Seiko Instruments Inc. Precision Machinery Division

Seiko Seiki Co., Ltd., the predecessor of Seiko Instruments Inc., was in charge of designing and manufacturing dedicated machine tools for watch manufacturing, and has focused on developing machines that can handle high precision and high productivity.

At the 1st Japan International Machine Tool Fair in 1964, Seiko Seiki exhibited the cylindrical grinder AUG25 for the first time and received favorable reviews. After that, we started the development of an internal grinder that developed the mechanism of a cylindrical grinder as the next product. In 1966, we exhibited the first product as an internal grinder, SIG3, at the 2nd Japan International machine tool fair. At that time, we started manufacturing and selling internal grinders.

Since then, we have provided a large number of internal grinders to manufacturing fields that require high processing accuracy, such as automobile parts and bearings, and have made progress with customers in the field of precision parts manufacturing.

Our technological philosophy of “Craftsmanship”, “Miniaturization” and “Efficiency” has been the key to all of our products.

To the future, we will continue to sincerely respond to customer requests through precision technology, without being bound by stereotypes.

Grinding is an important process that determines the accuracy of products in the manufacture of precision parts, and high machining accuracy is required for grinders. At the manufacturing sites of automobile parts and ball bearings, for which we have provided a large number of internal grinders, high productivity as well as processing accuracy is required. To meet such needs, we have continued our efforts to improve not only grinding accuracy but also processing efficiency.

Especially for grinding of small-diameter hole, in addition to the smaller diameter of the grindstone, the diameter of the quill that supports the grindstone is also smaller. Therefore, the rigidity of the tool support structure decreases, and it becomes difficult to improve productivity while maintaining high grinding accuracy.

We have solved these problems based on the know-how cultivated through many years of experience. We will continue to solve our customers' issues regarding accuracy and productivity.

In internal grinding, the diameter of the grindstone is inevitably smaller than the diameter of hole, so it is necessary to rotate the grindstone at a higher speed in order to obtain high machining accuracy and machining efficiency.

It is said that the peripheral speed ratio of the machined surface to the peripheral speed of the grindstone is about 0.02 to 0.05. For example, in the case of grinding a hole of φ30 mm, if the workpiece is rotated at 2,000 rpm, the grindstone must be rotated at 50,000 rpm. In addition, products are often required to have high shape accuracy, and not only high-speed rotation but also high rotation accuracy and rigidity are required.

At the time when the development of the internal grinder was started, the high frequency spindles for internal grinding were mainly made overseas. Therefore, we thought that the development of a high-frequency spindle with higher accuracy and rigidity than overseas products was the first priority, and started the development of our own high-frequency spindle. Since then, internal grinders equipped with in-house developed spindles have delivered more than 5,000 units to precision parts processing sites such as automobile parts and ball bearings.

Our strength and pride is that we can develop and manufacture high-speed, high-rigidity, high-precision grinding spindles, which can be said to be the heart of internal grinders.