Deburring and Tolerances - Is there a Standard for deburring or removing material?

[Skooma]

Is there a Standard for deburring or removing material? The only one I'm familiar with is BAC5300 and that's boeing drawings.

#1) The problem I currently have: The drawing will say something like "Edge break and Deburr .015 Max Unless otherwise specified", and the guys use up their full allowance and end up creating a knifes edge on a tube because they knocked out the flat in the process. We had something recently where a tube had about .012 of wall left on each end with a burr, so the guys went in and knocked the burr out along with the flat at each end creating a knife edge in the process. Nothing on the drawing prevents them from doing this since all features are still in tolerance. BAC has 20% rule to prevent this but I can't make them use a boeing standard on a non-boeing drawing.

#2) Kinda same problem: Using all their tolerance to the point of removing a feature completely.
The drawing will ay something like ".xx = plus or minus .03" and a drawing might have a feature like radius .015, so it never fails I will get a guy who will run the feature without a radius then tell me "drawing says plus or minus .03". Once again BAC5300 prevents this nonsense but not with certain customers drawings and procedures. I haven't been able to find anything relating to this in any of the ASME y14.5 tolerancing...

Any help is appreciated, Thank You.

 

[Jim Wynne]

Is there a Standard for deburring or removing material? The only one I'm familiar with is BAC5300 and that's boeing drawings.

#1) The problem I currently have: The drawing will say something like "Edge break and Deburr .015 Max Unless otherwise specified", and the guys use up their full allowance and end up creating a knifes edge on a tube because they knocked out the flat in the process. We had something recently where a tube had about .012 of wall left on each end with a burr, so the guys went in and knocked the burr out along with the flat at each end creating a knife edge in the process. Nothing on the drawing prevents them from doing this since all features are still in tolerance. BAC has 20% rule to prevent this but I can't make them use a boeing standard on a non-boeing drawing.

There is no standard that I know of, but if this sort of thing is causing problems you need to fix the process and perhaps establish internal (your own) requirements.

#2) Kinda same problem: Using all their tolerance to the point of removing a feature completely.
The drawing will ay something like ".xx = plus or minus .03" and a drawing might have a feature like radius .015, so it never fails I will get a guy who will run the feature without a radius then tell me "drawing says plus or minus .03". Once again BAC5300 prevents this nonsense but not with certain customers drawings and procedures. I haven't been able to find anything relating to this in any of the ASME y14.5 tolerancing...

This is a result of a poorly-dimensioned drawing. While specifying that a radius should be present means that a radius should be present, if the specification is at odds with the block tolerance, it's the fault of the designer. Again, there's nothing to prevent you from establishing your own requirement. ASME Y14.5M won't help any more than the Boeing spec.

 

[Skooma]

Thank You.

 

[Kronos147]

At one company I was at, I had the following internal spec:


1.0
Purpose
1.1
This procedure establishes the Manufacturing and Quality inspection criteria for burrs and de-burred parts.


2.0
Scope
2.1
The intent of this specification is to define burr conditions, eliminate judgments and establish accept / reject criteria for parts.


3.0
Conflict Statement
3.1
As there is no standardized specification for deburring and burr classification, this document will represent the J & M Products, Inc. standard
3.2
As there is no definition on clamp blueprints other than statements such as “remove burrs and sharp edges,” this document will represent the J & M Products, Inc. definition of burrs and Deburring


4.0
Production
4.1
Parts will conform to the requirements set forth in the part drawing and to this specification.
4.2
Where required, parts will be deburred to conform to the requirements.


5.0
Definitions
5.1
Burr - Non-functional material extending from the surface of a part.



Class 1 Burr
Parts that have gone through (at least) First Operations. This classification of the surface/edge condition is generally detectable by the naked eye or as a non-smooth blemish or nick detectable through tactile means. The removal of a burr is performed using common shop tools or sent to an outside processor for deburring. The presence of a burr could cause installation issues with the part.
Class 2 Burr
Refers to raw materials as delivered from the vendor. This classification of the surface/edge condition is generally detectable by the naked eye or as a non-smooth blemish or nick detectable through tactile means.. The material is to be dispositioned as per WIQC 8.0 Quality Control NCP (Nonconforming Product) Process and will most likely result in a return to vendor disposition.
Class 3 Burr
The condition of the edge/surface is detected only with the aid of magnification. This classification would not affect form, fit, or function.



5.2
De-burr - Removal of non-functional material


6.0
Inspection Requirements

Inspection assumptions: Part is clean and free from debris (other than lubrication). There shall be proper lighting and an ability to manipulate the part to discover burrs from a variety of angles.
6.1
Inspect part with the naked eye.

NOTE: If required, an optical comparator or magnification may be engaged for this process.
6.2
Inspect part through tactile means in order to detect a non-smooth blemish(es) or nick(s).


7.0
Deburring Requirements
7.1
Duburring may be done by J & M Products, Inc. production personnel for a specific lot of parts, under the specific guidelines of a Production Manager, Production Supervisor, or designee after such disposition has been determined as per WIQC 8.0 Quality Control NCP (Nonconforming Product) Process.
7.2
Duburring may be done by J & M Products, Inc. approved suppliers as per Purchase Order requirements
7.3
No burrs shall be allowed that would cause a safety concern for handling of the part.


8.0
Re-Inspection Requirements

Inspection assumptions: Part is clean and free from debris (other than lubrication). There shall be proper lighting and an ability to manipulate the part to discover burrs from a variety of angles.
8.1
Inspect part with the naked eye.

NOTE: If required, an optical comparator or magnification may be engaged for this process.
8.2
Inspect part through tactile means in order to detect a non-smooth blemish(es) or nick(s).
8.3
No burrs shall be allowed that would cause a safety concern for handling of the part.


Feel free to use any or all of this.