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From an Inspection and Test Checklist for flange heaters (the number is the same on both lines):

enter image description here

I wonder what the difference between "Design Drawing" (or is it "Drawings"?) and "Manufacturing Drawing(s)" is. Is it that Mfg. Dwg. merely represents some part of Design Dwg. (sheet no.3) that is copied for use in the production shop? Or are there some additions\changes?

Sorry if this is a very basic question. I tried to translate this document and dropped the translation because I found it quite hard to understand many of the terms used, especially in the condensed context of a checklist. But I remembered some terms, and it made me curious.

P.S. I was told on a translators' site that it could possibly mean "Manufacturer's Drawing Number" in this context. I wonder if that's true.

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    $\begingroup$ Without looking at the actual drawing of knowing the company who created them, I would guess that a mfg drawing would include details of how to process the product. For example, it could be something like use machine x and program y with fixture z to make features a,b, and c. $\endgroup$ – GisMofx May 14 '16 at 13:56
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This describes the difference. http://www.vista-industrial.com/blog/engineering-drawings-vs-manufacturing-drawings/

To summarize:

A design drawing or engineering drawing is a complete specification of the finished product - in other words, it shows the important properties of each part (dimensions, materials, specifications for electrical components, etc), and how the parts work together.

A manufacturing drawing has a more limited function. It tells you how to make each a particular part, but nothing else.

In your example of a heater, the design drawing would specify the sizes of the screws or bolts that fix different parts of the heater together, but the heater company won't make any manufacturing drawings for the screws or bolts - they will buy those parts ready made.

On the other hand, the company that makes the bolts and screws will have detailed manufacturing drawings showing exactly how to make a bolt from a plain metal rod, or whatever type of raw material they use, but they won't have any engineering drawings that show how the bolts are used after they have sold them.

Often one "drawing" consists of several pages, or "sheets" (before computers, these were literally several physical sheets of paper). In your example, perhaps the design drawing was the first sheet, and the manufacturing drawing for each component of the heater was on a separate sheet - for example the manufacturing drawing for the "shell" was sheet 3 of the complete set. A complete set of drawings for a complex device may contain hundreds or even thousands of sheets.

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  • $\begingroup$ Thank you! P.S. I was told on a translators' site that it could possibly mean "Manufacturer's Drawing Number" in this context. I wonder if that's true. A strange appearance of "g" in the abbreviation in that case. $\endgroup$ – CopperKettle May 15 '16 at 1:55
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    $\begingroup$ Well, "Design" and "Manufacturing" could be the names of two departments in the company, rather than just English adjectives. But if the numbers are identical, speaking as an engineer I would assume that "Drawing No D12345" refers to the whole document (containing several sheets), and "Drawing No D12345 sheet 3 (Shell)" refers to just one sheet. (The people who make the shell don't need a copy of the other sheets of the complete drawing - everything they need to know should be on Sheet 3). $\endgroup$ – alephzero May 15 '16 at 2:17

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