Formerly with an almost exclusive focus on producing equipment such as resuscitators used by paramedics and first responders in pre-hospital care and the emergency services, Halstead-based Meditech has since the Covid pandemic moved strongly into the supply of medical equipment to National Health Service and private hospitals. This development has seen the company’s turnover increase more than five-fold since 2020, as has its factory space. Understandably, such rapid growth has necessitated careful control over many aspects of the business, especially manufacturing.
The company’s first Citizen lathe, a Cincom 20 mm bar capacity L20, was bought in 2008 following a decision by managing director Chris Buckenham to bring all production in-house. Until then, only a few brass and aluminium items like regulator bodies and valve components were machined on site in multiple setups on CNC fixed-head turning centres, manual lathes and milling machines.
The remainder were being sourced from subcontract suppliers in the UK and overseas. However, some components supplied from Asia were proving problematic during assembly, so complete control over the manufacturing function to ensure top quality and timely delivery of Meditech products was the goal.
A further objective was the production of components in as few operations as possible, preferably in one visit to a machine. Mr Buckenham had become aware of the capabilities of sliding-head turn-milling technology and visited the MACH 2008 show to find out more. After a tour around the halls, it rapidly became apparent to him from the quality of Cincom lathes, their capability and the ease of access for setups, that Citizen Machinery would be the preferred supplier, so a deposit was paid there and then for the first L20.
Its arrival on the shop floor in June that year, in the words of Mr Buckenham, “revolutionised production overnight”. It was the start of a programme of Citizen lathe acquisitions that has resulted in the delivery of a total of seven twin-spindle models over the years. A second L20 of higher specification was installed five years later. Then a third with even more capability, an L20-XIILFV with a programmable, 135-degree swivelling B-axis for complex angled machining at both the main and sub spindles, followed in August 2020 to help meet the higher workload during the pandemic.
This latest-generation lathe is characterised by the integration of LFV (low frequency vibration) technology, a proprietary Citizen innovation that uses servo-controlled oscillation to break chips into manageable fragments. It drastically improves the machining of stringy materials like stainless steels and plastics, much of which are cut on-site, preventing swarf from coiling around the tool and workpiece and potentially damaging both. Additionally, it boosts productivity by avoiding having to stop the lathe to clear ribbons of swarf from the working area.
Prior to delivery of the third L20, to turn-mill larger components Meditech expanded its portfolio of Citizen lathes with a fixed-head machine from the supplier’s Miyano range. It was an ABX-64THY with three Y-axis tool turrets and a bar capacity of 64 mm. Delivered in 2015, it replaced a similar machine from a different supplier that was performing badly and set the medical equipment manufacturer on the road to becoming a Citizen-lathe-only company.
A similar Miyano with enhanced speed, power and thermal stability to allow longer periods of unattended operation, including overnight, was added in 2023 to expand production capacity for larger components, some of which are prismatic in shape without any turned features. Both Miyanos also benefit from superimposed machining capability, which enables three different tools to be in cut simultaneously for elevated levels of productivity.
After installation of the first Miyano, it was the turn of a larger-capacity Cincom to arrive in 2019, an L32-XIILFV to take advantage of its gang rather than turret tooling arrangement to deliver faster cycle times. This machine, which also has a programmable B-axis carrying live tools that can work on either spindle, was delivered with an expansion kit to allow bar up to 38 mm in diameter to be processed, if required.
Notable is that, from the outset, the lathe has been operated exclusively without its guide bush in place, with the bar clamped in the spindle collet. Principal machine operator Ian Ronsky, who comes from an aerospace background, finds that the absence of the bush interface affords additional workpiece support, allowing more efficient roughing without risking vibration.
He said, “Deflection of a part when machining larger-diameter, stiffer bars up to 32 mm is not a problem, even though the general tolerance we hold on workpieces is tight at ± 10 microns.
“Any component whose length is more than the 80 mm headstock travel I simply rechuck. In non-guide-bush mode, we have the advantage of using less expensive bar and remnant lengths are much shorter, saving even more cost.”
The most recent Citizen lathe to be delivered, an L12-XLFV, is the smallest machine with a bar capacity of 12 mm. About one-fifth of the parts Meditech turns are below this diameter and the nimble machine allows their production significantly faster than on an L20, while also freeing the three larger lathes for other, more appropriate work. In common with the more recent Cincom deliveries, it also has the LFV chip breaking software, as will all future models destined for the Halstead factory, such is the advantage it provides when machining malleable materials.
