A vacuum cleaner is a cleaning device used to absorb dust. Vacuum cleaners can be divided into vertical, horizontal and portable types according to their structure. Working principle of a vacuum cleaner is to use an electric motor to drive blades to rotate at high speed, generate negative air pressure in a 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.
Part shown in figure below is a vacuum cleaner dust bucket part. Vacuum cleaners can be divided into vertical, horizontal and portable types according to their structure. There are household vacuum cleaners and car vacuum cleaners. Sizes and specifications are different. Specific specifications depend on different styles and uses. This article takes vacuum cleaner dust bucket part as an example to introduce in detail design points and technical summary of vacuum cleaner injection mold. Dust bucket part is shown in figure below:

 

Product Analysis
Figure below 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 below, and an inner slider structure is required. (4) Height of plastic part is 160mm, and ejection design of mold is the key.

 

Product glue injection
In order to ensure uniform glue injection and filling of round barrel-shaped products, mold preferably adopts a three-plate mold structure with a fine sprue. Each cavity product adopts 3 points of glue injection, and glue injection points are directly on rib position.

 

Mold structure analysis
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 pay attention to: avoid phenomenon that plastic part can be removed from slider but cannot be removed from inner mold. If height of slider rubber coating is not enough, product will interfere with inner mold when it is ejected, as shown in following figure:

 

Problem: Avoid removing slider but not inner mold

 

When designing this mold structure, it is necessary to pay attention to prevent plastic part from being removed from slider but cannot be removed from inner mold. Height of slider rubber coating must be sufficient. When designing mold, you can draw lines in CAD to verify, or you can take a screenshot to PPT to draw lines to verify, as shown in following figure. 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 following figure. If slider rubber coating reaches yellow line position, plastic part can be removed from slider but cannot be removed from inner mold, and plastic part will interfere with inner mold when it is demolded. If slider rubber coating reaches green line position, plastic part buckle position can be demolded smoothly. Slider rubber coating height 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, as shown in figure below.

 

This mold is an "inner slider + push ring ejection" structure. After fixed and movable molds are opened, mold relies on push ring to eject plastic parts. Pusher fixed plate is pushed by injection molding machine through oil cylinder and reset under action of 4 reset rods. Demolding mechanism of this mold adopts "push rod + push ring" structure. After fixed and movable molds are opened, lateral mechanism is cored, mold relies on mold ejection system to eject plastic parts. Pusher fixed plate is mechanically pushed by injection molding machine through KO hole and reset under action of 4 reset rods.

 

Overall front mold

 

Overall back mold