The steps of drawing machining drawing are as follows:
Analyze parts and determine expression scheme
Before drawing, you should first understand the name and function of the part, its position in the machine or component and the assembly connection relationship. On the premise of clarifying the structural shape of the part, combined with its working position and processing position, determine which of the four types of typical parts (shaft sleeve, disk cover, fork frame box) mentioned above, and then determine the appropriate expression scheme according to the expression characteristics of this kind of parts.
When selecting the expression scheme, the following two points should be paid attention to:
1. The number of views should be appropriate
It should be considered to minimize the dotted lines in the view and properly use a small number of dotted lines. On the premise of clearly expressing the shape of each part of the part, strive to express concisely, the number of views is appropriate, and avoid repeated expression as much as possible.
2. The expression method should be appropriate
According to the internal and external structure shape of the part, the expression of each view should have its focus and purpose, and the expression of the main structure and local structure should also be clear. At the same time, it is necessary to consider the reasonable layout of graphics, such as the basic view is configured in the specified way.
Sketch parts
Part sketch is the part drawing drawn by hand. It is an important basis for drawing part drawings and assembly drawings when mapping components. When drawing a part sketch, it is required to visually measure the size of the part, determine the drawing scale, and draw it by hand. The general steps are as follows:
1. Understand and analyze the parts and determine the expression scheme
Determine the appropriate drawing scale and sheet according to the size, complexity and expression scheme of the parts. It's best to use checkered paper for sketching.
2. Draw the drawing frame line and title bar, and determine the location line of the main view, such as the main axis, center line and drawing datum line.
3. Visually check the freehand drawing. Draw the outline of the main structure first, and then the outline of the secondary structure. The relevant views of each structure should be drawn together to conform to the projection characteristics. At the combination of adjacent structures, the increase or decrease of drawing lines should be considered (such as intersection lines at the intersection, wireless at the tangent, etc.). Finally, complete all drawings.
4. Check and correct the whole drawing and erase unnecessary lines; Determine the dimension datum in three directions, and draw the extension lines, dimension lines and dimension arrows of all dimensions; Draw a section line.
5. Measure and determine all dimensions. For the dimensions of standard structures (such as keyway, chamfer, etc.), please refer to relevant manuals or calculate before filling in.
6. Note the necessary technical requirements, fill in the title bar, and complete the part sketch.
Draw working drawing of parts
On the basis of the completion of the part sketch, combined with the actual production situation and processing experience, the part sketch is comprehensively checked first, and then the part drawing is drawn.
When checking the sketch, we usually pay attention to several problems, such as whether the expression scheme is reasonable and complete, whether the dimensions are clear, complete, correct and reasonable, and whether the proposed technical requirements can meet the process requirements and realize the performance requirements of the parts.
After the sketch is checked and corrected, start to draw the part working drawing. The drawing steps of part working
drawing are as follows:
1. Analyze the part and select the representation scheme.
2. Determine the drawing scale and frame, and draw the drawing frame line and the positioning line of the main view.
3. Draw a draft.
4. Check and correct the draft, deepen all drawings and draw a section line after it is correct.
5. Draw the extension line, dimension line and dimension arrow, and note the dimension value and technical requirements.
6. Fill in the title block, check and complete the part working drawing.