for Stamping Die Sets

Features of Cross Roller Unit and Flat Roller Unit

The GuideMax is available in two standard types - a cross roller unit in which cross rollers are arranged, a flat unit in which needle rollers are arranged, so that the appropriate unit can be selected according to the type of the stamping and the stamping die size.

Cross Roller Unit

Roller bearings are alternately arranged on the 90fV - shape raceway. The ratio of the roller diameter to the roller diameter to the roller length is almost 1:1, so rollers hardly incline under operation (prevention of skew phenomenon.)
Since each of the roller bearings is inclined 45fV from the center of the post(or bushing), the pressure cone apex distance is long and therfore the roller bearings works more effectively as the post diameter becomes larger in relation to the moment weight. Roller bearings in odd-numbered rows are in contact with posts in a swirly manner , alternately roller bearings in even-numbered rows in a swirly manner,so the number of idle roller bearings can be minimized in all directions and errors such as poor perpendicularity of the installed post can be made up, achieving outstanding straightness and repeated accuracy.

Applications: Stamping Dies and machinical equipemnts requiring high perpendicularity, high speed, and high rigidity.
( Stamping Dies for lead frames, connectors, relays, thin films, and semiconductor-related device )

Flat Roller Unit

A lot of needle rollers are arranged on a flat raceway. For roller bearings retention system based on‚ Enomoto's molding technology, the clearance between roller bearings and retention material is extremely minimized and therefore a great numbers of roller bearings can be arranged in a limited area, attaining rigidity as high as that of the plain guide posts.
Normally, a skew phenomenon ( inclined roller motion ) is more likely to occur as the roller bearings become longer in relation to the roller diameter. When this phenomenon occurs, various problems ( for example, a quick increase in frictional resistance, shortened roller life-span, impaired precision, and an increase in torque ) arise. To solve these problems, perpendicularity, parallelism, and accuracies of guidance have been improved by the GuideMax bearing system as far as possible. Furthermore, the roller bearings retention material is manufactured of special resin so that the minimum clearance needed to rotate the roller smoothly is maintained, allowing the proper position to be kept constantly.

Flat roller unit is supplied to a mechanical z-axis usage, not to a stamping toolings.

Crowning

Effect of Passage of Roller upon Bushing End
A guide post for stamping die is classified under the non-circulating roller type because the retainer (of the roller bearings) moves by one-half of the stroke length. When the stroke is long, the roller moves in and out of the bushing in many cases. The roller bearings which is larger than the clearance attempts to enter the clearance suddenly to apply pre-load to the narrow clearance. At this time, a very large force called Hertz stress is exerted upon the bushing end, resulting in early peeling, shortened life-span, and strong vibration.
That is, the product performance greatly depends on the shape of the bushing end.

Crowning of GuideMax Posts/Bushings Ends
To reduce the Hertz stress, both ends of the GuideMax bushings are R-chamfered and both ends of the raceway are crowned. That is, gentle "relief " (round of linear) of several micrometers 5~10(mm) is provided for both ends of the bushing roller raceway, starting at the center toward the ends by NC.
Thus, the roller is smoothly guided into the bushing and consequently the Hertz stress is reduced significantly, assuring the designed lifetime and prevention of vibration. The top of the post is also crowned to assure safety during installation or when the retainer protrudes from the top of the post.

© Copyright 2001, Enomoto USA