PierArg
Guest
Hi.
I honestly did not involve geometric tolerances (which all remain as they are).
the final quota will be 15 -0,3/+0,3
I honestly did not involve geometric tolerances (which all remain as they are).
the final quota will be 15 -0,3/+0,3
meccanicamg
Guest
sin that if faces are parallel and get two trapezes remains greater than +/-0.3
Er Presidente
Guest
Please excuse me!
PierArg
Guest
I don't follow you.
simlaz
Guest
I keep having some doubts.. .
If I put a dimensional tolerance with an admissible range i, the further form tolerance and even position tolerance can be greater than i?
the values of the dimensional tolerance range, the tolerance of form (for example flatness) and position (for example parallelism) are somehow linked to each other? in the sense that one cannot be greater than the other? or...?
Thanks again
meccanicamg
Guest
with the caliber I mix a quota between two very small planes. if I mount with the comparison and key the two surfaces I see the flatness. are two different things even if geometric tolerances should be within dimensional tolerance. but depending on the measurement instruments adopted may be that geometric tolerance is beyond the dimensional tolerance limit, introducing systematic errors inherent in the measurement method itself.
PierArg
Guest
return on my steps and quoting what said by mechanicalmg.body to:
minimum = 10-0,1-0,02-0,05-0,02
= 10+0,1+0,02+0,05+0,02
body b:
minimum = 10-0,2-0,03-0,06-0,03
= 10+0,2+0,03+0,06+0,03
However it is quite absurd to have all those tolerances of form, not even a jonson block.
do the accounts and a+b becomes
maximum = maximum to +max b
minimum = minimum a + minimum b
I would say it's elementary
@simlaz: let alone what I wrote in the previous post because it is wrong
meccanicamg
Guest
the principle of independence has been introduced in 1989, as a fundamental principle for the assignment of tolerances, according to which “each dimensional or geometric prescription specified on a design must be respected independently, unless it is prescribed, on the design, a particular relationship. Therefore, in the absence of specific indications, geometric tolerances apply without taking into account the size of the element, and its prescriptions (dimensional and geometric) must be treated as independent needs."
I quoted a links found here.
Since we are in 2012 geometric and dimensional tolerances live in two separate worlds, therefore the worst condition is the overlap of effects.
I quoted a links found here.
Since we are in 2012 geometric and dimensional tolerances live in two separate worlds, therefore the worst condition is the overlap of effects.
paulpaul
Guest
Unfortunately, on tolerances there is no identity of views between designers, workshops, etc.: the norm quoted by mechanicsmg had the objective to put an end to doubts on the interdependence between dimensional and geometric tolerances, allowing to evaluate tolerances independently from each other. So yes, in the example mentioned, the shocks must be added one by one to find the total deviation, and a possible pass/not pass caliber of the axieme - if it makes sense - should be built with hole height between maxa+maxb and mina+minb, considering all the geometric and dimensional tolerances present. If this rule is applied, it should always be cited in cartilage, because time ago it was believed (and thick still now) that dimensional tolerances placed limits to geometric tolerances, in which case in our example min/max deviations would actually be given by the sum of min/max deviations but only dimensional tolerances. Of course, in this situation geometric tolerances would make sense only when they are understood in dimensional ones (although I personally believe this principle is valid even in the case of independence!).
this second situation can be in a certain way achieved also following the new norm by placing the "e" in the circle near the quota, to indicate a need for envelope: in this case the element must always be understood in the perfect form defined by the condition of maximum material defined by dimensional tolerance and geometric tolerance can be omitted.
this second situation can be in a certain way achieved also following the new norm by placing the "e" in the circle near the quota, to indicate a need for envelope: in this case the element must always be understood in the perfect form defined by the condition of maximum material defined by dimensional tolerance and geometric tolerance can be omitted.
paulpaul
Guest
incorrect corrige: I meant obviously nominal height+maxa+maxb
Hi.
doc84
Guest
Since we are in 2019, the question is still unclear: does the iso want the principle of independence but we from good designers do not rely on the presence or not of the indication of correct invilusion or mmc? and how to sum them opens a crazy and beautiful world of some programs for analysis of tolerances that should manage the complexity of the calculation
meccanicamg
Guest
Just don't use them....when they're complicated they're leaving.
However, they are independent. I am already less if you use iso 22768....which however say is not the maximum of the correct....so after 20 years we still do not know how history is.
However, they are independent. I am already less if you use iso 22768....which however say is not the maximum of the correct....so after 20 years we still do not know how history is.
doc84
Guest
I use them from the first day when I drew a line on a drawing, the tolerance analysis of the two separate worlds is known and feasible. I am growing on the combined calculation through the manual "dimensioning and tolerancencing" of drake.