Plastic Injection Molding Design Manual

1.1 General Provisions for Plastic Injection Molding Design Drawings

The purpose of mold drawings is to provide a scientific, reliable, comprehensive, and cost-effective basis for mold manufacturing. These standards apply to the entire process of mold development, manufacturing, and maintenance.

1.1.1 Drawing Dimensions, Title Blocks, and Revision Blocks

1.1.1.1 Drawing Frame Format and Sheet Sizes (see Table 1-1)

Table 1-1 Drawing Frame Format and Sheet Sizes (GB/T 14689—2008) mm

1.1.1.2 Title Blocks and Revision Blocks (see Figures 1-1 to 1-3)

Mold Assembly Drawing Title Block (Figure 1-1)

Mold Part Drawing Title Block (Revised) (Figure 1-2)

Mold Drawing Revision Block (Figure 1-3)

1.1.1.3 Title Block Instructions

1. Molding design All drawings must have a title block. The title block must be filled out completely. Signatures must be handwritten, not entered on a computer. Full names must be signed, and red or pencil signatures are not allowed. The handwriting must be neat and规范.

2. The size of the title block and revision block shall be drawn at 1:1 according to the automatically generated dimensions and shall not be scaled arbitrarily. When drawing at a scale other than 1:1, the title block shall be scaled according to the printing scale to ensure that the title block size remains unchanged. That is, the title block size on the printed drawing shall be the same for 1:1, 2:1, and 1:2 prints.

3. All data in the title block must be clear and correct. If any information is unclear or missing, a "?" shall be filled in, especially for the shrinkage rate.

4. If a drawing is completed by multiple people, all data must be unified, including character height, font, color, etc.

5. Molding design The drawing scale is expressed as \(A:B\). \(A\) is the dimension drawn on the drawing, and \(B\) is the actual dimension of the mold part. If \(AB\), it is an enlarged scale; if the scale remains unchanged, it is expressed as 1:1. In mold design, 1:1 scale should be used as much as possible. When printing drawings, assembly drawings should be printed at 1:1 as much as possible, and part drawings should be scaled according to actual needs. The principle is to clearly express the shape of the part. If enlargement or reduction is necessary during drawing, the scale should be selected in accordance with national standard GB/T 14690—1993, as shown in Table 1-2.

1.1.1.4 Bill of Materials Instructions

The bill of materials (see Figure 1-4) is only required for assembly drawings. It should detail part numbers, part names, dimensions or specifications, materials, etc. The bill of materials is sometimes listed separately and printed on A4 paper.

1.1.1.5 Revision Block Instructions

After the drawing is issued, if changes are needed, the drawing must be updated and reissued. Meanwhile, the previous version of the drawing must be收回 and stamped with the "Cancelled" special stamp. The company shall formulate the "Technical Document Management Regulations for the Design Department" to ensure that design documents are controllable.

1.1.1.6 Projection Methods

There are two projection methods: the first-angle projection method and the third-angle projection method, as shown in Table 1-3. Different countries use different projection methods for technical drawings. GB and ISO standards generally use the first-angle projection method.