Probably the oldest steel business in the world, the history of Forgemasters is like a patchwork quilt. Dating back to the 1750’s, the plotted history weaves-in famous Sheffield names such as Vickers, Firth Brown and British Steel. Like the global steel industry, renowned Sheffield Forgemasters International Ltd (SFIL) has seen much change over the last two centuries, but with significant investment, the South Yorkshire manufacturer retains a niche position in the global nuclear, offshore, power generation, materials processing and defence industries. Manufacturing the world’s largest castings up to 350 tonnes, and complex forgings weighing up to 180 tonnes, SFIL is unique in its ability to go from raw material to finished parts.

Staying ahead of the industry requires significant investment levels and in 2008, SFIL strategically invested £12m in its North Machine Shop with the arrival of five heavy-duty machine tools. This decision was based on a limited and diminishing subcontract supply chain and excessive subcontract costs. SFIL told MTD magazine that prior to the investment in the Northern Machine Shop, the cost of transporting extremely large components for external subcontract machining would stand at an eye-watering £100,000 – each way! An average transportation bill of £200,000 to ship parts to a subcontractor; genuinely highlights the costs and scale of economies involved.

Leap forward 10 years and the modern day issue for SFIL is still transport – moving large parts from one machine to another. The inherent time spent moving and setting-up large parts and the risk to quality and consistency is still huge. This is why SFIL has now invested £6m in two BOST machines, the VTL and a RAM boring machine. Supplied and commissioned by McDowell Machine Tools, the UK & Ireland partners for BOST for over 8 years; the VTL was commissioned in September with the RAM borer set for full production in January 2019.

BOST is a privately-owned company located near San Sebastian in the North of Spain. The VTL Series is BOST’s flagship product with table diameters from 1.5m to 10m and machining heights up to 6m. They can be configured from a double column two-axis design to a single column 6-axis design with weight capacities up to 400 tonne on the table.

Discussing the importance of 5-axis one-hit machining on components of colossal scale and the significance of the new BOST VTL, Ian Nicholls, the Sheffield Forgemasters International Group Quality and Technical Director, says: “We have milling, turning and boring machines but the difficulty lies in moving the components from one machine to another, you risk losing precision and consistency. So, when you have parts right at the limits of the existing machine and to really high tolerances, ideally you want to be able to cut them on one machine. The fact that this technology is now available through BOST is a big step forward.”

We are regularly working to hundredths of a millimetre on components which may be measured in metres – and it is difficult to achieve when co-ordinating activities between machines. The BOST VTL is all about taking technology that is normally associated with small machines and making it available to parts up to 4m high and 8.5m diameter.

BOST Removes the Risk

If you look at our quality record, much of the risk is tied up in finish machining. So, by the time you’ve forged the part, heat treated it, pre-machined it, heat treated it again and then mechanically tested it; technically the part can be perfect and then you take it to finish machining and there is a huge amount of risk. That risk is heightened when you are using two, three or four machines. Added to all this, the parts we manufacture are continually becoming more complex.

Looking at the investment levels in the business, Mr Nicholls continues: “As a medium to large enterprise and being a private company, we are driven by re-investing our profits back into the business. We have invested virtually all of our profits back into the company and that has added up to more than £50m in the last 10 to 15 years. The latest BOST investment is among the most exciting as it is right at the cutting edge of technology.”

Referring to why SFIL purchased the machines, Mr Nicholls continues: “We bought the machines for both capacity and quality purposes. The capabilities of the BOST machine were previously captured by several machines working in combination to make the final part. The benefit of the BOST is that all those processes are now done on one machine. So, we mitigate the risk of moving from machine to machine. This increases our confidence in the accuracy we can achieve and also our efficiency.”

Serving Niche Markets…Globally

“Unlike many companies steeped in tradition and heritage, we are a big export company. We are very much linked to major global projects. So, the oil and gas industry was once dominated by the North-Sea and Norway, then it moved to a global market and we supply to that. At the moment, we are heavily focused on defence and the BOST machine is really targeted at completing a lot of products we make for the defence industry, such as large cylindrical and dome components with highly complex protrusions on the parts. There are parts for new submarines that can only be manufactured on the BOST. If you think about it from the capability of a small multi-axis machine, we are scaling that up to a size that can take jobs 4m high, 8.5m diameter swing and 100 tonne – that is what this machine is all about.”

The reason we chose BOST is because the machine is very heavily engineered and robust. It’s their concentration on what underpins good quality and what de-risks manufacture for the customer that has made BOST a preferred supplier.

“The inherent risks when moving parts from one machine to another include the risk in the set-up and the time taken to re-set the part for each machining operation. So, being able to use this facility to do all the operations on one machine, means we save all that set-up time. That has great advantages for throughput and precision. The BOST machine has some very intelligent built-in systems that help it to maintain precision as it goes along. This ensures we are not losing accuracy over time with wear and tear on the machine. It has self-calibration and self-measurement functions that make repeatability a given factor.”

“In terms of productivity, we can push feed rates whilst the driven head allows us to manipulate and maximise cutting tool utilisation in terms of machining strategies that will improve cycle times, surface finishes and prolong tool life. I can’t emphasise just how much of a step forward this machine is, in terms of capability. The advantages in terms of throughput time are going to be huge.”

Despite only recently completing the ‘prove-out’ and ‘early-production’ stages, the early indications are that machining times are eight times faster than previous methods and throughput on some components is expected to fall from 5 weeks to 3.

Scaling to the Top of the Supply Chain

“As a business with national defence contracts, we cannot subcontract parts outside the UK. We may be able to subcontract work to UK companies, but there is nobody in the UK with the capability or capacity to fulfil the remit of what we do. In essence, if we didn’t have this new machine there would be no other UK company capable of fulfilling contracts in the national interest.”

“A lot of the components we make now have to be produced in the UK supply chain and the capability and supply chain outside Forgemasters just isn’t there to make components of this type, size or complexity. So, Forgemasters ‘raison d’être’ really is that we go from creating the material in terms of melting the liquid steel to delivering the finished component. We wouldn’t be able to do that for the latest nuclear and defence contracts if we didn’t have the investment in this machine.”

The Installation Project

Unlike the average machine tool that arrives on a lorry and is manoeuvred with a forklift, the BOST VTL installation required meticulous planning, team work and project management. With a Y-axis weight of 65 tonne, just one axis of the BOST VTL weighs in at more than the average machine tool, delivery lorry and forklift combined.