November 2012 Archives

One of the important achievements of the automation is to stablize the production quality of products at high levels. In addition, there are other manufacturing processes that are quality improved by secondary effect of automation ([Fig.1]). In this session, the latter case will be explained.

Example description: Automating a molded product extraction of plastic injection molding process

- With plastic injection molding, the molded plastic products are produced by injecting melted plastic into metal molds, then plasticized by cooling down.

- For the molding processs, a plastic injection molding machine ([Fig.2]) and a mold ([Fig.3]) are used.

- By replacing the molded plastic product extraction process from human work to extraction robot automation, injection molding quality can often be improved.

Since its starting in 2001, the 1st year of the 21st century, the Low Cost Automation Technology Course has reached the Vol. 400. Our environment has changed largely in these 8 years. The investment monies have flowed into oil and other resources, the automotive society has changed with soaring gasoline prices, hybrid automobiles have resurfaced in popularity, and further advent of electric and hydrogen fueled cars are awaited.

If the first decade of the 21st century is denoted with a representative technology reformation of gasoline combustion energy and rolling friction to clean energy and rolling friction, bio-mechanisms would be in utilization by the last decade of the 21st century.

- [Fig.1] is a bacteria.

- [Fig.2] is an explanation of this bacteria's motion method where it moves in swimming-like motion with its rotating filaments.

- [Fig.3] mechanically explains the bacteria's cellular structure of rotating filaments.

- It has a similar structure with automated machinery: Bearing=Rings, Coupling=Hook, Drive shaft=Filament, Enclosure=Membrane would represent structural components of today's automated machinery.

Problems such as friction and wear may not present any issues on life problem as they do today due to its biochemical effects.

Since the ball screws are designed based on rolling steel ball bearings, product service life calculations are backed by a solid theoretical system.

(1) Life of rolling ball bearings

(2) Life of a typical ball screw (Life in a narrow sense)

Other than ball screws with high preloads, the typical ball screw life can be approximately determined by the following calculation formula (07 MISUMI Catalog, P2532)

Increased demand for the ball screw noise reduction is due to, not only to the conventional production factory environments, but increased ball screw applications in quiet environments (low noise levels) such as offices, hospitals, and food production lines. Furthermore, ball screw noise reduction links to improved functionalities such as energy savings and extended operational life, thus it is inevitable for performance increase.

(1) About ball screw noise reduction

Comparisons are made below between the construction and noise generating conditions of rolling ball bearings, rolling ball bearing style linear guides, and ball screws.

(2) Noise source (= vibration source) of ball screws

(3) Noise reduction measures as a mechanical system