Dimension + MAX (or MIN that matter)
Dimension + MAX (or MIN that matter)
(OP)
When you have a Dimension calling out MAX on a drawing (1.000 MAX), what keeps the machinist from giving you .800?
Is there a standard for this callout?
Thanks.
Is there a standard for this callout?
Thanks.





RE: Dimension + MAX (or MIN that matter)
Nothing. Probably just "good workmanship"
The machinist can give you 0 (zero). It is smaller than 1.000
Just my opinion
How you make a distinction between: "good workmanship" versus "poor workmanship". By having a fully defined drawing.
1.000 MAX = The drawing/feature is not fully defined = drawing incomplete.
RE: Dimension + MAX (or MIN that matter)
intent will be clear, and the unspecified limit can be zero or approach infinity and will not result in a condition detrimental to the design."
“Know the rules well, so you can break them effectively.”
-Dalai Lama XIV
RE: Dimension + MAX (or MIN that matter)
I think that for what I would call a "complete feature of size" it wouldn't be useful, i.e. thickness of a plate, or diameter of a hole or cylinder.
It's a tool that can be used, if used correctly and intelligently.
To answer the OP question, there is no standard that I am aware for this - what you see is what you get:
1.000 MAX = 0.000-1.000
RE: Dimension + MAX (or MIN that matter)
RE: Dimension + MAX (or MIN that matter)
See also here: http://www.eng-tips.com/viewthread.cfm?qid=256540
And here: http://www.eng-tips.com/viewthread.cfm?qid=364277
RE: Dimension + MAX (or MIN that matter)
I agree with the others.
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
As mentioned, nothing stops the machinist giving you .800 since .800 is less than 1.000 in any form of math I can think of that would apply.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Dimension + MAX (or MIN that matter)
MIN or MAX is placed after a dimension where other
elements of the design definitely determine the other
unspecified limit. Features, such as depths of holes,
lengths of threads, comer radii, chamfers, etc., may be
limited in this way. Single limits are used where the
intent will be clear, and the unspecified limit can be zero
or approach infinity and will not result in a condition
detrimental to the deSign.
RE: Dimension + MAX (or MIN that matter)
If you can live with anything below that, like .800, so be it.
If you can't have .002 for example, that callout the limit tolerance needed.
Calling out "1.00 MAX leaves it to the machinist to make it anything 1.00 or below. It's also up to the engineer to make sure whatever the material is that the last process made to the part that the design holds up to 1.00 MAX (shrinkage, expansion, etc).
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
RE: Dimension + MAX (or MIN that matter)
It doesn't make a difference if "R.12 MAX" vs "R.13 MAX" is called out, the machinist has to make it per print.
When I call out an internal radius, I always look at the available tool size that can fit to help the machinist.
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
RE: Dimension + MAX (or MIN that matter)
I agree, I get the point.
It comes down to designing the part. Machine time, cost, ease of mfg, all has to be looked at.
But, whatever the drawing shows, the machinist has to make the part per print. Having a callout 1.00 MAX may (or may not) help make the part cheaper.
If the dim is a radius, the machinist can use a dull tool to make any radius smaller than 1.00.
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
You make a valid point though TWJR, making a bit of allowance for DFM while tolerancing things should be common/good practice but isn't always.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Dimension + MAX (or MIN that matter)
RE: Dimension + MAX (or MIN that matter)
I think you misunderstand me. I wasn't directly responding to the OP's issue. I was adding some useful info (to me) in general terms, when specifying MAX in the case of an internal radius. As a person with one foot in manufacturing (I design and program CNCs) I'm acutely aware of how a seemingly little thing can drive up the cost of a part. To say the machinist simply "has to make the part to the print" is technically true, but we as designers should be trying to make the parts as easy to make (read: cheaper) as possible without impacting the function. I'm sorry if it sounds like I'm trying to hijack this thread. I'm not. I was just trying to be helpful, but apparently I'm being taken to the woodshed.
RE: Dimension + MAX (or MIN that matter)
I understand.
But, your response "To say the machinist simply "has to make the part to the print" is technically true" seems to me that you think it's not 100% true?
Machinists have to make the part to print, regardless how the designer (or whomever) made the drawing.
I agree the drawing needs to be complete and as cheap as possible, that's why the drawings need to be checked.
I see drawings every day that are dimensioned wrong and right, but misinterpreted wrong. So, it's our jobs to make them readable and understandable.
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
RE: Dimension + MAX (or MIN that matter)
All TWJR is saying is that the difference between ".12 MAX" and ".13 MAX" is quite significant. So simply rounding to the nearest even number is /NOT/ always the wisest decision. If the designer CAN tolerate .13, it is wise to do so, rather than rounding to .12. If talking about the IR of an otherwise rectangular pocket, the difference between .12 and .13 MAX IR is a tool change, a great shortening of tool path and therefore cut time, as well as money.
No one is saying anyone should make parts that are not true to print - it was suggested that you think about the context of your "rounding" and pick the best number for the design (including cost) rather than sticking to mindless rules (always round halves to the nearest even number) without considering their repurcussions.
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NX8.0, Solidworks 2014, AutoCAD, Enovia V5
RE: Dimension + MAX (or MIN that matter)
Designers/Engineers that have never touched a machine or tool don't understand how important it is to understand machining practices, or tool sizing.
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Dimension + MAX (or MIN that matter)
Chris, CSWA
SolidWorks 14
SolidWorks Legion
RE: Dimension + MAX (or MIN that matter)
_________________________________________
NX8.0, Solidworks 2014, AutoCAD, Enovia V5