BICYCLE AFTERMARKET COMPONENTS MANUFACTURER INSTALLS SIXTEENTH CITIZEN LATHE - Citizen Machinery

In September 2024, a third-generation Cincom A20-VIILFV sliding-head turning and milling centre of 20 mm bar capacity was added to the small parts turning section at bicycle aftermarket components manufacturer, Hope Technology, Barnoldswick. Then in May this year, a 12 mm bar capacity Cincom L12-VIILFV arrived on the shop floor. Supplied by Citizen Machinery UK, they were respectively the eighth and ninth sliding-head lathes to be purchased from the Japanese machine builder’s UK subsidiary, or the previous sales and service agent NC Engineering, since 2004. In addition, from 2013 until now, seven Citizen Miyano fixed-head lathes have been supplied.

Hope Technology employs around 150 people and exports half of its rapidly expanding portfolio of products to more than 40 countries. The highly successful British business, which was founded in 1989 by ex-Rolls-Royce aero engineers Ian Weatherill, who is now CEO, and the late Simon Sharp was based on a quest to make mountain biking safer by developing and producing a disc brake as an alternative to less effective cantilever brakes.

The company produces 100 percent of its products in-house from top quality materials, mainly aluminium bar, billet, sheet and forgings, plus stainless steel, brass and carbon fibre. It not only machines everything in Barnoldswick to control precision and quality, but also heat treats, anodises, polishes and assembles on-site.

The third person to join the company, also in 1989 from the same aero engine manufacturer, was the current works and production manager Lindley Pate. His long-term employment puts him in an ideal position to comment on the purchase and use of the more than 70 CNC machine tools currently in use in the factory.

He explained, “We are constantly buying machines to cope with the sheer volume of orders and the latest Cincom is no exception. When we opened our first factory in Nelson, we opted for another make of sliding-head lathe, three of which are still in occasional use.

“However, the mainstay of the Swiss turning section are the six 20 mm bar capacity models we have sourced from Citizen, plus a 16 mm and a 32 mm model and now the 12 mm sliding-head lathe. It was the speed of the machines and their ability to match our larger volume production needs that prompted the swap to this supplier.”

It is a similar story with the lathes in the larger bar-fed fixed-head turning section, which are up to 65 mm capacity. Between 2013 and 2020, seven Citizen Miyano turn-mill centres were installed, six of 42 mm capacity and one 51 mm lathe. Production of many parts within the capacity of these machines has been transferred to them from larger lathes to allow quicker cycles on the more suitably sized production centres. One example is a bicycle rear cassette lockring made from 7075 aluminium, which is now produced in a significantly shorter cycle time on a Miyano.

Mr Pate added, “As with all of the production plant we buy, it is the level of service from the supplier, in this case Citizen, as well as the productivity of the machines that are paramount and lead to our repeated purchase of Cincom and Miyano lathes.”

An ability to maintain production output reliably around the clock is crucial for all plant in Barnoldswick in order to maintain global delivery schedules. Consequently, it has been decided to retrofit swarf conveyors to the two newest Cincom A20s to prevent aluminium swarf building up in their machining areas, allowing long periods of lights-out running.

Citizen’s programmable LFV (low frequency vibration) chip breaking functionality in the control fitted to the latest three A20s helps in this regard. It ensures that swarf is broken into short chips that are easy to remove, rather than becoming ribbons that wrap around the component and tool. This scenario is avoided by switching in LFV during problematic sections of a cutting cycle. It means that the lathe does not have to be stopped for manual removal of tangled swarf, which would lead to lost production and possible damage to the part being machined and/or the cutter.

Modern Cincom lathes have the additional advantage of the option of removing the guide bush if it is expedient to do so. While until now this has rarely been done in Barnoldswick, the supervisor in charge of the small parts turning section, Andy Savage, is intending to take advantage of the capability. It will save material cost when machining parts shorter than typically two and a half times their diameter, a geometry that does not deflect appreciably in the radial direction when the tool engages the bar with the guide bush absent. The benefit is two-fold. First, it allows extruded bar to be used, as on the fixed-head lathes, rather than more expensive drawn bar. Second, each bar remnant is two to three times shorter, saving a considerable amount of material.

Continual use is made by Hope Technology staff of Citizen Machinery’s Alkart Wizard software, which speeds CNC program preparation for both the Miyano and Cincom lathe models. It provides a user interface that simplifies complex tasks by breaking them down into a series of easy-to-follow steps. To assist in program development and reduce the potential for errors, Alkart Wizard incorporates a library of pre-defined machining processes and graphical diagrams. The software also allows users to save and reuse portions of CNC programs that have been created, helping to save time and increase efficiency.

Mr Pate concluded, “Tolerances held on our products are normally fairly open, but +0.01 mm has to be achieved on bearing diameters, a level of accuracy that is no problem for Citizen lathes. Our continued purchase of them over a period of more than two decades is primarily down to their reliability, however, ensuring we can get product out of the door quickly to our markets around the world.”