Background technique
Higher and higher to the lightweight requirements of product with the development of electronics industry, these products include smart phone, pen
Remember this computer, walkman, digital camera, wearable device and other portable equipments.The parts of these electronic products and structure
Wall thickness is all very thin, and normally shape is all very complicated, flows away from all very long.As far as possible lightweight for complex appearance part and
It is particularly significant for structure, at the same also require there is enough intensity, thermal diffusion to get well, will also anti-electromagnetic interference.
Material market for manufacturing various 3C electronic product casings and part was once injection molding plastics completely and was monopolized, so
And the modulus due to the modulus of plastics lower than metal is compared, the plastic products obtained with common injection moulding method, structure
Performance is difficult to reach the requirement of electronic product.Compared with plastics, magnesium alloy parts not only have metallic luster and texture, Er Qieyou
Higher rigidity, without buckling deformation and bubble, air marks or shallow nest.Although the specific gravity of magnesium is higher than plastics, its ratio
Intensity, impact resistance and rigidity are all more much higher than plastics, can manufacture lighter and thinner part.
Injection molding principle is used for metal forming process by semisolid injection molding technology, be it is a kind of low-melting alloy into
Row fusing uses a kind of integrated molding side with high speed, high pressure molding technology is carried out in raw material injection metal die
Die casting and injection technique are combined into one by formula, and mold and moulding material are similar to semisolid pressure casting technique, and technical process then approaches
In injection moulding.
At room temperature, granular raw material magnesium alloy by hopper forced conveyance into barrel, the spiral shell that is rotated in barrel
Rotation body makes alloying pellet to mold movement;When it passes through the heating position of barrel, alloying pellet is in semisolid;In injection cylinder
Under the action of formed with pressing it into preheated mold at a high speed.
In semisolid injection moulding, for flowing away from longer part, since the thermal capacity of magnesium alloy is lower, it is easy very
The quality of the filling for leading to effect type chamber and last part is solidified fastly.It to solve the above-mentioned problems, in the prior art can be with
Multiple injection ports are set in opposite face or side, inject semi-solid metal into mold simultaneously by multiple injection ports
Mode realizes the long injection moulding than big part of stream.However, surface tension increase causes since molten metal is in arrow path
Its mobility decline, if the arrow path in part at a distance from injection port farther out, molten metal pass through arrow path when temperature lower than note
The surface tension increase simultaneously of loophole temperature causes its solidification to stop flowing and influence Forming Quality.
In order to increase mobility of the molten metal in arrow path in semisolid injection moulding, the matter of injection moulding element is improved
Amount and performance, propose a kind of improved technical solution, and injection port is arranged according to the position in the minimum region of height longitudinal in type chamber
Position, to enable the molten metal of injection before cooling by arrow path, so that stopping flowing will not being solidified.However,
Type it is intracavitary there are multiple arrow paths when, setting injection port may be still far with a distance from arrow path, cause influence molding matter
Amount.
Summary of the invention
The present invention provides a kind of mold and mold injection molding technique, can be intracavitary there are when multiple arrow paths in type,
Can increase semisolid injection moulding in mobility of the molten metal in arrow path, thus improve injection moulding element quality and
Performance.
As one aspect of the present invention, a kind of die design method is provided, includes the following steps: (1) according to workpiece
Shape determines the structure of upper die holder and lower die holder;(2) according to the structure of upper die holder and lower die holder, mold cavity shapes are determined;
(3) according to the front view of mold cavity shapes and left view or right view, the region that longitudinal height is minimum in die cavity section is determined;
(4) judge in die cavity section whether the minimum region of longitudinal height is simply connected region, if it is entering step (5);Otherwise into
Enter step (6);(5) it according to the top view of mold cavity shapes, determines the position of centre of gravity in the minimum region of longitudinal direction height, determines that this is heavy
At a distance from four sides in heart position and dynamic model seat;(5.1) position of centre of gravity and four lateral distances of the dynamic model seat are determined most
The first injection port is arranged in short side, the projected position by the position of centre of gravity in the side;(5.2) determine the first injection port with
The intersection point of mold cavity shapes;(5.3) mold cavity shapes edge and the intersection point are calculated apart from farthest point, determines dynamic model seat and the point distance
Shortest side, the projected position by this in the side are arranged the second injection port, terminate the setting of mold injection port;(6) root
According to the top view of mold cavity shapes, the position of centre of gravity in the minimum region of longitudinal direction height is determined, calculate position of centre of gravity and this is longitudinal high
The shortest distance for spending each sub-regions in minimum region, judges whether the maximum value of each shortest distance is less than threshold value, if
(5) are entered step less than threshold value, otherwise enter step (7);It (7) is multiple Dan Lian by the minimum region division of longitudinal height
Logical subregion, is respectively set corresponding injection port for each simply connected subregion.
Preferably, in the step (7), for the center of gravity of each simply connected subregion, itself and the dynamic model are determined respectively
Corresponding injection port is arranged in four shortest sides of lateral distance of seat, the projected position by position of centre of gravity in the side.
Preferably, the threshold value is the 1/5 of upper die holder cross section long side.
As another aspect of the present invention, the mold of above-mentioned die design method design is provided, injection is used to prepare
Shaping workpiece, comprising: cover half seat and dynamic model seat;Inner space after the cover half seat and the molding of dynamic model seat forms die cavity;
The section that the die cavity has longitudinal height different;There are two injection port or multiple injection ports for the die cavity side tool, are used for
To the die cavity injection moulding material.
Specific embodiment
In order to illustrate more clearly of technical solution of the present invention, embodiment will be used simply to be situated between the present invention below
Continue, it should be apparent that, be described below in be only one embodiment of the present of invention, for those of ordinary skill in the art come
It says, without any creative labor, other technical solutions can also be obtained according to these embodiments, also belonged to
Disclosure of the invention range.
The mold of the embodiment of the present invention, for the part and structure by injection moulding preparation electronics industry, including intelligence
Mobile phone, laptop, walkman, digital camera, wearable device and other portable equipments.Mold includes cover half seat and moves
Inner space after die holder, cover half seat and the molding of dynamic model seat forms die cavity, and injection port is arranged on mold, is injected by semisolid
The magnesium alloy of molten condition is injected the rear of mold by injection port and formed by forming technique.There is longitudinal height not in die cavity
Same section, wherein the height of longitudinal height Minimum Area is lower than 0.5mm, in arrow path, surface tension increases molten magnesium alloy
Cause its mobility to decline, its solidification is easy to cause to stop flowing and influence Forming Quality.
A kind of die design method of the embodiment of the present invention includes the following steps: (1) according to the shape of workpiece referring to Fig. 1
Shape determines the structure of upper die holder and lower die holder;(2) according to the structure of upper die holder and lower die holder, mold cavity shapes are determined;(3)
According to the front view of mold cavity shapes and left view or right view, the region that longitudinal height is minimum in die cavity section is determined;(4)
Judge in die cavity section whether the minimum region of longitudinal height is simply connected region, if it is entering step (5);Otherwise enter step
Suddenly (6);(5) it according to the top view of mold cavity shapes, determines the position of centre of gravity in the minimum region of longitudinal direction height, determines the center of gravity position
It sets at a distance from four sides of dynamic model seat;(5.1) determine that four lateral distances of the position of centre of gravity and the dynamic model seat are shortest
The first injection port is arranged in side, the projected position by the position of centre of gravity in the side;(5.2) the first injection port and die cavity are determined
The intersection point of shape;(5.3) mold cavity shapes edge and the intersection point are calculated apart from farthest point, determines that dynamic model seat and point distance are most short
Side, by this side projected position be arranged the second injection port, terminate mold injection port setting;(6) according to mould
The top view of chamber shape determines the position of centre of gravity in the minimum region of longitudinal direction height, calculates position of centre of gravity and longitudinal height most
The shortest distance of each sub-regions in low region, judges whether the maximum value of each shortest distance is less than threshold value, if it is less than
Threshold value enters step (5), otherwise enters step (7);It (7) is multiple simply connected by the minimum region division of longitudinal height
Corresponding injection port is respectively set for each simply connected subregion in region.
In step (1), mould is determined according to the shape of workpiece by the shape that the human-computer interaction interface of system inputs workpiece
The upper die holder of tool and the structure of lower die holder;Wherein upper die holder is dynamic model seat, and the lower die holder is cover half seat.
In step (2), by the structure according to upper die holder and lower die holder, mold cavity shapes are determined, referring to fig. 2 middle die cavity shape
The view of shape.
In step (3), according to the front view of mold cavity shapes and left view or right view, determine longitudinal in die cavity section
Highly minimum region.(b) and Fig. 3 (b) referring to fig. 2 are determined longitudinal high in die cavity section by the front view in die cavity section
Spend minimum region 10(10 ') horizontal direction X axis coordinate, (c) and Fig. 3 (c), pass through the right side in die cavity section referring to fig. 2
View, determine in the minimum region 10(10 ' of longitudinal height) horizontal direction Y axis coordinate.
It whether is simply connected region according to the region for judging that longitudinal height is minimum in die cavity section in step (4), if it is
Simply connected region then enters step (5) as shown in Figure 2;Otherwise, as shown in Figure 3, (6) are entered step.
In step (5), according to the top view of mold cavity shapes, the position of centre of gravity in the minimum region of longitudinal direction height is determined, really
The fixed position of centre of gravity is at a distance from four sides of dynamic model seat.Referring to fig. 2 (a), according to the top view of mold cavity shapes, determine that die cavity is cut
The position of centre of gravity 11 in the minimum region 10 of longitudinal height in face, further determine that position of centre of gravity 11 and four sides of dynamic model seat away from
From.
In step (5.1), at a distance from four sides of position of centre of gravity 11 and dynamic model seat determined in step (5), determine
The dynamic model seat side nearest apart from position of centre of gravity 11, selects the side as the side where the first injection port, by position of centre of gravity
The first injection port is arranged in 11 projected position in the side, so that the molten magnesium alloy injected from the first injection port can be apart from vertical
The region minimum to height is nearest, so as to increase the mobility in arrow path.
In step (5.2), according to the position of the first injection port determined in step (5.1), the first injection port and mould are determined
The intersection point 12 of chamber shape, the intersection point 12 are the position that molten magnesium alloy inputs die cavity.
In step (5.3), according to 12 position of intersection point calculated in step (5.2), mold cavity shapes edge and the intersection point are calculated
12, apart from farthest point 13, determine dynamic model seat and projected position of the point 13 apart from shortest side, by the point 13 in the side
Second injection port is set.Due to the injection point 13 of second injection port and the injection position distance of the first injection point 12
Farthest, so as to reduce injection molten magnesium alloy stream away from, thus avoid molten magnesium alloy solidification influence Forming Quality.
In step (6), according to the top view of mold cavity shapes, referring to Fig. 3 (a), the minimum region of longitudinal direction height is determined
Position of centre of gravity 11, calculates the shortest distance of position of centre of gravity 11 and each sub-regions in longitudinal highly minimum region, and judgement is each
Whether the maximum value of a shortest distance is less than threshold value, if it is less than threshold value, indicates the first injection determined by the position of centre of gravity
The stream that the molten magnesium alloy of mouth injection reaches arrow path enters step (5) and follow-up process, determines the first injection away from meeting the requirements
Mouth and the second injection port;Otherwise (7) are entered step.
In step (7), the minimum region 10,10 ' of longitudinal height is divided into multiple simply connected subregions, for each list
Corresponding injection port is respectively set in communicated subarea.Wherein, for the center of gravity of each simply connected subregion, itself and institute are determined respectively
Four shortest sides of lateral distance of dynamic model seat are stated, corresponding injection port is arranged in the projected position by position of centre of gravity in the side.
It should be noted that, in this document, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to
Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those
Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or equipment
Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that
There is also other identical elements in process, method, article or equipment including the element.
The above is only the preferred embodiment of the present invention, protection scope of the present invention is not limited merely to above-described embodiment,
All technical solutions belonged under thinking of the present invention all belong to the scope of protection of the present invention.For the ordinary skill people of the art
For member, several improvements and modifications without departing from the principles of the present invention should be regarded as falling into protection scope of the present invention.