techniques for measurement of threaded hole position hole location study - sandia natl lab.pdf ·...
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Techniques for Measurement of Threaded Hole Position
Tony BryceSandia National Laboratories
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy under contract DE-AC04-94AL85000.
“The funny part of metrology is that we're never right, we just have to tell people how wrong we are, and hope the wrong part is right enough!”
Joseph CeremugaSandia National Laboratories (Livermore, CA)
How should the position be established?
� ANSI Y14.5M-1994• Section 2.9
– “Each tolerance of orientation or position and datum reference specified for a screw thread applies to the axis of the thread derived from the pitch cylinder.”
• Figure 5-6 – “Note that the length of the tolerance zone is equal to
the length of the feature, unless otherwise specified on the drawing.”
• Projected tolerance zone applications
To comply with ANSI Y14.5M� Measure the feature or gage –
• as a cylinder • in multiple circle sections
– Line generated between circle centers serves as the axis
� Axis is used to determine pierce points at ends of feature or evaluation length• Zeiss UMESS UX will evaluate these
points as L1 & L2 for TP calculations and report worst case deviation
CMM Methods� Direct probing of the thread form
• Issues– Chips, burrs– Establishing pitch cylinder
• Not able to probe pitch diameter directly
� Probing a threaded/cylinder gage• Issues
– $ - Cost of gage– Inconvenience of installing (time = money $)– Establishing pitch cylinder
• Various gages each using a different method to locate the pitch cylinder
How did we get interested in this?
Threaded Holes on a Curved Surface
Threaded Holes on a Curved Surface
Threaded Holes on a Curved Surface
Off-Line CMM Programming� Silma CimStation Inspection
Curved Surface Issue� Standard threaded/cylinder gage does
not seat properly?
Rocking Motion
Technique is needed that is not influenced by the surface the hole is on!
What to do?� Evaluate techniques � Perform R & R tests using various
techniques on a flat surface• Test pieces having a 2 inch outside
diameter with ¼”-20 thread in center– Aluminum part
• Diameter and face turned on lathe • Drill and tap hole
– Steel part• Gage quality lapped thread with outside diameter
and face ground to pitch diameter axis
Test Piece Datum’s• Datum A = Top surface • Datum B = 2” outside diameter• Datum C = 0.25” through hole• Establish DRF - ABC
Threaded / Cylinder Gages� Obtain all available types on the market
• Jo-Plug – Cylinder with straight thread and shoulder face
perpendicular to axis• Tru-Pos
– Tapered thread for interference fit• CL Flex Plug
– Split thread for compliance fit• Multi-Ball Gage
– Expanding balls fit to pitch diameter
Jo-Plug (Spence Industries Inc.)
CL Flex Plug (Glastonbury/Southern Gage)
Tru-Pos Locator (LaVezzi Precision Inc. )
Multi-Ball (True Precision Corp. )
R&R Test Parameters for Threaded / Cylinder gages
� Using UMESS UX with PCM routines, probe a total of 32 points* on the cylinder• 8 equally spaced points at 4 different
levels over the length of the cylinder
– * 24 points (8 equally spaced points at 3 levels) used on CL Flex Gage due to short cylinder length
R&R Test Parameters
� Establish pierce points of cylinder axis with Datum A (top surface) and at –0.5” below Datum A
� Record X & Y position at both pierce points• Should show repeatability of not just
Datum A location, but of the cylinder orientation (tilt).
Jo-Plug (Spence Industries Inc.)
CL Flex Plug (Glastonbury/Southern Gage)
Tru-Pos Locator (LaVezzi Precision Inc. )
Tru-Pos Locator (LaVezzi Precision Inc. )
Multi-Ball (True Precision Corp.)
Multi-Ball (True Precision Corp. )
Multi-Ball (True Precision Corp. )
Direct Probing of Thread
� Use Zeiss PCM thread routine• Measure circles at both ends of threaded
hole. (8 equally spaced points)• Construct a line through the centers of
both circles• Establish pierce points at Datum A (top
surface) and at –0.5” below Datum A
PCM Measurement
PCM Measurement
PCM Measurement
� Many CAD models show threaded holes as plain cylinders (minor diameter) and could be programmed in a helical path to establish pitch cylinder
� Use pass through commands via Silma Cim Station Inspection
Off-Line CMM Programming
Test Parameters
� CNC Program written to measure datum features and establish W-Pos
� Measure position using each of the five techniques
� Loop program for a total of 10 runs• Loop includes establishing W-Pos
� Run the CNC program on 3 different CMM’s
CMM’s Used & Specifications� Prismo (9/12/7)
• 1D = 2.2 microns + L / 300• 3D = 2.7 microns + L / 300
� Contura (7/10/6)• 1D = 2.0 microns + L / 300• 3D = 2.3 microns + L / 300
� UPMC 550 (CAA)• 1D = 0.9 microns + L / 400• 3D = 1.3 microns + L / 300
– L = Length in millimeters
CMM Software
� UMESS UX• Version 8.7
Prismo
Contura
UPMC 550
Test Results –Steel Test Piece
Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00009 0.00003 -0.00019 0.00001Y -0.00012 0.00002 -0.00020 0.00001
Tru-PosX -0.00016 0.00002 0.00050 0.00003Y -0.00002 0.00001 -0.00015 0.00003
CL FlexX -0.00002 0.00019 -0.00033 0.00019Y -0.00014 0.00014 -0.00054 0.00014
Multi-BallX 0.00002 0.00006 0.00041 0.00002Y -0.00019 0.00003 0.00012 0.00008
PCMX -0.00015 0.00002 0.00060 0.00001Y -0.00015 0.00002 0.00060 0.00001
Datum A Projected -0.5"
Contura
Results In Inches
Test Results – ConturaSteel Test Piece
0.0013 TP
Results In Inches
0.0017 TP
Gages PCM
Test Results –Steel Test Piece
Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00013 0.00005 -0.00013 0.00002Y -0.00010 0.00002 -0.00010 0.00004
Tru-PosX -0.00014 0.00002 -0.00014 0.00001Y -0.00003 0.00002 -0.00003 0.00003
CL FlexX -0.00022 0.00014 -0.00021 0.00022Y -0.00002 0.00015 -0.00002 0.00024
Multi-BallX 0.00005 0.00008 0.00004 0.00003Y -0.00024 0.00004 -0.00025 0.00006
PCMX 0.00162 0.00001 0.00162 0.00001Y -0.00017 0.00001 -0.00018 0.00017
Prismo
Datum A Projected -0.5"Results In Inches
Test Results – PrismoSteel Test Piece
Results In Inches
0.0005 TP 0.0033 TP
Gages PCM
Test Results –Steel Test Piece
Jo-Plug Position Std. Dev. Position Std. DevX -0.00011 0.00002 -0.00019 0.00001Y -0.00012 0.00002 -0.00020 0.00001
Tru-PosX -0.00017 0.00001 0.00050 0.00003Y 0.00001 0.00001 -0.00015 0.00003
CL FlexX -0.00026 0.00009 -0.00033 0.00019Y -0.00014 0.00007 -0.00054 0.00014
Multi-BallX 0.00004 0.00006 0.00041 0.00002Y -0.00014 0.00003 0.00012 0.00008
PCMX -0.00018 0.00001 0.00060 0.00001Y -0.00018 0.00001 0.00060 0.00001
UPMC 550
Projected -0.5"Datum AResults In Inches
Test Results – UPMC550Steel Test Piece
Results In Inches
0.0012 TP 0.0017 TP
Gages PCM
Test Results –Steel Test Piece
Jo-Plug Position Std. Dev. Position Std. DevX -0.00011 0.00002 -0.00017 0.00003Y -0.00011 0.00001 -0.00017 0.00006
Tru-PosX -0.00016 0.00002 0.00029 0.00037Y -0.00001 0.00002 -0.00011 0.00007
CL FlexX -0.00017 0.00013 -0.00029 0.00007Y -0.00010 0.00007 -0.00037 0.00030
Multi-BallX 0.00004 0.00002 0.00029 0.00021Y -0.00019 0.00005 -0.00001 0.00021
PCMX 0.00043 0.00103 0.00094 0.00059Y -0.00017 0.00001 0.00034 0.00045
Datum A Projected -0.5"
Average All CMM's
Results In Inches
Test Results – Average of all CMM’sSteel Test Piece
Results In Inches
0.0009 TP 0.0019 TP
Gages PCM
Test Results –Aluminum Test Piece
Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00084 0.00016 -0.00088 0.00010Y 0.00107 0.00005 0.00107 0.00002
Tru-PosX -0.00022 0.00005 -0.00094 0.00008Y 0.00137 0.00005 0.00149 0.00027
CL FlexX -0.00046 0.00025 -0.00140 0.00028Y 0.00098 0.00026 0.00101 0.00034
Multi-BallX 0.00011 0.00020 -0.00089 0.00016Y 0.00112 0.00010 0.00138 0.00008
PCMX 0.00085 0.00002 -0.00033 0.00002Y -0.00006 0.00001 0.00032 0.00001
Datum A Projected -0.5"
Contura
Results In Inches
Test Results – ConturaAluminum Test Piece
Results In Inches
0.0035 TP 0.0017 TP
Gages PCM
Test Results –Aluminum Test Piece
Jo-Plug Position Std. Dev. Position Std. Dev.X -0.00082 0.00007 -0.00082 0.00007Y 0.00111 0.00006 0.00214 0.00007
Tru-PosX -0.00018 0.00003 -0.00018 0.00012Y 0.00129 0.00005 0.00129 0.00012
CL FlexX -0.00043 0.00037 -0.00045 0.00044Y 0.00133 0.00029 0.00135 0.00041
Multi-BallX 0.00037 0.00019 0.00036 0.00014Y 0.00116 0.00013 0.00118 0.00011
PCMX 0.00075 0.00002 0.00075 0.00001Y 0.00003 0.00005 0.00004 0.00008
Datum A Projected -0.5"
Prismo
Results In Inches
Test Results – PrismoAluminum Test Piece
Results In Inches
0.0046 TP 0.0015 TP
Gages PCM
Test Results –Aluminum Test Piece
Jo-Plug Position Std. Dev. Position Std. DevX -0.00081 0.00017 -0.00095 0.00007Y 0.00112 0.00013 0.00101 0.00005
Tru-PosX -0.00013 0.00009 -0.00071 0.00006Y 0.00128 0.00005 0.00140 0.00006
CL FlexX -0.00051 0.00027 -0.00134 0.00027Y 0.00107 0.00033 0.00101 0.00040
Multi-BallX 0.00041 0.00017 -0.00131 0.00013Y 0.00124 0.00014 0.00106 0.00016
PCMX 0.00079 0.00003 -0.00037 0.00001Y 0.00015 0.00009 0.00005 0.00004
Datum A Projected -0.5"
UPMC 550
Results In Inches
Test Results – UPMC550Aluminum Test Piece
Results In Inches
0.0034 TP 0.0016 TP
Gages PCM
Test Results –Aluminum Test Piece
Jo-Plug Position Std. Dev. Position Std. DevX -0.00082 0.00002 -0.00088 0.00007Y 0.00110 0.00002 0.00141 0.00063
Tru-PosX -0.00018 0.00004 -0.00061 0.00039Y 0.00132 0.00005 0.00140 0.00010
CL FlexX -0.00047 0.00004 -0.00106 0.00053Y 0.00113 0.00018 0.00112 0.00019
Multi-BallX 0.00029 0.00016 -0.00061 0.00087Y 0.00117 0.00006 0.00120 0.00016
PCMX 0.00080 0.00005 0.00002 0.00064Y 0.00004 0.00010 0.00014 0.00015
Datum A Projected -0.5"
Average All CMM's
Results In Inches
Test Results – All CMM’sAluminum Test Piece
Results In Inches
0.0033 TP 0.0016 TP
Gages PCM
Test Result Summary
Manufacturer’s
� Jo – Plug• Spence Industries Inc.
– 800-991-1396– http:// www.jo-plug.com
� Multi – Ball • True Precision Corporation
– 317-899-0899– http://www.trueprecisioncorp.com
Manufacturer’s
� CL Flex Plug• Glastonbury / Southern Gage
– 800-229-4243– http://www.gsgage.com
� Tru-Pos• LaVezzi Precision Inc.
– 800-323-1772– http://www.lavezzi.com
Questions?