Linn Products Ltd
, which designs and manufactures high-end audio equipment, recently installed ‘an advanced’ custom-designed automated manufacturing cell at its 7,200m2
facility in Glasgow. The ‘state of the art’ Synergi cell from Leamington Spa-based Mills CNC Ltd
— the exclusive distributor of Doosan machine tools in the UK and Ireland — represents a significant investment for Linn.
The cell comprises a new Heidenhain-controlled Doosan DVF 5000 five-axis machining centre, a Fanuc industrial six-axis robot with a 45kg payload capacity, and an integrated racking system that holds up to 24 pallets onto which workpieces are clamped.
The pallets are then loaded, via the robot, into the DVF 5000 and machined components are unloaded from the machine and stored in predetermined positions back on the racking system.
A 2m-high safety cage that encloses the robot and pallet racking system to protect operators, features a two-way access door that allows machined components to be removed from the cell and new workpieces to be introduced into it.
There is also a 17in touchscreen HMI driven by Mills’ proprietary Synergi software that controls the cell and provides a seamless interface between the machine tool, robot and associated equipment. Since being installed, the cell has proved its worth, running overnight and over weekends — unattended. ‘Best in the business’
Linn Products, which was established in 1973 and employs around 160 people, designs and manufacturers ‘iconic hi-fi equipment’, with products like its Sondek LP12 turntable and its Majik, Selekt, Akurate and Klimax DSM network music players widely acknowledged as being among ‘the best in the business’ for their design, build and sound quality.
Chris O’Brien, Linn’s director of operations, said: “Our products are built to exacting quality standards and precision using the best materials and components available. A great deal of care and attention is given to every stage of the design, manufacturing and assembly processes. At Linn, the details really do matter.”
The company is committed to continuous improvement, and integral to this are the regular investments it makes in its people, its plant and equipment, as well as its systems and processes.
To maintain quality and control lead-times and costs, Linn has been increasing and strengthening its in-house machining capacity and capabilities over the past few years, which included the company investing in Doosan three- and five-axis machining centres supplied by Mills CNC.
Mr O’Brien continued: “Our high-end products are machined from solid aluminium. They are ‘hollowed out’ and feature a number of chambers, separated by thin walls, where electrical and electronic components are housed.
“Product exteriors are machined to a mirror finish using a large-diameter fly-cutter that mills the entire surface in one pass. Removal amounts on premium products can be more than 80%, and part cycle times for the roughing, semi-finishing and finishing operations can amount to several hours.”
In early 2020 Linn’s machining capabilities were under pressure, with the manufacture of its ‘soon-to-be-launched’ Klimax DSM system in full swing building up stock in time for the product launch; demand for Linn’s established, products was also high.
Mr O’Brien explained: “Not having sufficient in-house machining capacity at our fingertips was creating a pinch point that was affecting all the other areas of our operation.
“The outbreak of the pandemic with its travel restrictions, staff furloughs, social distancing and lockdowns only exacerbated the difficult position we were in. We looked at a number of options to help us address the situation, ranging from hiring more staff and running an additional shift — not easy during the pandemic — through to sub-contracting work out.” Automation option
As it transpired, the company did not consider that either option provided the solution required and began investigating automated systems as the means to meet its immediate and future machining requirements.
“From a flexibility, productivity and a ‘best return on investment’ perspective we began thinking about investing in a new high-performance machining centre with integrated automation, rather than acquiring another stand-alone machine, as lights-out unattended operation would give the production efficiencies we were seeking. Having previously bought three Doosan machines from Mills CNC we contacted the company to discuss our requirements.”
The turn-key Synergi cell described earlier features a customised multi-pallet system, as opposed to an off-the-shelf type with 4 or 12 pallets.
Mr O’Brien added: “For us to have a fully autonomous cell that could run unattended from Friday afternoons through to Monday mornings, we required more capacity — hence the 24-pallet system.”
Specific features built into the cell to ensure process security and reliability include: RFID tagging on every pallet for fast and accurate job location and identification; remote monitoring and diagnostic facilities that send email alerts to designated members of Linn’s staff, while also allowing Mills’ engineers to intervene and diagnose any operational issues; tool inspection and detection; and pallet/part checking.
Linn’s automated manufacturing cell was delivered and installed at the beginning of November 2020 and, following on-site training for six operators, was fully-operational by the end of the month. As a result of investing in the cell Linn has significantly improved its productivity and efficiencies.
Mr O’Brien concluded: “We are no stranger to automation, already having a fully automated warehouse with AGVs. However, this investment is our first involving a machine tool. A great measure of success of a new machine or system is when you wonder how you coped without it, and that is certainly the case with our new Synergi cell.”