hexagon logo
Register Sign in
  • Replies 14 replies
  • Subscribers 223 subscribers
  • Views 158 views
  • Users 0 members are here
Options
Related

Parallelism calculation method

Leandre Vienat
Hello

I need to perform a parallelism with external material calculation method how can I do?
I can't find a compute option for parallelism. In the help it seems to me that I found that flatness and parallelism are in Chebyshev.
Can someone give me some clarification on this? PC-DMIS 2019R2 version
Thanks in advance

My best regards

Léandre Vienat
  • Not sure that's available in Xactmeasure.

    You could probable construct primary datum planes from the measured planes hits and use that as a workaround.

    neil.challinor can probably confirm if this is correct.

    ​​​​​​​
  • From the 2019 R2 help documentation...

    "You can construct a plane that is external to the material (tangent to the peaks or the high points) on a surface. You can then use this feature as a datum in alignments or dimensions. Do not dimension a primary datum plane. That is not its purpose. You should use it only as a datum feature."

    https://docs.hexagonmi.com/pcdmis/2019.2/en/helpcenter/index.htm?rhcsh=1&rhnewwnd=0#t=mergedProjects%2Fcore%2F16_const_topics%2FConstructing_a_Primary_Datum.htm

    You would need to upgrade to 2020 R2 or higher and use the geometric tolerance command - parallelism with the tangent plane modifier applied.
  • This is as close as you could get using the tools available in PC-DMIS 2019 R2... 

    PLN2 =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,NONE,LEAST_SQR
THEO/<0,51.751,-8.592>,<-1,0,0>
ACTL/<0.011,51.751,-8.592>,<-0.9999999,-0.0002066,0.0004264>
TARG/<0,51.751,-8.592>,<-1,0,0>
ANGLE VEC=<0,0,1>,SQUARE
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=6,NUMROWS=7
SPACER=0
AVOIDANCE MOVE=BOTH,DISTANCE=10
USE BOUNDARY OFFSET=YES,OFFSET=1
SHOW HITS=NO
PLN3 =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,NONE,LEAST_SQR
THEO/<120,38.223,-34.508>,<1,0,0>
ACTL/<119.988,38.223,-34.508>,<0.9999997,0.0001967,-0.0007477>
TARG/<120,38.223,-34.508>,<1,0,0>
ANGLE VEC=<0,0,-1>,SQUARE
SHOW FEATURE PARAMETERS=NO
SHOW CONTACT PARAMETERS=YES
NUMHITS=4,NUMROWS=3
SPACER=0
AVOIDANCE MOVE=BOTH,DISTANCE=10
USE BOUNDARY OFFSET=YES,OFFSET=1
SHOW HITS=NO
PLN4 =FEAT/PLANE,CARTESIAN,TRIANGLE,NO
THEO/<0,30.944,-28.524>,<-1,0,0>
ACTL/<-0.048,30.943,-28.51>,<-1,-0.0002747,0.0001187>
CONSTR/PLANE,PRIMARY_DATUM,PLN2,,
MATH_TYPE/CONSTRAINED_L2,BFRE
PLN5 =FEAT/PLANE,CARTESIAN,TRIANGLE,NO
THEO/<120,31.933,-35.395>,<1,0,0>
ACTL/<120.015,31.928,-35.406>,<0.9999997,0.0003978,-0.0006768>
CONSTR/PLANE,PRIMARY_DATUM,PLN3,,
MATH_TYPE/CONSTRAINED_L2,BFRE
$$ NO,
.
. You cannot dimension a primary datum plane because it has no hits
. and will always report zero deviation
.
DIM PARL6= PARALLELISM OF PLANE PLN5,RFS TO PLANE PLN4,RFS UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
M 0.000 0.010 0.000 0.000 0.000 0.000 #--------
$$ NO,
.
. Instead, create and alignment that levels to the primary datum plane
. then construct generic points that represent the extremes of the surface
. (in this case the 4 corners)
. then construct a BF plane from the generic points
.
A4 =ALIGNMENT/START,RECALL:A3_DCC3,LIST=YES
ALIGNMENT/LEVEL,XPLUS,PLN5
ALIGNMENT/ROTATE,ZPLUS,TO,PLN1_DCC,ABOUT,XMINUS
ALIGNMENT/TRANS,XAXIS,PLN5
ALIGNMENT/TRANS,YAXIS,LIN1_DCC
ALIGNMENT/TRANS,ZAXIS,PLN1_DCC
ALIGNMENT/END
F1 =GENERIC/POINT,DEPENDENT,CARTESIAN,$
NOM/XYZ,<0,0,-20.7>,$
MEAS/XYZ,<0,0,-20.7>,$
NOM/IJK,<1,0,0>,$
MEAS/IJK,<1,0,0>
F2 =GENERIC/POINT,DEPENDENT,CARTESIAN,$
NOM/XYZ,<0,60,-20.7>,$
MEAS/XYZ,<0,60,-20.7>,$
NOM/IJK,<1,0,0>,$
MEAS/IJK,<1,0,0>
F3 =GENERIC/POINT,DEPENDENT,CARTESIAN,$
NOM/XYZ,<0,60,-50>,$
MEAS/XYZ,<0,60,-50>,$
NOM/IJK,<1,0,0>,$
MEAS/IJK,<1,0,0>
F4 =GENERIC/POINT,DEPENDENT,CARTESIAN,$
NOM/XYZ,<0,0,-50>,$
MEAS/XYZ,<0,0,-50>,$
NOM/IJK,<1,0,0>,$
MEAS/IJK,<1,0,0>
PLN6 =FEAT/PLANE,CARTESIAN,TRIANGLE,NO,LEAST_SQR
THEO/<0,30,-35.35>,<1,0,0>
ACTL/<0,30,-35.35>,<1,0,0>
CONSTR/PLANE,BF,F1,F2,F3,F4,,
OUTLIER_REMOVAL/OFF,3
FILTER/OFF,WAVELENGTH=0
$$ NO,
.
. Finally, define the first priary datum plane as datum A and report
. parallelism of newly constructed plane (PLN6) using XactMeasure
.
DATDEF/A,FEATURES=PLN4,,
FCFPARL1 =PARALLELISM : PLN6
FEATCTRLFRAME/SHOWPARAMS=YES,SHOWEXPANDED=YES,
CADGRAPH=ON,REPORTGRAPH=OFF,TEXT=OFF,MULT=500.00,A RROWDENSITY=100,OUTPUT=BOTH,UNITS=MM,
STANDARDTYPE=ASME_Y14_5
DIMENSION/PARALLELISM,0.01,<PZ>,<type>,<len>,<wid>,A,<dat>,< dat>
NOTE/FCFPARL1
FEATURES/PLN6,,
$$ NO,
.
. or use Legacy dimensioning
.
DIM PARL5= PARALLELISM OF PLANE PLN6,RFS TO PLANE PLN4,RFS UNITS=MM ,$
GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
M 0.000 0.010 0.000 0.024 0.024 0.014 -------->
  • Create a L2 constrained plane on the datum, then Assign/V1=DOT(PL2.HIT[1..PL2.NUMHITS].XYZ-PL1.XYZ,PL1.IJK]
    In ISO world, use minimax algo.
  • Here in english for V2009 : (page 914 and 920)
    https://files.ms.hexagonmi.com/public/docs/v2009manual/eng_pcdmis_v2009_core_manual_pdf.zip

    for 2019R1 in french : (14_Construction_de_nouveaux_éléments_à_partir_d'éléments_existants - page 86)
    https://files.ms.hexagonmi.com/public/docs/v2019r1manual/frn_pcdmis_2019r1_core_manual.zip

    Hope this helps !
    have a nice sunday, all !
  • When measuring parallelism, why does it matter what plane you select first? shouldn't the parallelism between two planes measure the same no matter what plane is selected first?
  • If the two surfaces were the same size and you take points at the same place on those surfaces it shouldn't matter.
    If one surface is longer or wider then it absolutely matters.

    Imagine a wedge shaped paralleligram where the top surface is half the length of the bottom surface. If you place the part on the surface place with the large end down and sweep the top you'll get one value. If the same part is placed with the small end down then you will get about twice the deviation. (Overly simplified example that assumes the two surfaces are very flat.)
  • in reply to kingsld1
    What if the surfaces are not the same size but the points are taken at the same place?
© 2024 Hexagon AB and/or its subsidiaries. Privacy Policy | Cloud Services Agreement