first drawing

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					   First 2D drawing

   Task. Draw axes and contour of a detail, set dimensions, insert drawing frame. All drawing
   has to be prepared under drawing rules and drawing standards valid in our country.




1. When you load AutoCAD program, by default, Create New Drawing dialog box should be
   displayed on screen.




   NOTE Make sure you have picked Metric default drawing settings.

   When you begin a new drawing, AutoCAD creates a special layer named “0”. By default,
   layer 0 is assigned colour number 7 (white or black depending upon your background colour),
   the CONTINUOUS linetype, a lineweight of DEFAULT (0.25 mm), and Normal plot style.
   Layer “0” cannot be deleted or renamed.




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2. The drawing area on your screen is not identical to your drawing limits. Switch the GRID
   mode on to see your “paper” sheet. The dotted area shows the limits of your drawing. By
   default your drawing limits should be 420, 297 mm (A3 format). If you need to change
   drawing limits use command LIMITS.




3. To prepare layers for your drawing use command LAYER (la)         . It’s recommend not to use
   layer “0”, but to create your own layers for your drawing. Create new layers for your drawing
   AXES, DETAIL, DIMENSIONS, FRAME. Pick the colour you like for each new layer.

   NOTE You can give names for layers what ever you like, but it’s recommend to name them
        according to it content




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4. Change linetype for AXES layer. Select the linetype of this layer.




    §   In Select Linetype dialog box click LOAD.
    §   In the Load or Reload Linetypes dialog box select linetype you need - DASHDOT and
        click OK.




    §   Select the new linetype and click OK. After this step you should see such a result in the
        main Layer properties dialog box.




5. Select due lineweight for all layers.




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6. Set layer AXES current




7. Draw axes:




   §   Using command LINE (l) draw axes L1 and L2 an approximate length.

   NOTE Don’t forget ORTHO mode for drawing orthogonal (horizontal and vertical) lines.

   §   Using command OFFSET (o) make copy of L2 through distance 140 (you’ll get line L3).
   §   Using command CIRCLE (c) draw circle C1 (centre point P1 at the intersection of L1 and
       L3; radius 60).
   §   Using command RAY draw lines R1 and R2 (start point at the point P1; thought point
       @10<10 (R1) and @10<40 (R2)).




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8. Set layer DETAIL current (use command LAYER (la)) and draw contour of the detail.




                                                    Using command FILLET (f) round arc A1
   Draw circles by task using command
                                                    (radius 30; select A1 and big circle).
   CIRCLE (c).
   Using command ARC (a) draw arc A1 (centre
   point P1; start point P2 (intersection); end
   point P3 (approximately)).




   Using command OFFSET (o) make copy of            Using command TRIM (tr) erase drawing
   arc A1 through distance 30 (you’ll get arc A2)   parts is not need.
   Using command ARC (a) draw arc A3 (start
   point P5 (intersection); end point P6
   (intersection); radius 15).




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   Using command MIRROR (mi) make a copy            Using commands TRIM (tr) and BREAK (br)
   of left part of the drawing (P7 (endpoint) and   delete parts of the drawing you don’t need.
   P8 (intersection) the points of symmetry
   line).
9. Draw upside of the detail:




   Using command CIRCLE (c) draw circles C2         Using command OFFSET (o) make copies up
   and C3.                                          and down (lines L5 and L4) through dist. 5.




   Using command ARRAY (ar) draw lines L6           Using command BOUNDARY (bo) pick in
   and L7 (select lines L4 and L5; make Polar       areas P9-P12 to create boundaries.
   array around centre point P9; make 4 items;
   rotate 360 degrees).


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    Erase elements of the drawing leaving only
    created boundaries B1-B4.
    Using command ROTATE (ro) rotate
    boundaries (select B1-B4; centre point P9;
    rotation angle 45 degrees)                                          Result
10. Now, when the contour is finished, dimensions have to be set, but before doing that
    dimension style has to be corrected according standards valid in our country. Turn on
    dimension toolbar group.




    §   Turn on Dimension Style Manager dialog box clicking on Dimension Style button   .
    §   In Dimension Style Manager dialog box click New and write your own New Style Name in
        Create New Dimension Style dialog box and click Continue.




    §   In New Dimension Style: Mine dialog box in Lines and Arrows page in Arrowheads
        window, set Arrow size – 3.5;




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   §   In New Dimension Style: Mine dialog box in Text page, in Text Appearance window, set
       Text height – 3.5; Text Placement window, set Offset from dim line – 1; and in Text
       Alignment window, select ISO Standard. Click OK.




   §   In Dimension Style Manager dialog box select style Mine, click Set Current and close
       Dimension Style Manager dialog box.


11. Set DIMENSIONS layer current and draw dimensions.

   NOTE Check length of all axes. It has to be 3-5 mm extended over element which symmetry
        it marks.



                                                        Linear dimension.
                                                    Specify first extension line origin
                                                    P1 (osnap endpoint) then second one
                                                    P2 (osnap endpoint). Specify dimension
                                                    line location P3 (approximately).

                                                        Aligned dimension.
                                                    Specify first extension line
                                                    P4 (osnap nearest) then second one
                                                    P5 (osnap perpendicular), dimension line
                                                    location approximately.

                                                        Angular dimension.
                                                    Select first element line E1 then second one
                                                    E2. Specify dimension arc line location
                                                    approximately. Repeat the command and
                                                    specify angular dimension between lines E2
                                                    and E3.




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                                                     Radius dimension.
                                                 Click the button and select arc on point P6.
                                                 Then specify dimension line location with
                                                 the cursor on a point P7. Dimension text
                                                 will be set by default (R30).

                                                     Diameter dimension.
                                                 Click the button and select circle on point
                                                 P8. Then specify dimension line location
                                                 with the cursor on a point P9. Dimension
                                                 text will be set by default (ø80).




If you need to set dimension text value not by default, you can change it on command
executing. Press the button and the follow command options on a command line.

     Command: DIMDIAMETER
     Select arc or circle: specify circle on point P10
     Dimension text = 12
     Specify dimension line location or [Mtext/Text/Angle]: t
     Enter dimension text <12>: 5 holes %%c12
     Specify dimension line location or [Mtext/Text/Angle]: specify line
     location on point P11

NOTE Symbols %%C written on command line is equal of symbol ? on a screen.




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Matai šitas failiukas šiek tiek nepabaigtas. Praradau
paskutine šio failo e-versija, turiu tik atspausdinta. Rytoj
tikriausiai “damušiu”.




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posted:4/1/2011
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