A vacuum cleaner is a cleaning device used to absorb dust. According to structure, vacuum cleaners can be divided into vertical, horizontal and portable types. Working principle of a vacuum cleaner is to use an electric motor to drive blades to rotate at high speed, generate air negative pressure in sealed shell, and absorb dust. Vacuum cleaners are household appliances, and vacuum cleaner molds are generally more complex. Among injection molds, vacuum cleaner molds are second only to molds for OA office supplies such as automobiles, printers, and copiers. This article takes dust bucket of a vacuum cleaner product as an example to introduce in detail design points and experience of a vacuum cleaner dust bucket part mold.

 

Figure 1-2 shows a vacuum cleaner dust bucket part of a certain brand. Material is PP, which belongs to appearance part. Size of plastic part is: D79.9x157.5mm. Characteristics of plastic part are as follows: (1) Appearance parts. Appearance surface of plastic part is not allowed to have spots, shrinkage depressions, weld marks, flash and other defects (2) Plastic part is a round barrel-shaped part, and glue needs to be filled evenly. (3) There is no undercut on outer side of plastic part, and there are 4 small undercuts on inner side of plastic part, namely S1, S2, S3, and S4, as shown in Figure 1-3, an inner slider structure is required. (4) Height of plastic part is 160mm, and ejection design of mold is focus.

 

According to structural characteristics and appearance requirements of vacuum cleaner dust bucket plastic part, in order to ensure uniform filling of round barrel-shaped products, mold preferably adopts a three-plate mold structure with a fine sprue. Mold cavity is arranged as: 1X2, and each cavity product adopts 3 points of glue injection, and glue injection point is directly on rib position. Since S1, S2, S3, and S4 of this mold are on inner side of plastic part, undercut area is small and buckle position is 1mm, inner slider core pulling structure (commonly known as reverse position) of movable mold "bend pin + slider" is preferred. Maximum outer dimensions of this mold are: 300*450*591 (mm).

 

Fixed and movable molds of this mold adopt mold core treatment (commonly known as inlay), and mold core is inlaid on upper end surface of product. Since plastic parts are barrel-shaped products, in order to fully and evenly cool products, save materials for easy processing of mold, fixed and movable molds are treated with inserts. Fixed mold core adopts 718 and movable mold insert adopts 738H. Fixed and movable mold molding parts of mold are all inlaid. Principle of molding part design is to minimize size while ensuring strength and life of mold, so as to reduce manufacturing cost and production cost of mold.

Plastic parts are arranged as: 1X2, and simplified fine sprue is used for glue injection. In order to ensure uniform filling of round barrel-shaped products, mold preferably adopts a fine sprue three-plate mold structure, each cavity product adopts 3 points for glue injection, and glue injection point is directly on rib position.

 

According to structural characteristics and appearance requirements of vacuum cleaner dust bucket products, in order to ensure uniform filling of round barrel products, mold preferably adopts a three-plate mold structure with a fine sprue, and each cavity product adopts 3-point filling. Upper end of plastic part adopts form of a mold insert, fixed and movable molds are treated as inserts. Fixed mold needs to be made of inserts for cooling convenience, and movable mold is also made of inserts. In order to facilitate demolding of product, mold uses a push ring (a kind of push block) to eject, as shown in Figure 1-6.

 

Since mold S1, S2, S3, and S4 are on inner side of plastic part, undercut area is small and buckle position is 1mm, inner slider core pulling structure (commonly known as reverse position) of movable mold "bend pin + slider" is preferred. When designing this mold structure, it is necessary to avoid phenomenon that plastic part can be removed from slider but cannot be removed from inner mold. If height of slider rubber coating here is not enough, product will interfere with inner mold when it is ejected, as shown in Figures 1-7 and 1-8.

 

When designing this mold structure, it is necessary to prevent plastic part from being removed from slider but not from inner mold. Height of slider rubber coating must be sufficient. When designing mold, you can draw lines in CAD for verification, or you can take a screenshot and draw lines on PPT for verification. As shown in Figure 1-9, red line in figure must be within green line of slider, that is, height of slider rubber coating must be at least beyond green line shown in Figure 8. If slider rubber coating reaches yellow line position, plastic part will be removed from slider but will not be removed from inner mold, and plastic part will interfere with inner mold when demolding. If slider rubber coating reaches green line position, plastic part buckle can be demolded smoothly. Height of slider rubber coating must exceed undercut line of plastic part, so that plastic part can be smoothly removed from both slider and inner mold.

 

Due to appearance characteristics of vacuum cleaner dust bucket product, mold needs to be cooled fully and evenly. Therefore, fixed mold is cooled by annular water transportation, and movable mold insert is cooled by water well.

 

This mold adopts "inner slider + push ring ejection + annular water transportation". Mold structure is quite unique. For this type of barrel-shaped products, it is a typical structure of vacuum cleaner molds and has great reference value for similar molds. Demoulding of this mold is smooth, movement of each mechanism is smooth, and mold is safe, stable and reliable. After mold trial production, assembly effect is good and size is stable. It has been recognized and praised by customers and has created certain economic benefits for customers.