ASME 14.24 Engineering Drawing - Purchased Parts?

[CWhitworth]

Hello All,

What type of engineering drawing should we use for a purchased(COTS) parts? And what ASME standard is it defined by for reference? There has to be one in the ASME Y14.24.

My company is currently implementing Procurement Control Drawings, Vendor Control Drawings and Source Control Drawings to define purchased parts that are interchangeable.

Where it get's confusing is that they are trying to use on of these types to define a purchased part that is not interchangeable with any other items. For example, certain electrical items such as, terminal blocks only work with certain electrical parts provided by the same manufacturer. (End Caps, Other terminal block types)[pre][/pre]

Thank you

 

[3DDave]

Is there a requirement to provide interchangeable vendors?

Typically for a Vendor Item Control Drawing only the sources allowed on the drawing are to be purchased. If that means only one entry then that's it.

Be aware that any time one depends on a vendor there is the chance for them to make some change you won't like if you don't specify a significant amount of controls on it. Having been burned one time by a vendor that redesigned the part to be mounted in an entirely different manner but didn't change the part number, I can say that some are weasels. I had another place give me the go-around because they were in the process of changing all of their part numbers so when I looked at their only source of info (their website) I got to see different numbers than when procurement looked at a different segment that had the exact same part. And yeah, my conversation with that supplier wasn't refreshing - "Just put down either one, we'll figure it out."

So, put as many of the critical dimensions and characteristics on the drawing and not just some fast overview if you want to avoid them yanking the rug from beneath you.

 

[CWhitworth]

Thanks for the response 3DDave,

The problem lies when we want to select a drawing style from the ASME Y14.24 - Engineering Drawing Types.

PCD, VCD, and SCD are all great for controlling interchangeability.(the definition of control drawings is to control items that are interchangeable)

But what about when you just want to release a drawing for a COTS part, where you have an OEM and an OEM PN.

Is there any drawing style for standard COTS parts?

Thanks again!

 

[looslib]

Does the vendor have a drawing of their part? Just use that for your reference, especially if you are using their part number.
If you are using your own part number, I would call it a SCD, if the part can be supplied by multiple vendors or a VCD if it is a single source item.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[MintJulep]

Isn't this exactly what a Vendor Item Control Drawing is for?

 

[greenimi]

Per Y14.24-2020
The purpose of this Appendix is to identify procurement control drawing (PCD) practices that were covered in ASME Y14.24-2012. The PCD type duplicates requirements for a VICD or SOCD. It is recommended that, for
future designs, a VICD or SOCD be used rather than a PCD. The requirements for PCDs have been moved to this Appendix and will be removed from this Standard after time has passed to permit industry to transition to the preferred practices within the body of this Standard.

Therefore, if you can identify the differences between VICD and SOCD (the only two that are applicable per the current version of the standard) and apply those (differences) in your specific case, then you would be able to make a educated decision on which type of drawing you are dealing with.

 

[CWhitworth]

looslib - With our current system all items released must have a unique part number and a drawing. So that's why I'm trying to figure out what drawing type to use.

MintJulep - I agree with what you are saying. If its for a COTS item we could use a VCD and list the OEM and OEM PN in the requirements section for acceptance criteria and in addition to that list the supply sources. I would say we could do the same with PCD right?

Greenimi - Thanks for the update. My company just references the 2012 version currently so it's good to know that PCD's are getting axed. So SCD requires qualification testing and VCD doesn't, in summary.

Another Question: There is acceptance criteria, which is required by the VCD and then there is qualification criteria and acceptance criteria, which is required by the SCD.

What is the difference?

3.1 Acceptance Criteria
acceptance criteria: the quality provisions, including
inspection and test requirements, that establish the
acceptability of an item. It may range from testing the
item in its use environment, to verification of electrical/
mechanical characteristics, to a simple visual inspection.

3.38 Qualification
qualification: the formal process by which a manufacturer’s
product is examined for compliance with the procurement
requirements of a source control drawing for
the purpose of approving the manufacturer as a source
of supply.

Is qualification documentation provided by a manufacturer or OEM that their product meets our SCD requirements?