Tolerance Profile Surface or Profile Line
Tolerance Profile Surface or Profile Line
(OP)
Hello everybody, who know wich is the diference between Profile Surface or Profile Line, i know Profile Surface, but, iam not sure of Profile line, and i dont know exactly when we must use this tolerance, and how we must apply it.





RE: Tolerance Profile Surface or Profile Line
In a stamping operation, profile of a line (2 dimensional) is used show the shape of the blank in critical areas. It is understood that the dimensions are taken at the cut and not the break. It is measured at the edge of the part.
I have also seen profile of a line utilized on a section of a door seal. By section, I mean that a slice 90 degrees to its length is taken and mounted. Using a Optical Comparitor (shadowgraph) one can compare the outline of the shape to a template with the inner and outer boundaries of profile of a line reflected. It the section was within the boundaries, the part conforms to requirements.
Hope this helps
DD
RE: Tolerance Profile Surface or Profile Line
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RE: Tolerance Profile Surface or Profile Line
Chris
Systems Analyst, I.S.
SolidWorks/PDMWorks 05
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RE: Tolerance Profile Surface or Profile Line
RE: Tolerance Profile Surface or Profile Line
Jim Sykes, P.Eng, GDTP-S
Profile Services
CAD-Documentation-GD&T-Product Development
RE: Tolerance Profile Surface or Profile Line
RE: Tolerance Profile Surface or Profile Line
I assume your line is a curve of some kind.
You can insert points on your line and attach dimensions to them. This should be easy on any CAD package. This technique is illustrated in several places in ASME Y14.5M-1994.
This all assumes that you do not have an equation or something else that describes your line.
If your line is straight, you can attach X/Y dimensions to each end. If your line is straight and orthogonal, you just use conventional dimensions.
The ASME Y14.5M profile tolerances are functional no matter what your approach. In the case of curves, the old +/- tolerances are practically meaningless.
JHG
RE: Tolerance Profile Surface or Profile Line
RE: Tolerance Profile Surface or Profile Line
In the automotive supplier base, each dimension on the drawing is numbered. Let's say this profile is number 28. If we have 14 points shown with basic dimensions, letter each one so that we have 28a, 28b, etc.
If we have a profile (surface or line) with 0.1 mm, it defaults to a +/- from the theoretical shown with basic dimensions. The would be +/- 0.05 mm. Using a coordinate measuring machine (CMM), we could show how far the surface is away from each theoretical point.
As an example, 28a could be -0.033 while 28b could be +0.035. This would make the Customer happy.
The absolute best way of measuring profiles on curves, etc. is with a CMM, servo motor and a scan mode. One would feed in the basic dimensions and tolerance. The equipment would create a tolerance zone and scan the surface at predetermined intervals.
Hope this helps.
RE: Tolerance Profile Surface or Profile Line
I take it you have numbers for the nominal form of your curve. The GD&T profile tolerance provides a zone that your face must be contained within. A profile tolerance of 1mm states that the tolerance zone is 1mm wide, centred on your nominal position. This completely describes a range of acceptable forms.
It would be possible to go into your CAD drawing/model, and use some sort of offset to show the tolerance zone to scale. You could apply your 14_dimensions to the upper and lower range. This is a complex, obfuscated way to show something GD&T shows clearly and unambiguously.
Who designed the part? Are you trying to explain your design to them, or are you trying to show you can fabricate and inspect their part?
JHG
RE: Tolerance Profile Surface or Profile Line
When we check a profile we list the nominal I.E. X=26.829, Y=44.789 and show the actual I.E. X=26.820, Y=44.785.
If there is an error it is shown in the positive or negative and shown normal to contour I.E. Error -.003
Cheers
I don't know anything but the people that do.
RE: Tolerance Profile Surface or Profile Line
This is a "pawl" used in a gear box. It's a pretty simple part to machine really. Lots of radii locations programmed on a machining center. Its for a company overseas that is mandating a mountain of ppwk.
thundair, your error example doesn't compute to me. Is there a formula for that. How is the error calculated? In your reports do you report the deviation off of each X Y nom/act? If so, is the overall "actual" error reported as the average, worst case, range?
I have a CMM so I can generate the data needed.
I'm getting there thanks to you guys.
RE: Tolerance Profile Surface or Profile Line
Does this deviation from nominal fit inside the profile tolerance zone? A profile of 0.3 had give you a +/- 0.15 tolerance zone centered about nominal.
Are you measuring relative to the "Datum Reference Frame"?
Tom Rhodes, GDTP-S
QMC LLC; www.qmc.com
Senior Dimensional Management Engineer.
CeTOL 6 Sigma