ASME Y14.5 Proposal on Feature of Size

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# ASME Y14.5 Proposal on Feature of Size - PowerPoint PPT Presentation

ASME Y14.5 Proposal on Feature of Size. Topics. How to ensure minimum size is met on a feature of size where portions (or in some cases all) of the features are not opposed. Clarify the definition of “size” in Y14.5. Understand the definition of “size” from Y14.5.1

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## ASME Y14.5 Proposal on Feature of Size

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ASME Y14.5

Proposal

on

Feature of Size

ASME Y14.5 presentation by Alex Krulikowski May 2005

Topics

• How to ensure minimum size is met on a feature of size where portions (or in some cases all) of the features are not opposed.
• Clarify the definition of “size” in Y14.5.
• Understand the definition of “size” from Y14.5.1
• Using the size definition from Y14.5.1 to clarify what size means in Y14.5
• Proposal to change Y14.5 to clarify: actual local size, opposed, size, and feature of size

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “feature of size” from Y14.5

1.3.17 Feature of Size. One cylindrical or spherical surface, or set of two opposed elements or opposed parallel surfaces, associated with a size dimension.

ASME Y14.5 presentation by Alex Krulikowski May 2005

ASME Y14.5 presentation by Alex Krulikowski May 2005

ASME Y14.5 presentation by Alex Krulikowski May 2005

Tab

Tab

Slot

A

B

C

D

E

F

Facing _________

Surfaces

Surfaces

from each other

Considered Facing

A & B

Away

Opposed

Opposed

B & C

Towards

B & D

Same Direction

Same

C & D

Away

Opposed

E & F

Towards

Opposed

ASME Y14.5 presentation by Alex Krulikowski May 2005

ASME Y14.5 presentation by Alex Krulikowski May 2005

1.

2.

A

A

B

B

Surfaces A and B are

Surfaces A and B are

different lengths

different shapes

3.

4.

A

A

B

B

Surfaces A and B are offset

Surfaces A and B contain

gaps and interruptions

Examples of Partially Opposed Features

ASME Y14.5 presentation by Alex Krulikowski May 2005

A

1.

2.

A

Distance A contains line

elements of different lengths

Distance A contains

offset line elements

Examples of Partially Opposed Line Elements

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Cylindrical Shapes with Truncated Ends

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Interrupted Features of Size

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Partially Opposed from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Partially Opposed from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Partially Opposed from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Partially Opposed from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Partially Opposed

• There are at least 18 examples of partially opposed features of size in Y14.5.
• There are numerous cases of partially opposed features of size in industry.
• Partially opposed features of size cause problems when determining the LMC size in the non-opposed areas.

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “feature of size” from Y14.5

1.3.17 Feature of Size. One cylindrical or spherical surface, or set of two opposed elements or opposed parallel surfaces, associated with a size dimension.

ASME Y14.5 presentation by Alex Krulikowski May 2005

In Y14.5 the definition for size is limited.

Definition of “Size” from Y14.5

5-1

Assumes Rule #1 is in effect

ASME Y14.5 presentation by Alex Krulikowski May 2005

Actual

local size

Definition of “Size” from Y14.5

Problems with “Actual Local Size”

• The direction of measurement is not described, resulting in many answers possible for the value.

5-1

• It describes a “two-point” measurement
• Only works with “opposed points”

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5

5-1

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

However, Y14.5 does not define how size is interpreted when Rule #1 is overridden

Definition of “Size” from Y14.5

ASME Y14.5 presentation by Alex Krulikowski May 2005

Y14.5 invokes Y14.5.1 which defines how size is interpreted both with and without Rule #1.

Y14.5 Invokes Y14.5.1

5-1

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5.1

ASME Y14.5 presentation by Alex Krulikowski May 2005

MMC

LMC

SPINE

Definition of “Size” from Y14.5.1

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5.1

Spine Types

• A 0-dimensional spine is a point, and applies to spherical features.
• A 1-dimensional spine is a simple (non-intersecting curve in space, and applies to cylindrical features.
• A 2-dimensional spine is a simple (non-intersecting surface, and applies to parallel plane features.

A

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5.1

A

ASME Y14.5 presentation by Alex Krulikowski May 2005

Definition of “Size” from Y14.5.1

A

ASME Y14.5 presentation by Alex Krulikowski May 2005

When perfect form at MMC is required

Definition of “Size” from Y14.5.1

A

ASME Y14.5 presentation by Alex Krulikowski May 2005

When perfect form at MMC is required

Definition of “Size” from Y14.5.1

A

ASME Y14.5 presentation by Alex Krulikowski May 2005

Size and Partially Opposed Features

In Y14.5

In Y14.5.1

• Does not require fully opposed features.
• Does not use the term actual local size. Uses two half space boundaries to define the size tolerance zone.
• Explanation for use with max or min size definition
• Works with or without Rule #1.
• Actual local size requires fully opposed surfaces.
• Actual local size is defined as a two-point measurement. There is no direction for the measurement defined. Should actual local size be defined as a tolerance zone?
• Actual local size is only explained as a method for checking a minimum distance.
• How is a max size checked when Rule #1 is overridden as in figure 6-3?

ASME Y14.5 presentation by Alex Krulikowski May 2005

Size according to Y14.5

The 64.6 – 65.0 diameter is considered a feature of size.

Using the Y14.5 definition of size, it is impossible to measure the actual local size of the diameter.

ASME Y14.5 presentation by Alex Krulikowski May 2005

Now lets look at how the same size dimension would be interpreted using Y14.5.1

ASME Y14.5 presentation by Alex Krulikowski May 2005

Size according to Y14.5.1

The 64.6 – 65.0 diameter is considered a feature of size.

Using the Y14.5.1 definition of size, the size tolerance zone of the 64.6-65.0 diameter is defined by two half space boundaries.

The boundaries are established by two balls: The MMC limit is defined by a ball equal to the MMC size. The LMC limit is defined by a ball equal to the LMC limit.

The balls are moved along appropriate spines to define the tolerance zone.

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Size Using Y14.5.1

Drawing

Meaning

10.6 MMC boundary

10.6

10.0

MMC ball

LMC ball

No difficulty measuring the portion of the feature that does not have opposed points

ASME Y14.5 presentation by Alex Krulikowski May 2005

Examples of Size Using Y14.5.1

Drawing

Meaning

10.6 MMC boundary

10.6

10.0

MMC ball

LMC ball

No difficulty measuring the portion of the feature that does not have opposed points

ASME Y14.5 presentation by Alex Krulikowski May 2005

Recommendations

Proposed Text

Text in Y14.5M-1994

1.3.24 Size, Actual. The general term for the size of a feature. See ASME Y14.5.1 paragraphs 2.3.1 and 2.3.2 for an explanation of variations in size.

5-1

Text in Y14.5M-1994

Proposed Text

Delete paragraph 1.3.25 and replace all instances of Actual local size with Actual Size. (11 places in text and 4 places in figures)

ASME Y14.5 presentation by Alex Krulikowski May 2005

Recommendations

Proposed Text

Text in Y14.5M-1994

2.7 LIMITS OF SIZE

Unless otherwise specified (by specification of a straightness control applied to a size dimension, or a note as described in paragraph 2.7.2), the limits of size prescribe the extent within which variations of geometric form, as well as size are allowed.This control applies solely to individual features of size as defined in para. 1.3.17.

5-1

ASME Y14.5 presentation by Alex Krulikowski May 2005

Recommendations

• Show the MMC and LMC balls located along spines in several examples
• Add a paragraph and examples to explain “opposed”
• Add a paragraph and examples of features of size with partially opposed features.

ASME Y14.5 presentation by Alex Krulikowski May 2005

The end

ASME Y14.5 presentation by Alex Krulikowski May 2005