Doubt about Location...

[Chapo]

Hello my people, Everything OK? This is my first Thread but I have learned much reading in this forum.
I have a doubt about TP and Location. If the print tell me 4.0 in TP about datum B and C; 4.0 in TP about Datum A. How much tolerance I must have in Location?
I need send location to Datapage because I use some graphics.
I understand the formula of TP. For example: Datum A I can have a deviation of 2 mm and I will have 4.0 in TP. Is it my location 2 mm? Am I OK?

[dtmtim]

Hello my people, Everything OK? This is my first Thread but I have learned much reading in this forum.
I have a doubt about TP and Location. If the print tell me 4.0 in TP about datum B and C; 4.0 in TP about Datum A. How much tolerance I must have in Location?
I need send location to Datapage because I use some graphics.
I understand the formula of TP. For example: Datum A I can have a deviation of 2 mm and I will have 4.0 in TP. Is it my location 2 mm? Am I OK?

Is the true pos at MMC, LMC or RFS? If it is RFS then there is no bonus tolerance applied and TP can be calculated with the following formula ...

2*SQRT(DX^2 + DY^2 + DZ^2)

Where DX, DY and DZ represents the deviation from basic relative to your 3 datums. If it is at MMC or LMC then the size of the feature and possibly some of the datums (if they have LMC, or MMC in the FCF) have to be taken into account.

HTH.

t.

[Chapo]

Thanks dtmtim, my TP is RFS. But if I want to dimension in Location no TP How do you know how much is the tolerance in +/- ?

[cmmguy]

Some people use ½ the tolerance ie. ±2.0 in your case. Some will argue that you should never do this. Some dont care.

[Chapo]

Is exactly what I need to Know cmmguy. What is the Correct or the best way to apply Location when the print is in TP?

[cmmguy]

Report TP as it is intended and report axes values as "reference only" measured values with no tolerance.

[Roberto]

Hello my people, Everything OK? This is my first Thread but I have learned much reading in this forum.
I have a doubt about TP and Location. If the print tell me 4.0 in TP about datum B and C; 4.0 in TP about Datum A. How much tolerance I must have in Location?
I need send location to Datapage because I use some graphics.
I understand the formula of TP. For example: Datum A I can have a deviation of 2 mm and I will have 4.0 in TP. Is it my location 2 mm? Am I OK?

Hey Chapo!

As the other colleagues said, the basic dimensions (X,Y,Z) are reference only and should have no tolerance.

Here in my job, when a die maker asks me about what axis to move and how much (in order to fix TP) I use 1/2 if TP is unilateral (one axis only) and 1/3 when two axis (i.e. X,Y) in your case will be about +/-1.4.

Hope it helps.