【转帖】are parting lines included, or excluded

yang686526

are parting lines included, or excluded.
in the notes of a print:
maximum parting line permissible:
   thickness: 0.18
   extension: 0.10
dimensioning and tolerancing in accordance with asme y14.5m-1994
on the field of the drawing is ?40.4 ±0.1
if the part is produced to ?40.5, how much flash extension is permissible? or what would the diameter measure across the parting line - suggesting the parting line lies on the ?40.4 surface.
1.4(d), (e), & (f)
is the dimension (0.10) subject to more than one interpretation?
is specifying parting line equivalent to specifying drill or tap?
should the thickness and extension also be highlighted as non-mandatory (mfg data)?
does the print reference y14.8, this is the casting spec?
quote:
3.14 parting lines
forging parting lines shoule be shown on the drawing and depicted as a phantom line extending beyond the part in applicable views.  parting lines, where shown, shall be identitied (see fig. 3-3 and fig 3-9).  parting lines are generally not shown on casting drawings.
the last paragraph makes sense if you see the rest of the spec i think it's based on if you have a combined casting & machining drawing or separate drawings.  or it may be a difference between casting and forging drawings, i just realized i'm not sure.
as to the note i'd guess it was talking about flash extension, which is on the parting line.  it could be referening mis match as well/instead but it's not clear to me.
if i understand the spec correctly the the flash tolerance is usually a separate requirement.
quote:
3.8 flash extension
the limits of permissible flash extension shall be specified on the drawing.  flash extension may exceed perfect form boundary at mmc unless otherwise specified. [see figs. 3-4(a) and (b)].
i'm not very knowledgable on castings/forgings but hope this helps.
kenat, probably the least qualified checker you'll ever meet...
knowledgable enough to point me to a standard i was not aware of.
you qualified for another feather in your checker hat. thanks.
glad to be of help.
the only caution i'd make is the the 14.8 standard says:
quote:
1.1.2 reference to this standard.
where drawings are based on this standard, this fact shall be noted on the drawings or in a document referenced on the drawings.  references to this standard shall state "asme y14.8m-1996."
so it's debatable if the conventions in 14.8 apply to your drawing if it's not referenced on the drawing.  however, 14.5 does list 14.8 as a reference (para 1.2) so you could argue that counts as "document reference on the drawings" but it's a bit weak to me, i've had the designer explicitly ref 14.8 on the drawing even though 14.5 is already referenced.
kenat, probably the least qualified checker you'll ever meet...
i was hoping this post would not exceed the 80 plus postings due to debatability (more than one interpretation?).
the specification references aided in clarification.
3.8 states that a ?40.7 dimension is an acceptable part.
you are an asset to this community.
wait--does you part have holes around a bolt circle? if not, i think we're ok.   
v
i have always taken flash & parting line notes to be allowed departures from perfect form at the parting line only.  so the  diameter away from the parting line can only be 40.5 to 40.4.  40.7 over two diametrically opposed parting lines would only meet the design intent if the diameter is at it's maximum and flash on both sides was exactly equal.  i would disqualify any inspector who measured 40.7 and told me the part was good.  they need to measure the diameter and flash separately.
actually, there are 3 raised diametrical datum pads equal spaced on a diametrical surface. basically dimensioned and feature control frame toleranced, thank-you very much.
that aside, the asme y14.5m-1994 came out before the asme y14.8m-1996 and therefore references the asme y14.5m-1989. weak became weaker. the case will be presented to reference this on current documents as revisions are made as well as future issues.
dgallup - as i familiarize myself with the 14.8 that is coming to light. i was stating the unstated worse of the worse case. and i vaguely recall reading that the flash extrusion is measured from where the flash intersects with the drafted wall out for compliance.

vc66,
there is flashing around a circle! as long as we don't add basic to the flashing, we'll be ok.  
chris
solidworks/pdmworks 08 3.1
autocad 06/08
but how many places?