"Screws" are the most widely used and imperative components for machine system manufacturing. They are classified by shapes, sizes and strength (class) according to the standards of JIS, ISO and etc. However, in many LCA design scenarios, the selection of the screws is relied upon the engineers' guessing based on experiences, as well as what's available on the shelf for assembly work sites. The tech. seminar will explain the tips and pointers as well as principles of "Screws".

(1) Design troubles in LCA designs

The LCA automation systems and fixtures are mostly fastened by the use of screws (incl. nuts and bolts). Therefore, designing with screws affect the following items.

Therefore, screw designing cannot be overlooked for the LCA designs that are lean and functional.

(2) Screw troubles during designing and post implementation

Screw troubles during designing and after the implementation can be classified as two of the following.

(a) Troubles arising LCA assembly and fastening ---- When there are LCA design errors

-Example

1. Correct bolts to fit the counterbore holes and thread depths are not in stock
2. Screw position is not aligned with mating threads.
3. Damaged threads during assembly.
4. Part is deformed from tightening force.

(b) Troubles arising when time has past after fastening ---- Errors in strength evaluation during designing.

-Example

1. Screws coming loose causing the parts to be misaligned causing equipment damages.
2. Destruction of bolts
   Both a) and b) are caused by the designer's ineptitude during designing.