Peter Lehmann turns the tables on university’s VMC 

A member of the Russell Group, the University of York has more than 30 academic departments, amongst them the University’s Department of Chemistry.

The department’s research groups cover a wide variety of disciplines, including atmospheric chemistry, renewable technologies and both medical and neuroimaging, all of which are supported by the work of a multi-disciplinary mechanical workshop.

Led by senior technician, Mark Roper, the workshop’s skilled staff undertake a wide range of projects, including designing and building bespoke instruments and apparatus for research and teaching purposes. Given the diverse demands placed on the workshop, the flexibility of its machine tools is vital to its effective operation. Therefore, when the need arises to purchase new equipment, Mr Roper looks for cost-effective products that add value and increase machining capabilities.

This policy is reflected in the recent purchase of a Peter Lehmann AG CNC rotary table that is now fitted to a DMG Mori CMX 600V, 3-axis vertical machining centre (VMC). The Lehmann TF-507510 model was chosen as it provided the required levels of precision, ease of use and flexibility.

In addition, the innovative design and low profile of the TF-507510 ensures minimum intrusion into machine tools’ working envelopes. Therefore, when compared to conventional, bulky rotary tables, the use of the compact TF-507510 results in much greater space being made available for spindle and tool movement.

Since being put into operation, the Lehmann CNC rotary table has significantly increased the effectiveness of the workshop’s VMC by enabling it to perform high-efficient 3+2 axis machining.

Mark Roper explains: “Our DMG Mori CMX 600V VMC has an X,Y,Z capacity of 600 x 560 x 510mm and its 900 x 560mm table has a maximum load capability of 600kg. Although the VMC’s specification allows us to produce a wide range of complex and accurate 3-axis work, we recently looked to further expand its capabilities into 3+2 through the addition of a CNC rotary table.

“As we have enjoyed the trouble-free operation of an older Lehmann CNC rotary table for over 10 years, we were aware of the quality of the company’s products. However, we wanted to make sure that we purchased the correct product for our own particular use and ensure we received best value for money, so in addition to Lehmann products we also looked at other brands and models. Having considered their merits of several CNC rotary tables we decided that the TF-507510 was ideal for our use.”

He continues: “Given the amount of one-off components we produce and the small production runs we perform, we need each of our machine tools to be adaptable. The Lehmann CNC rotary table has made a significant contribution in this area as it allows our 3-axis DMG Mori VMC to now perform efficient 5-axis machining.

“Fitting the rotary table has proven to be a practical way add to achieve five-sided machining in a single setup and to eliminate steps in our production process. Furthermore, the rigidity of the rotary table and its high clamping forces allows high cutting forces to be applied and high-precision workpieces to be produced.”

The TF-507510 CNC rotary table, as purchased by Mr Roper, is based on a solid steel baseplate that has two through bores, clamping elements and T-slot fittings. Secure clamping is assured by the use of a pneumatic-hydraulic system that applies a force of up to 800Nm, whilst a high-level of precision is aided by the use of a PGD backlash-free, long-life gear unit.

Lehmann CNC rotary tables represent a cost-effective means of entry into 5-axis machining for users of 3-axis VMCs. In this application, the tables are able to deliver a tilting A-axis and/or a rotational C-axis.

The extra available machining space that results from the use of the rotary tables means that additional workholding devices can be located alongside them. They are able to remain in the machine, or if required can be quickly removed and later replaced to suit the machining tasks being performed.

When involved in serial production a flexible VMC/Lehmann CNC rotary table combination provides a major advantage over the use of a 5-axis machining centre. By mounting additional workholding next to the rotary table, a virtual 6-axis condition is created.

In this arrangement, following the five-sided machining of a workpiece located on the rotary table, without interruption, machining operations can be performed on the next workpiece in a batch that is held in the adjacent workholding.

As CNC rotary tables are located inside users’ existing 3-axis VMCs, the problems associated finding floor space for an additional large machine tool are avoided. As the multiple advantages of purchasing a Lehmann CNC rotary table are gained without the need to invest in a 5-axis machine tool, a rapid return on investment soon follows.

Peter Lehmann has been involved in the design and manufacture of high-quality rotary tables for more than 40 years. Products are based on an innovative, standard modular system.

Peter Lehmann AG

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