implementing/enforcing a different drawing standard 3

[cowski]

Long story short, we currently use a "company standard" that is loosely based on ASME and we are looking to fully implement one of the recognized standards. Due to the global nature of the company we are leaning toward ISO (but that hasn't been decided yet). We know that we will need to acquire a copy of and get training on the chosen standard (probably several rounds of it). For those that have been through this process, what advice can you give? What hidden issues should we be aware of?

 

[Belanger]

Two random thoughts:
-- Using the ASME Y14.5 standard doesn't meant that a company isn't international.
-- The ISO tolerancing system is much more intertwined with other ISO standards (research the "GPS Matrix").

If you already have one foot in that GPS world then ISO tolerancing would be they way to go. But since you stated that the internal standard is already loosely based on ASME, then ASME Y14.5 sounds like the best bet.

 

[Hallec]

You'll need training, yes. And you'll all need years of practice both reading and implementing proper geometric controls, creating proper DWG titles, creating formats, drawing standards for text, dims, notes, rev blocks, etc. - It's quite an undertaking to be adopting a standard - ISO or ASME.

I'd suggest ASME personally, as after working with both for some time, I believe ASME drafting standards to be more legible and easier to read... But I'm not sure which one is more widely used in your industry, and that would probably be a rather large consideration. Who are your experts and what are they most familiar with? Will you be inspecting your product using GD&T? And does your inspection team have more familiarity with one over the other? How about your suppliers? Will they understand your new drawings?

Good luck!

I'm not a vegetarian because I dislike meat... I'm a vegetarian because I HATE PLANTS!!

 

[TheTick]

Be prepare for whining and gobs of passive resistance.

 

[cowski]

By "global nature" of the company, I should clarify that they have acquired several smaller competitors over the years. One of the larger ones is based in Germany and they currently use the ISO standard. To date, we have largely operated as independent entities; but moving forward, we'll need to share design data between locations. Since my location needs to adopt a recognized standard, it made more sense that we should go with ISO rather than forcing everyone to move to a new standard (unless there is a really good reason to...).

I'm not familiar with the GPS matrix, I'll need to do some research. Thanks for the tip.

 

[Belanger]

Also, in addition to the tolerancing aspect, think about which "projection" method you'll want to use for your drawings. Since you mentioned Germany, I suspect their prints use first-angle projection, but in North America the norm is third-angle projection. (Get ready for battles on that one!)

Whichever side wins that "projection" battle will probably mean the scales tip toward that faction for your tolerancing standard -- often ISO tolerancing and first-angle projection go together, while ASME and third-angle projection go together, although this is not an absolute requirement.

 

[greenimi]

Since you mentioned Germany, I suspect their prints use first-angle projection, but in North American the norm is third-angle projection. (Get ready for battles on that one!)

Whichever side wins that "projection" battle will probably mean the scales tip toward that faction for your tolerancing standard -- often ISO tolerancing and first-angle projection go together, while ASME and third-angle projection go together, although this is not an absolute requirement.[/b]

Got GO direclty to MBD and no need for that battle ....just saying.....

 

[TheTick]

My dad got an engineering degree at Universität Hamburg. He would be the first to tell you third-angle is superior.

 

[Tmoose]

And if parts like shafts with bolt patterns are made in the US that 1st angle symbol needs to large and bold, and there should probably be a highly visible note note sounding an alarm.
And end views need to be identified with section type arrows for the next couple of years to protect your good suppliers from the tragedy of incorrect parts.

If the supplier is German or another long time ISO user, perhaps similar precautions need to be taken with 3rd angle drawings.

I think I heard ASTM Y14.5 rule 1 is not recognized by ISO.
Now THAT is a virtual IED with fatal potential.

 

[TheTick]

Always always ALWAYS use the cone symbol to show first- or third-angle. Show, don't tell.

 

[BiPolarMoment]

Always always ALWAYS use the cone symbol to show first- or third-angle. Show, don't tell.

It's remarkable how many 3rd party drawings I've seen that don't have that indication... I also had a fun chore some time ago converting a bunch of drawing blocks to show the correct projection symbol (rather than correcting the projection as that would have been a nightmare). I probably violated a standard if we followed any... oh well.

Personally I prefer first-angle projection as I find it more intuitive for small objects I might turn over on top of my desk but after a decade working in third-angle I really don't mind either way.

 

[AndrewTT]

My experience in implementing ASME Y14.5-2009 at my company.

1) I second what The Tick states about passive resistance. Get ready.

2) Watch out for people who claim they already understand the standard because we "used GD&T at my old job". If they are not certified or have not read the standard themselves then there is a good chance they misunderstand most of what they claim to know. I like to start by asking them what rule #1 is or to give me an example of a regular feature of size. This is usually enough to tell me everything I need to know.

3) Agree with the sentiment that if you use 1st angle projection you need to make it abundantly clear on the dwg. We were machining some parts for our German counterparts and the drawing stated 1st angle projection in the title block. The lab manager asked me to look at the print because the views didn't make sense. I showed him the 1st angle projection symbol. He didn't know it was "a thing". Either did our machinist, who has almost 20 years experience.

 

[metrologic]

Sometimes I see design drawings with two title blocks right next to each other, one indicating ISO GD&T with 1st angle, and another indicating Y14.5 with 3rd angle.

 

[powerhound]

As I see it, third angle is more intuitive. On a 3rd angle print, if you want to see what the right side of the part looks like you look to the right of the main view. Same with the left and the top. On a 1st angle rotation, if you want to see what the right side looks like, you have to look to the left of the main view. If you want to see what the top of the part looks like, you have to look to the bottom of the main view. Just my opinion and reasoning.

John Acosta, GDTP Senior Level
Manufacturing Engineering Tech

 

[TheTick]

One vexing thing about 1st-angle is that section views are still 3rd-angle. Pick a lane!

 

[3DDave]

1st angle is what you would see if the real part was sitting on the drawing board (or the electronic equivalent.)

Roll the part to the right, the left side is facing up. Rolled towards the top and the bottom side is exposed.

Section views aren't from rolling but by forcing a view direction.

It's a different sort of intuitive, but I prefer 3rd angle.

A contrarian in a 1st angle situation would make all views with view arrows and place them with 3rd angle locations.

3rd angle is how the packaging for animal crackers (for example) is laid out to fold into a box that looks like a rail car. Those boxes were, at 5 or 6 years old, interesting to unfold and see the way they were made, pre-disposing me no doubt to 3rd angle. Bribe me with more cookies and maybe I'd like 1st angle better.