Reading of Assembly Drawings

Reading and Detailed Drafting of Assembly Drawings

QuestionS for SELFcheck

Dimensions in the Assembly Drawing

The followings dimensions are marked in the assembly drawing of an article:

1. Overall dimensions, which characterize height, length and width of an article or its the greatest diameter. If one of these dimensions is changed after wards the shipment of mobile parts, thus, dimensions in extreme positions of mobile parts are shown on the drawing.

2. Fixing or assembly dimensions, necessary for correct connection of parts, located in direct connection in an article.

3. Setting and conjunctive dimensions, which determine dimensions of elements, due to them an article is installed or joined to another article.

4. Operating dimensions which show some calculation and structural descriptions of an article.

The dimensions of separate parts or their elements are not shown in the assembly drawing.

1. What is assembly drawing?

2. What must assembly drawing contain?

3. How making assembly drawing?

4. What are part numbers?

5. What dimensions we should put in the assembly drawing?

To read an assembly drawing means to understand setting, structure, principle of work of the represented article. Thus co-operation, methods of connection and shape of every part are taking into consideration.

The name of an article and the scale of a representation are finded out after title block. Due to the representations and parts list by the part numbers we determine from what parts and what amount article consists of, what kind of parts are drawn on every representation, how they are joined and co-operated. Thus a special attention should be paid to fragmentary views, sections, and detail sections.

Having found out the setting of an assembly unit and principles of its work, the geometrical shape of separate parts are analyzed. For this purpose all representations of a part on the drawing should be attentively learned, projection connection between representations, position of cutting planes with the help of which sectional views and sections are executed by should be found out. It should be remembered that shading of sections of the same part is identical on all of representations.

The final stage of reading a drawing is to determine the sequence of assembling and disassembling of an article.

The main place while reading the assembly drawing occupies the study of a shape of every separate part.

When determining a geometrical shape of a part it should be remembered that it can’t be fully found out from the representations. It is explained by the presence of general view of an article of row of simplifications, legalized standards, on the drawing.

So chamfers, fillets, grooves and similar elements are not drawn on the drawings of general view. But these elements must be drawn on detail drawings of parts.

Дата добавления: 2014-10-15