Cost-efficient and sustainable machine overhaul

In 1871, Ernst Körting invented the steam jet injector as a boiler feed pump and founded the company Gebrüder Körting in Hanover with his brother Berthold. Today Körting Hannover GmbH has subsidiaries in Brazil, China, India, Malaysia and Poland, and ranks as a leading manufacturer in the development and production of application-specific jet pumps, vacuum engineering products and environmental technology.

The company manufactures its demanding components on CNC machine tools from DMG Mori, among others. They include a DMU 125 FD duoBLOCK installed in 2006, which has been made fit for at least another 10 years thanks to a general overhaul completed in 2022. Jet pump ejectors for wastewater treatment application are made of polypropylene and have been produced this machine since its arrival. In 2021 Körting considered investing in a new machining centre.

“However, the DMU 125 FD duoBLOCK was technically suited to our requirements, so we decided to commission DMG Mori Used Machines to overhaul our existing model,” explains plant manager Jürgen Sack, who outlines some of the many benefits. “Firstly, we would have had to invest at least twice as much for a new model. Secondly, the overhaul did not require any changes on the shop floor and we were able to continue using our existing tools and equipment, such a fixtures and NC programs. Thanks to the manufacturer’s more modern, high quality parts, the accuracy of the machine is also improved. What’s more, we benefit from a six-month warranty and 10-year availability of spare parts and service.”
For further information www.dmgmori.com

A successful large-scale mill-turn project

Soraluce customer, Krones, from Neutraubling, Germany, required a mill-turn machine with a fixed portal and two movable milling and turning rotary tables, each with a diameter of 6 m, in double-table design and a high degree of automation. To complicated matters, the project commenced in the middle of the Covid-19 pandemic.

All arrangements could only take place by telephone and video call – a visit to the manufacturer´s plant or to the customer during the decision-making phase of the investment was ruled out for safety reasons. The customer´s concept was supported by figures, data and 3D simulations, but finally seeing the finished machine, a PR 6000 2T, after the months of planning and discussion – 32 m long, 14 m wide and weighing just under 300 tonnes – is a whole different story. It is not just a large portal milling and turning machine, but one of the largest machines with a double-table design in Germany.

While machining on one milling and turning rotary table, set-up can take place on the other. At Krones, the company uses the machine to produce roundels for bottling in the food industry. With a tool-change system featuring 500 tools and an ABB robot for the changeover, the degree of automation is optimal. Process control comes courtesy of a Siemens Sinumerik One CNC. Soraluce created a digital twin for the plant that simplified and shortened commissioning on site considerably.

A follow-up order for a fully automated production line with three portal milling and turning machines connected to a large pallet station and central tool magazine, confirms the confidence in Soraluce. Machine tools from Soraluce are available in the UK from TW Ward CNC Machinery.
For further information www.soraluce.com

Supersizing Wind Power Production

Denmark-based HACO A/S has invested in two large-capacity Droop+Rein portal-type machining centres from Starrag to meet the rising demand for components for larger offshore wind power turbines having outputs of up to 16 MW. The new machines will perform the complete machining of components such as rotor housings (with diameters up to 10,000 mm; though sizes up to 11,500 mm are also now under consideration), as well as front and stator sheets, brake discs, and other components. HACO’s ‘supersizing’ of its production enhances its established (60 years) contract manufacturing success.

When it comes to wind power, Denmark is leading the way: electricity generated by wind power fulfils 40% of the country’s energy requirements, and HACO’s prime customer, Valmont SM A/S, is a leader in the supply of steel components to the wind-power sector.

HACO currently processes around 10,000 tonnes of high-strength steel each year, but the wind-power sector is now also looking increasingly at the use of aluminium alloys, castings and composites, so the company’s investment in the two new machines was taken with these materials in mind.

The choice of Droop+Rein machines for this significant investment was based on HACO’s long-standing experience with Starrag on machine reliability/longevity, customer service, machine price and the delivery schedule of the new duo. Until now, Valmont has been transporting the welded blanks to HACO’s site 100 km away but, with this multi-year contract now embracing larger components, the two companies have decided on a more sustainable form of collaboration which sees HACO establishing a subsidiary plant for the two new machines close to Valmont’s HQ, which is near the sea to allow convenient shipping.
For further information www.starrag.com

Renishaw opens technology centre in India

To support its rapidly growing customer base in India, Renishaw opened a new technology centre in Bangalore last month. The new facility provides customers with access to demonstrations of the company’s solutions for metrology and material analysis. Spanning 12,000 sq m, the site houses Renishaw’s technical, operations, and sales and marketing teams, as well as the warehouse and technology centre.

The centre allows companies to work with engineers to understand how their processes can become more efficient and productive using Renishaw technologies. Visitors will be able to view demonstrations of the company’s product portfolio, including its metrology equipment for process control applications. The investment is seen as crucial in enabling Renishaw to keep up with India’s rapid industrial growth.
For further information www.renishaw.com

SUBCONTRACTOR BUYS SLIDING-HEAD LATHE FOR HIGH PRODUCTIVITY AND “AN EASY LIFE”

These days, when turning and milling components less than 38 mm in diameter, it is difficult to justify using a fixed-headstock CNC lathe, such is the high level of capability, productivity and flexibility of modern sliding-head turning centres. This is the view of Martin Lock, owner of 55-years-established subcontract machining firm PES Engineering, based in Burnham-on-Crouch, Essex, who recently took delivery of a Cincom L32-XLFV sliding-head lathe from Citizen Machinery UK.

He says: “We held off investing in this technology before, as up to about five years ago sliding-head lathes were not as flexible as their fixed-head counterparts in terms of their power or the number of tools in the working area. Consequently they could not produce such a wide variety of components, but that is no longer the case. Modern sliding-head lathes are able to produce anything a fixed-head equivalent can, and on average completes the same cycles in two-thirds of the time. It is down to the speed of movement of the gang tooling and the wealth of static and live cutters that can be deployed.”

PES Engineering has over the years developed a reputation for supplying components in small to medium size batches, typically 3000 to 5000-off. The company often produces larger quantities for Kanban call-off by customers. Materials range from stainless steels, which account for half of throughput, to plastics, which make up another 20%. Both tend to generate stringy swarf when machined on the subcontractor’s fixed-head lathes.

Swarf invariably wraps around the tool and the component, risking damage and prematurely wearing the cutting edge of the carbide inserts. To mitigate abrasion it is necessary to reduce feed rates, at the expense of production output. Furthermore, it is generally necessary to stop a lathe regularly to remove the swarf, making light-outs running virtually impossible unless processing a free-cutting material like brass. All of this negatively impacts productivity and profitability.

There are no such problems on the Cincom sliding-head lathe as it is equipped with Citizen’s programmable low frequency vibration (LFV) software. Loaded in the operating system of the Mitsubishi control, LFV breaks the swarf into smaller chips. Launched five years ago, the three modes of LFV developed to improve turning, grooving, drilling, boring, threading and parting-off not only avoid bird’s-nesting, but also reduce or eliminate the need to use expensive and energy-hungry high-pressure coolant equipment.

“LFV has removed much of the aggravation of turning stainless steels, which gives us a much easier life,” says Lock. “We can machine efficiently everything from 304, which is billed as free-cutting but really is not, through to highly alloyed marine grades. With LFV, oscillation of the spindle relative to the axis feed motion momentarily and repeatedly lifts the tool clear of the component surface. It has the effect of breaking the swarf before it has a chance to form a string and also lowers the temperature at the point of cutting, reducing work hardening of the metal and preventing built-up edge on the insert.”

He continues: “We have LFV switched on permanently when machining plastics and it works perfectly, even on nylon. When processing stainless steel, for nine out of 10 components we produce it is engaged for typically half of the cycle and always for parting-off. Programming the function to stop when it is not needed limits the milliseconds of slightly decreased metal removal rate when the tool is air cutting.”

Strategies that Lock previously used to control swarf length included introducing peck feeding and dwells, which extended cycle times and accelerated tool wear, and experimenting with different chip-breaker designs on the insert. None of this is needed any more, as he says most materials chip like brass simply by selecting cutting parameters out of Citizen’s LFV manual.

At the end of last year, two 40 mm capacity fixed-head lathes producing 304 stainless steel medical parts broke down on the same afternoon, prompting Lock to look for a replacement. As sliding-head technology had advanced sufficiently, he decided to go down this route. He was in regular contact with another subcontractor with which he occasionally shares work. That company operates 10 Citizen lathes, including LFV Cincoms, which have proved reliable and accurate over the years. Once a machine is warmed up and set, tolerances do not move and machining to within microns is routine.

It therefore made sense for PES Engineering to opt for the Citizen brand. An L32-XLFV was duly ordered with a conversion kit that allows stock up to 38 mm in diameter to be fed from an Iemca 3 m bar magazine. Immediately apparent was the sheer speed of the machine, with many parts coming off more than twice as quickly compared with the output from one of the ageing fixed-head lathes. In one extreme case when turning a plastic part unattended, 400-off were produced in two hours instead of over a full manned shift.

Two tools can be in cut simultaneously on the slider for high levels of productivity. Moreover the latest-generation L32-XLFV has a Y2 axis on the sub-spindle, allowing cutting operations to be shared more evenly between it and the main spindle, minimising cycle times.

In the first three months of operation, the slider produced 20,000 parts of around three dozen varieties, all but one of which were in length less than 2.5 times the diameter. The majority were therefore not classical sliding-head work, so Mr Lock plans to take advantage of the ability on most Cincoms, including the L32, to remove the guide bush. The main advantages are the ability to use less expensive bar, as straightness and dimensional variation are not so much an issue, and a four-fold reduction in remnant length at the end of each bar, leading to significant material savings.

The Cincom is not only the first sliding-head lathe that Lock has bought, but it also represents the first time he has dealt with Citizen Machinery UK. He has been impressed with the supplier’s service, which he describes as “refreshing”.

“We’ve had fantastic human interaction and service from everybody in the company, from the sales team through ordering, machine installation and commissioning to service back-up,” he says. “If we email or phone Citizen’s service department, we receive a call back in half an hour – sometimes within a couple of minutes – something other suppliers never seem to do in our experience. With the Cincom being our first slider, we were reliant on prompt and comprehensive telephone advice at the outset and still are to some extent. It has proved invaluable.”

Established in 1967 by Lock’s father Clifford and a partner who subsequently left, PES Engineering derives its turnover from milling and turning in approximately equal measure. Industries served include aerospace, automotive, medical, hydraulic, rail and electronic connectors, and customers are to be found throughout the UK as well as in the US and Germany.

In conclusion, Lock says: “Automating the turning side of our business using a bar feeder is much easier, cheaper and less space consuming than retrofitting one of our machining centres with robotic machine tending. So I decided that investment in autonomous turning and milling of components in one hit was the way forward, and it is proving to be the right choice.

He adds: “We will now progress to turning on the L32 without the guide bush for all but the longest shaft-type components, which are rare orders for us at the moment as we are not known as a sliding-head shop, but of course we are now in a position to fulfil that work. The expectation is that we will also use the Cincom for machining purely prismatic parts with no turning at all apart from parting-off, which will go some way to automating production of some of our milled parts as well.”
For further information www.citizenmachinery.co.uk