metric diminsioning

[bobdee]

Is there a way in pro/e to have metric dimension conform to ASME Y15.5 standards. Her is the issue I am having. Basic dimensions state no trailing zero's also if dimension is less than whole number use a zero to left of decimal place.


Thanks in advace for any help


bob d

 

[dr_gallup]

Yes.

 

[dr_gallup]

You didn't ask how.

 

[bobdee]

could you explian please

 

[dr_gallup]

In the drawing setup file:

lead_trail_zeros std_metric

 

[bobdee]

thts correct. but if i want basic dim 55 and want a regular dim as 12.50 have do I keep the zero on 12.50 but not on 55 without going to properties for each dim

 

[dr_gallup]

That would be incorrect.

 

[bobdee]

follow up please. I will give and examble. i want a dimemsion from datum to hole of basic 55mm. Form hole to hole basic 65mm. I want overall length to be 121.20. hole size to be 3.4mm but if i 3.40mm I can use our standard tol block if +/-.13. gtol box 0.20. So is there a set up function that will let me keep 55 and 65mm dim basic without zero's overall length at 121.20 and gtol at 0.20. So fa if we change setup we either all the trailing zero's showing 55.00 65.00 basic and 121.20 along with 0.20. If we change setup all zero's go away before and after decimal point. Sorry if I did not explain it well enough hopfully this well help. thanks for your time





bob

 

[dakeb1]

Bob,


I set my tolerance standard to ANSI and dimension in metric. Setup parameter lead_trail_zeros is set to "both".


For your basic dimensions click the dimension properties and change number of decimal places to zero in each case. Your GTOLs will still have 2dp.


Non-basic dimensions can have as many dp as you want. Any tolerance applied must have the same number of dp.


Dave

 

[bobdee]

thanks Dave that is what we are doing currently. We are looking to see if there is a setup to do it automatic. thanks for the help





bob

 

[kdem]

If you are going by the standard trailing zeros are notused with millimeter dimensions. The only timetrailing zerosare used is with tolerances where one tolerance has more decimal places than the other. You see this when thetolerance modeis limits or plus-minus.

 

[looslib]

You need to decide if you want to follow the standard or use your own dimensioning scheme.


Metric dimensioning does NOT use trailing zero's as place holders for tolerancing. You need to adjust your thinking to this concept and add tolerances where needed if the drawing defaults are not tight enough.


When one company I worked for had the note on the drawings stating that the drawing was dimensioned in accordance with ASME Y14.5-1994, I modified the CAD system standards to refelect that. About 3 days later I get called into a meeting to discuss why the drawings were not toleranced as the manufacturing department wanted them with tighter tolerances that the trailing zero 'provided'. I had to explain that you can have it, put that dimension would have to be individually toleranced.

 

[dakeb1]

Which ASME standard covers general tolerance blocks? I am sure I have seen number of dp after the point used to determine general tolerance values.

 

[dakeb1]

Yes, itis in Fig. 13 of ASME Y14.1M-2005.

 

[looslib]

You can have general tolerances on metric drawings, just can't use a trailing zero to get the tolerance.


A dimension of 24.00 does not exist in metric drawings that conform to ASNE Y14.5. It is not only done for tolerance reasons, but for ease in reading a drawing. When I see a 24.00 dimension, I assume the drawing is done in inches. Likewise, if I see a hole that is 0.8, I assume it is a metric drawing, because inch drawings don't use the leading zero.


If you want the 24 dimension to have a tighter tolerance, then you need to explicitly tolerance the value, 24 +/- 0.8 or use 24.8/23.2 as the drawing value.

 

[dakeb1]

Where I work they do it exactly like that, they use number ofdp to determine accuracy. Almost every company I have worked in does it. They go against the standards. Even ISO doesn't allow trailing zeroes for metric, not just ASME. Getting companies to change, now theres a thing...

 

[dakeb1]

With ISO drawings, the way of controlling generaltolerances is by specifying ISO 2768. Is there an ASME equivalent? How do you specify general metric tolerances under ASME standards?

 

[looslib]

General tolerances are controlled just the same way for both english or metric drawings. You just have to realize that trailing zeros are not used in metric dimensioning. This means that you mave have more dimensions on your drawing with explicit dimensions.