Mitsubishi Heavy Industries Technical Review Vol. 51 No. 3 (September 2014)
47

Innovative Multi-servo System Wrap-around Caser- Reduction of Life Cycle Cost -M i ts u b i s h i H e a v y I n d u s t r i e s
F o o d & P a c k a g i n g M a c h i n e r y C o , L td ,Mitsubishi Heavy Industries Food & Packaging Machinery Co., Ltd. (hereinafter referred toas MHISK) has contributed to domestic and overseas physical distribution/sales methods throughthe delivery of more than 4,000 packaging machines to various fields mainly including the foodand beverage industry. In recent years, delivery to countries abroad has been increasing mainly inAsia, and therefore MHISK is required to respond flexibly to external changes such as a shift tomachines that conform to local conditions (specificity) and the requests of the destination areas.
In addition, domestic market demand has increasingly focused on not only the quality andperformance of the machine itself, but also its compatibility with constantly-changing external
circumstances such as reviews of packaging materials for resource saving and cost cutting, theimprovement of container shapes in consideration of consumer preferences, and the concretizationof control criteria for ensuring packaging quality.

|1. Integration of mechanical components and servo technology
1.1

Diversification of demanded specifications

MHISK’s packaging machine is a so-called caser that automatically performs external
packaging (cardboard boxing) of the products to produce packaged boxes that are used for selling
units or transporting units. Many casers are used for food and beverage products including drinks(PET bottles and cans) and instant noodles (Figure 1).

Figure 1

Process flow of caser

The machines that play a central role among MHISK’s casers are beverage casers. Even
when a PET bottle, one of the typical packaged products of the beverage caser, is considered, there
are a wide variety of container specifications including shape, size, and hardness. The trend
towards the diversification of containers is going to continue to increase on a global basis.
The operation of a packaging machine has become complicated as seen in the increased number

Mitsubishi Heavy Industries Technical Review Vol. 51 No. 3 (September 2014)
48of parameters such as alignment and speed that have to be set as a result of an increased number ofcontainer types. In addition, mechanical components used in a packaging machine inevitably have
uncertainties such as age deterioration including the elongation and backlash of chains. As a result,some customers face difficulty in terms of maintaining the optimum machine conditions.
For easy maintenance of constant packaging quality, MHISK has developed a multi-servo
system that enables a packaging machine to have functions to make a database of set values and tounderstand the real-time conditions of each machine part.

1.2

Multi-servo system

Existing beverage packaging machines use a single motor as the drive source, and theiractuator structure contains various mechanical components linked in a complicated manner.
The developed multi-servo system eliminates drive transmission mechanisms only, and stilluses local mechanical components that are an accumulation of past technologies. Multiple
servomotors are located locally at places where drive is needed and controlled fully synchronously.
As a result, the integration of the advantages of mechanical components and servo technologies isestablished (Figure 2 and Figure 3).

Figure 2 Drive components of conventional
packaging machine

Figure 3 Drive components of new
packaging machine

Mechanically linked system is employed.

Multi-servo driving system is employed.

The establishment of a multi-servo system is expected to bring the following effects.
Shift from analog management to digital management
Digitalization due to use of the servo allows for numeric conversion of set values andthe creation of databases. In addition, visualized management, such as monitoring andcomparing with past results, of data for securing and maintaining the machine functions andquality, including the position, speed and torque data, is made possible.
(2) Reduction of life cycle cost
Electric power consumption can be reduced due to employment of high-efficient motor
and reduction of drive transmission loss. The elimination of drive chains, etc., allows for thereduction of cost for periodic maintenance.
(3) Improvement of machine operation environment
The reduction of mechanical links significantly improves the low-noise characteristics
and maintainability of the machine. The enhancement of the man-machine interfaceincluding visualization improves operability. In addition, the ability to monitor operational
data contributes to preventative maintenance.
(1)|2. New technology responding to changing times
2.1

Change of external circumstances

In the beverage container field, in addition to appearance characteristics such as size andform, the weight reduction (thinning) of the materials that constitute the container has also beenadvancing. Such changes in containers have the potential to turn the functions that conventionallydepended on the container itself (the shape based on the shape retaining strength and certain rules)
on their heads. In this way, the roles of packaged products and the machine have been changing
over time.
Therefore it is necessary for packaging machine technologies to advance in response to theMitsubishi Heavy Industries Technical Review Vol. 51 No. 3 (September 2014)49

expansion of their assigned role. MHISK has developed its own technology, the fingerlessgrouping mechanism, based on a new idea.

2.2

Fingerless grouping mechanism

To package beverage containers, a grouping process that divides containers into thepackaging unit (specified number) is required. Existing machines perform grouping by inserting abar-shaped finger stopper into a gap of the container row on the conveyer from below to block thecontainers that follow. Because this method is based on a container strength higher than a certain
level that can withstand the force generated by blocking the conveyed containers, it is not suitablefor containers that have a lower strength due to weight reduction.
The fingerless grouping mechanism eliminates the finger stopper, which may cause thedeformation of the containers, and employs a grouping method that uses a speed difference
between conveyers.
The operation principles of the fingerless grouping mechanism are as follows.
(1) Containers flowing on the conveyer are placed on a movable sheet material, referred to as amobile sheet, and they move at the same speed as the conveyer (Figure 4).
(2) When the containers are transferred to the subsequent conveyer, a sheet of the length
corresponding to the packaging unit (specified number) of containers is pulled out. The
containers that were on the removed part of the sheet are conveyed by the subsequentconveyer (Figure 5).
(3) Because the subsequent conveyer is faster than the first conveyer, containers on thesubsequent conveyer are separated from the containers remaining on the sheet.

Figure 4 Operation principle of fingerlessgrouping mechanism [1]Containers are placed on the mobile sheet and thenconveyed.

Figure 5 Operation principle of fingerlessgrouping mechanism [2]The mobile sheet is pulled out and the containers aretransferred to the subsequent conveyer.

The establishment of the fingerless grouping mechanism has enabled the elimination of amechanism that applies unreasonable force to containers and allows the machine to handle
weight-reduced containers that were not compatible with existing packaging machines. In addition,
the fingerless grouping mechanism has increased the leeway the machine has to deal with theevolution of containers that is expected to continue to advance in the future.
The fingerless grouping mechanism can not only handle weight-reduced containers, but also
results in the following advantages.
(1) Easier container size changeover
The time required for container size changeover can be shortened because the finger
stopper that needs to be changed according to the container diameter to be packaged iseliminated. Although the evolution of containers has a tendency to make the container sizechangeover complex, the elimination of the finger stopper contributes to reduced labor.
(2) Improvement of maintainability
The elimination of the finger stopper mechanism installed under the conveyer canmake space for maintenance in the machine and improve easiness of cleaning.
MHISK’s unique fingerless grouping mechanism technology is unprecedented in the industry
and can generate synergistic effects when combined with the multi-servo system. MHISK’s casers
equipped with this combination have acquired a favorable reputation from many customers.