Globally renowned as a leading designer and manufacturer of high-fidelity sound system equipment, such as turntables, streaming systems, amps and speakers, Linn Products employs approximately 160 people at the company’s impressive Glasgow headquarters. Rather than pursue a business model of planned obsolescence, due to the modular nature of Linn Products’ hardware and software, all of the company’s systems are upgradeable. In addition to the ability to evolve, the enduring quality and longevity of the company’s systems ensures the best sound possible for the lifetime of each product.

Quality permeates every aspect of Linn’s activities. To ensure the build quality of the company’s products – and to guarantee their sound reproduction and clarity – in addition to long lasting performance, the company’s staff perform painstaking inspection routines throughout all stages of manufacture.

In order to reduce the company’s reliance on subcontractors, further increase the autonomous nature of its manufacturing operation and provide even greater control over the quality of its components, Linn Products recently made several investments in advanced machine tools.

These investments included the purchase of a bespoke manufacturing cell from Mills CNC. The fully automated system includes a Doosan DVF 5000 five-axis machine tool and a Fanuc six-axis industrial robot. The impressive new cell now runs unattended overnight and at weekends, and has provided significant productivity gains.

Due to the enhanced accuracy capabilities and the high-yield nature of Linn Products’ new manufacturing plant, Chris O’Brien, director of operations, searched for an advanced CMM that had the ability to keep pace with the company’s increased production of precise components. Following a successful and practical demonstration at Mitutoyo’s East Kilbride showroom, an order was placed for a recently launched Crysta-Apex S series CNC CMM.

Explaining Linn Products’ passionate quality philosophy and the purchase of the Crysta-Apex S, O’Brien says: “Ever since Linn Products was stablished in 1973, we have constantly pushed technology forwards in the pursuit of perfect sound. From our very first product, the iconic Sondek LP12 turntable, we have been at the forefront of audio technology.

“All of our high-fidelity sound systems are assembled by hand at our Glasgow factory, and each one bears the name of the person who made it,” he continues. “Our systems are engineered to extraordinarily tight tolerances. To help ensure the continuing quality of our products and guarantee their prolonged performance, all systems are subject to painstaking inspection and testing at each stage of manufacture. Then, prior to despatch, we thoroughly test every product to ensure that it delivers outstanding performance.

After bringing the machining of many of its previously outsourced components in-house, Linn Products needed to source a highly efficient and accurate means of providing inspection.

“Having considered other options, a demonstration of a Crysta-Apex S at our local Mitutoyo showroom proved that it was the ideal advanced CMM for our demanding needs,” says O’Brien. “As it had the ideal size to accommodate our components, we ordered a Crysta-Apex S544 model with a capacity of 500 x 400 x 400 mm.

“Following our new Mitutoyo CMM’s trouble-free installation, our engineering staff were trained in its operation,” continues O’Brien. “As the CMM’s operating system and software are so logical and intuitive, our staff could soon perform a range of inspection routines. Although, when needed they can request help over the telephone from Mitutoyo’s technical staff. Our Crysta-Apex S series machine is now making a significant contribution to Linn Products’ quality management systems.”

Mitutoyo CMMs come in a wide range of sizes and accuracy classes, enabling them to cover practically all precision 3D measuring applications. A large variety of contact and non-contact probes are available, allowing users to perform a wide range of different measurement routines. Complementing Mitutoyo’s CMM hardware, the company’s powerful, yet easy-to-use analysis software allows the interpretation of all measurement results in the timely manner that is so essential for keeping pace with today’s fast-paced production speeds.

The Crysta-Apex S series of high-accuracy CNC CMMs guarantee a maximum permissible length measurement error of E0,MPE = (1.7+3L/1000) μm [500/700/900 series]. In addition, the CMMs deliver a maximum drive speed of 519 mm/s and a maximum acceleration of 2309 mm/s2, resulting in an increase of almost 100 mm in drive distance per second when compared with general-purpose CNC CMMs.

Designed to deliver high rigidity, Mitutoyo’s Crysta-Apex S series CMMs feature unyielding structures. The Y-axis guide rails, which are attached to one side of the granite surface plates, help the machines to maintain high levels of accuracy over years of use. The CMM’s air bearings are located on the bottom faces of the guide rails; also on the front, rear and upper surfaces of the X-axis slider unit. This arrangement helps to minimise vibration, even during high-speed, high-acceleration movements, and ensure stable linear motion. The high-speed and high-acceleration qualities of Crysta-Apex S CMMs dramatically reduces measuring times, says Mitutoyo.

In addition to being a CMM suitable for use in pristine quality departments, thanks to the use of a temperature compensation system, Crysta-Apex S CMMs are able to guarantee the accuracy of measurement under temperature conditions of 16 to 26°C. The temperature compensation system is based on permanently installed temperature sensors located on each scale, working together with sensors placed on the workpiece.

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A clear statement of intent

Mills CNC, the exclusive distributor of Doosan machine tools in the UK and Ireland, has supplied design, manufacturing and fabrication specialist – D & M Design and Fabrication Ltd – with four new Doosan machines.

The first two machines to arrive were a Puma 2600SY Mk II multi-tasking lathe with sub-spindle and Y-axis capabilities and a large-capacity DNM 6700 vertical machining centre with an integrated Nikken 4th-axis unit. These are now joined by a second DNM 6700 machine and a Lynx 2100A lathe featuring a Hydrafeed short magazine servo-driven barfeed.

The acquisition of four high-performance Doosan machines is a considerable and formidable CNC machining resource and, as was the intention, has helped D&M to augment the range of services it can offer. In addition, the investment has opened up a whole new set of opportunities and a completely new revenue stream (the machining and supply of high-precision, complex parts in small to medium volumes to new customers) that the company is keen to exploit.

D&M is committed to continuous improvement and, over its 11-year history, has made regular and significant investment in its people, plant and equipment – and in its systems and processes.
Says Michael Barratt, co-owner and director: “A constant theme running through all our investment plans is improving our manufacturing capabilities; not just on increasing production capacity. We are always looking to manufacture things better, faster and more economically.”

D&M is first and foremost a fabrication specialist. Prior to creating its own in-house machine shop, the company would subcontract its machining requirements to local companies. The situation was not ideal for a number of reasons.

Explains Dave Mawer, co-owner and director: “Not all customers needed or required their parts to be machined. However, for those that did, some issues – primarily concerning lead time fulfilment – were evident. Our customers like, and respond well, to a single source and single point of contact approach where we are in control of all aspects of the job, with all processes taking place under our roof. Having to outsource machining work meant that we were not in full control. And, if any issues occurred during machining it would, in all likelihood, have a negative impact on delivery times; possibly on part quality/accuracy too.”

The outbreak of the pandemic and its impact on D&M’s suppliers compounded matters, affecting access to high-quality subcontract machining services.

“Covid-19 focused our minds,” recalls Barratt. “We couldn’t guarantee to customers when we’d be able to deliver their parts because we were having difficulty locating subcontract machining resources per se – let alone ones that could meet the delivery times we and our customers required. It got to the stage where the lack of in-house machining services was causing us to lose work. This was the catalyst, and it set things in motion.”

Creating a machine shop from scratch in the middle of the pandemic, while keeping the core fabrication business going, would have been a tall order for many, but not for D&M.
“We tackled the project like every other and broke it down into its constituent parts,” says Mawer. “As there was no space in the existing manufacturing facility, we made the decision to build a brand new, purpose-built and dedicated machine shop on land available to us: adjacent to where our welding and fabrication operations take place.

“We wanted the new machine shop to look and be impressive,” he continues. “Our intention was to create a fully-functional machine shop that would not only be the in-house machining resource for our design and fabrication customers, but become a stand-alone precision machining subcontractor that offers high-quality and competitively priced CNC services to existing and new customers.”

The machine shop facility is 3700 sq ft in size and provides ample room for expansion.

Another key decision confronting the directors was recruiting skilled and experienced members of staff to operate and program the machines, and to run the machine shop.

Says Barratt: “As well as having a good reputation we have strong relationships with manufacturers in the area. Both helped us to attract the right people. We initially recruited two people for the new machine shop, but such has been the growing demand for our services that we are looking to recruit an additional machinist.”

Some companies, when setting up a machine shop from scratch, may start their new venture by acquiring used/pre-owned machines. This was not the case with D&M, which straight out of the gate invested in a large Doosan DNM 6700 machining centre featuring a 4th-axis unit and a Doosan Puma 2600SY II lathe with a sub-spindle, driven tools and an integrated Y axis.
“We decided to invest in new machine tools and set about researching the market to narrow down our choice of machine tool supplier,” states Mawer.

D&M adopted a rigorous and systematic approach. The directors talked to their peers, undertook extensive desk research and visited a number of suppliers to discuss their needs.
Says Barratt: “As we didn’t know the machine tool market, the sales process adopted by the different suppliers was important to us. Out of everyone we spoke to, we responded best to the sales staff from Mills CNC. They took the time to listen and understand what we were trying to achieve: there was no ‘hard sell’ involved. We ultimately invested in two Doosan machines from Mills because we wanted to offer quality machining services and build a reputation based on accuracy, quick turnarounds and competitive pricing.”

With the new building ready and the people and new machines in place, D&M – having already informed customers about its new machine shop – waited in eager anticipation for things to take off. The company did not have to wait long.

“Demand for our machining services from existing customers and a whole tranche of new ones has been exceptional,” says Mawer

So much so, in fact, that within two months of operation the company had virtually exhausted its capacity and ordered an additional two machines – its second DNM 6700 machining centre and a Lynx 2100 lathe with integrated barfeed.

Concludes Barratt: “There is no denying that it’s been an eventful time. From a standing start we now have a well-resourced and successfully operating machine shop. The decision to invest in advanced and multi-tasking Doosan machine tools has paid off. We are able to achieve impressive part cycle times and machine high-precision, complex components in single set ups. And we are able to meet tight delivery deadlines.”

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Stainless steel shotgun is start-up’s first project

Clay shooting is a popular global activity as well as being one of the 42 Olympic disciplines and, as in any sport, the quality of the equipment is paramount. One enthusiast who is determined to manufacture a range of affordable yet high-quality shotguns and bring them within the financial reach of a wider market is Christopher Iaciofano, who set up RIMD in Fleet Marsden, near Aylesbury, in January 2021.

To produce metal parts for the guns, he has installed a Hurco five-axis CNC machining centre and a Dean Smith and Grace (DSG) 6.5-tonne manual lathe that was specially adapted in-house to enable the highly accurate deep-hole drilling of barrels. The first gun will be marketed as the ‘Chiltern’ later this year through an established manufacturer of traditional hand-crafted shotguns.

The rationale for establishing the venture was Iaciofano’s identification of a gap in the engineering marketplace for a company capable of undertaking the functions needed to launch a new product – research, innovation, manufacturing and development (RIMD). The company says it is able to remove some or all of these elements from a customer’s activities and inject a high level of expertise to achieve a superior end product and accelerate time-to-market. There is a special focus on R&D, which is generally the first area to be neglected in favour of day-to-day activities.

Having gained a BSc in mechanical engineering at Bournemouth University, Iaciofano subsequently worked in the oil and gas sector. He was responsible for designing and manufacturing chemical injection equipment capable of withstanding pressures up to 3000 bar utilising a diverse range of exotic materials, which he became expert in machining.

With that knowledge and having an antipathy towards the mild steel parts on his own shotgun rusting, he decided to design and construct a new version from a special blend of PH17-4 hardened stainless steel. This material is particularly difficult to machine, as it is sticky and requires very sharp cutters, yet has a hardness of 38 HRc and above, which tends to wear the tooling quickly. To make matters worse, very small drills are involved in production, as well as milling cutters down to 0.6 mm in diameter.

Hurco offers two main styles of integrated five-axis vertical machining centre, one with a swivelling trunnion supporting a rotary table, and the other with a B-axis spindle and a horizontal rotary table. Neither design was suitable for RIMD, as it would have been impossible to mill the outside of the one-piece shotgun barrel from a 76 mm diameter, 900 mm long billet without buying an excessively large machine.

The answer was to purchase a Hurco VMX42HSi three-axis VMC equipped with a Kitagawa two-axis compound rotary table positioned at the far right-hand side of the machining area. The latter enables the 900 mm barrel billet, which has already had the two bores roughed and finished on the DSG, to be fixtured by picking up on the bores and rotated. It is then possible to mill the entire outside along its length using the VMC’s 1000 mm X axis. In the process, the barrel reduces to about 1.2 mm wall thickness and 1.4 kg, just 5% of the original billet weight of 28 kg.

The machine is equipped with an 18,000 rpm spindle, so very high surface finishes are possible. Linear scales provide ultra-precise feedback of the orthogonal axis positions to the control. In addition, the table feeds its rotary positions back to the proprietary Hurco WinMax CNC, which is capable of controlling all five axis motions simultaneously. Many such programs help produce components for the Chiltern gun, all of which come off the Hurco in one operation to within 5 µm dimensional accuracy on all critical features.

Most of the remaining cycles are 3+2, with the rotary axes positioned and clamped to present the part to the spindle in convenient orientations, thus maximising machining efficiency. All programming takes place using either SolidCAM or GibbsCAM, rather than directly at the WinMax control, although the latter conversational software remains a convenient option for future projects.

Iaciofano concludes: “Our immediate business plan is to complete the shotgun venture through to series production and take on another couple of projects. They will be either the cradle-to-grave development of a new product of our own design, or manufacturing support for a third party’s project to relieve them of some of their work.

“It is also a target to take on smaller projects from individuals with great ideas but without the means to bring them to market, and to offer free development and manufacturing for a share of the company,” he adds. “Our intention is to more than double our factory space to 4500 sq ft by expanding into an adjacent unit.”

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Lockheed Martin has extended its use of MakerBot 3D printers to produce parts and designs for its upcoming space projects. MakerBot 3D printers have been in use for about five years, providing easily accessible 3D printing for Lockheed Martin’s team of engineers in a host of projects.

Lockheed Martin is a global aerospace and defence company, with a mission to connect, protect and explore. The company focuses on next-generation and generation-after-next technologies. In alliance with General Motors, Lockheed Martin is developing a new fully-autonomous lunar rover that could find use in NASA’s Artemis programme. This is a team that pays homage to the original Apollo rover, the development of which also involved GM.

Some early design and development elements of the rover’s autonomy system take place at Lockheed Martin’s state-of-the art R&D facility in Palo Alto, California. The Advanced Technology Center (ATC) is well-equipped with a variety of cutting-edge technologies, including a lab full of 3D printers.

The latest addition to the ATC’s lab is the MakerBot Method X 3D printing platform. With Method X, the team can print parts in materials like nylon, carbon fibre and ABS, providing the performance needed for accurate testing. Moreover, thanks to Method X’s heated chamber, Makerbot says the parts are dimensionally accurate without any variable warping that often comes with a typical desktop 3D printer.

“At ATC, we have multiple MakerBot printers that help with quick turnaround times,” says Aaron Christian, senior mechanical engineer, Lockheed Martin Space. “I will design a part, print it, and have it in my hand just hours later. This allows me to test the 3D-printed part, identify weak points, adjust the model, send it back to print overnight, and have the next iteration in the morning. 3D printing lets me do fast and iterative design, reducing wait times for a part from weeks to hours.”

Lockheed Martin engineers are testing a multitude of applications designed for the lunar rover. Christian and his teammates are using Method X to print a number of parts for prototyping and proof of concept for the rover project, including embedded systems housings, sensor mounts and other custom components.
“The MakerBot METHOD X produces dimensionally tolerant parts right out of the box – and for all sorts of projects,” says Christian. “You can print multiple parts that mate together.”

Many of these components are printed in MakerBot ABS and designed to withstand desert heat, UV exposure, moisture and other environmental conditions. In combination with Stratasys SR-30 soluble supports, parts printed using MakerBot ABS provide a smoother surface finish compared with breakaway supports. Printing with dissolvable supports also enables more organic shapes that would have been otherwise impossible to produce through traditional machining. In short, 3D printing encourages engineers to think outside of the box more than ever before.

“We’re in the very early stages of development and the rover we have at ATC is a testbed that we designed and developed in-house,” explains Christian. “This affordable, modular testbed facilitates quick changes using 3D printing to modify the design for other applications, whether it be military, search and rescue, nuclear applications, or any extreme environment autonomy needs.”

3D printing lets the team test parts affordably, iteratively and modularly. One of the components printed for the rover was a mount for a LIDAR, a sensor that can help determine the proximity of objects around it. Broadly used in self-driving vehicles, Lockheed Martin uses LIDAR in many of its autonomy projects. The mount was designed to sit on the rover, a completely modular robot system, so it was printed in ABS to handle more extreme conditions than typical PLA. The mount also allows engineers to continuously swap out the LIDAR with different sensors, such as a stereo camera, direction antenna, RGB camera or rangefinder. It has a complex organic shape that can be difficult to achieve via traditional machining. The mount also has generous access to ensure proper airflow and keep the part cool and temperature-regulated on the robots.

An embedded electronics housing is designed to go inside the rover, or in other robots at the ATC. Although the housing was printed in PLA, due to its hexagonal shape it offers robust strength. This design also lends itself well to the open airflow needed to cool the system, while still protecting the device.

In addition to printing prototypes, Lockheed Martin is using 3D printing for production parts that will go into various space-going platforms.

“A big advantage for testing and flying 3D-printed parts for space applications is that it simplifies the design,” says Christian. “You can create more complex shapes, and it reduces the number of fasteners and parts needed, which is a huge cost saving because that’s one less part that has to be tested or assembled. This also opens up for future in-situ assembly in space. You have designed, printed and tested the part on Earth. Now you know that, in the future, you can 3D-print the same part in space because you have shown that the material and part work there.”

Manufacturing in space is expensive but appealing for future applications and missions. Now, bulk materials can be flown into space to 3D-print multiple parts and structures, rather than flying each component out individually. Combining that with a digital inventory of part files, 3D printing in space reduces costs by eliminating the need for storage and multiple trips.

“The digital inventory concept helps push our digital transformation forward – you have digital designs that you can ship up, where you just print the parts and have them assembled on location,” concludes Christian.

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Turning centre helps subcontractor blossom

After winning a prestigious power generation project to turn critical stainless steel components, subcontract manufacturer Fairbrother & Grimshaw (Engineering) Ltd recognised that it needed to reconsider its machining strategy to improve cycle times and shop-floor throughput. The upshot was the arrival of a Nakamura-Tome AS200LMYSF turning centre from the Engineering Technology Group (ETG).

Based in Cherry Tree on the outskirts of Blackburn, Fairbrother & Grimshaw has a long-established relationship with ETG that dates back to buying recognised brands for more than a generation, prior to some brands being rolled into the ETG portfolio. In 2017, the relationship with ETG really blossomed for the company when it acquired two Quaser MV184 three-axis machining centres with Nikken 4th-axis rotary units from ETG.

Commenting upon the previously acquired Quaser MV184 machining centres, Fairbrother & Grimshaw managing director Neil Grimshaw recalls: “We needed to replace an ageing Bridgeport machine and, after doing our due diligence, we bought a Quaser MV184 from ETG. We liked it so much, we had a second one installed. The quality of machines from ETG is second to none and this is equalled by their customer service and support. That is one reason why, when we looked at a new turning centre, we opted for the Nakamura-Tome from ETG.”

The 12-employee company had won a long-term contract for 50-off stainless 316 components each month; and the challenging parts required three operations on a turning centre followed by 4th-axis machining on one of the Quaser MV184 machines. Fairbrother & Grimshaw recognised an opportunity to expedite the process with one-hit machining, while acknowledging that if its existing CNC turning centre had a breakdown, completing the monthly order would be problematic. Despite extensive market research, the Nakamura-Tome AS200LMYSF won the day with its twin-spindle configuration, long-bed specification, milling capability and Y axis that provides a 90% increase in turning length. With a longer Z-axis travel and a Hydrafeed barfeed, the new addition supports the production of complete parts either via its 8-inch chucking capacity or 65 mm automated barfeeding capacity.

Installing the Nakamura-Tome AS200LMYSF delivered results immediately, as Grimshaw confirms: “The Nakamura is like having four machines in one. By using the Y-axis milling and the sub-spindle facility, our parts are coming off the machine in one-hit. The benefits include a drastic reduction in set-ups, the elimination of second-ops and an overall cycle time reduction of more than 50%.”

He continues: “One-hit machining reduces the manual handling of parts, reduces human intervention and improves the overall quality and consistency of a batch of parts. We’ve recently installed a new Axiom Too CMM and the parts coming off the Nakamura are not only high in quality with excellent surface finishes, but the dimensions are consistent with zero deviation.”

With nine CNC machining centres and four CNC turning centres, the new Nakamura-Tome AS200LMYSF is bridging the gap between the two departments, permitting more milling work to be completed in a single operation in the turning department. This is gradually increasing capacity in the milling department as fewer parts require secondary milling operations.

Grimshaw says: “While we primarily bought the machine for the power generation part, we are witnessing similar savings on other legacy work that we’re transferring to the Nakamura. For example, we have a regular 1000-off series run of washers for the rail industry that was previously two operations. By transferring this to the Nakamura, we are machining the parts in one-hit, alleviating milling work from our 4th-axis Quaser and reducing our cycle times by more than 30%. Furthermore, with the barfeed facility, we can run the Nakamura unmanned until the batch is complete – saving on labour costs. Likewise, we have a die component for the food industry that is required in volumes of less than 100-off and the two turning operations and three milling operations are now a single operation on the Nakamura.”

The objective is to move more work to the Nakamura-Tome AS200LMYSF, but for Fairbrother & Grimshaw there is no urgency in expediting all its work to the new acquisition.

“We are moving legacy components onto the Nakamura when the opportunity arises but, as a busy machine shop running a three-shift pattern, our shop-floor team has to gradually build their confidence and competence on the machine,” states Grimshaw. “In this respect, ETG has been absolutely fantastic in supporting our machinists with any queries or issues they may have. Another appealing factor with the new Nakamura-Tome AS200LMYSF is the large-screen CNC control system. Young engineers want to be using the latest technology and the Nakamura has this in abundance.”

As the company gains confidence with the Nakamura, the benefits will continue to surface for Fairbrother & Grimshaw.

“Although we bought the Nakamura-Tome AS200LMYSF for a particular job, we knew it would reap rewards with other components,” says Grimshaw. “As that comes to fruition, we are seeing set-ups, cycle times and manual input continually decreasing. Additionally, we’re seeing throughput, quality, consistency, surface finishes and even staff motivation improving as a result of the investment.”

“As our experience with the new machine grows, we have the opportunity to both alleviate the capacity burden from our milling department by completing more milling work on the Nakamura, and look for new types of work,” concludes Grimshaw. “We can already see the added potential this machine is giving us to enter new markets and take on more challenging work. This really does offer us some exciting opportunities, while making our business even more competitive.”

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