RU2205085C1 - Method for making drawing die plates and sections - Google Patents

Abstract

FIELD: manufacture of drawing die plates of devices for producing fibers of melts of thermosoftening materials. SUBSTANCE: metallic protrusions are formed on blank at acting upon its flat surface by means of punch with single or doubled row of openings and with predetermined forming stroke. EFFECT: enhanced efficiency, lowered metal consumption, enlarged manufacturing possibilities. 2 cl, 7 dwg

Description

 The invention relates to the building materials industry, in particular to methods for manufacturing spunbond plates in devices for producing fiber from melts of thermoplastic materials, such as glass.

 Devices for producing fiber from thermoplastic materials (glass melting devices (vessels), feeders, etc.), as a rule, are small-sized resistance electric furnaces made of platinum-based alloys, including a housing, a die plate limiting it from below, and current leads.

 Thermal preparation of the melt takes place in the device casing, and at the exit of die tubes 3–5 mm long, 1–3 mm inner diameter and 0.2–1 mm wall thickness, the necessary conditions are created for fiber formation. The number of dies in various types of devices ranges from 100 to 2000-4000. Large-sized die plates, as a rule, are made of prefabricated die sections with intermediate stiffeners that reduce creep deformation during the operation of glass melting devices.

 Known methods for the manufacture of spinneret assemblies of glass melting devices, including obtaining a perforated plate, into each hole of which tubular billets (dies) are inserted, and welding for hermetically connecting the plate to the walls of the spinnerets. In this case, both various fusion welding methods (plasma, electron beam, laser (see, for example, RF patent 2040494, С 03 B 37/09, 1992), and diffusion (solid-phase) welding (US patent 4461191, NKI, can be used) 76/107 S, 1984).

 The disadvantage of these methods is their low productivity. In addition, in a weld made by fusion welding, the structure of heat-resistant dispersion-hardened materials used for the manufacture of spinneret plates is destroyed, which leads to a decrease in the operational characteristics of the latter. The use of diffusion welding significantly limits the density of the spinneret field due to the technologically necessary support flange on the spinnerets, which adversely affects the dimensions of the spinneret plates and, therefore, the cost-effectiveness of the devices.

 There is also a known method of manufacturing die plates based on forming operations on a workpiece by stamping metal protrusions and subsequent deep drawing of sections with metal protrusions into dies (Loewenstein KL The Manufacturing Technology of Continuous Glass Fibers., ESPC, New York, 1973, p. 95- 97). In this case, the protrusion is formed by crimping the workpiece with a punch on a die with holes, the location of which corresponds to the location of the dies on the die plate. The metal of the workpiece under the action of the punch is thinned over the flat surface of the matrix and concentrated in its holes.

 The disadvantage of this method is the low productivity - the step with which the matrix moves with the workpiece when forming the protrusions relative to the punch should not be large (usually 2-3 mm). Otherwise, since the metal "flows" in all directions during crimping, the shift of the already compressed metal relative to the matrix and the protrusions formed in its holes can lead to the separation of the latter from the workpiece. In addition, the protrusions of the metal on the workpiece are asymmetrical: the height of the cone in the direction of crimping the workpiece is greater than on the opposite side.

 With further processing, this leads to a different thickness of the dies, increased wear and destruction of working tools for drawing. In this regard, it is necessary to melt the protrusions using welding equipment to give them a symmetrical shape, which also reduces the productivity of the method.

The closest in technical essence and the achieved result is a method of manufacturing spunbond sections of devices for producing fibers from a melt of thermoplastic materials (US patent 3514841, NKI 228-155, 1970), including forming protrusions of metal on a blank of a spinneret plate, surfacing of additional metal or alloy on each protrusion to increase its height (volume) and stamping of metal protrusions with surfacing dies. Moreover, the operation of forming protrusions (obtaining a relief that repeats the location of the dies on the die plate) is proposed to be carried out in one of three ways:
- crimping the workpiece with a punch on the surface of the matrix with holes (similar to the one described above);
- crimping the workpiece by rolling on a matrix with holes (the molding of the protrusions is similar to the previous version, but the role of the punch is played by rollers);
- crimping the workpiece on a flat surface with a punch with several rows of holes (the metal of the workpiece is thinned to the required thickness, and the sections under the holes in the punch become somewhat thicker than the original thickness of the workpiece).

 The disadvantage of this method is its significant complexity, since the above options do not allow crimping the workpiece protrusions of sufficient volume for forming by stamping the required dimensions of the dies. The consequence of this is the introduction of an additional metal surfacing operation on each formed protrusion.

 Another disadvantage of the prototype is the need to use in its implementation of massive expensive matrices of tool alloy steel with precisely located holes (up to 2000 or more). It is known that during drawing operations the billet of a spinneret plate increases in size (the distance between periodically spaced spinneret rows increases), and these changes depend on the configuration of the spinnerets, the properties of the material, technological transitions, the condition of working tools, etc. Thus, when changing one of the parameters (as well as in cases when it is necessary to change the period of arrangement of the die rows or increase their number), it becomes necessary to manufacture new dies with corresponding changes in the arrangement of rows of holes and taking into account that the final dimensions of the die plate do not exit beyond established tolerances.

 The objective of the present invention is to increase productivity, reduce material consumption and expand the technological capabilities of the method of manufacturing spunbond sections and plates.

The problem is solved in that in the known method of manufacturing spinneret plates and sections of devices for producing fiber from thermoplastic materials, which includes forming protrusions of a metal on a blank of a spinneret plate by crimping the blank on a flat surface with a punch with holes and stamping dies, the molding of protrusions is performed with a punch with a single or with a double row of holes and a stamping step of at least (S + d) / 2 + (Tt),
where S is the width of the punch;
d is the field width of the holes on the punch;
T is the initial thickness of the workpiece;
t is the thickness of the die section (plate),
moreover, preferably the stamping step for forming the protrusions should be in the range from (S + d) / 2 + (Tt) to S.

 The technical result is achieved by the fact that each step of crimping a workpiece by a punch occurs under equivalent conditions: metal, crimping with parts of the punch without holes, flows both to its center (to the area of the holes) and to the periphery. Due to this, almost symmetrical metal protrusions are formed on the preform of the die plate (section), the size of which is determined by the degree of deformation of the preform during crimping. The number of crimping steps and, consequently, die rows on the die section or plate is limited only by the dimensions of the blanks and the capabilities of the devices that feed the blanks into the die working space. Moreover, the step size and, consequently, the period of location of the protrusions (die rows) can quickly change within the above limits without replacing the punch.

 Dies on a spinneret plate (section) are usually grouped in transverse single (Fig. 1) or double rows (Fig. 2), and the period of arrangement of rows of spinnerets is from 8 to 16 mm. The view of the punches from the side of the holes for receiving the corresponding blanks with protrusions shown in Fig.3. The width S of the punch for crimping is determined by the period of location of the protrusions on the workpiece and the amount of deformation of the workpiece during stamping, and the diameter and location of the holes by the geometric parameters of the matrix for subsequent drawing of the dies.

 In FIG. 5 and 6 illustrate the possibility of changing the period of the arrangement of the protrusions on the compressed blank of the die section without changing the punch (by changing the stamping step G in the range from [(S + d) / 2 + (Tt)] to S in cases where a constant thickness is required During the stroke of the punch 1 (1 'is the position of the punch at the time of the previous step of crimping the workpiece), the workpiece 2 is crimped down from the initial thickness T to t, while the metal of the workpiece penetrates the holes of the punch 3, forming protrusions 4. It can be seen that at a stamping step G less than [(S + d) / 2 + (Tt)] gender e holes of the punch is above the already squeezed surface of the workpiece after the first and subsequent steps, and during the working stroke of the punch down, truncated metal protrusions are formed correspondingly, from which it is not possible to obtain spinnerets of the necessary geometric parameters.

 When the stamping step G is greater than S, sections of a greater thickness remain on the billet of the spinneret section than in the region adjacent to the protrusions (Fig. 7). Such sections can serve as elements that increase the rigidity of the spinneret plate under creep conditions, or they can be crimped to the required thickness during further processing.

 Example 1. A plate made of PlRd20 alloy with a thickness of T = 1.8 mm and a size of 60 x 270 mm is placed in a stamp that includes a lower working plate, a punch with a double row of holes and an automatic device for feeding the workpiece.

 Punch dimensions: length (in the direction perpendicular to the stamping direction) taking into account the mounting holes 100 mm, width S 11 mm, height 11 mm. On the surface of the punch facing the lower working plate, there are 24 (12 + 12) holes with a diameter of 3.4 mm with a pitch in the direction of the length of the punch 3.9 mm, the center distance of the holes along the width of the punch 3.5 mm. Thus, the width d of the hole field is 6.9 mm.

 Using a hydraulic press during the downward stroke of the punch, the workpiece is crimped to a thickness of t = 1.3 mm and the protrusions are formed, while the grippers of the feeding device are moved by the value of the stamping step G = 9 mm. During the upward stroke of the punch, the workpiece is fed by a step device G. Next, the stamping cycle is repeated 34 times and a workpiece with 816 protrusions is obtained, from which dies are formed on a special stamp by drawing and volumetric stamping. The result is an 816-die plate with a die length (distance between the axes of the extreme dies) of 317 mm and a period of arrangement of twin die rows of 9.5 mm.

 Example 2. A plate made of an alloy PlRd20 with a thickness of 1.8 mm and a size of 60 x 270 mm is placed in a stamp that includes a lower working plate, a punch with a double row of holes and an automatic device for feeding the workpiece.

 The punch is the same as in example 1.

The workpiece is crimped to a thickness of 1.3 mm and the protrusions are formed, while the grippers of the feeding device are moved by the stamping pitch G 10.5 mm. During the upward stroke of the punch, the workpiece is fed by a step G. The next stamping cycle is repeated 17 times, the workpiece is fed into a step G ₁ 15 mm and 17 cycles of crimping the workpiece are repeated with step G. From a workpiece with 816 protrusions, a special stamp is formed dies. The result is an 816-spinneret plate with a spinneret field length (distance between the axes of the extreme spinnerets) of 373 mm, a spacing period of spunbands of 11 mm and an enlarged interfilter gap in the center.

 Thus, for stamping various spinneret plates (examples 1 and 2), one punch with overall dimensions of 100 x 11 x 11 mm and 24 holes was required. For stamping the same spinneret plates by a known method currently used in industry, various tool steel dies with dimensions of the order of 400 • 70 • 20 mm and 816 holes, made with high precision both in configuration and location, are needed .

 The technical and economic effect of the use of the invention is expressed in increasing productivity by 1.2-1.5 times, reducing material consumption and laboriousness of manufacturing tooling in and expanding the technological capabilities of the method of manufacturing spunbond plates (sections).

Claims (2)

1. A method of manufacturing a die plate and sections of devices for producing fiber from thermoplastic materials, comprising forming protrusions of a metal on a preform of a die plate by crimping a preform on a flat surface with a punch with holes and stamping dies, characterized in that the molding of the protrusions is performed with a single or double row punch holes, and the stamping step is at least
[(S + d) / 2 + (Tt)],
where S is the width of the punch;
d is the field width of the holes on the punch;
T is the initial thickness of the workpiece;
t is the thickness of the die plate.  2. The method according to p. 1, characterized in that the stamping step is from [(S + d) / 2 + (T-t)] to S.

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