Category Archives for Survey Results

Survey Results on Size Dimensions Based on Y14.5

Introduction

A few weeks ago, I surveyed on the interpretation of size dimensions based on Y14.5.  I posted the survey on several group boards on LinkedIn. This article compiles the results of the  survey.

Before I discuss the results, I would like to thank all the people that participated in the survey. Their contribution allows all of us to look at the questions in this survey from many users viewpoint.

I use these surveys as the "voice of industry" in my work on standards committees. I also believe they are helpful for the readers to know how their use of tolerancing concepts compare to others around the world. 

Purpose of this survey

The purpose of this survey was to find out if various groups in industry interpret and verify the minimum limit (or local size) of size dimensions.as a two point requirement or as a theoretical swept sphere requirement. . (The survey does not address the effects of Rule #1)

GD&T and Inspection Skill Levels of Survey Participants

The figure above shows the GD&T and Inspection skill levels of the survey participants.  This information is important because it shows that most of the responses came from very knowledgeable participants.

Participants Area of Work

The chart above shows that the main two areas of participation were from Engineering/design and quality/inspection. The questions were designed for the engineering community and the inspection community. 

Questions Presented to Both the Engineering /Design and Quality/Inspection Participants

The intent of the question in the figure above is to determine if the participants felt the requirement for the minimum size limit should be verified with a two-point measurement or a theoretical spherical ball.The responses show that the majority (67%) of participants feel that a two-point measurement can be used to verify the minimum limit of a size dimension. However, there is not a uniform interpretation in industry. 

A few descriptions from the "Other" responses on how the minimum size limit should be verified are below. 

  • "Both in inspection two-points and in some cases per Y14.5.1 ball check for a bended tube."
  • "If using a CMM, some points, usually 6, taken around the diameter, the best fit circle taken through the points"
  • "It is my understanding that if you take the smallest two-point measurement of the diameter, it will be the largest theoretical sphere that will pass through the diameter"

The question in the figure above is similar to the previous question about a diameter. It is interesting that when presented with a block even more people selected the response of the two point measurement.

A few descriptions from the "Other" responses on how the minimum size limit should be verified are below. 

  • "The smallest two-point measurement. The term "size dimension" should be clearly defined in Y14.5 in the definition section. It is good timing to include in the next version, it is used throughout the text".
  • "If using a CMM, we would expect measurement  points, to be taken across the surface and a best-fit plane is used - this is good enough for us."
  • "The size of the largest perfect form 2D section that can be passed through the material"

The question in the figure above asked the participants to select an answer based on the Y14.5 -2009 standard. The two point measurement still has the highest response rate. The chart shows there is variation in the interpretation of a size dimension.

Questions presented only to the Quality/Inspection Participants

The figure above shows that the amount of tolerance is the most significant factor in the choice of a measurement device for the minimum limit of a size dimension. I am a bit surprised that the standard referenced on the drawing did not score higher.

The figure above shows the two-point measurement (micrometer/caliper) is the most common method for verifying the minimum limit of a size dimension in industry. closely followed by  CMM verification. I find it interesting that the swept ball algorithm is rarely used.

Conclusions


NOTE:

These survey results are based on participant responses from 27 countries. There were 147 participants total. 61% of the responses were from the U.S. and the remainder from the international community. The highest response rates internationally were from India, Canada, and Great Britain.

Although the participation is significant, it is not high enough to make an accurate assessment of the interpretation of size dimensions in industry, but, it does provide us with information to make useful insights on the topics even though it is not a definitive answer.

The survey results indicate that the minimum limit of a size dimension is not uniformly understood by engineers, designers, quality personnel, and inspectors in industry. The variation in understanding size dimensions is partially becaโ€‹use this topic is not covered thoroughly in the Y14.5 and Y14.5.1 standards.

Size can matter

In a number of cases, any of the methods used to verify the lower limit of a size dimension described in this survey would be adequate for the function of a part. However, in certain cases, the method of verifying a size dimension can make a difference between a functional part and a failed product. (e.g. minimum wall thickness, allowable roundness deviation, etc.)

Assumptions are effective barriers to precise communications

If you create drawings, precise communications can make the difference between a  successful product and failure. Where the interpretation of the minimum limit of a size dimension can make a difference in the function of your part, I recommend that you specify how the size dimensions should be interpreted (or verified).

Do you intend the minimum limit of size dimensions to be interpreted as a two point requirement (as implied in Y14.5) or as a  theoretical swept ball requirement (as shown in Y14.5.1)? 

Until the Y14.5 and Y15.1 standards adequately cover how to interpret size dimensions, consider one of the following actions:

  • check
    Add a general note to your drawings to establish a default for how size dimensions are to be interpreted.
  • check
    If your company uses an addendum to the Y14.5 standard,  add a section that documents how size dimensions are to be interpreted/verified. Click here to the read addendum article.
  • check
    Create a measurement plan that covers the method for verifying size dimensions and reference it in your drawings..

Final thoughts

In hindsight, I can think of several additional questions that would have been useful to ask in this survey. It is always a trade-off between the depth and length of these studies. If you have an opinion on how many survey questions would not discourage participants, leave a comment or send me an email. Thanks.

I hope you found the survey results informative. If you like the article, please share it with your friends on on social media. Feel free to leave a comment about your experiences with size dimensions or on any aspect of this article.

Thanks again to all the survey participants.

Continue reading

Survey Results on the Usage of ISO GPS and ASME Y14.5 Standards.

Introduction

A few weeks ago, I surveyed on whether the ISO GPS or ASME Y14.5-2009 standard is more widely used on drawings in industry. I posted the survey on several group boards on LinkedIn. This article compiles the results of the ISO GPS and ASME Y14.5 standards survey.

Before I discuss the results, I would like to thank all the people that participated in the survey. Their contribution allows all of us to look at the questions in this survey from many users viewpoint.

NOTE:
Since the survey is comparing the use of the Y14.5 (a US standard) and the ISO GPS (an International standard) standards, the results are shown as a comparison of US responses and International responses.

Participation Results

The figure above shows that the International response rate was slightly higher than the US response rate. There were 133 total responses from 27 different countries. The US had 63 responses and their were 70 responses from the International community. The highest response rates of the International participants were from India, Poland, and Brazil.

Type and Size of Industries Surveyed

The survey had participants from a variety of industries. 

The survey responses came from employees working in companies from less than 100 to over 100,00 employees. The chart above shows that 53% of the participants work in companies with more than 10,000 employees.

The first three questions of the survey are focused on gathering information about the participants. Their country and the industry they work in and the size of the company. The next section of the article will explain details about which tolerancing standards are used on drawings in their companies.. 

Current Tolerancing Standards Used on Drawings in US and International Companies.

Whether the ASME Y14.5 or ISO GPS standard is more widely used on drawings is the main question in the survey. My students and customers have often asked me this question. My colleagues in the ISO GPS and ASME standards community talk about it as well.

The survey shows that the ASME Y14.5 standard is widely used (86%) in the US and is used significantly Internationally(56%). 

NOTE:

This survey is based on 133 responses from 27 countries. Although the participation is significant, it is not high enough to make an accurate assessment of the use of tolerancing standards in industry globally. However, it does provide us with information to make useful insights on the use of standards even though it is not a definitive answer.

Survey Participants Recommendation on the use of the ISO GPS or ASME Y14.5 tolerance standards.

Keep in mind; the question below is asking an opinion of the participants.

When asked, "If your company was evaluating which tolerancing standards to use in the future, what would be your recommendation?"

Most of the participants  (67%) responded the ASME Y14.5 tolerancing standard as their preference and both ASME Y14.5 and ISO GPS as their second choice (20%).

The three most common responses from the US participants are below. The standard they recommended is shown in bold. (The number in parentheses is the number of participants with similar comments.)

  • check
    ASME Y14.5 - "We currently use this standard." (12)
  • check
    ASME Y14.5 - "ASME training is a lot easier. Helpful to have nearly all of the info in one document." (9)
  • check
    ASME Y14.5 - "Y14.5 is the most widely used standard." (8)

The three most common responses from the International participants are below. The standard they recommended is shown in bold.(The number in parentheses is the number of participants with similar comments.)

  • check
    ASME Y14.5 -"Easier to understand. Fewer standards. Focused on design intent." (12)
  • check
    ASME  Y14.5 - "Customer requires Y14.5". (12)
  • check
    Both ASME & ISO GPS-"The customer dictates the standards we use"(12)

โ€‹

A few additional interesting comments from individual US survey participants are below.

  • check
     Both ASME & ISO GPS - "I see that ISO shall gain a technical advantage due to GPS approach, whereas ASME is a down to earth shop floor standard."
  • check
    ASME Y14.5 - "ASME Y14.5 is more comprehensive and less volatile. ISO standards may have some elegant solutions; however, I find them very challenging to implement on a corporate and extended enterprise (include supply base) basis."
  • check
    ASME Y14.5 -  "ASME Y14.5 standards are not as complicated as ISO GPS standards over the times about drawings having to refer to multiple versions of standards which are updated and the drawings are assumed to have new interpretations."
  • check
    ASME Y14.5 - "Y14.5 is based on the function of the part. Y14.5 is a complete package, not an unsynchronized collection of many standards like ISO. Y14.5 is less ambiguous than ISO."

A few additional interesting comments from individual International survey participants are below.

  • check
    ISO GPS -"ASME standards are not well spread in European & Africans areas. - Concepts and principles are not at all the same between ASME and ISO.  A Dual life is not realistic. - Theoretically and legally speaking, ASME Y14.5 is a regional standard, not an international one! - "Invocation principle (cf. ISO 8015) gives priority to ISO standards, by default."
  • check
    ASME Y14.5 - Y14.5 is a user-friendly, one book/ISO is a matrix of standards, Y14.5 is revised approx. once per 10 years/ISO standards more frequently. There are enough GD&T books and reference material explaining Y14.5 on the market."
  • check
    ASME Y14.5 - "our company is more than 40 years old. At the beginning, we used ISO standards since 2001. We are using ASME Y14 but we have some old drawings with ISO standard, we realize that is is better to use just one standard and we chose ASME as our standard

Conclusion


Based on the survey responses, I feel that the survey suggests three things:

  • check
    The ASME Y14.5 standard is used in the US and Internationally and is the preferred standard by most of the survey participants.
  • check
    The ASME Y14.5 standard is easier to learn and easier to use than the ISO GPS standards. The ease of use of the ASME Y14.5 standard coincides with my experience in working with standards in industry.
  • check
    The multiple standard approach of the ISO GPS standards seems to be problematic for industry. However, the completeness of the ISO GPS standards may provide a technical advantage over the ASME Y14.5 standard.

I hope you found the survey results informative. If you liked the article, please share it with your friends on Linkedin. Feel free to leave a comment about your experiences with these standards or on any aspect of this article.

For all of my colleagues in the ASME and ISO standards committees, I am just the messenger of the survey responses.

Thanks again to all the survey participants.

Continue reading