We recently finished the installation of another of our large X-BHD machines. These are bridge, or gantry type, with a head that manoeuvres on x, y and z axes over a large test bed. Designing and building these Brinell hardness testers – which can weigh over ten tonnes – has become one of our specialities. I say “become”, because it’s a side of the business that has grown entirely naturally, since our first such machine in 2003, and the learning curve was initially very steep. Having an X-BHD enables our clients to test the large forgings, billets and other components that are standard in a steelworks, but which simply would not fit within the test-envelope of a typical floor-standing or bench-top tester.
Of course, our clients would like nothing better than a machine so large that almost any size of forging could be tested, but they are also realists who appreciate that workshop roof height, getting the machine components through the roller door in the first place and, of course, fabrication cost, are significant constraints, so they tend to be machines that fall within the dimensional limits of 6m x 4m x 5m with a test head-to-bed clearance of 2m or under One notable exception was the machine we nicknamed ‘Big Blue’; a 12 tonne behemoth we installed in Northern Europe; almost certainly the largest metal hardness tester ever built in the UK.
The decision to order a bridge type Brinell machine is not taken lightly and is always the subject of protracted discussion with our clients (the process may take a year or more where people are preparing capex for future budgets). In the world of the oil & gas multinational the sums involved are far from eyebrow-raising, but they still amount to a significant workshop outlay and – given the specialist nature of hardness testing – one which few engineers feel qualified to consider in any depth. So, there’s a great deal of information sharing involved; from the clients to ensure we have the fullest possible knowledge of their requirements and from us to provide the much-sought capability assurance. Of course, the fact that there are so many Foundrax bridge machines out in industry is a great reassurance to clients who are somewhat daunted.
In 2022 we were approached by a major Italian steel producer with exactly the sort of need that an X-BHD caters for: big forgings and castings, from a variety of steels. Everything we need to know on such a project can be ascertained by a phone or video call but there is a significant risk that any misunderstandings at the client brief stage could materialise into horribly expensive errors later, so this must be a thorough, meticulously-handled process and it’s one where a site visit is called for (whether it’s Italy or not!). And this machine was slightly special.
Having returned with all the necessary information, we then spent considerable time refining and clarifying our understanding and discussing design points with the customer in order to get everything just right. Our Production Manager, in turn, was then tied up by discussions with our sub-contractors and purchasing manager who, in turn, had to ensure that every component could be sourced on time – and lead times for hundreds of our components have increased significantly since 2020. Only towards the conclusion of these efforts could work commence on the quotation, obviously a multi-page document.
The specification for this Brinell tester included an integral milling machine, in the same housing as the indenter head, to allow operators to precisely remove a few millimetres of material from test samples and present the indenter with a flat, level test area, free of any decarburised layer, as required for accurate testing. This integral milling head eliminates hand-grinding from the test process; descending directly onto the test sample to cut an Archimedes spiral, thereby minimising noise and material waste as well as the need for the attendant protective gear. The milling machine was designed specifically for this application and it required its own firmware. Moreover, the entire machine build had to take place at our second unit, as all available space in No1 Workshop was already taken up by a bridge machine being built for a Polish client, so this was a logistically more complicated build than normal, with some of our very specialised equipment being shared between the two sites.
A machine of this sort takes approximately 12-16 weeks to build, including the production time to make design changes and to fabricate the main structure etc. When two are under construction at once, as in this case, that can more than double. Every such machine (in fact every machine we make, whether a bridge machine or a bench top model) is an opportunity for design tweaks and software enhancements, and, of course, the somewhat clichéd “lessons learned” session afterwards. Sometimes the lesson learned is as simple as “Triple check the dimensions have been understood by the transport company so that they send the right lorry to collect it!”
