Tunalover
Mechanical
- Mar 28, 2002
- 1,179
The use of reference designators in lieu of find numbers on PWA drawings is widley practiced. But what about other assemblies besides PWAs?
I've used reference designators on general assembly drawings in years past but our CM Manager refuses to allow them. Her rationale is that in her career she's seen them used only on PWA drawings.
I contend that ref des are a great advantage on other assy drawings for their brevity and for their use in lieu of find numbers. For example, consider the following note:
ADHESIVE SHALL BE APPLIED TO A11 ON THE HATCHED REGION ONLY.
The use of the reference designator A11 in this note:
A. Makes the note resistant to any change in the find number; if the parts list find number ever changes then the note will need no correction.
B. Simplifies the note. For example, if the item is a NETWORK TRANSPONDER it's certainly faster and simpler to refer to the item as A11 rather than as TRANSPONDER or FIND NUMBER 12.
C. Makes the note resistant to change in item description. For example, as the product history evolves maybe a design change will change the item to a GLOBAL TRANSCEIVER. Again, the note will remain unchanged.
D. Empowers the use of reference designator chaining which makes it painless to refer to components at lower assemblies.
The advantages of using reference designators in lieu of description or find number is obvious to me yet there are people (like our CM Manager) who don't realize the benefits or have never seen it done.
Is there a CM standard somewhere that says this may be done Long ago we used IEEE 200 (or it's ANSI clone) but it is cancelled. There is now an IEEE 315 which seems to pick up where IEEE 200 left. But beginning with ASME Y14.100, where does it say reference designator may be used in lieu of find numbers? In fact, where does it say if (and how to) assign reference designators to parts and assemblies?
I liked the reference designator method also because it (if properly done) makes it easy (and concise) to identify a component in even the most complex system by chaining them together (with each ref des representing a level of assy).
Tunalover
I've used reference designators on general assembly drawings in years past but our CM Manager refuses to allow them. Her rationale is that in her career she's seen them used only on PWA drawings.
I contend that ref des are a great advantage on other assy drawings for their brevity and for their use in lieu of find numbers. For example, consider the following note:
ADHESIVE SHALL BE APPLIED TO A11 ON THE HATCHED REGION ONLY.
The use of the reference designator A11 in this note:
A. Makes the note resistant to any change in the find number; if the parts list find number ever changes then the note will need no correction.
B. Simplifies the note. For example, if the item is a NETWORK TRANSPONDER it's certainly faster and simpler to refer to the item as A11 rather than as TRANSPONDER or FIND NUMBER 12.
C. Makes the note resistant to change in item description. For example, as the product history evolves maybe a design change will change the item to a GLOBAL TRANSCEIVER. Again, the note will remain unchanged.
D. Empowers the use of reference designator chaining which makes it painless to refer to components at lower assemblies.
The advantages of using reference designators in lieu of description or find number is obvious to me yet there are people (like our CM Manager) who don't realize the benefits or have never seen it done.
Is there a CM standard somewhere that says this may be done Long ago we used IEEE 200 (or it's ANSI clone) but it is cancelled. There is now an IEEE 315 which seems to pick up where IEEE 200 left. But beginning with ASME Y14.100, where does it say reference designator may be used in lieu of find numbers? In fact, where does it say if (and how to) assign reference designators to parts and assemblies?
I liked the reference designator method also because it (if properly done) makes it easy (and concise) to identify a component in even the most complex system by chaining them together (with each ref des representing a level of assy).
Tunalover
