How to draw a machined part drawing

Part drawings are drawn when designing, mapping, or parts. The accuracy of the part drawing directly affects the performance of the machine or part. So for designers who draw machined parts drawings, the requirements are very high. This article will give a detailed introduction to the drawing of machined parts drawings.

I. Analyze parts and determine the expression plan

Before drawing a picture, you need to understand the name of the part, its function, and its position and assembly connection in the machine or part. Under the premise of clarifying the structural shape of the part, combined with its working position and processing position, it is determined which one of the four types of typical parts (the bushing cover fork box type) mentioned above, and then according to this The expression characteristics of the class parts determine the appropriate expression scheme.

When choosing an expression scheme, you should pay attention to the following two points:

1, the number of views should be appropriate

Consideration should be given to minimizing the dashed lines in the view and properly applying a small number of dashes. In order to satisfy the expression of the shape of each part of the part, the expression should be concise, the number of views should be just right, and repeated expression should be avoided as much as possible.

2, the expression method should be appropriate

According to the internal and external structural shape of the part, the expression of each view should have its focus and purpose, and the expression of the main structure and the local structure should be distinct. At the same time, it is necessary to consider the reasonable layout of the graphics, such as the basic view configured in the prescribed manner.

Second, draw a part sketch

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

1. Understand the analysis of parts and determine the expression plan

Determine the appropriate drawing scale and frame based on the size, complexity, and presentation of the part. It is best to use a checkered paper for sketching.

2. Draw a frame line and a title bar to define the position lines of the main view, such as the main axis, the center line, and the drawing reference line.

3, visual test hand drawing. First draw the outline of the main structure, then draw the outline of the secondary structure. The relevant views of each structure should be drawn together to match the projection characteristics. At the combination of adjacent structures, the increase and decrease of the graph should be considered (such as intersections at intersections, wireless at tangency, etc.). Finally complete all the graphics.

4. Check and correct the whole picture, erase unnecessary lines; determine the size reference in three directions, draw the size line, size line and size arrow of all sizes; draw the section line.

5. Measure and determine all dimensions. For the size of standard structures (such as keyways, chamfers, etc.), please refer to the relevant manual or calculate and then fill out.

6. Write the necessary technical requirements, fill in the title bar, and complete the sketch of the part.

Second, drawing parts work diagram

On the basis of completing the sketch of the part, combined with the actual production situation and the experience of the processing technology, the part sketch is first checked and the part drawing is drawn.

When reviewing sketches, usually pay attention to several questions, such as whether the expression scheme is reasonable and complete, whether the dimensioning is clear and complete, correct and reasonable, and whether the proposed technical requirements can meet the process requirements and achieve the performance requirements of the parts.

After the sketch check is corrected, start drawing the part work drawing. The drawing steps of the part drawing are as follows:

1. Analyze parts and select an expression plan.

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

3. Draw a draft map.

4, check the revised draft, deepen all the graphics after the error, draw the section line.

5. Draw the dimension line, dimension line and size arrow, and write the size value and technical requirements.

6. Fill in the title bar, check and complete the part work drawing.