Hair dryer blower injection mold design

Time：2022-05-30 09:34:02 / Popularity： / Source：

Product of hair dryer is shown in Figure 1. Maximum external dimensions of product are 91.5 mm * 61.30 mm * 52.95 mm, average thickness of plastic part is 2.50 mm, plastic part material is PP, shrinkage rate is 1.016, and plastic part weight is 29.10 grams. Technical requirements for plastic parts are that there shall be no defects such as peaks, underfilling, flow lines, pores, warpage deformation, silver lines, cold materials, and spray lines.

Figure 1 Product map of hair dryer
Shape of product is very similar to a cowboy hat, bottom is a regular circle, and there are 3 arc-shaped raised buckles around circumference, which are evenly distributed along circumference of 120゜. There are 3 other bosses along circumference, but no mold undercut is formed. Upper end is flat, and the two ends are raised like a pointed boat. For such a product shape, experienced mold designers can see at a glance that product shape seems simple, but mold structure is quite complex, requiring sliders on outside and inner sliders on inside. Due to warped shape at both ends, even if there is no 3-circle stopper, outer shape needs to be designed as a slider, and inside should also be an inner slider. Maximum inner diameter of this product is only 53.34mm, but stroke of a single inner slider is 15mm. Now two inner sliders are needed, and the total stroke is 30mm. In addition to thickness of the two inner sliders, internal space is very tight, which is the biggest difficulty in designing this pair of molds.

Figure 2 Outline drawing of blower duct mold

Figure 3 Combination diagram of rear die slider

Figure 4 Front die inclined elastic slider

Figure 5 Secondary ejection analysis
Shape of plastic parts is very simple at first glance, but mold is a complex mold, and it is easy to make mistakes if you are not careful. When designing mold, it is first necessary to analyze mold opening direction of mold. Combined with method of combining gate, ejection and parting surface, circular position is selected in rear mold, and flat mouth is in mold opening direction of front mold.
Mold design is ranked 2 cavities, and it is arranged in a straight line, so that oblique elastic sliders of front mold of the two cavities can be used on same slider, as shown in Figure 5. Runners are opened on each of the two sliders. It should be noted that nozzle material needs to be positioned and cannot be stuck on any slider. A thimble is added at the bottom of runner material, and thimble needs to be ground into a conical shape to facilitate positioning of runner material.
Mold base is non-standard mold base DI3545. Dust-proof plates are designed on both sides of thimble plate, and a long hanging mold beam is designed, as shown in Figure 2. For molds exported to Europe, customers all require design of long hanging mold beams, which are painted red with paint.
Air outlet of plastic part is a flat mouth, and inner mold core cannot be released from rear mold, so inner slider must be designed. For this purpose, a floating mold plate is designed to demold inner slide. In particular, it should be pointed out that two small inserts are designed in fixed mold part of flat mouth at both ends to solve problem of insufficient internal space and insufficient space for inner slider to come out of inverted buckle. After designing small slider, length of inner slider is reduced, which effectively solves problem.
After mold is opened, oblique elastic slider of front mold first demolds shape of plastic part. Demoulding of rear mold combined with secondary ejection solves this problem. Shovel of inner slider is designed on upper thimble plate. There are three shovels in total, and one shovel in the middle is shared by the two cavities. First, ejector stick of injection molding machine pushes upper ejector plate, which drives upper ejector plate and shovel and floating plate of inner slider to disengage from middle insert. Continue to push out, under action of buckle machine, lower thimble plate stops moving forward, and upper thimble plate continues to push inner slider to complete internal core pulling.
Adequate cooling circuits are designed on the front and rear molds and front mold oblique elastic sliders. Insulation plates are designed on the front and rear mold panels and bottom plate to prevent heat exchange between mold and injection molding machine, ensure normal operation of injection molding.

Gud Mould Industry Co., Ltd

Hair dryer blower injection mold design

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