Entry-level Leadwell V-30iT proves to be the ideal solution

Pair of Leadwell V-30iT five-axis machining centres on the shopfloor at G&J (CNC) Services' Kent factory

Many prismatic machining contracts are ideally fulfilled on a five-axis machining centre, which enables components to be produced cost effectively. It is because the two rotary axes are able to position the component quickly and automatically in various orientations for milling and drilling, without the need for expensive fixtures and multiple set-ups by hand. A problem arises, however, if the components being produced do not command a high selling price, as most five-axis plant tends to be expensive and investment often cannot be justified.

Paddock Wood sub-contractor G&J (CNC) Services, part of the CTN Group, has found the ideal solution - the Leadwell V-30iT 3+2-axis BT40 machining centre from WH-Lead, Towcester. The entry-level price of less than six figures belies the five-axis machine’s extensive capabilities. The hourly rate that the sub-contractor charges based on the investment allows less complex prismatic components to be produced efficiently at prices that compare favourably with those quoted by competitors in low-wage countries.

Of novel configuration, the V-30iT has a 205mm diameter rotary table mounted on a swivelling trunnion driven from one side. It is supported on the other side not by a simple bearing block, but by a similar unit built into the side of a 450 x 300mm fixed table. It is unusual on a machine that is already inexpensive to find such a major addition. The fixed table can be used to complete a three-axis operation on a part weighing up to 50kg before it is transferred to the rotary table. By that time, the part must weigh no more than 35kg if it is to undergo machining at up to 45deg tilt, or 25kg if the trunnion position is steeper.

Charlie Naismith, the owner of G&J (CNC) Services, is in a good position to comment on the merits of the Taiwanese-built machine compared with more expensive, fully interpolating five-axis machining centres of German and Japanese origin used at his other four engineering sites in the South East of England. The group of companies, CTN Group, boasts around 100 CNC machine tools of which 10 are five-axis models.

Pictured left: The V-30iT is unusual in that the left-hand side of the swivelling trunnion with rotary table is supported by a bearing in the side of an adjacent fixed table, so 3-axis machining and three- to five-axis machining on the same part can be completed without it leaving the working area. Alternatively separate jobs may be undertaken on each table

Mr Naismith said: “Depending on the value of the parts being machined, which is normally down to their complexity and the material used, you have to make sure the figures add up. Much of our throughput is fairly simple 3+2-axis work in mild steel and aluminium that customers will not pay a premium for, so the Leadwell machine is perfect.

“Actually we use it in three-axis mode for much of the time, but the five-axis functionality is there for when we need it, saving costs associated with workholding, handling and work-in-progress. At the same time it helps with accuracy by being able to access parts with shorter tools and by cutting down on manual re-fixturing.”

Well specified
He also appreciates the ergonomics of the V-30iT, pointing out that the rotary table when flat is at the same level as the fixed table, so there are no clearance issues. The machine is also well specified, with X, Y and Z travels of 800 x 460 x 387mm, roller bearing guideways, a 12,000rev/min spindle, a 24-position tool magazine with 1.8sec cutter exchange and 48m/min rapids in the X and Y, and 36m/min in Z.

Control is provided by a Fanuc 0i-MF Plus CNC system, although Siemens, Fagor and Heidenhain are optional, as are specification of 4+1 or full five-axis interpolation. Another benefit of 3+2 CNC apart from the lower cost, according to Mr Naismith, is that engineers in the Paddock Wood factory can step up to five-axis machining and build a portfolio of new work around the enhanced capability, while taking advantage of the extra three-axis capacity for regular work.

The first Leadwell machine, which was also G&J (CNC) Services’ first five-axis machine, was installed in 2021. Its purchase was prompted by the need to produce a particular agricultural industry component that would not have been feasible to put onto a three-axis machine.

Pictured right: Another view of the twin-table arrangement, showing Op1 on the right and Op2 on the left being carried out on an aluminium gearbox assembly part. A typical batch size of prismatic parts produced by G&J (CNC) Services is 300, although it can be as high as 3,000 or as low as one-off

A second, identical machining centre followed a year later to provide extra capacity and equipment redundancy. Both machines were available ex-stock from WH-Lead's Towcester showroom and delivered within a fortnight, together with Renishaw tool and workpiece probing, Filtermist extraction and a post processor for the sub-contractor’s OneCNC CAD/CAM system. WH-Lead’s customary high level of ongoing after-sales service and support is being provided.

Generally speaking, parts that previously required four or five separate operations are now produced in two, sometimes without leaving the V-30iT if pre-machining is done on one of the tables. A typical component cited by Mr Naismith for a fluid transfer equipment manufacturer is produced in this way, resulting in a 30% shorter floor-to-floor time compared with when it was produced in four operations on different three-axis machines.

A further advantage of the new process route is that operator walk-away intervals are longer, allowing more meaningful work to be performed elsewhere in the factory while machining is in progress. As a result, it is likely that more and more jobs at G&J (CNC) Services will be transferred to the five-axis plant as time progresses.