The family-owned Japanese group Ishida is a major player in the food-packaging machinery industry, with a world-wide turnover of more than 500 million euros. Perhaps surprisingly, almost all of the component parts that go into its automated weighing, filling, packing, handling and inspection equipment are made by sub-contractors, while assembly is carried out at Ishida factories in Japan, Korea, China, Brazil and the UK.
However, group policy on sub-contracting is about to change, largely due to the success of a UK subsidiary in Poole, Dorset, and its use of four Hurco machining centres. Here, 80% of the components for a new range of semi-automatic tray sealers are produced in-house. Prototype parts are also machined for larger in-line tray sealers assembled at Ishida Europe’s headquarters in Birmingham, while customers’ bespoke tray sealer tools are designed and manufactured in Poole.
In the long term, the core production of tray sealers will be brought in-house, with just very simple parts and seasonal over-capacity subcontracted. The main advantage to Ishida will be shorter lead times; other benefits are an enhanced ability to control component quality and scope for making higher margins by reducing sub-contracted machining costs.
Despite the recession in many European countries, the demand for tray sealer tools has been increasing over the years, as consumer demand for pre-packed fresh meat and ready meals has been on the rise. This had led to a need for high-speed packing lines and larger sealing tools to help food processors and packers meet the demand.
Ease of programming
The requirement to mill and drill these larger tools (mainly of C250 aluminium but sometimes 304 stainless steel), which can be over 1m long and weigh more than 300kg, prompted Ishida Poole to purchase its first Hurco
(www.hurco. com) vertical machining centre — a VMX50t — in 2009 (until then, the company had relied on other, smaller-capacity VMCs).
Ishida Poole production manager Chris Witheford says: “We noticed that a local sub-contractor to whom we regularly give work uses a similar Hurco machine. I was particularly impressed with the ease of programming using the supplier’s conversational software, WinMax, which is a Windows-based suite running on Hurco’s twin-screen control.
“Our tooling designs are based on core templates containing lots of repeating holes and pockets that need to be copied — sometimes rotated — and pasted elsewhere. The pattern location functionality within WinMax is ideal for this and saves a great deal of time. That is important to us, as batch sizes here are typically ones, twos and threes, so programming takes up a large part of overall production time.”
David Nielsen, machine shop team leader at Ishida Poole, adds: “WinMax is at least three-times quicker at creating programs than the conversational control on our previous VMCs, some of which are still in use for making spares; their control systems use Q-def programming. The latter tends to be laborious, whereas WinMax is more user-friendly.”
Simultaneous programming
Hurco’s WinMax controls can be used to prepare programs while a component is being machined. A graphic of the component is visible on the right-hand screen as the cutting paths are being created. At the end of the process, the entire cycle can be simulated to ensure that there are no interference issues.
This is particularly important when machining small batches, as a single scrapped part could be a high proportion of the total production run. The twin screen also improves staff confidence when running the program, bearing in mind that 80-90% of the solid material is removed to make a tooling plate. Cycle times vary from around 1hr for an insert up to a full shift for machining an entire plate.
Mr Nielsen says: “A valuable feature of the Hurco control for 2-D programming is that it accepts DXF files directly from our SolidWorks CAD system. One tooling plate might contain 120 holes, and it is very time-consuming and error-prone to key in the hole centres individually by hand, whereas WinMax picks them up automatically from the DXF data.
“When we have 3-D elements to program, like the front heater plate profile for a tool, we find it quicker to prepare those blocks using our OneCNC CAD/CAM package and then add them to 2-D elements written conversationallyin WinMax, using the NC Merge function,” says Mr Nielsen.
Networked machines
All of the machine tools on the shopfloor, which now include a further Hurco VMX50t and two smaller VMX42t machines purchased at MACH 2012, are networked to a server at Poole, together with the CAD/CAM systems. “Compared with programs previously written conversationally using other controls, those generated in WinMax are more standardised and clearer, which is an advantage for networking.”
The result is a seamless transmission of program data and tooling lists, ensuring that any Hurco machine can produce any part (subject to size compatibility) with a minimum of delay, creating a ‘lean’ production environment. Four operators (two fewer than previously), run the machine shop, despite there being more CNC machine tools — currently seven.
The specification of all the Hurco VMX machines includes a 12,000rev/min spindle with a chiller for high-speed cutting of aluminium, a dual-wound motor to provide high torque at low revs when machining stainless steel, and an eight-jet coolant ring for flooding the cutting area for efficient chip removal.
The four Hurco VMXs at Ishida Poole have transformed the company’s approach to prismatic machining and allowed it to take cost out of production. That is important, as the site is a cost centre within the group and constantly takes buy-or-make decisions based on the price of producing a part in-house compared with how much a sub-contractor would charge. Invariably, the internal production cost is lower, which fits with the firm's aim of bringing more of its manufacture in-house.