Use of AR in Field of view

[marshell]

If a part in the parts list is shown as AR, does the AR need to be shown next to the item bubble in teh Field of Drawing where a QTY normally would go?

Similar question... if the QTY of an item (bolt in a pattern for example) is obvious, does the QTY need shown next to the item bubble?

Thanks in advance.

 

[KENAT]

No, and you don't need to uniformly put qty next to every balloon either.

I only put quantity's next to balloons when the same item is being used in different applications.

E.g. if the same screw is being used to hold 2 completely different components to the base component then I'll put a balloon with qty at each place.

This has been discussed before on this forum at length, the ASME stds don't say much on it I think at least some of the below threads are relevant.

thread1103-327176
thread1103-206191
thread1103-203140
thread1103-233746
thread1103-164780

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[ewh]

I don't think "A/R" is required next to the callout, but I think it is good practice to put it there (just to be consistent with the second part of your question);
Yes, the QTY should be noted next to the item callout. Not all drawings make it obvious, and "obvious" may not be obvious to everyone.

"Know the rules well, so you can break them effectively."
-Dalai Lama XIV

 

[drawoh]

marshell,

I like how everybody assumes that AR means "As Required".

A lot of this depends on what CAD software you are running, and how you have set up your models. We set up adhesives and other chemicals as an empty part models. This causes the material to be added to the parts list. Then I put a note on the drawing tell them to apply "LUBRICATING THREADLOCKER" or whatever. My terminology conforms to whatever is on the bill of materials. I do not use item numbers. Epoxy and other adhesives should be applied as per the manufacturer's instructions. I don't have a convenient way to attach item balloons.

I provide quantities if it makes the drawing clearer. This is well supported in SolidWorks.

Your top priority is to provide clear instructions.

--
JHG

 

[Tunalover]

People are right to assume that "AR" means "As Required". That abbreviation is defined that way in ASME Y14.38 Abbreviations and Acronyms as well as in MIL-STD-12.


Tunalover

 

[fsincox]

True, It is also in ASME Y14.100 or the one on lists Y14.34, too. I just read those last night and I made special notice of that because we have always used "A/R".
Frank

 

[3DDave]

In cases for materials like thread locking compounds, the AR is a weak callout. A program I was on returned a big pile of precision hydraulic valves because they failed to work. The supplier did a tear down to diagnose the problem and suggested that their valves work better without being filled with thread locker. I presume the supplier charged the tear down time and a bunch more for sending back items and essentially blaming them for defective product.

What I have noticed is that manufacturing process planning has a tendency towards forcing design engineering to process on the drawing. So the thread locker should spec exactly how many milliliters should be applied to each and every screw and what the raw stock lengths of parts should be prior to machining the parts. These same guys tend to fight creating their own manufacturing standards because they don't want to be held responsible for the results, and want flexibility to make on-the-fly interpretations.

Again, for example, I worked with a threaded-in-bushing. The materials have weak interaction with thread locking compound on both sides; an aluminum part and a bronze bushing. So a high strength thread locker was called out. A smaller screw threaded into the bushing and a nominally lower strength locker was called out to retain the greater interacting steel screw. Manufacturing simplified the bill by using low strength on both sides. It made the joints equal and about half the time trying to remove the screw would instead remove the bushing with it.

This ridiculous behavior shows up especially poorly in sheet metal, where it's as if the design engineer should know how the nesting software will lay out the final parts and therefore be able to predict how many square inches of sheet, including lost material that can't be used, will go into each part.

tl;dr Don't use AR on the drawing if you can include notation for a process document that will tell how to tell an amount is sufficient, preferably by result. In other words, use AR if pouring on a gallon of the stuff can be determined as required by the new hire assembler.

 

[Tunalover]

3DDave, a note on the drawing to say to apply the threadlocker per the manufacturer's instructions SHOULD control that problem. The mfgr probably specifies only a drop or two per thread.


Tunalover

 

[3DDave]

One would think so, but a few thousand in ruined hydraulic valve says different. It really depends on the factory. In this case the same factory called one time to report that all the hydraulic fittings were defective and all needed to be changed from steel to stainless steel. Many vehicles had been assembled and shipped by then with no trouble. Investigation showed they didn't read the drum contents in the washing bay. Instead of a degreaser, they used etchant and stripped the plating off of all the fittings. I guess it was engineering's fault for not specifying -not- to use etchant as a cleaner. They also used a grinder and pistol drill at final assembly because they didn't want to use weld fixtures and instead welded critical-alignment parts as open setup.

Funny thing, they aren't alone. A guy I worked with was in a garden tool assembly plant that used a high-performance adhesive to hold the rubber handles on. Manufacturing engineering set up a dispenser to do just one drop, which no doubt spread to several square inches in the interference fit and retained the handles quite well. The guy in charge gets a panicked call that the factory suddenly ran out of the adhesive (they had a month's supply just a week before) so what was engineering going to do about that? Turns out the line worker just couldn't see how so little glue would work and liberally coated the handles, leading to a large amount of squeeze-out, getting glue everywhere and ruining the tools, and running through the adhesive at maybe 100 times the designed rate.

Reasonable people can look at the bottle and have some idea what to do. Even so, AR is often an invitation to get a pie in the face delivered with a note "You didn't say -not- to."

 

[tbuelna]

The only time "A/R" is used in the qty column of a BOM is for bulk materials like primer/paint/adhesive/sealants/etc. All other parts of a BOM should have a defined qty.

 

[KENAT]

Per Y14.38 I believe AR is the correct term - the '/' generally got dropped at least in my 2002 edition.

The AR is the quantitiy required, it's not the application instruction as such.

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[marshell]

AR is the way we use it.

From what I can read there is no black and white answer as to requiring the AR to be located near the item bubble. I can see reasoning on both sides, which is maybe why there is no definition for it. One of the do whatever your company feels comfortable doing.

We have been including the AR on the applicable bubbles, and all of a sudden checkers decided they don’t want to see it, so are having us remove it. I am of the opinion that it does not matter, and don’t require extra work to remove them if they are there.

 

[tbuelna]

While I prefer to use the actual part numbers, as opposed to find numbers (or bubbles) for callouts on assembly drawings, when there is a need to callout application of a bulk material like paint or adhesive, it is normally done using a flag note. And the flag note describes all of the bulk materials and processes required to apply them.

 

[mtkenney]

regarding qty callouts on balloons, the last place I worked had some very busy assy dwgs and every item that was a qty of 1 had a 1X next to the balloon.