Mitsubishi Heavy Industries Technical Review Vol. 50 No. 4 (December 2013)
26“MVR-Dχ” Vertical Precision Milling Machine
A Reliable and Useful Solution at Machine Shops
for Railway Equipment Parts

Large Machine Designing Section
E n g i n e e r i n g D e pa r t m e n t
M a c h i n e To o l

The MVR-Dχ series of portal bridge type, 5-face milling machines are valued by customers
as high-speed and high-precision efficient machine tools, in addition to having a high-rigidity
structure that enables heavy cutting. Since their release in 2008, Mitsubishi Heavy Industries (MHI)
has delivered more than 50 machines in the MVR-Dχ series to customers in all industrial
machinery fields including construction machinery, motors and machine tools. In particular, many
have been introduced to customers handling railway equipment. This document presents examplesof where standard machines in the MVR-Dχ series capable of heavy cutting were modified to meet
individual customer needs, and resulted in further improvement of production efficiency.

|1. Machine Configuration and Primary Specifications
Figure 1 and Table 1 show the machine configuration and primary specifications of theMVR-Dχ series. The MVR-Dχ series covers part widths ranging from 2800 to 4300 mm, allowing
customers to select a machine that is suitable for their needs. In this lineup, standard specification
machines, special specification machines and customized machines tailored for individual
customers are separated, and the machine configuration is designed for the modularization andstandardization of the unit. The MVR-Dχ series has a wide selection of machine sizes in response
to customer needs, including table widths (determinative of the overall machine size) ranging from2000 to 3500 mm, table lengths from 4000 to 14000 mm, table loading capacities up to 100 tons
and column heights of 2050 to 4050 mm. In addition, this series can respond to quick delivery
requests. The MVR-Dχ series can cut not only box type parts that consist of 90 degree angled
surfaces, but also parts that require the cutting of 30 or 45 degree angled surfaces or free form
surfaces. In addition, various cutting demands such as the cutting of deep inside areas or narrowportions can be met. To enable these capabilities, a configuration where an automatic exchange
type attachment suitable for the cutting part can be mounted on the ram end is employed. Theattachment specifications are determined individually depending on the portion to be cut through astudy of cutting based on the part drawing provided by the customer.

Figure 1

Machine configuration of MVR-Dχ series

Mitsubishi Heavy Industries Technical Review Vol. 50 No. 4 (December 2013)27

Table 1
Maximum size of part to becutMain body specifications

Dimensions

TravelSpindle

Attachment

Speed

Table work areaColumn height
Table, back andforthSaddle, side tosideRam, up anddown
Cross rail, upand down
Rotation speed
Power output
Table, back andforth
Saddle, side toside
Ram, up anddown
Cross rail, upand down

W
Lmm

HW
Lmm

Primary specifications
MVR-28/34Dχ MVR-33/39Dχ MVR-38/44Dχ MVR-43/49Dχ
2800
3300
3800
4300
Depending on table back and forth travel
3550
4050
(depending on column height) (depending on column height)
2000
2500
3000
3500
4000 to 8000
5000 to 14000
2050 to 3550
2550 to 4050

XTable work surface length +1000Y3400

3900

4400

4900

mm
ZW

Standard 1000/Special 1200
1200 to 3200
2200 to 3200
(depending on column height) (depending on column height)
min-1
7 to 4000
kW
Standard 45/Special 55

X24Y

2030m/min
ZW

Standard attachment
Special attachment

15
3

5

Standard dummy plate
Standard right angle head (fixed angle)
Universal head (can be indexed to any angle)
5-axis head (continuous angle positioning)
Special attachments suitable for part to be cut|2. Examples of Cutting
For customers in the field of railway equipment, standard MVR-Dχ machines combined withattachments tailored to the customer's specifications have been delivered for the efficient cutting ofrail parts, exterior parts of the Shinkansen, railway car bogies and engine cradles. Some examples
are shown below.
(1) Cutting of rails (Mi-Ne Seisakusho Co., Ltd)This is an example of rail cutting that takes advantage of the heavy cutting capability of
the MVR-Dχ series (Figure 2). Rail steel is very difficult to cut because cutting vibrations tend
to occur due to its plasticity and hardness. In this example, however, the high rigidity of themain structural body consisting of the column, the cross rail and the saddle, and the highrigidity of the tool attained by enhancing the cutting tool clamping force to the utmost enable
the reduction of cutting vibrations. In addition, custom modifications such as a change of thetable top face shape, the addition of a hydraulic supply path for the fixtures and other measuresmake it possible to mount the rail fixtures on the top face of the table, and this contributes to a
reduction of the time period for rail setup change.

Figure 2

Cutting of rails

Mitsubishi Heavy Industries Technical Review Vol. 50 No. 4 (December 2013)
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Cutting of Shinkansen exterior parts (Akahane Seisakusyo Co., LTD)
This example was provided in response to the needs of the customer, who needed tomachine both standard parts cut by the standard spindle and high value-added Shinkansen
exterior parts having free form surfaces with a single machine. To meet this need, the machine
structure was modified so that the automatic exchange type 5-axis head could be mounted on
the standard spindle (Figure 3).

Figure 3(3)Cutting of bogies
For the cutting of railway car bogies, because there are many surfaces that are not 90
degree angles, an attachment that can be indexed to various tilting angles is necessary. Inaddition, the spindle-through coolant function, which feeds coolant through the center of thetool, has also recently become necessary because of requests for improvement in cutting
efficiency. Responding to these requests, a universal head that can feed coolant through thecenter of the tool even during inclined surface cutting, which was not available in the past, canbe provided for the MVR-Dχ series (Figure 4).

Figure 4(4)Cutting of Shinkansen exterior parts

Cutting of bogies

Cutting of diesel engines
To cut diesel engines, an attachment with a special form suitable for the cutting portion isnecessary. For crankshaft holes, a thin right angle head for the cutting of deep and narrowportions is needed. For camshaft holes, an L-shaped right angle head is required (Figure 5).

Figure 5

Example of diesel engine cuttingMitsubishi Heavy Industries Technical Review Vol. 50 No. 4 (December 2013)29

To cut diesel V-engines, a universal head is used for the cutting of inclined surfaces andcylinder bores (Figure 6). By employing separate storage in addition to the standard drum typestorage for the many attachments necessary for the cutting of engines, automatic exchange ofattachments, and as a result unmanned engine cutting operation, have been realized.
Furthermore, it is important for the cutting of diesel engines to take measures against thermal
displacement because the machine size is bigger in response to the size of the part to be cut.
The MVR-Dχ series employs the thermally symmetrical structure of the machine body and uses
heat insulating materials to meet the needs for precision engine cutting.

Figure 6

Example of diesel V-engine cutting|3. Conclusion
The destination to which the greatest number of MVR-Dχ series machines have beendelivered are customers in the field of railway equipment. At the same time, the MVR-Dχ seriesmachines are valued by customers in all fields including construction machinery, motors andmachine tools.
MHI will further enhance the MVR-Dχ series machines by reflecting the opinions ofcustomers in product development, and continue to offer products that meet their needs.