Established in 2019 and based in Hereford,
Numachine Ltd specialises in the CNC machining of complex components where cost reduction, repeatability, and accuracy are paramount. The company has invested in the latest machining and metrology equipment and built ‘an enviable reputation’ in the automotive, medical, and aerospace sectors, for which quality standards are uncompromising.
However, Numachine says that one of the most critical elements to successful sub-contracting can be overlooked, that of cutting fluids, hence the partnership with metalworking fluid specialist
Oemeta (UK) Ltd, Middleton Cheney, which has delivered ‘measurable improvements in tool life, component cleanliness, and operational sustainability’.
George Hawkins, Numachine’s managing director, said: “Numachine specialises in machining parts from castings, aluminium, stainless steels, mild steels, and plastics. Around the middle of last year, we invited Oemeta’s Ryan Aviles to assess our metalworking fluid requirements, as we had been experiencing persistent issues with our existing coolant that were impacting both productivity and profitability.
“The main ones were with tapping and threading on our machines, especially in our castings, and we knew that taps were not lasting as long as they should. The implications of premature tap failure when machining casting can be severe — even resulting in scrapped components. Furthermore, when we removed parts from the machine, there was a residue of coolant on them, which would fall onto the floor or the bench. The result was not only the cost of losing coolant but also the resulting trip hazard.”
Mr Aviles from Oemeta UK takes up the story: “Numachine invited us in for a meeting, at which they shared a details of the challenges they were facing with their current coolant. These included spending too much on their tooling and suffering a lot of sticky residues on components and on the machine. The company also wanted to move to something more sustainable.”
After analysing the situation, Oemeta’s technical team identified the root cause of the residue formation. Mr Aviles continued: “We identified two ingredients that could be the cause of the residue formation. We removed these from the process by recommending Oemeta’s Estramet S95, a metalworking fluid that simultaneously addresses all three of Numachine’s concerns.”
Technical advantagesMr Aviles explained: “Estramet S95 was recommended as it is free from fossil fuels and made up of ester oil, which is essentially a vegetable-based oil and provided Numachine with a sustainable solution. Additionally, this fluid could also deliver a 20% increase in tooling efficiency. The formulation of Estramet S95 represents a significant advancement in technology.
Based on renewable ester oils rather than mineral oils, the fluid delivers superior lubrication characteristics at the cutting edge, reducing friction and heat generation during demanding operations such as tapping cast materials. This enhanced lubricity translates directly to extended and consistent tool life, which are critical for machining costly castings that require a significant level of machining.
“The ester base solution is also formulated to exhibit low residue characteristics, so components emerge from the machine clean and ready for subsequent operations, eliminating the secondary cleaning steps that were previously required; and beyond performance, Estramet S95’s environmental credentials align perfectly with Numachine’s sustainability targets, as the elimination of fossil fuels reduces the carbon footprint of the machining process, while the renewable ester base offers improved biodegradability compared to traditional mineral oil-based coolants.
Before committing to a complete fluid changeover, Numachine and Oemeta agreed to a comprehensive six-month trial period with clearly defined KPIs (key performance indicators). Mr Hawkins said: “Mr Aviles visited Numachine to outline the KPIs that they would monitor; and six months on we are still seeing improvements on tool life, misting, residue on components, and foaming — KPIs that are being monitored.
“From day one of the trials Numachine noticed that coolant residue was eliminated and parts were coming off machines clean, saving secondary part cleaning. The tool life also improved, reducing our tool spend to a level that covers the additional cost of the coolant — and more. The improvement in tool life is particularly significant, as the 20% increase in tooling efficiency translates directly to bottom-line savings, with reduced tool purchases, fewer machine stoppages for tool changes, and decreased scrap rates from tool breakage.
Highlighted benefitsDetailing the benefits, Mr Hawkins said: “Since introducing Oemeta’s Estramet S95, we have reduced our consumption and costs for taps and threadmills by almost 40%. Machining castings is a large part of our business, so we have analysed this closely. On a regular batch of cast parts that require 42 holes tapped to depths of 3xD, we were changing taps every 60 parts; it is now 90 parts before changing taps.
“However, the benefits of Estramet S95 extend well beyond tool life and component cleanliness. The reduction of in-machine misting creates a healthier working environment and reduces part changeover times, while lower foaming characteristics ensure consistent coolant delivery to the cutting zone, eliminating the performance variability that foam can cause in high-speed machining operations.
“Indeed, the misting of machines and coolant evaporation has completely disappeared, and the noticeable smell of coolant in the workshop has gone. The new coolant makes the working environment a much nicer place to be; and as we have a target of achieving ISO: 14001 accreditation soon, we know that changing coolant will be a major benefit in our drive to achieve this.”
Mr Aviles added: “We extended the trial to two additional machines, topping up over their existing coolant to demonstrate compatibility and to avoid complete tank dumps. This approach proves that Estramet S95 can be introduced gradually, without the expense and downtime of complete system flushes. Numachine has now started rolling out our coolant across all machines, although we are first sampling all machines to assess their coolant condition.
“However, supplying Estramet S95 is only the beginning of our relationship with Numachine. Our aftercare is critical to everything we do, and we need to make sure we are offering all necessary support and keeping the coolant in top condition. Our technician John regularly visits Numachine to complete their coolant testing and give detailed feedback.
“This ongoing technical support ensures that the coolant continues to perform optimally throughout its service life, with regular monitoring identifying any developing issues before they impact production and detailed reporting providing Numachine with quantifiable data on coolant performance and condition. This coolant management extends fluid life, ensuring the operational and economic benefits continue long-term.”
Mr Hawkins concluded: “Every machine is scheduled for a ‘deep clean’ every 12 weeks. Historically, the labour, machine downtime time, and waste fluid removal would cost us £250 per machine. With Oemeta, the machines are much cleaner at our scheduled clean-out dates, making our turnround times much shorter and reducing our costs and labour input by 50%.”