阅读说明：本技术 一种可回收的简易模具及其制备方法 (Recyclable simple mold and preparation method thereof ) 是由 张善寿 范振洋 尹学荣 于 2021-08-27 设计创作，主要内容包括：本发明属于简易模具生成技术领域,具体涉及一种可回收的简易模具及其制备方法。其是以金属粉末和粘结剂为原料,混炼定型后经机械加工得到的,其中粘结剂为热塑性工程高分子材料,所述粘结剂的玻璃化转变温度在200℃以上。所述制备方法包括混炼、定型、机械加工和回收。本发明提供的技术方案与现有技术相比具有如下优势：通过金属粉末与热塑性粘结剂获得的简易模具,与现有技术中采用高密度金属相比,成本低,加工易,并且具有足够试模的强度,最重要的事,本发明提供的技术方案中没有进行烧结,并且粘结剂加热可还原,因此加工模具中产生的边角料或者报废模具可以通过混炼再次使用,回收利用率极高。(The invention belongs to the technical field of simple mold generation, and particularly relates to a recyclable simple mold and a preparation method thereof. The metal powder-based heat-insulating adhesive is prepared by taking metal powder and an adhesive as raw materials, mixing, shaping and then machining, wherein the adhesive is a thermoplastic engineering high polymer material, and the glass transition temperature of the adhesive is more than 200 ℃. The preparation method comprises mixing, shaping, machining and recycling. Compared with the prior art, the technical scheme provided by the invention has the following advantages: compared with the prior art in which high-density metal is adopted, the simple die obtained by the metal powder and the thermoplastic binder has the advantages of low cost, easiness in processing, enough die testing strength and the most important thing.)

1. A recyclable simple die is characterized in that metal powder and a binder are used as raw materials, and the die is obtained by mixing, shaping and then machining, wherein the binder is a thermoplastic engineering high polymer material, and the glass transition temperature of the binder is more than 200 ℃.

2. The recyclable simple mold according to claim 1, wherein the adhesive is one or more selected from the group consisting of PA, PBT, PPS, PEEK, PEKK, and LCP.

3. The recyclable simple mold as claimed in claim 1, wherein the metal powder is selected from a group consisting of iron-based low alloy steel, stainless steel alloy, and cemented carbide.

4. The simple recyclable mold according to claim 1, wherein the metal powder has an equiaxed shape, the equiaxed shape is an object with an equiaxed degree of 0.8 or more, and the metal powder has a particle size of 5 to 50 μm.

5. The method for preparing the recyclable simple mold as set forth in any one of claims 1 to 4, comprising the steps of:

s1 mixing: placing metal powder and a binder into a mixer for heating and mixing to form a briquette body;

s2 sizing: transferring the block body into a model, controlling the temperature, vacuumizing and applying pressure, and demoulding after cooling to obtain a material block;

s3 machining: then, carrying out numerical control processing on the material block according to the design requirement of the product mold to obtain a simple mold;

s4 recovery: when the excess material cut out of the material block or the simple mold is not used, the material block can be formed again by being thrown into the mixing roll again, and a new simple mold can be formed through S2 and S3.

6. The method according to claim 5, wherein the volume ratio of the metal powder to the binder in step S1 is (50:50) - (70: 30).

7. The method according to claim 5, wherein the temperature in S2 is controlled at 240-.

8. The method according to claim 5, wherein the model in S2 is a cube, a cuboid, a cone, a frustum, a cylinder, a cone or a circular truncated cone, preferably a cube or a cuboid.

9. The method according to claim 5, wherein the step S2 is performed by using a press machine, the press machine comprises a stage for fixing the mold and a pressing module matched with the opening of the mold, the stage is used for heating the mold, the pressing module is pressed into the mold to press the built-in lump mass to fill the inner cavity of the mold and shape, and the pressing module is provided with a vacuum suction hole.

Technical Field

The invention belongs to the technical field of simple mold generation, and particularly relates to a recyclable simple mold and a preparation method thereof.

Background

Mold forming is a widely used product forming method, and particularly for some plastic products, injection mold forming is widely used due to the advantages of wide usability, convenient processing, high efficiency and the like. Certainly, according to different requirements, the injection mold can be used for processing pure polymer materials, and injecting various products mainly made of polymer materials, such as a feed material formed by mixing metal or ceramic powder with polymers, so as to obtain a product green body through preparation operation of manufacturing metal or ceramic parts, and then degreasing and sintering are carried out to obtain a final product; the technology can also be developed into high-temperature melt injection technology developed by using the principle of injection molding through a high-temperature resistant mold such as a die-casting molding method.

Unlike rapid hand plate and prototype fabrication, in which the mold product is filled into the cavity by injecting real material at high pressure and high temperature, the quality of the product is high and no pores exist, so that the demand for simple and staged molds is great, but the molds become scrap iron after being used, which is a serious disadvantage.

In addition, for some products with less demand, if the existing mold forming method and materials are adopted, the mold opening cost is too high, so that the product is limited to adopt the forming method, and if the raw material cost can be greatly reduced, the product can be produced by injection molding to realize small-batch high-quality products.

Disclosure of Invention

The invention provides a recyclable simple die and a preparation method thereof, which are used for solving the problems that the existing die is high in raw material cost and cannot be recycled.

In order to solve the technical problems, the technical scheme of the invention is as follows: the recyclable simple die is prepared by taking metal powder and a binder as raw materials, mixing and shaping the raw materials and then machining the raw materials, wherein the binder is a thermoplastic engineering high polymer material, and the glass transition temperature of the binder is more than 200 ℃.

Alternatively, the binder is selected from one or more of PA (polyamide), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), PEKK (polyether ketone), and LCP (liquid crystal polymer).

Optionally, the metal powder is selected from a ferrous low alloy steel, a stainless steel alloy or a cemented carbide.

Optionally, the metal powder has an equiaxed shape, the equiaxed shape means that the equiaxed degree of the object is above 0.8, and the particle size of the metal powder is 5-50 μm.

The equiaxed is defined as the ratio of the length of any one passing centroid to the average of any ten passing centroid lengths.

The invention also provides a preparation method of the recyclable simple mold, which comprises the following steps:

s1 mixing: placing metal powder and a binder into a mixer for heating and mixing to form a briquette body;

s2 sizing: transferring the block body into a model, controlling the temperature, vacuumizing and applying pressure, and demoulding after cooling to obtain a material block;

s3 machining: then, carrying out numerical control processing on the material block according to the design requirement of the product mold to obtain a simple mold;

s4 recovery: when the excess material cut out of the material block or the simple mold is not used, the material block can be formed again by being thrown into the mixing roll again, and a new simple mold can be formed through S2 and S3.

Optionally, the volume ratio of the metal powder to the binder in step S1 is (50:50) - (70: 30).

If the content of the metal powder is too high, the adhesive evaporates due to internal temperature rise due to too large frictional force between the powders, and the overall adhesiveness is insufficient.

Optionally, the mixing temperature in S1 is set according to different fusion points of the binder (220-350 ℃), and the flow index of the formed briquette after mixing is 500-1000g/10min (according to ISO1133, the flow index is measured according to the feed melting point temperature of 220-350 ℃, the load is 21.6kg, and the diameter of the capillary die is 2 mm).

The flow index is the mass of fluid passing through a standard die within 10min measured at a specific load applied to the material at a certain temperature. Optionally, in S2, the temperature is controlled at 240-380 deg.C, the vacuum degree is below 500torr, and the pressure is above 50 MPa.

The temperature of S2 is preferably controlled to be 20 ℃ higher than the melting point of the binder material.

Optionally, the model in S2 is a cube, a cuboid, a cone, a frustum, a cylinder, a cone or a circular truncated cone, preferably a cube or a cuboid.

Optionally, S2 is implemented by using a press, where the press includes a stage for fixing the mold and a pressing block matched with the opening of the mold, the stage heats the mold, the pressing block is pressed into the mold to press the built-in briquette to fill the inner cavity of the mold and form the briquette, and the pressing block is provided with a vacuum suction hole.

Compared with the prior art, the technical scheme provided by the invention has the following advantages: compared with the prior art in which high-density metal is adopted, the simple die obtained by the metal powder and the thermoplastic binder has the advantages of low cost, easiness in processing, enough die testing strength and the most important thing.

Drawings

FIG. 1 is a schematic structural view of an injection mold described in example 1;

FIG. 2 is a schematic flow diagram of a simple mold generation and recovery process for recycling;

FIG. 3 is a schematic diagram of the S2 sizing step described in example 1;

fig. 4 is a schematic view of the shape of the sample at the time of the strength test.

Shown in the figure:

11-a mould frame, 12-a front mould core insert, 13-a rear mould core insert, 14-a glue inlet hole, 15-an ejector pin hole, 21-a briquette body, 22-a model, 23-a carrying platform, 24-a pressing module, 25-a vacuum pumping hole and 26-a material block.

Detailed Description

For the convenience of understanding, the following description will be made with reference to examples of a recyclable simple mold and a method for manufacturing the same, which are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations and positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixed or detachably or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1

The objective is to form a temporary metal mold as shown in fig. 1, specifically, a front core insert 12 and a rear core insert 13 located in a mold frame 11, wherein a glue inlet hole 14 is also present on the front core insert 12 except for a product cavity, a plurality of thimble hole holes 15 are also present on the rear core insert 13 except for the product cavity, the product is made of HDPE (high density polyethylene) and has a melting point of about 135 ℃.

The front core insert 12 and the rear core insert 13 are formed in a similar manner, and a molding process of one of the product cavities is taken as an example to illustrate a molding method of a recyclable simple mold.

As shown in fig. 2, the process of producing and recovering the recyclable simple mold is roughly as follows:

s1 mixing: placing metal powder and a binder into a mixer for heating and mixing to form a briquette body;

wherein the metal powder is stainless steel 316L, the shape of the metal powder is an equiaxed body, the equiaxed degree is more than 0.8, the grain diameter is d50 ═ 10 mu m, and the equiaxed degree and the grain diameter are obtained by adopting a grain diameter distribution instrument for testing; the particle size needs to be selected to be smaller, otherwise, the particles cannot be mixed and agglomerated;

the binder is thermoplastic polymer material such as PA (220 deg.C), PBT (220 deg.C), PPS (270 deg.C), PEEK (340 deg.C), PEKK (340 deg.C) or LCP (350 deg.C), and the glass transition temperature is shown in parentheses and PPS (270 deg.C) is used in this embodiment.

The volume ratio of the metal powder to the binder in the step S1 is 60: 40;

the flow index of the mixed and refined agglomerate is about 850g/10min (according to ISO1133, the temperature is 250-300 ℃ according to the feeding melting point, the parameter for measuring the flow index is load 21.6kg, and the diameter of a capillary tube neck ring mold is 2mm), the condition that the flow index is too small can not ensure that the filling is fully uniform and compact in the next pressing process, and if the flow index is too large, the subsequent cooling time needs to be greatly prolonged.

S2 sizing: as shown in fig. 3, the briquette body 21 is transferred into a mold 22, the mold 22 is a rectangular parallelepiped with length × width × height of 250 × 250 × 120mm, and is implemented by using a press, the press comprises a carrier 23 for fixing the mold 22 and a press module 24 matched with an opening of the mold 22, the carrier 23 heats the mold 22, the press module 24 presses the built-in briquette body 21 into the mold 22 to fill the inner cavity of the mold 22 and shape the briquette body, the press module 24 is provided with a vacuum pumping hole 25, the temperature of the mold 22 is maintained at 290 ℃, that is, on the basis of ensuring the fluidity of the briquette body 21, the briquette body 21 is pumped by the vacuum pumping hole 25 and is pressurized by the press module 24, so that the briquette body 21 fills the mold 22 and is uniformly dispersed, pressed and compacted, and then cooled and demolded to obtain a briquette body 26;

s3 machining: then, carrying out numerical control machining on the material block 26 according to the design requirement of the product mold to obtain a simple mold I;

s4 recovery: when the excess material cut from the material block 26 in the numerical control processing process or the simple die is not used, the material is put into the mixing mill again to form a lump body again, and then a new simple die II is formed through S2 and S3.

Example 2 Performance testing

The strength and the processing number of the simple mold I prepared in example 1 and the simple mold II processed by the reclaimed materials are tested, and the experimental data are shown in Table 1.

Wherein the strength test process and conditions were a tensile elongation round bar turned as shown in FIG. 4, (diameter 10mm, middle length 50mm, diameter length 15mm at both sides, length 30mm at both sides)

The mold number test is that the processed mold core insert is used for injection molding, the product quality is checked, specifically, the single weight, the burr observation and the size observation of each injection blank are carried out, and the mold number is the number of times capable of keeping the product quality.

TABLE 1

Injection pressure of 60MPa for injection machine	Strength test	Modulus test
			Simple mould I (first material)	120MPa	385 times
Simple mould II (reclaimed material)	118MPa	350 times (times)

As can be seen from Table 1, the strength and the number of dies molded again after recycling were almost unchanged and could be completely recycled.

Finally, it should be noted that: the above examples are only for illustrating the technical solutions of the present invention, and are not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or some or all of the technical features may be equivalently replaced, and such modifications or replacements may not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.