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i need help with a big part with iterative

pcdmisstudent
Hey guys
so i have this big part, that the datums are defined by 3 datums points (three holes with sample hits that i did iterative with). I then constructed three theorietical planes (alignment planes) and defined those as ABC. Then i measured all the different features on the parted and called them out using FCF position.
the program works well, but some of my results gets weirdly high.
Ill upload pics with the datum targets (see black circles)
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  • Like the others already have stated, the tertiary/origin shall only be one circle. One could also argue if this really is a datum target system or if the engineer had a brain fart? It seems they are placed like datum targets, but the construction of the datums seem to be more like common datums (like the alignment described). Is it possible for you to get clarification from the designer?

    You have some hefty deviations on your alignment features as well, this is pre-iterative though:

    CIR_A2 =ELEM/KONTAKT/CIRKEL/STANDARDVÄRDE,REKTANGULÄRA,INRE,GAUSS
    TEOR/< 135.25,0,0>,<1,0,0>,25
    MÄTT/< 136.091,-0.196,-0.14>,<0.999958,-0.0085354,-0.0033285>,25.121
    MÅL/<135.25,0,0>,<1,0,0>

    CIR_A3 =ELEM/KONTAKT/CIRKEL/STANDARDVÄRDE,REKTANGULÄRA,INRE,GAUSS
    TEOR/< 135.25,22,200>,<1,0,0>,25
    MÄTT/< 136.185,21.793,199.887>,<0.9999188,-0.0070527,0.0106123>,25.125
    MÅL/<135.25,22,200>,<1,0,0>

    CIR_A1 =ELEM/KONTAKT/CIRKEL/STANDARDVÄRDE,REKTANGULÄRA,INRE,GAUSS
    TEOR/< -135.25,0,0>,<-1,0,0>,25
    MÄTT/< -134.666,0.425,0.533>,<-0.9999322,0.0116092,0.0008601>,25.121
    MÅL/<-135.25,0,0>,<-1,0,0>

    It seems like the part is skewed (swedish: skev)​​​ in this alignment.

    EDIT: The engineer responsible for the drawing mixes and matches with the datums. Datum target C1 and C2 should be created where the cross-symbol for these targets are located, which is centerline each hole and the OUTSIDE surface. But, looking at your snippet of the drawing, datum C is the midplane of the INSIDE surfaces?



    Can you post snippets where we can see datum [A] and datum as well?

    "Your" CAD trihedron doesn't match up with the trihedron on the drawing (it is rotated 90° around Z), just a heads-up. It doesn't have to match, but it is way, way easier for you if they did...
  • in reply to vpt.se
    oh oh yeah. these two plates are skewed, but within tolerance since its +- 1.5 mm.
    ok ty, BF 2D least square then? not good with BF alignments
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