All ODs on the part need to be concentric within 0.07 TIR - What does this imply

N

naghee

#1
Hello All,

A group of drawings with 3 stepped outside diameters has a note saying:
All ODs on the part needs to be concentric within 0.07 TIR
The drawing are over 24 yrs old, and do not follow a good Engg Dwg Practice.
The machining is done by holding one of the ODs (unmachined) on a chuck, an turing the center hole and one side of the part.
Then the part is held by the OD on the other side, and turned to complete the job.
During assembly, for some unknown reason the impellor jams in the volute at the neckring area.
We have been using a dial indicator to measure the variation (having the impellor on a shaft) and the variation is quite high, and go upto 0.10

The machinist say, they are following the dwg, and they are machining it right.

I want to know how do you interpret this Note?
 
Elsmar Forum Sponsor

Ronen E

Problem Solver
Staff member
Moderator
#2
Re: All ODs on the part needs to be concentric within 0.07 TIR - what does this imply

G'day mate,

As far as I remember 0.07 TIR means that a dial indicator should not travel more than 0.07 throughout a complete revolution of the workpiece. If the drawing states that all OD should be concentric within 0.07 TIR it means that no matter on which OD you hold, all others should indicate <=0.07.

If you tested this way (and used a reliable & calibrated measurement set-up) and got 0.10 then the part does not meet the requirement. In such a case I would guess that the lathe, or the holding mechanism for the second stage, are not good enough. However, from your description I'm not sure how exactly you hold the workpiece for the measurement. If you rely on the center hole as the rotation axis, then the above may not be applicable, because the requirement relates to OD.

I would say you need to measure the problematic parts carefully, in order to isolate the problem.

Cheers,
Ronen.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#3
Re: All ODs on the part needs to be concentric within 0.07 TIR - what does this imply

When production people complain that they are making the parts correctly, but quality measures them out of spec, I ask the production people to measure them in front of me to find out where the divergence is. Maybe they are measuring roundness instead of TIR. Hard to say without watching.
 
T

True Position

#4
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

IMHO To check the part, once it is fully machined, you should put each diameter into a zero spindle (or the lathe), and checking the TIR on each of the other diameters. If it's only a couple diameters and it would work you could also try rotating the part in a V block on each diameter and checking the runout at the other diameters. (Also, I'm assuming you do not have a CMM, if you do, use that, and just runout tolerance each diameter to each other diameter)

I would interpret that note as saying:
'All OD are to have a runout of less then 0.070 from each other OD'

The 'correct' modern definition of concentricity is almost never intended when it's used on a drawing (especially one that's 24 years old) and since TIR is specifically mentioned it's clear(to me) that runout is the tolerance intended.
 
Last edited by a moderator:
A

alspread

#5
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

I have to agree with True Position when he/she states that they probably mean runout. Concentricity would apply to the centerlines and not the diameter surface. Measuring the TIR on the surface of the diameter compounds the error by accumulating both the concentricity variation and the roundness varition together into one TIR number.
Not to confuse matters anymore, but has any consideration been given to total runout versus regular (any element) runout?
:confused:
 

Jim Wynne

Staff member
Admin
#6
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

IMHO To check the part, once it is fully machined, you should put each diameter into a zero spindle (or the lathe), and checking the TIR on each of the other diameters. If it's only a couple diameters and it would work you could also try rotating the part in a V block on each diameter and checking the runout at the other diameters. (Also, I'm assuming you do not have a CMM, if you do, use that, and just runout tolerance each diameter to each other diameter)

I would interpret that note as saying:
'All OD are to have a runout of less then 0.100 from each other OD'

The 'correct' modern definition of concentricity is almost never intended when it's used on a drawing (especially one that's 24 years old) and since TIR is specifically mentioned it's clear(to me) that runout is the tolerance intended.
I think maybe coaxiality (which is synonymous with the common denotation of concentricity) is more to the point; it's simply that all of the ODs must share a common centerline within the specified tolerance. A concentricity gage can be a handy thing to have for this sort of thing. (The link is an example, not an endorsement)
 
T

True Position

#7
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

I think maybe coaxiality (which is synonymous with the common denotation of concentricity) is more to the point; it's simply that all of the ODs must share a common centerline within the specified tolerance. A concentricity gage can be a handy thing to have for this sort of thing. (The link is an example, not an endorsement)
That gage is exactly the problem, it's checking runout on something called a 'concentricity gage' when in no way does it check the GD&T tolerance of concentricity.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#8
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

That gage is exactly the problem, it's checking runout on something called a 'concentricity gage' when in no way does it check the GD&T tolerance of concentricity.
That's true, it checks runout or roundness - depending on where you put the indicator. (I think it's name is a retro throwback.)

Concentricity in GD&T is typically used for rotating shafts. In this case concentricity may actually be applicable...when I hear the term impeller used...
 
T

True Position

#9
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

That's true, it checks runout or roundness - depending on where you put the indicator. (I think it's name is a retro throwback.)

Concentricity in GD&T is typically used for rotating shafts. In this case concentricity may actually be applicable...when I hear the term impeller used...
Off topic but interested:
I thought you could not check roundness accurately rotating directly on the part due to the potential of getting a part with lobing that hides some of the out of round. Same reason you can't use a V-block? I was always under the impression that you needed something which moved completely independent of the part. (Like the two types of roundness checkers or a CMM.)

It's almost certainly not ASME concentricity. A perfectly square bearing journal has perfect ASME concentricity (0.000) if the center of the square is at the axis center, but obviously would not have 0 TIR.
 

Stijloor

Staff member
Super Moderator
#10
Re: All ODs on the part needs to be concentric within 0.07 TIR - What does this imply

Off topic but interested:
I thought you could not check roundness accurately rotating directly on the part due to the potential of getting a part with lobing that hides some of the out of round. Same reason you can't use a V-block? I was always under the impression that you needed something which moved completely independent of the part. (Like the two types of roundness checkers or a CMM.)

It's almost certainly not ASME concentricity. A perfectly square bearing journal has perfect ASME concentricity if the center of the square is at the axis center, but obviously would not have 0 TIR.
Y14.5 specifies concentricity as median points of the controlled feature relative to a datum axis. ;)

Stijloor.
 
Thread starter Similar threads Forum Replies Date
A MDR ANNEX XI part A or Part B EU Medical Device Regulations 0
J Part submission warrant for Level 1 PPAP APQP and PPAP 1
K How to handle GTINs for different configurations of one device with one part number? Other Medical Device Related Standards 0
A 60601-1 : Integrated Dry ECG Electrodes = 2 Patient connections inside 1 applied part? IEC 60601 - Medical Electrical Equipment Safety Standards Series 5
E Zero part to part variation - Gage R&R project Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 15
0 To which part of 13485 does this refer? ISO 13485:2016 - Medical Device Quality Management Systems 3
D Separation of F-type applied part and remaining parts IEC 60601 - Medical Electrical Equipment Safety Standards Series 7
V Part selection for R&R studies Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
S ISO 9001:2015 vs 21 CFR Part 211 matrix Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 0
D CFR Title 14: Aeronautics and Space PART 120—DRUG AND ALCOHOL TESTING PROGRAM Federal Aviation Administration (FAA) Standards and Requirements 3
D Is PMCF really a continuous activity per Annex XIV,Part B? EU Medical Device Regulations 5
M 21 CFR 820 vs 21CFR820 vs 21 CFR Part 820 Document Control Systems, Procedures, Forms and Templates 3
N BF-type applied part MOPP vs secondary IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
D Relabelling a component that will be sold as a spare part - Do I become legal manufacturer? EU Medical Device Regulations 2
T Single Fault Condition IEC 60601 Clause 8.7.1 shorting Cr/Cl in Patient Applied Part IEC 60601 - Medical Electrical Equipment Safety Standards Series 7
D Partial FAI - AS9102 - One single drawing has 10 part numbers AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 5
Anonymous16-2 21 CFR Part 11 - Steps to take if we want to validate an electronic system Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 2
T ISO 13485 8.3 - Non-Conforming Materials - on-line rework or part of process? ISO 13485:2016 - Medical Device Quality Management Systems 11
DuncanGibbons Should the requirements FAA/EASA Part 21 be addressed within the QMS and AS9100D quality manual? AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 5
K IEC 62304 compliance - Code reviews as part of verification strategy IEC 62304 - Medical Device Software Life Cycle Processes 5
G Gage R&R - Where am I going wrong? Part of a FAIR submission (Aerospace) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
A 21 CFR part 11 - section 11.100 - Electronic Signature Certification Other US Medical Device Regulations 6
M AS9102B Detail Part/Assembly FAI Form 1 box 13; AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 2
M 2xMOPP insulation for Applied Part B. IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
A ISO 41001:2018 - Clause No.8 Operations Part Quality Management System (QMS) Manuals 2
NDesouza Getting Rid of Part Marking Errors Benchmarking 40
L Wearables 21 CFR Part 11 compliance Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 1
DuncanGibbons How are part cut out specimens made and tested? Manufacturing and Related Processes 1
S Internal calibrations - Part of an ISO 17025 accredited testing laboratory (Automotive) ISO 17025 related Discussions 16
Ed Panek 21 CFR Part 820 - FDA Label Requirements 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 8
S CQI-23 - Molding System Assessment - Control of part weight IATF 16949 - Automotive Quality Systems Standard 5
DuncanGibbons Looking for example aerospace part CAD files to be used for a case study Career and Occupation Discussions 2
T Overvoltages consideration in Applied Part for RMS Calculation. IEC 60601 - Medical Electrical Equipment Safety Standards Series 6
M Informational How to perform a clinical evaluation of medical devices – Part 2 – Level of clinical evidence and what sufficient clinical evidence means Medical Device and FDA Regulations and Standards News 9
E Part 11 Compliance, Excel living documents (i.e. document master list, equipment list, approved supplier list) Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 3
S FAIR - If we have not produced a part in over 2 years, but nothing has changed AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 5
P Scope of application for IEC 60601-1-11 Medical electrical equipment — Part 1-11 IEC 60601 - Medical Electrical Equipment Safety Standards Series 3
M Informational Creating a post market surveillance (PMS) system for medical devices – Part 1 Medical Device and FDA Regulations and Standards News 7
Ed Panek Part 11 Self Certify Memo - What else should it cover? Qualification and Validation (including 21 CFR Part 11) 5
M Informational How to perform a clinical evaluation of medical devices – Part 1 – Overview and sample of activities Medical Device and FDA Regulations and Standards News 0
rezayatmand IEC 60601-2-18 Medical electrical equipment - Part 2-18: Particular requirements for the basic safety and essential performance of endoscopic equipmen IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
R Question on determining defective units - I am not recording fixture to part rejected Statistical Analysis Tools, Techniques and SPC 5
C Serialised Defective Part Replacement EU Medical Device Regulations 4
B F-type applied part - Separation from ALL(?) other parts IEC 60601 - Medical Electrical Equipment Safety Standards Series 8
N Use part of high risk device for establishing low risk device EU Medical Device Regulations 0
N Can we take a part from 510k cleared medical device and use it in class I device? Other US Medical Device Regulations 3
F 21 CFR Part 11 - Implicit requirements - Validation plan for a Software as a Service Other US Medical Device Regulations 1
M Informational Some things the EU MDR 2017/745 does not tell you, but you may need to know to comply with it effectively – Part 1 Medical Device and FDA Regulations and Standards News 0
G PolyWorks Alignment Issue - How to align the part General Measurement Device and Calibration Topics 1
C 21 CFR Part 11- What about handwritten signatures? Other US Medical Device Regulations 1

Similar threads

Top Bottom