In the part machining industry, drawing is a very important operation, the accuracy of the drawing will directly affect the quality of the product, so for designers, drawings are the basis of the whole machining process, so how should we draw a good drawing paper.

1、 Analyze the parts and determine the expression scheme

Before drawing, we should know the name and function of the part, as well as its position in the machine or component and the assembly connection relationship. On the premise of clarifying the structure and shape of the part, combined with its working position and processing position, determine which one of the four typical parts mentioned above (shaft sleeve, disc cover, fork frame box type), and then determine the appropriate expression scheme according to the expression characteristics of such 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 reduce the number of dotted lines in the view and use a small number of dotted lines properly. On the premise of clearly expressing the shape of each part of the part, the expression should be concise, the number of views should be appropriate, and the repeated expression should be avoided as much as possible.

2. The expression 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 be clear. At the same time, it is necessary to consider the reasonable layout of graphics, such as the configuration of the basic view according to the provisions.

2、 Sketch parts

Part sketch is the part drawing drawn by hand, which is an important basis for drawing part drawing and assembly drawing. When drawing a sketch of a part, it is required to inspect the size of the part visually, determine the drawing scale, and draw by hand. The general steps are as follows:

1. Understand and analyze the parts and determine the expression scheme

According to the size, complexity and expression scheme of the part, the appropriate drawing scale and drawing frame are determined. The best way to draw a sketch is on checkered paper.

2. Draw the frame line and title bar to determine the location lines of the main views, such as the main axis, center line and drawing datum line. 3. Visual inspection of hand drawing. First draw the outline of the main structure, then draw the outline of the secondary structure. Relevant views of each structure should be drawn together to match the projection characteristics. At the joint of adjacent structures, the increase and decrease of graph lines should be considered (for example, there are intersecting lines at the intersection, wireless at the tangent position, etc.). Finally, complete all graphics.

4. Check and correct the whole drawing, wipe out the unnecessary drawing lines, determine the dimension datum of three directions, draw the extension line, dimension line and dimension arrow of all dimensions, and draw the section line. 5. Measure and determine all dimensions. For the dimension of standard structure (such as keyway, chamfering, etc.), please refer to the relevant manual or fill in after calculation. 6. Note the necessary technical requirements, fill in the title block, and complete the part sketch.

2、 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 checked comprehensively, 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 technical requirements proposed can meet the process requirements and the performance requirements of parts.

After checking and correcting the sketch, 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.

2. Determine the drawing scale and sheet, draw drawing frame line and positioning line of main view.

3. Draw a draft.

4. Check and correct the draft, deepen all graphics and draw the section line.

5. Draw extension line, dimension line and dimension arrow, and note dimension value and technical requirements.

6. Fill in the title block, check and complete the part drawing. After the designer has made the drawings of the parts, we can start machining. If you need to make all kinds of fixtures, precision mechanical parts, machine parts, mold parts, please consult us.