Flexible Finishing Machine
M-CM5AL Aimed at Automobile
Engine Cylinder BlockSALES DEPARTMENT, MACHINE TOOL DIVISIONIn manufacturing facilities for automotive parts, it has been a challenge to realize high-variety flexible-volume manufacturing in
the finishing process. The flexible finishing machining center M-CM5AL is a product that solves such a technical challenge and isused in many mass production lines. The following describes the features of the M-CM5AL and the advantages for manufacturinglines using this product.

Measuring head

1. Product specifications
Table 1 shows the major specifications of the M-CM5AL.
In addition to five machining axes (X, Y, Z, A, and B) anda magazine for standard tools, the machine has a special
magazine on its side face. The special magazine can store
three tools in total, including crank-bore finishing line bars
and machining accuracy measuring heads.

870 mm

2. Product features(1) Automatically changeable crank-bore finishing line bars
The M-CM5AL can automatically change line bars
with a tool length of 870 mm and a weight of 30 kg, as

Special crank-bore machining toolFig. 1 Special magazine

Table 1 Major machine specifications
HSK−100A

Max. spindle speed

6 000 min−1

Max. motor power
Axis travel
Rapid feed rate
Table

Tool magazine(Standard)

Tool magazine (Special)for (1) crank-borefinishing and (2)measuring of cylinderand crank bore

30 kW

X-axis

700 mm

Y-axis

610 mm

Z-axis1 200 mm

X-, Y-, and Z-axes

50 m/minStandard

B-axis

Optional

A-axis or AB-axes

Max. tool diametershown in Fig. 1. In addition, it uses a drawer-style linebar storage design for easy maintenance, including thecutting tool adjustment.
(2) Line boring with both ends supported
T he M- CM5A L enables the line boring with theConcentricity of crank bore

SpindleSize

250 mmMax. tool weight

15 kg

Max. tool length

360 mmTool storage capacity

20 tools

Tool change time (T-T)

2.5 secMax. tool diameter

145 mmMax. tool weight

30 kg

Max. tool length

870 mmTool storage capacity

3 tools

Tool change time (T-T)

8 sec

Required tolerance
Cpk 2.5

123

4

5
6
7
Workpiece No.

8910Fig. 2 Measured concentricity of crank bores (continuous machiningof 10 workpieces)

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 45 No. 3 (Sep. 2008)

43Standard range

Variation in measurements ( m)

OP120

1.2
0.6
0.0
−0.6

C/T60 sec
Production model
One model only(I4)A finishing line consisting of special-purpose machines
It is possible to integrate all tasks
C/T 60 secof the finishing process
Production model
into a single machine and adjust
Two models
the production volume(V6 and V8)by the number of machines.

−1.2
#1

#2

#3

#4

#5

#6

#7

#8

#9

OP130

#10

Data No.
Fig. 3 Variation in measurements with every tool change

OP120 & 130

workpiece supported by the line bar the both ends ofwhich are on the supports, which is a well-establishedmachining technique in mass -production lines. Asshown in Fig. 2, the machine offers a process capabilityof Cpk 2.5 in terms of concentricity of the crank bore incontinuous machining of 10 workpieces.
(3) Automatically changeable measuring heads
The M-CM5AL can automatically change the measuring
heads used for measuring machining accuracy of cylinderand crank bores. As shown in Fig. 3, it guarantees arepeatability of 1.5 μm or less in the measurement datafrom 10 workpieces.

A finishing line consisting of M-CM5ALsFig. 4 Comparison with a conventional special-purpose line

to a large difference in the bank angle of the cylinder
bore as well as the cylinder bore number. However, theM-CM5AL, equipped with an automatic tool changer andthe A- and B-axes controlled table, offers the capabilityof mixed production through the use of ID tags or othermeans.
(3) Improved cost efficiency
The graphs in Fig. 5 show results of the comparison
between a line consisting of conventional special-purpose
machines and a line using the M-CM5AL, in terms of
the relationship between production capacity and capital
investment (Fig. 5 (a)) and between production volumeand cost per workpiece (Fig. 5 (b)), respectively. In lines
consisting of conventional special-purpose machines, thecapital cost at the start-up and reduction of production isextremely large because investment is made taking into
account the maximum production volume. In contrast, inlines using the M-CM5AL, the cost per workpiece can bemaintained at a low level because capital investment can bemade based on the production volume and the production
facilities can be easily standardized among different lines
for potential convertibility. Thus, the M-CM5A L canimprove the cost efficiency per capital investment.

3. Advantages for manufacturing lines using this product(1) Stepped investment and adjustable production volume
Figure 4 compares a manufacturing line consistingof conventional special-purpose machines with thatconsisting of the M-CM5AL. The use of the M-CM5AL
allows all finishing tasks to be completed on a singlemachine, although conventionally a line of specialpurpose machines with several machining units must
be constructed for the finishing process. In addition,
varying production volume needs can be addressed by theuse of multiple M-CM5AL, by increasing or decreasing
the number of M-CM5AL in the manufacturing line.
(2) High-variety manufacturing
In a line consisting of conventional special-purpose
machines, it has been difficult to machine a mixture ofproducts, V6 and V8 cylinder blocks for example, due• Capital investment based on production volume• Reduced cost per workpiece: Line consistingof special-purpose machines

Investment

F+Vcost: Line consistingof M-CM5AL

050
100 150 200 250 300 350
Annual production capacity (thousands)(a) Investment breakeven050 100 150 200 250 300 350
Annual production volume (thousands)(b) Cost comparison

Fig. 5 Comparison of cost efficiency

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 45 No. 3 (Sep. 2008)44