Low Cost Automation Tutorial

#113 Clean Room Compatible LCA - 4: Layout Arrangements for Clean Room LCA

Category : Clean room technology

April13, 2012

Layout of LCA (Low Cost Automation) mechanisms for clean room usage are to be designed with emphasis on the following two knowledge's.

1. Consider the relationship of LCA and localized cleanliness formats (see Vol. 244).

2. Apply "3 principles of cleanliness" (see Vol. 114) to the areas where contaminations are to be avoided.

Here, LCA mechanism layout formats for clean room usage regarding the item 2. above explained.

Moving LCA mechanism will generate particulate. The key point is not to bring in any contamination into the process core (work area).
Contamination is introduced by air flow and gravity (free-fall). Devise mechanism layouts to avoid the effects.

■Example
a）	Drive mechanisms will generate particulates and lubrication scattering. These contaminants are relatively heavy and will fall by gravity. In order to obtain clean process cores, position the drive mechanisms below the process cores. (In case of Walking beam mechanisms and etc. (see [Fig.1])
b）	In case of Pressurized turbulence type of simplified clean designs, provide exhausts near the contamination generating mechanisms ([Photo 1]), or cover the entire mechanism and provide a localized exhaust ([Fig.2]).

[Fig.1] Example of locating the mechanism below the work are (Walking beam transfer mechanism)

[Fig.2] Example of localized exhausting

Make fixture structure and layout less prone to contacting and accumulating contaminants.
■Example
a) Fixtures that hold workpieces inverted or vertically.
b) Do not create any congested air flow on workpiece surfaces.
In order to obtain better cleaning effects, concentrate all the contamination generating mechanisms down flow.

[Fig.3] Layout improving examples of not creating air flow congestions on workpiece surfaces