CN115958764A - Injection molding multi-stage forming method - Google Patents

Abstract

The application relates to an injection molding multi-section forming method, wherein the injection molding multi-section forming method comprises the following steps: s1: performing injection molding and synchronous mold locking, and performing segmented mold pressing during injection molding according to the configuration of a product to be molded; s2: cooling the molten gel; s3: opening the mold; s4: and ejecting the molded product through the mold. When the method is used for injection molding, the injection action and the mold locking action are synchronously carried out at the same time, so that smooth discharge of gas in a mold is facilitated, the molding period is shortened, the product stress is dispersed, and the high requirement on the injection speed of a thin-wall product is lowered.

Description

Injection Molding Multi-stage Molding Method

technical field

The invention relates to the technical field of injection molding processing, in particular to an injection molding multi-stage molding method.

Background technique

At present, with the continuous development of science and technology, the diversification of injection molding products and the complexity of mold structure are increasing, and the quality requirements of users for injection molding products are becoming more and more stringent.

In the standard injection molding process, the action steps of a cycle are "mold closing and clamping-injection filling-melt cooling-molding-opening-ejecting product-taking product". The current production summary is that the actions in each cycle are performed in a single step. The molding cycle is long.

For ultra-thin-walled products, there are problems such as high injection pressure, difficult pressure maintenance, concentrated product stress, difficult molding, substandard quality inspection, high energy consumption and high cost.

For extremely thick-walled products, there are problems such as too long injection pressure holding time, long molding cycle, high energy consumption and high cost during injection molding.

Contents of the invention

The object of the present invention is to address the above disadvantages and provide a multi-stage injection molding method. During injection molding, the injection action and the mold locking action are carried out simultaneously, the molding cycle is shortened, and the stress of the product is dispersed.

In order to solve the above technical problems, the first aspect of the present invention provides a multi-stage injection molding method, comprising the following steps:

S1: Injection molding and synchronous mold locking, according to the required product configuration, perform segmental molding during injection molding;

S2: melt cooling;

S3: mold opening;

S4: Eject the formed product through the mold.

Further, the segmented molding includes the following steps:

S11: Set the compression start distance of the reserved cavity, and set the mold position state at the compression start distance as the mold compression start position; S12: Select the compression mode;

If it is the location compression mode, then execute the first compression procedure;

If it is the time compression mode, execute the second compression procedure.

Further, the starting position of the mold compression is that the compression plate of the mold is seamlessly combined with the fixed platen, and the spring of the compression plate is in an uncompressed state, and the cavity mold surfaces of the movable platen and the fixed platen of the mold are in a bonded state.

Further, the mold adopts a machine-hinged crankshaft clamping structure, and the position of the template crosshead at the starting position of compression is used as a position reference.

Further, the first compression procedure includes the following steps:

S110: Set several stages of compression positions, set the compression speed corresponding to each stage of compression position, set several stages of injection positions, and set the compression positions and injection positions in one-to-one correspondence;

S120: Carry out injection molding into the mold cavity, and when the injection filling reaches the first injection position, the mold compression starts from the mold compression starting position at the set compression speed, and moves the movable mold to the set first compression position; injection filling When reaching the second injection position, the mold compresses from the first compression position at the set compression speed, and moves the movable mold to the set second compression position; and so on, step by step injection and compression until the compression position is reached zero.

Further, in step S110, at least two stages are set for the compression position and the injection position.

Further, the second compression procedure includes the following steps:

S210: Set the multi-stage compression position, set the compression speed corresponding to each stage of compression position, set the monitoring time after each stage is in place, and set the injection position to 1 stage;

S220: Carry out injection molding into the mold cavity, and when the injection is filled to the first injection position, the mold is compressed from the starting position of the mold compression at the set compression speed, and the movable mold is moved to the set first compression position; then, After the monitoring time set in the first section has passed, the mold is compressed from the first section compression position at the set compression speed, and moves the movable mold to the set second section compression position; and so on, step by step compression until The compression position reaches zero.

Further, the movement is forward or backward, and in step S210, at least two stages of compression are set.

Further, the injection position is the forward position of the screw injection of the injection molding machine, and the forward stroke of each section of the injection molding machine screw is limited by each injection position; the zero point is the position where the mold clamping is completed; the monitoring time is The interval time between when the compression position of this segment is moved in place and when the compression position of the next segment starts to move.

In order to solve the above technical problems, the second aspect of the present invention provides an injection molding machine, which adopts the above-mentioned multi-stage injection molding method for injection molding.

Compared with the prior art, the present invention has the following beneficial effects: before injection molding, the compression plate of the mold is seamlessly combined with the fixed plate, and the spring of the compression plate is in an uncompressed state; during injection molding, the injection action is synchronized with the mold locking action , which is conducive to the smooth discharge of gas in the mold, shortens the molding cycle, disperses the stress of the product, and reduces the high requirement for the injection speed of thin-walled products.

Description of drawings

Below in conjunction with accompanying drawing, the patent of the present invention is further described.

Figure 1 is a flow chart of the injection molding multi-stage molding method.

Fig. 2 is a flow chart of the steps of segment molding.

FIG. 3 is a flow chart of the steps of the first compression procedure.

FIG. 4 is a flow chart of the steps of the second compression procedure.

Figure 5 is a product stress comparison chart.

Detailed ways

Preferred embodiments of the present invention are described in more detail below, however, it should be understood that the present invention can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the standard injection molding process, the action steps of a cycle are mold closing and clamping-injection filling-melt cooling-molding-opening-product ejection-taking products. The current production summary is that the actions in each cycle are single-step, and the molding cycle long. For ultra-thin-walled products, there are problems such as high injection pressure, difficult pressure maintenance, concentrated product stress, difficult molding, substandard quality inspection, high energy consumption and high cost. For extremely thick-walled products, there are problems such as too long injection pressure holding time, long molding cycle, high energy consumption and high cost during injection molding.

Example 1:

In view of the above technical problems, Embodiment 1 provides a multi-stage injection molding method. During injection molding, the injection action and the mold clamping action are carried out simultaneously, the molding cycle is shortened, and the stress of the product is dispersed.

As shown in Figure 1, it specifically includes the following steps:

S1: Injection molding and synchronous mold locking, according to the required product configuration, perform segmental molding during injection molding;

S2: melt cooling;

S3: mold opening;

S4: Eject the formed product through the mold.

As shown in Figure 2, described segmental molding comprises the following steps:

S11: Set the compression start distance of the reserved cavity, and set the mold position state at the compression start distance as the mold compression start position;

S12: select the compression mode;

If it is the location compression mode, then execute the first compression procedure;

If it is the time compression mode, execute the second compression procedure.

In this embodiment, the starting position of the mold compression is that the compression plate of the mold is seamlessly combined with the fixed platen, and the spring of the compression plate is in an uncompressed state, and the cavity mold surfaces of the movable platen and the fixed platen are in a bonded state. State, at the starting position of mold compression, the mold has been closed and there will be no glue leakage.

In practical applications, when the mold is at the starting position of mold compression, the volume of the cavity in the mold is greater than the volume after the mold is clamped and locked, and the injection of glue into the mold cavity can simultaneously close the mold and compress it. During use, by moving the movable template, the change The volume of the cavity in the mold, so as to realize the change of position.

In this embodiment, the mold adopts a machine-hinge crankshaft clamping structure, and the position of the template crosshead at the initial compression position is used as a position reference, and the moving distance of each segment of the compression position is the stroke of the template crosshead; There is a corresponding proportional relationship between the position and the position of the template mold. It is like a bicycle gear with a small gear. The position of each point is different. The movement of the crankshaft crosshead is greater than that of the template mold. The position of the template crosshead is used as a reference to facilitate the positioning of the mold template. position for more precise control.

As shown in Figure 3, described first compression program comprises the following steps:

S110: Set several compression positions, set the compression speed corresponding to each compression position, set several injection positions, the compression position and the injection position are set in one-to-one correspondence, and the moving distance of each compression position is the moving stroke of the template crosshead in this segment ;

S120: Carry out injection molding into the mold cavity, and when the injection filling reaches the first injection position, the mold compression starts from the mold compression starting position at the set compression speed, and moves the movable mold to the set first compression position; injection filling When reaching the second injection position, the mold compresses from the first compression position at the set compression speed, and moves the movable mold to the set second compression position; and so on, step by step injection and compression until the compression position is reached zero.

In this embodiment, in step S110, at least two stages are set for the compression position and the injection position.

As shown in Figure 4, described second compression program comprises the following steps:

S210: Set the multi-stage compression position, set the compression speed corresponding to each stage of compression position, set the monitoring time after each stage is in place, set the injection position as one stage, and the moving distance of each stage of compression position is the moving stroke of the template crosshead in this stage;

S220: Carry out injection molding into the mold cavity, and when the injection is filled to the first injection position, the mold is compressed from the starting position of the mold compression at the set compression speed, and the movable mold is moved to the set first compression position; then, After the monitoring time set in the first section has passed, the mold is compressed from the first section compression position at the set compression speed, and moves the movable mold to the set second section compression position; and so on, step by step compression until The compression position reaches zero.

In this embodiment, the movement is forward or backward, and in step S210, at least two stages of compression are set.

In this embodiment, the injection position is the forward position of the screw injection of the injection molding machine, and the forward stroke of each section of the injection molding screw is limited by each injection position; the zero point is the position where the mold closing is completed, and the mold closing Finished, the crankshaft crosshead is also stretched to the right position, and the mold is closed; the monitoring time is the interval time between when the compression position of this segment is moved in place and when the compression position of the next segment starts to move, and the next segment of compression will continue after the time is up.

As shown in Figure 5, through the product stress comparison chart, it can be clearly seen that the stress of the lens injection molded by the prior art on the left is concentrated, while the stress of the lens injection molded by this method on the right is relatively dispersed.

This method is synchronous with mold clamping during injection, multi-action linkage, not a single step, which shortens the molding cycle comprehensively.

In this method, when the mold is not completely closed and compressed (that is, the compression plate of the mold is seamlessly combined with the fixed plate, and the spring of the compression plate is in an uncompressed state), the injection will not leak glue at this time, so that the injection fills the mold cavity, and there is It is conducive to the smooth discharge of gas in the mold, so that the gas is not difficult to discharge when the mold is closed and locked and then injected.

This method is aimed at products that are too thin or have a thin center and thick edges. When the cavity is not completely closed, the injection is given priority, which is beneficial for the plastic fluid to pass through the position where the cavity is too small, and to fill the cavity of the mold well, so that Product stress distribution.

Example 2:

Embodiment 2 provides a specific application example of processing injection molded lenses by applying Embodiment 1.

When using position compression mode:

In the initial state, the template crosshead is at the starting position of mold compression, and the stroke distance from the template crosshead to the zero point is 45 mm.

The compression position is set to 5 sections, and the travel distance from the template crosshead to the zero point for each compression position is 45mm, 35mm, 25mm, 20mm, and 0mm;

The compression speed of each stage is 350mm/s, 200mm/s, 400mm/s, 200mm/s, 300mm/s respectively;

The injection position is set to 5 sections, namely 30mm, 20mm, 15mm, 10mm, and 5mm.

When using time compression mode:

In the initial state, the crosshead of the template is at the zero position, and the travel distance from the crosshead of the template to the zero point is 0mm;

The compression position is set to 5 sections, and the travel distance from the template crosshead to the zero point for each compression position is 2mm, 1mm, 2mm, 1mm, and 0mm;

The compression speed of each section is 39mm/s;

The injection position is set to 30mm for the first segment;

The monitoring time of the first compression position is 1 second, the monitoring time of the second compression position is 2 seconds, the monitoring time of the third compression position is 1.5 seconds, and the monitoring time of the fourth compression position is 2 seconds.

Example 3:

Embodiment 3 provides an injection molding machine, which adopts the multi-stage injection molding method of Embodiment 1 for injection molding.

The relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. In all examples shown and discussed herein, any specific values should be construed as exemplary only, and not as limitations. Therefore, other examples of the exemplary embodiment may have different values. It should be noted that like numerals and letters indicate like items, therefore, once an item is defined, it does not require further discussion in the ensuing text.

In the description of the present application, it should be understood that orientation words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" etc. indicate the orientation Or positional relationship is generally based on the orientation or positional relationship shown, only for the convenience of describing the application and simplifying the description, in the absence of a contrary statement, these orientation words do not indicate and imply that the device or element referred to must have A specific orientation or construction and operation in a specific orientation should not be construed as limiting the scope of the present application; the orientation words "inside and outside" refer to inside and outside relative to the outline of each component itself.

For the convenience of description, spatially relative terms, such as "on", "above", "on the surface", "above", etc., can be used here to describe the spatial position relationship of features . It will be understood that spatially relative terms are intended to encompass different orientations in use or operation in addition to the described orientation.

In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing corresponding components. To limit the protection scope of this application.

If this application discloses or relates to parts or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (such as using bolts or screws), or it can also be understood as: Non-detachable fixed connection (such as riveting, welding), of course, the mutual fixed connection can also be replaced by an integrated structure (such as manufactured by casting process in one piece) (except that the integral forming process cannot be adopted obviously).

The above-listed preferred embodiments have further described the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included within the protection scope of the present invention.

Claims (10)

1. An injection molding multi-section forming method is characterized by comprising the following steps:

s1: performing injection molding and synchronous mold locking, and performing segmented mold pressing during injection molding according to the configuration of a product to be molded;

s2: cooling the molten gel;

s3: opening the mold;

s4: and ejecting the molded product through the mold.

2. The injection molding multi-segment molding method according to claim 1, wherein the segment molding comprises the steps of:

s11: setting a compression starting distance of the reserved cavity, and setting a mold position state at the compression starting distance as a mold compression starting position; s12: selecting a compression mode;

if the position compression mode is adopted, executing a first compression program;

if the compression mode is time compression mode, executing a second compression procedure.

3. The multi-stage molding method for injection molding according to claim 2, wherein the initial position of the mold compression is a seamless combination of the compression plate and the fixed mold plate of the mold, the spring of the compression plate is in an uncompressed state, and the molding surfaces of the cavities of the movable mold plate and the fixed mold plate of the mold are in a fit state.

4. The injection molding multi-stage molding method according to claim 3, wherein the mold employs a crank clamping mechanism with a mechanical hinge, and a position of the crosshead of the mold plate at the compression start position is used as a positional reference.

5. The injection molding multi-stage molding method according to claim 2, wherein the first compression process comprises the steps of:

s110: setting a plurality of compression positions, setting a compression speed corresponding to each compression position, and setting a plurality of injection positions, wherein the compression positions and the injection positions are arranged in a one-to-one correspondence manner;

s120: injecting the plastic into a mold cavity, and moving a movable mold to a set first section compression position at a set compression speed from a mold compression initial position by mold compression when the plastic is injected and filled to the first section injection position; when the injection is filled to the second-stage injection position, the mould compresses, and the movable mould is moved to the set second-stage compression position from the first-stage compression position at the set compression speed; and the injection and the compression are gradually segmented by analogy until the compression position reaches the zero point.

6. The injection molding multi-stage molding method according to claim 5, wherein at least two stages are provided for each of the compression position and the injection position in step S110.

7. The injection molding multi-stage molding method according to claim 5, wherein the second compression process comprises the steps of:

s210: setting a plurality of sections of compression positions, setting a compression speed corresponding to each section of compression position, setting monitoring time after each section is in place, and setting an injection position as 1 section;

s220: injecting the plastic into a mold cavity, and moving a movable mold to a set first section compression position at a set compression speed from a mold compression initial position by mold compression when the plastic is injected and filled to the first section injection position; then, after the first section of set monitoring time, the die compression moves the movable die from the first section of compression position to the set second section of compression position at the set compression speed; and the compression is gradually segmented until the compression position reaches the zero point.

8. The injection molding multi-stage molding method according to claim 7, wherein the movement is forward or backward, and at least two stages are provided at the compression position in step S210.

9. An injection molding multi-stage molding method according to claim 7, wherein the injection position is an advancing position of the injection machine screw for injecting the shot, and an advancing stroke of each stage of the injection machine screw for injecting the shot is defined by each stage of the injection position.

10. The injection molding multi-stage molding process of claim 7, wherein the zero point is a position at which mold closing is completed; the monitoring time is the interval time from the compression position to the next compression position after the compression position is moved in place.

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