The parts, essentially base castings and guideways for special purpose machines are made from cast iron and steel. The castings are large (1.2m long x 640mm wide) and typically weigh up to 500kg. They are machined in small batches (typically 1-offs through to 5- or 6-offs) to exacting dimensional tolerances (0.01mm) across the part and exacting surface finishes (Ra 1.6μm).
Birds Precision supplies the parts direct to this customer and, according to owner and managing director, Chris Bird: “They have to be right first time – every time.”
The quality, lead-time fulfilment and cost demands of this customer and others like it, were amongst the main reasons why Birds Precision invested in the Doosan DNM 6700XL.
Mr Bird explains: “To maintain our preferred partner relationship with existing customers and win new business contracts with new and existing clients we made the strategic decision to upgrade our machine tool capacity and capabilities.”
As a consequence, the company’s machine tools that were being used to machine the large guideway parts were soon the focus of attention.
“We had been using Herbert DeVlieg horizontal jig mill borers to machine these types of parts, Mr Bird says. “Although these machines, despite their age, were still capable of delivering the accuracies required, it was becoming increasingly difficult to source spare parts for them. We realised that this situation would only become more acute over time and so we decided to search the market for an alternative.”
The machine tool decision-making process was implemented by consensus, with a number of the company’s younger members of staff playing the lead role in contacting machine tool suppliers and drawing up a shortlist of potential machine tools that could meet the company’s immediate and future machining requirements.
“The future of the company lies to a large extent in our ability to recruit, and retain, top young talent,” Mr Bird affirms. “Our recently-introduced apprentice programme, which enables our apprentices to gain valuable skills, relevant work experience and nationally recognised qualifications, is helping us meet this objective.
“Another aspect to our commitment to investing in young people is involving them, where possible, in the future direction of the company and trusting them with important decisions such as future machine tool acquisitions.”
Although not a Doosan machine tool user at the time, staff from Birds Precision had visited Mills CNC’s stand at MACH 2018 where they had seen a number of Doosan vertical machining centres being put through their paces.
One of these members of staff was machine shop manager Tom Bird, who says: “Mills CNC has a good reputation in the market and we liked the Doosan machines we saw on their stand. So much so in fact that we invited sales staff from Mills to visit us at our facility to discuss our future requirements.”
It was during these discussions that Birds Precision was alerted to the imminent introduction of the new Doosan DNM 6700XL machine – a VMC with a 2.1m X-axis stroke.
In addition to its large capacity the DNM 6700XL is equipped with a powerful spindle (18.5kW/15,000rpm) with 20 bar through-spindle-coolant capability, a large work table (2,200mm x 570mm) and an integrated thermal compensation system that minimises the effects of heat generation and regulates thermal expansion ensuring high component accuracies and process optimisation.
Tom Bird explains: “The technical specifications of the DNM 6700XL, including its size, rigidity and power, ticked all the right boxes for us. We also liked the machine’s competitive price, quick availability and the fact that it was backed by Mills CNC’s dependable aftersales service and support.
“Furthermore, because the DNM 6700XL is a new machine we were convinced that it would help differentiate us in the market and a provide us with a distinct competitive advantage.”
Since being installed the DNM 6700XL hasn’t missed a beat and staff at Birds Precision have been impressed with its cutting performance, especially its high stock removal capabilities and its ability to maintain high volumetric accuracy over long machining runs.
Chris Bird concludes: “Such is the accuracy and surface finish of the parts being produced on the DNM 6700XL that they no longer need to be ground and hand scraped. The DNM 6700XL represents a significant investment for us but armed with this technology we are confident about our future growth and prosperity.”
Mills CNC www.millscnc.co.uk
Birds Precision www.birdsprecision.co.uk
