Müller, the market leader in compact high-pressure for sliding headstock automatic lathes, transfers the main features and key technologies of existing product concepts and uses them to develop an intelligent system construction kit for unique compact energy-efficient high-pressure lubrication for higher flushing capacities.

The requirements with regard to cooling and high pressure in machining centres and lathes are vastly different from those of sliding headstock automatic lathes. Higher flushing capacities both in high pressure and flood cooling are essential. The optimum production results and safety, as well as efficient processes, can only be achieved with the “rightˮ flushing capacities, in particular with regard to dimensioning.

combiloop CL4 G – no more oversizing, inefficiency or wasting space

More than almost any other company, Müller is committed to developing and manufacturing particularly efficient and above all compact systems in good designs. “We have often been asked by partners and customers who appreciate our solutions from the field of swiss turning, about systems for their smaller machining centres. Whenever possible, we have then served them with predecessor models, although they would usually have been special units, not least with regard to delivery time, and this was not necessarily an area that we were focusing onˮ, explains Martin Müller, Managing Director of Müller Hydraulik GmbH. “ However, at our customers, again and again we saw something of which we thought was pretty bad: large lubricating systems or even high-pressure systems – in some cases bigger than the actual machine – standing next to small lathes. Units that often pump 300 l/min – for processes that require a maximum of 80–120 l/min. And then in use with inefficient technologies.ˮ

A standard practice model such as this is often a combination of compact belt filter and several constant pumps. The lack of compression effects in conjunction with the afore-mentioned oversizing also means that higher cooling capacities are required – all of which means that tremendous amounts of energy are consumed. As the result of these negative consequences for the customer and other considerations – inefficiency (costs, capacity) and the tremendous waste of space – the Müller team has addressed this problem in greater depth over the past two or three years.

combiloop CL4 G = efficiency³ + flexibility³ – for applications of up to 150 l/min flushing capacity

In doing so, it was clear from the start that it would not be possible to (nor would one want to) address these solutions on the big mass market in the field of machining centres and lathes. Rather, the task was to create a genuine Müller solution for a clearly defined group of users with smaller machining centres, both for retrofitting and for the initial equipment – efficient, powerful, particularly compact and in a good design. Customer enquiries and market experience gave rise to a relevant cluster of requirements with regard to tank and flushing capacities as well as pressure requirements. It was found that different quantities of pumps and pump configurations had to be facilitated. This resulted in the idea of a modular system consisting of three different basic versions in different basic sizes that the equipment options could then be added to.

This means that a range of budgets can be accommodated as well as the application-based practical requirements. The entry-level option, combiloop CL4 G-400, is a basic version with which the 400-l clean liquid tank does not necessarily have to have an automatic filter, but can alternatively be operated with a less expensive cascading filter. This consists of a pre-filter and a fine filter. This filter principle extends the lifetime, and facilitates greater flushing capacities (up to 60 l / 65 l per minute). Instead of exchangeable filters, the cascading filter uses washable filter elements, including large-scale ones – again, in order to minimise wear and thus operating costs overall.

// combiloop CL4 G-400

“The entry-level product combiloop CL4 G-400 gives us an attractive price/performance ratio for customers who don’t necessarily want to invest in better technology, such as fully-automatic filtration or an automatic filterˮ, Martin Müller sums up the product features, adding: “On the other hand, the versions combiloop CL4 G-600 and CL4 G-800 are available as full-flow filtration systems with large automatic filters of up to 150 l as high-end solutions.ˮ Automatic filtration is essential on the large versions. It eliminates the requirement for wear materials, in other words there are no consumables as there are with, for instance, the compact belt filter, which is usually the choice on this type of system.

The concept is generally aimed at achieving maximum energy efficiency by means of regulating pump technology and clever controls. This uses lower driving powers, which in turns means less input, and thus less heat generation in the cooling medium. If cooling is still required despite this, then a lower cooling capacity is required than, for instance, with constant pump-based systems.

The following table contains the main technical details of the different versions:

Technical DataCL4G-400CL4G-600CL4G-800             
  • Power supply 3∼/ PE 400 V / 50 Hz
  • Up to 2
  • Up to 3
  • Up to 4
Flow rate
and pressure
  • Max. 60 l/min, max. 300 bar
  • Max. 130 l/min, max. 300 bar
Filtration / Filter fineness
  • Cascading filter (500/40 μm)
  • Automatic filter (40 μm)
  • Automatic filter (40 μm)
  • Cutting oil
  • Water emulsion (min. 8 % oil content)
Service connections
  • Up to 10 controllable service connections

A number of different pump configurations (quantity, output) is available for all product versions in order to provide the maximum adjustment despite the high level of standardisation. Thus, for instance, the combiloop CL 4G-800 can be fitted with different pump configurations – e.g., two low-pressure and two high-pressure pumps – on the clean liquid tank.

// combiloop CL4 G-800

“We are extremely flexible, and can respond very well to customers’ wishes. And yet we have a modular system. We are able to stock and plan better. All in all, the modular system also helps us to create our production processes and delivery times more positively. In principle, along with the added value for customers in the actual use, this was one of the thoughts behind the further development of the predecessor versions to the standard programme CL4 G-400, CL4 G-600 and CL4 G-800. Then there is also the idea that important functions – such as the cooler of 4.5 kW, 7.5 kW or 12 kW, which was specially developed for us – can be retrofitted at any time if you realise there is a need for it, which again prevents you from having to spend money unnecessarilyˮ, explains Jürgen Müller, Technical Director and Head of Development. “Alternatively, of course, a panel heat exchanger can also be fitted for those who have already installed a cold water supply. We deliberately opt for the tried-and-tested. However, when it comes to technology, control and the options for configuration and retrofitting, we have not only reorganised things, but we have created many new things, and then integrated them in a new, modern look. The strength of our customers’ response tells us that we are on the right track.ˮ  

Use (retrofitting and initial equipment) “pre-programmedˮ – on Miyano, Gildemeister, Mazak and Doosan machines

Retrofitting in particular usually uses standard interfaces that are then shown in the customer’s tool machine. However, the combiloop CL4 G also sets standards in interface programming. In line with the close, friendly associations between Müller and leading machine constructors, interfaces have been created for various Gildemeister products (Sprint, GM) and for smaller Mazak and Doosan machines as well as, of course, for its long-term partner Miyano of Citizen. Machine communication, and with that the operation, is smooth and effective – including the initial equipment.

Jürgen Müller sums up: “Generally and conclusively, it can be said that in the combiloop CL4 G, we not only offer the perfect complement to the combiloop range, but also the transfer of our core competencies – filtration and high-pressure production – in a new segment. In principle, a combiloop CL4 G, and let’s leave out the cascading filter, is actually a product that stands next to the machine and when run in the CL in two or three shifts actually requires no effort on the part of the operator, and enables the known benefits of high-pressure cooling for smaller machining centres and lathes to be provided in a very compact form. And that’s what it’s all about.ˮ

// combiloop CL4 G-600


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