Hastings-based Hivac Engineering (www.hivac.co.uk) is a well-established specialist in the manufacture of ultra-high-vacuum chambers and equipment used in surface science, semiconductor and synchrotron particle acceleration.

For the latter, think CERN and the Large Hadron Collider in Switzerland; or closer to home, Diamond Light Source in Oxfordshire. The type of work that Hivac undertakes is, therefore, generally low-volume R&D-type large components — albeit to extremely tight tolerances.

Many of the products manufactured by the company are welded assemblies comprising a number of machined components — some straightforward, others complex. This work is a mix of ‘made to drawing’ and in-house design, for which Hivac uses 3-D CAD and Finite Element Analysis. A common thread throughout is the finished accuracy of the welded assemblies, which have to be finish-machined using large-capacity and accurate machine tools.

Managing director Paul Lennard says: “Our investment in machine tools is driven by market requirements, so if we need a machine, we will buy it. Most of our work is in stainless steel, but we also machine refractory materials such as tantalum, molybdenum and high-temperature ceramics such as Macor and Shapal.

"As a result, we need robust machines that can not only accommodate the size of part that we make, but also achieve the quality of machined finish that our customers and products require.”

Investment in machine capacity at Hivac backs up this point, with a heavyweight XYZ 2010 vertical machining centre and an XYZ XL 1100 extra-large lathe from Burlescombe-based XYZ Machine Tools (www.xyzmachinetools.com) being the most recent additions.

Key to the decision to buy the XYZ 2010 VMC was its construction, which features a substantial cast base rather than a fabricated one. This 20,000kg machine gives Hivac a robust machining platform, while the standard 1,000mm of travel in the Y axis — combined with the 2,000 and 800mm of travel in the X and Z axes — provides a large machining envelope within a relatively compact footprint. Hivac also took the fourth-axis option for even greater versatility.

“We need machines that are capable of machining straightforward and complex parts, and this is what you get with the XYZ machines,” says Mr Lennard. “This is helped by the use of the Siemens ShopMill 828D control system, which we find extremely easy to use thanks to its conversational programming.”

Changes in personnel and production requirements were drivers in the selection of the XYZ XL 1100 lathe, which was installed in October 2015. Much of the large-diameter turning work at Hivac had been done on manual machines, but the skills required to use this type of equipment were causing a bottleneck in production.

This led to Mr Lennard looking for an alternative, and the criteria for the lathe were much the same as for the machining centre; it had to be robust, easy to use and have a relatively compact footprint.

“The XYZ XL 1100 met all these criteria. It is an 8,000kg machine with a cast construction; and with the bed length that we specified, the footprint is only 3,930 x 2,300mm — yet we can swing 1,100mm over the bed.”

The XL 1100 uses a Siemens 840D control, in this case the ShopTurn variant. Both the ShopTurn and ShopMill controls make use of Siemens JobShop Concept, which simplifies all of the on-screen prompts and ensures that programming is quick and easy. Confidence in the resulting program is enhanced by Siemens’ Line Trace graphics, which allow the
operator to view the program as it progresses through each stage of the cycle, with full 3-D graphics assisting the process.

In conclusion, Mr Lennard said: “When it comes to investing in machine tools, we generally know what we want; and with XYZ, we know what we will get. The machines are well constructed, the service and support are excellent, and we feel that we get looked after.

"We must do as these latest two machines take our XYZ plant list to nine — five CNC lathes and machining centres with the Siemens control, and four mills and lathes with the ProtoTrak control.”