I would like to know how people here define a part as being opposite hand. We have a problem with new guys to our industry explaining what our definition is. For example, a flat patterened part when installed on the left hand side of the vehicle is pulled down to formers, this gives it a curvature, the same flat part is used on the right hand side of the vehicle, the sheet metal part having holes and cutouts also pulled to give it curvature. These parts are in effect opposite hand parts due to the reversed curvature in each part, but they will 'spring back' to the same flat part when removed. We define these parts as opposite hand parts and number them accordingly as different parts as their 'in use' form is in fact opposite hand.
never hurts to have a drawing of the finished part. if it's a true mirrored part, no dims, material or general notes are on the drawing. just a reference to the mirror part. :)
I wrote a CAD procedure for me which might help a bit. It doesn't cover all possible scenarios, but it's a start. It was mostly intended to keep subcontractors doing things in reasonable fashion so that huge amounts of cleanup time would not be required and so that people could be reasonably expected to work with someone else's files. SOME of the procedure I've quoted below, mostly to clarify when to create configurations and independent files for mirrored components, and when one can use Derived-type parts and assemblies. And yeh it does contain some weasel words like "should" and "if possible", etc, simply because there will always be reasonable exceptions to ironclad rules. But I did say "shall" in some places, and I intended that to be ironclad. You may disagree with the approach, but you can depart from it as you like and you can also try to put it in simpler terms (good luck -- it ain't even as easy as it looks). As mentioned, it's just a beginning.
----------------- When Parts need to have a corresponding mirror image (or opposite) Part it is preferable to create the opposite Part as a configuration rather than as a mirrored derived Part if possible -- in so doing creating opposite Features which are either suppressed or unsuppressed depending on the configuration. Derived, Joined, Split or Cavity Parts or Assemblies may be used without restriction at the design concept stage, but after a concept has been decided or accepted by project management, they should not be used except in certain instances, including as listed below and as specified by project management.
?If the Base of opposite Parts are significantly different then creation of a mirrored derived opposite Part can be considered logical and is acceptable. ?In the case of complex Features in opposite Parts, the creation or modification of which is very time-consuming, derived mirrored Parts are acceptable. ?When Tooling (even deliverable tooling, as opposed to deliverable product) is to be designed it may be created via Derived, Joined, Split or Cavity methods. ?The creation of mirrored Derived Assemblies is acceptable when it avoids an extensive amount of component Mating.
Derived, Joined, Split or Cavity Parts or Assemblies should, if practical and if the exceptions above do not apply, be converted to configurations or independent Parts/Assemblies after the stage where design concept is accepted and before Drawings are created. Breaking a derived relationship is not an acceptable method for making Parts or Assemblies independent.
In all instances of Part or Assembly mirrored components, part numbering shall be used that makes obvious the mirrored relationship. A suffix shall be attached to both original component part number and mirrored derived components? part numbers to indicate left-hand ("-LH") or right-hand ("-RH"), or top or upper (?-T?) or bottom or lower (?-B) or front or fore ("-F") or rear or aft ("-R"), unless a client part numbering system conflicts with this practice. In the case of tooling, the prefix ?Tool? and optionally a dash number (if more than one tool is necessary for a particular part or assembly) shall be added to the part number for the component for which the tool is to be used.
We make a lot of opposite hand, or as we call them left hand or right hand, depending on which side of our cart the piece is on. We give each piece a separate part number, such as, left hand piece 110900 and right hand piece
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