Consider an LCA-nization (simplified automating) scenario using an actuator on a single axis manual slide mechanism. The Vol. 19 discussion was based on an premise of manually moving the work holders, and durability in slide mechanism design and material selections were not concerned. However, the reliability design becomes of an importance focus for LCAs using actuators.

The discussion will be based on a structure where a single axis slide mechanism replaced with a miniature linear guide (FA Mechanical Catalog P/N: SEB, etc.)

Various actuator characteristics [Table 1] and classifications [Fig.2] are shown below. Hydraulic cylinder types are not included since LCA scheme generally does not require the large actuating forces of the hydraulic driven schemes.

For an LCA actuator selection process, which of either the drive or the controls is more important must first be considered. Since the pneumatic systems use compressed air and not well suited for the control of velocity. When controllability is of more importance, electrically controlled systems are the better choice. In this discussion, an air cylinder was chosen since the application does not require velocity or position control capabilities.

[Table 1] Actuator Characteristic Comparisons

Actuating Force Responsive- ness Controll- ability Ease of Use Cost Size Pneumatic Linear motion is directly utilized Inferior Position Control Easy to Maintain Increased Length Electrical Rotary Motion Utilized Requires ball screws, etc. for linear motion Position/ Force Control Possible Requires technical aptitudes Rather High Low Profile Possible

[Fig.2] Actuator Classifications (Incl. Linear & Rotary)