RU2508176C1 - Production device of specimens from castable curing resins - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: device includes a detachable hollow housing, in which a running channel is formed by means of spacers. The housing is formed by detachable side walls, upper and lower cover plates attached to the side walls. Spacers in the housing are installed so that they can be removed. A limit stop is installed from above or from below relative to each spacer and has the possibility of back-and-forth movement relative to the spacer. In the upper cover plate a provision is made for elements, one of which is intended for connection of the running channel to a specimen material vessel, and in the other one - for connection of the running channel to a vacuum pump.

EFFECT: obtaining quality specimens without any defects and without any additional processing.

3 cl, 5 dwg

Description

The invention relates to equipment for the manufacture of samples and can be used for the manufacture of batches of flat samples from castable curable resins intended for complex tensile testing, three-point bending.

Currently, samples of injection materials are made using various devices.

So, for example, GOST 22349-77 "Castable curing resins. Production of test specimens" shows the design of molds for making type 2 and 6 specimens according to GOST 11262-76 "Plastics. Tensile test method." Samples are made by pouring into molds without pressure, followed by machining of the cast plates. In this case, samples for each individual test method are made simultaneously from one resin composition.

Known tooling for sample preparation, containing plates with holes in the corners, on the bottom of which by means of glue fasten fiber bundles. Plates with fiber bundles glued to them by means of fasteners inserted into the holes are assembled in a single unit. Next, the prepared block is filled with resin (epoxy, polystyrene, acrylic and / or mixtures thereof), after which the snap-in is dismantled by removing the fasteners, the frozen block is removed with the built-in sample of the bundle or thread, the ends of the bundles extending outside the block are cut, the sample is polished ( see RF patent for utility model No. 8,033, IPC G01B 5/06, published April 10, 2009).

As a result of the analysis of the known solution, it should be noted that the samples obtained during its use are not of high quality, since air bubbles located in a chaotic order remain in the block during resin pouring, which changes the properties of the samples, and when polishing the samples can be damaged.

A device for producing samples is known, containing a base on which a matrix with an internal cavity is rigidly fixed. At the base along its central axis, a threaded hole is made, covered with a lid. A thrust device is included in the threaded hole, which is arranged to move along this threaded hole to remove the sample from the matrix. The ejector device is a screw with an external thread corresponding to the threaded hole of the described device.

The device is additionally equipped with removable walls that are adjacent to the walls forming the cavity or adjacent to the outer walls of the matrix. Removable walls are made of polymeric materials (polypropylene, polyethylene, etc.) that hold the mixture of the test substance (coke) and epoxy. The execution of the outer wall is possible using adhesive tape (adhesive tape). When grinding, these walls do not prevent grinding of the main sample, since they have significantly lower hardness.

The internal cavity of the matrix can be made stepwise with a decrease in the diameter of the steps to the base. The presence of steps with different diameters allows the use of removable walls of the required diameter, which provides control of the flow rate of the epoxy used, as well as regulation of the diameter of the surface to be grinded.

A cap with a diameter corresponding to the minimum diameter of the internal removable wall is placed over the threaded hole in the matrix. The cover is made of any polymeric material (polyethylene, polypropylene, PET, etc.) and serves to prevent the epoxy from entering the threaded hole, which facilitates the further removal of the cured sample from the matrix and also reduces the consumption of epoxy during sample preparation. An additional effect of using the lid is to redistribute the load on the cured sample when removing it using an ejector device, which eliminates cracking of the cured sample and violation of its integrity.

For the operation of the device, the sample is made from a mixture of the test material with a hardening binder in the air (epoxy resin). The mixture is poured into the cavity of the matrix with the walls and left in the air for hardening.

After completion of the hardening process, the device, together with the sample placed in it, is subjected to grinding and polishing to obtain thin sections. At the same time, the rigidly fixed matrix on the base, together with the cover covering the threaded hole, do not allow the sample to deform and shift when fixing and grinding the sample. After the grinding process is completed, the sample is pushed out of the device using the ejector tool without damage or violation of any surfaces. After extraction of the sample, the device is completely ready for reuse (see RF patent for utility model No. 115479, IPC G01N 1/00, published April 27, 2012).

As a result of the analysis of the known device, it should be noted that the implementation of the device for manufacturing samples in this form allows not only to produce samples in the device, but also to grind and polish them without removing them from the device, and only after these operations remove samples. However, the process of pouring the sample is accompanied by the ingress of gases into it, and mechanical processing, no matter how carefully it was carried out, leads to damage to the sample, for example, in the form of surface cracks.

A device (chill mold) for casting samples is known, comprising a body made in the form of two half-molds having a vertical plane of the connector. A strut is located coaxially with the vertical axis of symmetry in the housing. Symmetrically to the riser from two sides relative to it, in the half-shells of the body there are formed forming cavities separated by spacers, communicating with each other and forming a sprue channel in communication with the riser. The sprue channel is also connected to the profit located above the forming cavities.

During the operation of the device, the melt is poured through the riser into the body cavity and, through the gate channel, enters the mold cavity of the samples and gradually fills in the profit, which feeds the samples during crystallization and is a sample for chemical analysis. After cooling, the half-forms of the case are disconnected and samples are removed for subsequent processing (see RF patent No. 2188741, IPC B22D 15/00, published September 10, 2002) - the closest analogue.

As a result of the analysis of the known device, it should be noted that during the casting of samples it eliminates the ingress of gases, slag, oxide films into the cavity of the samples and provides additional power to the castings, which prevents the appearance of looseness and allows you to get samples with a homogeneous structure and stably uniform distribution of all elements along the length sample. However, when using this device, considerable time is spent on the machining of cast samples, necessary to remove profits, for the final shaping of the samples.

Thus, traditional methods of manufacturing samples by injection molding without pressure require prior evacuation of the binder to remove air bubbles. Casting without preliminary evacuation into the cavity of the gate channels in the “open air” cannot guarantee that the bubbles will not be re-formed during the pouring of the mold. In addition, when removing cured samples from hard forms, there is a risk of mechanical damage up to destruction. A decrease in adhesive interaction with the walls of the mold is provided by the use of release agents (liquids). To ensure the manufacture of samples with flat planes and without subsequent deformations, they are pushed out of the mold from the side of the lower surface of the matrix. In this case, there is a risk of damage to the working part of the sample. When several samples are poured simultaneously into the sprue mold, problems arise associated with the extraction of the samples connected by the sprues and the removal of the sprues, which can also lead to chip formation and destruction of the samples.

The technical result of the present invention is the creation of a device for the manufacture of samples, providing high-quality samples practically without defects, without additional processing due to the combination of vacuum cycles in a single technological operation, feeding a binder into the gate mold and removing the gate without additional mechanical processing of the samples.

The specified technical result is ensured by the fact that in the device for the manufacture of samples from injection curable resins containing a detachable hollow body, in which a sprue channel for forming samples is formed by spacers, it is new that the body is formed by detachable side walls, upper and lower covers attached to the side walls. Spacers in the housing are removable. Above or below relative to each spacer, a limiter is installed that can reciprocate with respect to the spacer. Elements are provided in the top cover, one of which is used to connect the gating channel to the container for sample material, and the other to connect the gating channel to the vacuum pump.

Advantageously, the device can be equipped with a spacer element made in the form of a bolt mounted in the side walls of the housing, and each stopper can be made in the form of a plate in contact with a screw screwed into the threaded hole of the upper or lower cover.

The essence of the claimed device is illustrated by graphic materials on which:

- figure 1 is a diagram of the manufacture of samples in the claimed device;

- figure 2 - device, General view, one of the side walls is removed;

- figure 3 is a complete assembly;

- figure 4 - location in the housing end limiters;

- figure 5 is the location of the spacer bolt.

Figure 1 shows a diagram of the manufacture of samples in the inventive device from castable curable resins containing a detachable hollow body 2, in which, by means of spacers, a sprue channel 3 is formed for molding samples. Elements are provided in the top cover of the housing 2, one of which 4 is used to connect the gate channel 3 to the sample material container 1 while monitoring the pressure in the vacuum chamber 5 using a control vacuum gauge 6, and another element 7 is used to connect the gate channel 3 through the resin collector 8 and a control vacuum gauge 9 with a vacuum pump 10.

A device for manufacturing samples from injection curable resins (FIG. 2-FIG. 5) consists of a hollow detachable housing formed by a lower cover 11, side walls 12 and 13, and a top cover 14. The side walls are fastened to each other by means of fasteners (for example, bolts). For their exact relative installation, centering pins are provided. The top cover 14 is attached to the upper plane of the side walls by means of fasteners 17 (for example, screws). The lower cover to the lower plane of the side walls, is fixed in the same way - by means of fasteners (for example, screws).

The spacers 18 are removably mounted in the body cavity. The spacers are installed by means of pins entering the holes of the spacers and the pin holes 19 of the side walls 12 and 13. The spacers are installed at a certain distance from each other, and their height is less than the distance from the top cover 14 to the bottom 11.

At the top or bottom of each spacer 18 there is a stopper 20 made in the form of a plate and having the possibility of vertical (in the drawing plane) reciprocating movement, for example, by means of a screw 21 screwed into the threaded hole of the upper (or lower) cover.

Spacers 18 may have a different shape, which is due to the fact that their shape and dimensions define the shape and dimensions of the samples.

The free space between the spacers 18 forms the sprue channel 3, which is located in the region of the plane of the connector of the side walls of the housing 12 and 13. The input of the sprue channel is element 22 (for example, a threaded hole or fitting) made in the top cover, and the output is element 23 (for example , threaded hole or fitting) made in the top cover.

The device can be equipped with a spacer bolt 24 screwed into one of the side walls and abutting against the other side wall.

Spacers 18 can be interchangeable, of various shapes and sizes, and their set can be included in the device, which expands its functionality.

The device is prepared for operation as follows.

The side walls 12 and 13 are disconnected. By means of pins, spacers 18 of a given shape and size are attached to the side wall 12 or 13. Connect the side walls by means of a screw connection 16 and tighten the walls with bolts 15. The pins are located in the pin holes of both side walls 12 and 13, which ensures a constant position of the spacers 18. Screw the spacer bolt 24. Fasten the upper and lower covers to the side walls. The stops 20 by means of screws 21 are retracted to their original position, in which they are in contact with the upper and lower covers. The body cavity of the assembled device is sealed. Spacers 18 with side surfaces in contact with the inner surfaces of the side walls. The side walls of the mold, spacers 18 and stoppers 20 of the device are made of steel, followed by chrome plating and providing a roughness of the working surfaces Ra 0.160 μm.

The device is assembled.

The element 22 of the upper cover is connected via a vacuum channel 4 with a capacity 1 located in the vacuum chamber 5 with the starting material (resin) for sample preparation. Element 23 is connected by a vacuum channel 7 to a vacuum pump 10. In the vacuum channels, adjustable valves (not shown) are provided.

The device is ready to go.

To prepare samples in the device, a vacuum pump 10 is turned on and the gate channel 3, vacuum channel 4 and vacuum chamber 5 are evacuated. The vacuum process must be carried out before air bubbles are removed from the resin container. After completion of the evacuation process, the gating channel 3 with a capacity of 1 is reported, as a result of which the resin is supplied to the gating channel, which is carried out by vacuum without the use of additional means. Gradually, the sprue channel is completely filled with a mass of resin. After filling the gate channel 3, the lateral profile of the samples is completely formed. For the final molding of samples along their end part, excess resin is removed from the gate channel, which is carried out by means of stoppers 20, by sequentially screwing screws 21 into the upper or lower wall 14 or 11, leading the stopper in movement towards the spacer, which allows molding the end parts of the samples and, thereby, eliminate the need for machining the end of the samples. It should be noted that the movement of the stoppers 20 must be carried out in a staggered manner, starting from the resin injection side, in order to ensure the removal of excess resin in the unlimited gating mold cavities in which the samples are cured. To extract samples and prepare the device for further use, disconnect the channels 4 and 7, separate the upper 14 and lower 11 covers, rotate the spacer bolt 24 to disconnect the side walls 12 and 13, the stops 20 by means of screws 21 are reset and the finished samples are removed from the device, which do not require further processing.

Using the proposed device provides high-quality samples by eliminating the ingress of gases into the samples, as well as eliminating the mechanical processing of the obtained samples before using them.

Claims (3)

1. A device for the manufacture of samples from injection curable resins containing a detachable hollow body, in which, by means of spacers, a sprue channel is formed for molding samples, characterized in that the body is formed by detachable side walls, upper and lower covers attached to the side walls, spacers in the housing are removably mounted, and a limiter is installed on the top or bottom of each spacer with the possibility of reciprocating movement spacers, while in the upper cover there are elements, one of which is designed to connect the gating channel to the container for sample material, and the other to connect the gating channel to the vacuum pump. 2. The device according to claim 1, characterized in that it is equipped with a spacer element made in the form of a bolt mounted in the side walls of the housing. 3. The device according to claim 1, characterized in that each limiter is made in the form of a plate in contact with a screw screwed into the threaded hole of the upper or lower cover.

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