variations in mould sizes are all now machined complete in a single operation on the Wele machining centre.
“We design and develop each mould to suit the material specification, which can also include cross-blended types, direct from customer supplied 3D models or drawings of the gasket or seal they require,” says quality manager Jo Privett. “This can be extremely demanding and often draws on our 35 years of production expertise where finished component thickness can vary between just 2 and 20 mm. However, there are added complexities due to geometry applied to the form, special radii and the transition between areas into both the bottom and top halves of each mould.”
Clearly, machining accuracy and especially consistency is important to TRP. While the final moulded component can be to a tolerance of ±0.15 mm, to ensure maximum production life from the mould, process sizes are normally maintained very close to bottom of the designed tolerance band, which can mean within 0.08 mm. However, even more demanding is that tolerances of form in the mould can be as tight as 0.03 mm.
Here, the accuracy and repeatability of the Wele LB421 has proven critical and is now well-proven, even when the 4000 x 2000 mm machine table is fully loaded with mould plates.

The mould plates are retained in place using magnetic pads, and tolerances have to be maintained across the whole table area. This is aided by the 15-tonne capacity table design that incorporates triple sets of heavy linear roller guideways on the X axis; an advantage for stable machining against most machines of this type, which have only two.
Recently, following almost three years of continuous production, as part of the company’s regular quality audit, it was decided to lightly re-skim the 1225 magnetic pads which are fitted to the table. These provide a datum and hold each mould in place, giving total access to the top surface of the mould plate and eliminating the use of clamps. When completed, the inspection report qualified that the total area of the table had be machined within 10 µm.
Originally formed in 1981, TRP Sealing Systems has progressively grown to become a global business while still maintaining 80% of sales within Europe. The company has set up manufacturing operations under control from Hereford in China and India to serve the Asian and Middle East markets, plus a facility in Romania. As a private company TRP employs some 750 people worldwide, with 300 based in the UK where all design and process engineering takes place. Serving customers in the automotive industry, TRP is also a regular supplier to the electronics, biotechnology, food, medical, chemical, marine, power generation, oil and gas, aerospace and defence sectors.
An important part of the company’s success is its advanced laboratory for compilation of material specifications and seal development, which involves the tailoring of special polymers to suit specific and often ground-breaking applications. This ties in with TRP’s in-house tool design and prototyping service, where the latest rapid-prototyping equipment, including laser and 3D printing, is installed. There is also a facility to produce bonded-metal components.
“The Wele machine is a flagship investment, not only due to the specification that creates the ideal manufacturing and economic production environment, but also because 2D CNC Machinery fully appreciated our needs and has continued to provide high levels of ongoing support as we progressively develop our toolroom operation,” says managing director Simon Children.
The Wele LB421 has axis travels of 4060 mm in X, 2180 mm in Y (2800 mm optional) and 800 mm in Z (up to 1400 mm optional), and each has high accuracy positioning through Heidenhain linear scales. The direct drive spindle motor is powered by a 30 kW motor providing a maximum speed of 15,000 rpm. A 32 tool magazine is standard, and included in the machine specification is a Renishaw OMP60 optical transmission probing system for automatic workpiece measurement. Control is by Fanuc 31iMb with an AICC (1000 bps) data server.
Previously TRP used external UK mould suppliers, but now 99% of production is within the business. With regard to the Wele installation, machine programmer and setter-operator Dean Sletcher explains its versatility as a production solution: “When we have to produce moulds for volume component production, we set the machine table with two mould base plates and a top plate. Each plate in our standard requirement is 22.5 mm thick and produced out of EN8 or P20 material, and can be up to 3900 x 1700 mm in size. Having a complete set of moulds in production on the same table helps to ensure we can maintain our standards uniformly.”
Once set, production is continuous, running unmanned at night and through weekends. Sletcher has the machine’s Fanuc 31i MB control connected to his mobile phone to alert him should the process stop, at which time he returns to the factory to reset and continue the production cycle.
Milling cycles form the majority of production processes using standard carbide cutters between 0.4 mm diameter for profiling and 63 mm diameter for face milling. Mostly, depths-of-cut tend to be around 4 mm. U-drills of 14, 20 and 24 mm diameter are used for producing mould clamping holes.
“Due to the predominance of small tools, we specified the machine with a 30 kW, ISO BT40 taper, and a direct-drive spindle in place of the normal BT50 taper specification,” says Sletcher. “This allows us to effectively machine at speeds up to 15,000 rpm as we perform extensive profiling and surfacing of seal features without the use of form tools. As moulds are compression types and run hot at 160°C, there is no requirement for drilling deep cooling holes.
For further information www.2dcnc.co.uk

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