3. Motor Core
  4. MAC System


Motor Core

MAC System

MAC System

MAC system, stands for “Mitsui Automatic Core assembly system” is an innovative In-Die motor cores manufacturing system which was developed by Mitsui in 1975 in order to drastically improve the productivity of Motor Cores.

Since its first release in 1978, MAC system has been highly praised by electric manufacturers world-wide. One set of punching die, peripheral devices and its controller compose a MAC system.

MAC System features stacking lamination while pressuring by hydraulic cylinder.
This back-pressure method by hydraulic cylinder enable to produce quality motor cores with large sized materials as well as thin materials.
By introducing the MAC system, the core of the large diameter motor such as large drive motors of electric vehicle can also be made with high accuracy.

View the details of MAC system controller

Upon a user’s request technical training is available to support installation and most efficient operation of MAC system.

Improvement of quality
It is possible to carry out core-turning and alternate interlocking so as to control the decrease in product quality due to the variation in material quality.


Thickness of coiled material is not uniform. Therefore, even if the difference in thickness on a piece of material sheet is slight, the total difference will be significant when several tens of material sheets are laminated.
In order to eliminate such a significant difference, a core under forming by lamination in a die is turned by 90 or 180 degrees, by which the difference produced by lamination can be minimized.Finally, the accuracy of straightness, squareness and parallelism can be increased.

Alternate interlocks

Alternate interlocks
In conventional interlocking, a gap is generated at the corner (shown by a blue arrow) due to the bend dimensions, causing an undesirable wider gap between material sheets.
In the case of alternate interlock, the cut and bend direction is alternated so as to make a space at the corner portion (shown in a red arrow), reducing the gap between material sheets.

Capable of producing various shapes

MAC system can produce cores of various shapes such as skewed, V-skewed and counter-bored as well as straight.

Capable of producing various shapes