According to the national professional definition, mold design is: the personnel who are engaged in the digital design of enterprise mold, including cavity mold and cold stamping die, on the basis of traditional mold design, make full use of digital design tools, improve the quality of mold design, and shorten the mold design cycle.

concept

The overall structure of stamping die can be divided into two parts:

(1) Common parts.

(2) The part that changes according to the product. The common parts can be standardized or standardized, and the parts that change according to the products are difficult to be standardized.

Specifications

1. Composition of formwork

According to the type, composition and difference of stamping die, there are two kinds of stamping die structure, i.e. forward configuration type and reverse configuration type. The former is the most commonly used structure, while the latter is mainly used for drawing forming dies or matching special dies.

2. Mold specification

(1) Mold size and locking screw

The size of the formwork shall be larger than the working area, and the standard formwork size shall be selected. The position of the locking screw of the template is related to the type and size of the template. One of the most common single engineering mold using locking screws in four corners, the most standard form of work area can be widely used. Locking screws are most often used for long and continuous molds at four corners and in the middle.

(2) Thickness of formwork

The thickness of the die is absolutely related to the structure of the die, the type of stamping, the force of stamping and the precision of stamping. It is difficult to determine the thickness of the die according to the theoretical calculation. Generally, it is obtained by experience. The thickness of the die used in the design should be as few as possible, and the die height and clamping height should be standardized to facilitate procurement and inventory management.

Template design

The main formworks of continuous die include punch fixing plate, pressing plate, concave formworks, etc. according to the accuracy of stamping products, production quantity, processing equipment and method of die, and maintenance mode of die, there are three forms as follows: (1) block type, (2) yoke type, (3) insert type.

1. Block type

Integral formwork is also known as integral construction, and its processing shape must be closed. The whole template is mainly used for simple structure or low precision mold, and its processing mode is mainly cutting (without heat treatment). The template adopting heat treatment must be processed by wire cutting, discharge machining and grinding. When the size of the template is long (continuous mold), two or more pieces of one body will be used together.

2. yoke

The central part of the yoke type formwork is processed into a concave groove to assemble the block products. According to the application requirements, the concave groove can be formed by other templates. The advantages of the yoke type formwork structure are: the groove part is easy to process, the width of the groove part can be adjusted, and the processing accuracy is good, etc. But low rigidity is its disadvantage.

The design considerations of yoke formwork are as follows:

(1) The inlay of yoke plate structure and block parts shall be in the middle or light matching mode. If the strong pressure matching is adopted, the yoke plate will change.

(2) The yoke plate has the function of maintaining the block parts. In order to bear the side pressure and surface pressure of the block parts, it must be rigid enough. In addition, in order to make the groove part of yoke plate closely combined with the block part, the corner of groove part shall be processed into a gap. If the corner of groove part of yoke plate cannot be processed into a gap, the block part shall be processed into a gap.

(3) The shape of the block parts should be considered in the segmentation, and the datum plane must be defined. In order to avoid deformation during stamping, attention should also be paid to the shape of each block part.

(4) When the yoke plate is assembled into many pieces of block parts, the pitch changes due to the accumulated processing error of each block part. The solution is that the middle block parts are designed to be adjustable.

(5) The block parts adopt the mould structure of side-by-side combination, because the block parts will bear the side pressure during the punching process, resulting in the gap between the block parts or the inclination of the block parts. This phenomenon is an important reason for poor stamping size, chip blocking and so on, so we must have adequate countermeasures.

(6) According to its size and shape, there are five fixation methods for the massive parts in the yoke plate: A. fixed with locking screw, B. fixed with key, C. fixed with "a" key, D. fixed with shoulder, e. fixed by pressing the above pressure parts (such as guide plate).

3. Insert type

The circular or square concave part is processed in the formwork, and the massive parts are inlaid into the formwork. This kind of formwork is called inlay structure, which has less accumulated machining tolerance, high rigidity, and good accuracy reproducibility in decomposition and assembly. Because of the advantages of easy machining, accuracy of machining, and less engineering in the final adjustment, the insert template structure has become the mainstream of precision stamping die, but its disadvantage is the need for high precision hole processing machine.

When the continuous stamping die is constructed with this template, in order to make the template have high rigidity requirements, the empty station is designed. The precautions for the construction of inlaid formwork are as follows:

(1) Machining of embedded holes: vertical milling machine (or jig milling machine), comprehensive machining machine, jig boring machine, jig grinding machine, wire cutting discharge machining machine, etc. are used for the machining of embedded holes of formwork. In order to improve the machining accuracy of the wire cut EDM, the secondary or more wire cut machining is used.

(2) Fixing method of inserts: the decisive factors of fixing method of inserts include the accuracy of machining, the ease of assembly and decomposition, the possibility of adjustment, etc. There are four fixing methods for the insert: A. screw fixation, B. shoulder fixation, C. toe block fixation, D. upper part of the insert is pressed by plate. The fixing method of the embedded parts of the concave formwork also adopts the press fit method. At this time, it is necessary to avoid