Interpretation of tolerences in Fig 3.4

Date 02-25-2006 11:54

All of the WPS in my shop are as shown in figure 3.4. I do not consider the tolerances at all when writting a WPS.
Lets use TC-U4b.
R=0 to 1/8 the detailer can make it 0 to 3/16 and the shop can make it 0 to 1/4. all are still pre-qualified.

f= 0 to 1/8 detailer can make it 0 to 3/16 and if the shop wants the welder to carbon arc through half an inch it is still pre-qualified.

a= 60 degrees detailer can make it from 60 to 70 degrees and the shop can make it 65 to 80 degrees.

Bottom line is as long as the detailer does not exceed his/her tolerances and the shop does not exceed the tolerances allowed for them the joint designation is still prequalified.

By Saleem Date 02-27-2006 04:54

Thanks for the explannation which is very useful to me.

By 803056

Date 02-25-2006 18:17

It is my understanding that if the detailer does not list the "as detailed" tolerance" on the drawing, i.e., the welding symbol, then the "as fit-up" tolerances are added/subtracted to the basic dimensions listed for the joint detail.
condition 1 - "basic" plus "as fitup"

If the detailer takes advantage of the "as detailed" tolerances and adds those dimensions to the basic dimension of the joint detail in the welding symbol, the shop may then add/subtract the "as fit-up" dimensions to the as detailed dimensions.
condition 2 - "basic" plus "as detailed" plus "as fitup"

Good luck - Al

By Saleem Date 02-27-2006 05:02

Thanks for ur clarification. It seems more logical to mention "As detailed " tolerences in WPS so that the shop can proceed with that to make fit up. The QC can inspect to ensure that the actual measurements are well within the "As fit up" tolerence with reference to the "As deatied " in WPS.