Of a Parts

Requirements to the Detail Drawings and Sketches

Detail Drawings and Sketches of Parts

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5. How are graphic documents subdivided?

Detail Drawing — A machine usually consists of several parts. A part is called an element or detail. The detail drawing gives the complete information for manufacture of each of the separate part. It is mainly meant for shop floor.

The detail drawing of a part is a designer document, which contains the representation of a part and other information, necessary for its making and control.

A freehand sketch is a drawing made without the use of drawing instruments. In afreehand sketch, all the rules of graphic language are as rigidly observed as a scale drawing. Freehand sketches are not to any scale but they should be in good proportion according to the shape of the object. Freehand sketch is an important tool for an engineer or a draughtsman and is useful in various applications.

Asketchis a draft of temporal character, intended for the non-permanent use, executed, as a rule, from a hand, without the observance of scale, but with the maintainance of proportion of elements of a part.

A detail drawing and a sketch must contain:

а) minimal, but sufficient number of representations (views, sectional views, sections) which fully find out the form of a part;

b) all necessary sizes;

c) denotation of roughness of all surfaces;

d) information about material, heat treatment, coverage which a part must have before assembly etc.

The basic requirements to the detail drawings and sketches of parts are following:

1. A separate drawing is done on every part on formats according to State Standard 2.301-68. A title block of a drawing must be done according to State Standard 2.104-68.

2. Сonventional denotation of material is in the title block. It consists of the name of material, its grade and a standard, for example for parts from steel «Steel 20 State Standard 1050-88», «St 3 State Standard 380-2005», for parts from the cast iron «Gray Cast Iron State Standard 1412-85 », for parts from the bronze «Br. OCS 3-12-5 State Standard 6713-79» etc.

3. The mass of a part is put in title block in kilograms, not marking the units of measuring.

4. The scale of representation on the detail drawing s is chosen according to State Standard 2.302-68.

5. The detail drawing s, as a rule, are done on all of the parts which form an article. Separate drawings on the following parts are allowded to not do: a) made of cutting-off high quality rolled section; b) permanent joints (welded, soldered etc.), if the design of parts is simple and do not require more than three-four sizes, which are drawn on the assembly drawing.

6. Sizes and denotations of roughness of surfaces a part must have before the assembly of a product are marked on the detail drawing or sketch.

Дата добавления: 2014-10-15