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Standard for identifying features on Engineering Drawings?

J Taylor

J Taylor

Automotive
Oct 27, 2022
4
Experienced CMM Programmer (30+ yrs), worked exclusively in the Automotive sector, worked mainly with customer supplied drawings.
On most of these drawings, features such as holes/bores & faces are identified with some kind of method,
for example, on a Cylinder Head each one of the faces is allocated a number, for example Fire Face 1000, Cover Face 2000,
Exhaust Face 3000, Inlet Face 4000, Font Face 5000 & Rear Face 6000.
Then each bore/hole on say the Fire face will be identified with a B, so B1001, B1002 etc, the same for example Bolt hole Spot faces identified with F for Face, F1001, F1002 etc.
I currently am working for a company, where the design & drawings are created in house, none of the drawings have any features identified.
Because of this, they create what they call a Feature Map, which comprises of either a Drawing or Cad screen shot of each face, then they identify each feature using the same method as described above, B for Bore/Hole & F for Face.
The problem is, each person that creates the Feature Map, is doing it slightly different, some are doing it by machine operation, & the same hole could be H4012 on Op20, but H4002 on Op100 when finished, this makes thing a lot harder than it should be.

So, the question is, is there a standard for identifying features on Engineering Drawings?
In my time I have seen H for Hole, B for Bore & F for Face.
What about External Diameters, such as a Gear pin (D for Diameter)?
Should/could there be Id's for Chamfers (C), Rads (R) or Threads (T)?

If there is a standard, I have ammunition to call a meeting and suggest either it is added to the drawing or adopted to the Feature map creation process.
Thanks
 
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It sounds like you were previously used to either a particular maker or some small group of makers.

There doesn't seem to be an ASME standard on naming features; even Y14.41 Digital Product Definition Data Practices seems to leave it to the underlying software to maintain names and that as an image in one example (at least in the current Public Review Draft.)
 
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JTaylor - interesting question - I don't have an answer. But the methodology you previously used makes sense. I am going to ping the machine shops I work with to see if feature identification would be beneficial to the interpretation of the technical drawings I supply to them. Regardless, of whether there is a standard, do you believe you will get push back from the various stakeholders in your shop for your suggestion to standardize the feature identification?
 
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You're dealing with manufacturing drawings rather than product definition drawings (Y14.x), and the only such standards I have seen are company specific.
 
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It should have been covered in ASME Y14.41 so that agreement can be had between design/engineering and inspection.
 
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J Taylor, I'm not aware of a standard. At my last direct employer, in Product Development Engineering we resolved this as your earlier employer did, by committing to enumerate each drawing specification on the Engineering Part Drawings. We used a simple sequential enumeration with no "coding" built into it. It worked out well for everyone, as it saved everyone else the effort while avoiding duplication. Everyone internally and externally was happy to have it done in advance and to simply use our enumeration. It is used internally by product development, manufacturing engineering, and quality engineering, and externally by the suppliers.
 
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3DDave said:
It should have been covered in ASME Y14.41 so that agreement can be had between design/engineering and inspection.
Click to expand...
Y14.41 pertains to product definition (titled Digital Product Definition Data Practices), not the methods used to produce it. What is required, not how to get there.
 
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Each feature is part of the product and is there to be inspected. There is no other use of Y14.5 to Y14.41 or the remainder of the Y14.X series. Further, Y14.41 is specifically an interchange standard, showing how Y14.5 is interchanged in digital form with a preference to automated tools. The only way to identify a feature to a user by automated tools is by giving it a unique identifier. This has zero affect on "the methods used to produce it."


It is very frustrating to see a committee dodge the primary responsibility in favor of making a huge effort to tattoo "GD&T" on every page after that had been rejected by the Y14.5 standard.
 
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Standardizing feature identification on engineering drawings can definitely improve consistency and reduce confusion, especially when working with different teams or manufacturers. While there isn’t always a universal standard beyond general guidelines like ASME Y14.5 for GD&T, some companies create their own internal systems to streamline this process.

One practical approach I've seen is using digital tools or platforms that allow you to annotate CAD models directly. This makes it easier to share clear, visual information with manufacturing teams and avoid misinterpretations during production—a valuable practice in both engineering and technical marketing when clarity and precision are key.
 
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Brian Malone said:
JTaylor - interesting question - I don't have an answer. But the methodology you previously used makes sense. I am going to ping the machine shops I work with to see if feature identification would be beneficial to the interpretation of the technical drawings I supply to them. Regardless, of whether there is a standard, do you believe you will get push back from the various stakeholders in your shop for your suggestion to standardize the feature identification?
Click to expand...
Due to the fact the designer(s) have never added these details, I wonder if they may see it as "extra work", also the people using different methods may think their way is the correct way. I probably will at some point bring this up and suggest the data is added to future Job's drawings, I'm pretty sure they won't want to amend drawings for existing Jobs.
I'm a contractor at the company, and sometimes this can cause friction with full time employees.
 
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J Taylor said:
Due to the fact the designer(s) have never added these details, I wonder if they may see it as "extra work", also the people using different methods may think their way is the correct way. I probably will at some point bring this up and suggest the data is added to future Job's drawings, I'm pretty sure they won't want to amend drawings for existing Jobs.
I'm a contractor at the company, and sometimes this can cause friction with full time employees.
Click to expand...
They probably do see it as extra work, and it is indeed extra work for the Designer in making the drawings. The right question is, however: Does it result in more or less work overall for the organization and its suppliers and customers? I think in the end you'll find it is less work and more efficient for the overall business.
 
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J Taylor said:
Experienced CMM Programmer (30+ yrs), worked exclusively in the Automotive sector, worked mainly with customer supplied drawings.
On most of these drawings, features such as holes/bores & faces are identified with some kind of method,
for example, on a Cylinder Head each one of the faces is allocated a number, for example Fire Face 1000, Cover Face 2000,
Exhaust Face 3000, Inlet Face 4000, Font Face 5000 & Rear Face 6000.
Then each bore/hole on say the Fire face will be identified with a B, so B1001, B1002 etc, the same for example Bolt hole Spot faces identified with F for Face, F1001, F1002 etc.
I currently am working for a company, where the design & drawings are created in house, none of the drawings have any features identified.
Because of this, they create what they call a Feature Map, which comprises of either a Drawing or Cad screen shot of each face, then they identify each feature using the same method as described above, B for Bore/Hole & F for Face.
The problem is, each person that creates the Feature Map, is doing it slightly different, some are doing it by machine operation, & the same hole could be H4012 on Op20, but H4002 on Op100 when finished, this makes thing a lot harder than it should be.

So, the question is, is there a standard for identifying features on Engineering Drawings?
In my time I have seen H for Hole, B for Bore & F for Face.
What about External Diameters, such as a Gear pin (D for Diameter)?
Should/could there be Id's for Chamfers (C), Rads (R) or Threads (T)?

If there is a standard, I have ammunition to call a meeting and suggest either it is added to the drawing or adopted to the Feature map creation process.
Thanks
Click to expand...
Well how long have you been contracted.
While I don't agree with this method it has been working. And it's an internal procedure.
Give it time.
There is improcess inspection and final inspection. How are their QC procedures setup.
 
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Eventually it boils down to labeling each surface and each edge so that every aspect of the part is traceable. This is already part of a CAD model which makes it a natural to have been part of ASME Y14.41. To put that information on a 2D drawing is tedious as is extracting that information from a 2D drawing. Is there a supplementary table on the drawing that lists all the IDs, including those that are skipped/removed during the development process, so that everyone knows that all of them have been accounted for at each step in the process? More work.

It does make sense if there is such a large non-conformance rate such that engineering is constantly getting calls about missing or mis-located surfaces or damaged edges, but that would be a call to identify and eliminate the reason for the non-conformances.
 
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One thing that may be missed by some folks is that with super-high-volume production environments, such as automotive, statistical process control becomes very important. In the automotive industry, it is mandated. That means that every dimension and specification on every part drawing has to be accounted in a control plan, even if it is only checked annually. If you have 3 different sets of M6 tapped holes on a part, you can imagine the confusion that might arise in the control plan and in inspection reports. The enumeration of specifications (including dimensions) cuts through all of that by giving unique references common to all users of the part drawing.
 
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