CN115122553A - PTFE suspension material thin plate extrusion method - Google Patents

PTFE suspension material thin plate extrusion method Download PDF

Info

Publication number
CN115122553A
CN115122553A CN202210885561.9A CN202210885561A CN115122553A CN 115122553 A CN115122553 A CN 115122553A CN 202210885561 A CN202210885561 A CN 202210885561A CN 115122553 A CN115122553 A CN 115122553A
Authority
CN
China
Prior art keywords
mold
tray
die
die cavity
cavity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210885561.9A
Other languages
Chinese (zh)
Inventor
杨文光
杨烨
王帅
靳予
陈朝曦
孙克原
林丰
王孝刚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nanjing Comptech Composites Corp
Original Assignee
Nanjing Comptech Composites Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanjing Comptech Composites Corp filed Critical Nanjing Comptech Composites Corp
Priority to CN202210885561.9A priority Critical patent/CN115122553A/en
Publication of CN115122553A publication Critical patent/CN115122553A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
    • B29C43/14—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles in several steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/34—Feeding the material to the mould or the compression means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/36—Moulds for making articles of definite length, i.e. discrete articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/52—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
    • B29C43/32—Component parts, details or accessories; Auxiliary operations
    • B29C43/34—Feeding the material to the mould or the compression means
    • B29C2043/3488—Feeding the material to the mould or the compression means uniformly distributed into the mould
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2007/00—Flat articles, e.g. films or sheets
    • B29L2007/002—Panels; Plates; Sheets

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

The patent provides a PTFE suspension material sheet extrusion method, which can extrude PTFE sheets with uniform thickness and good mechanical property, and has high production efficiency and low production cost. The method comprises the following steps: filling: placing PTFE powder materials on the tray bottom of a tray; an outer mold is arranged below the disc bottom, and a shaping mold is arranged below the outer mold; the outer mold and the shaping mold are internally provided with a mold cavity which is communicated up and down, and the periphery of the lower part of the outer mold is provided with a heating device; a plug for preventing the material from directly falling through the die cavity is placed in the die cavity in advance; the material enters the die cavity through the rotation of the material tray; pressing: the mold core extends into the mold cavity to extrude the material in the mold cavity, and the material is extruded; refilling and melting: the mold core moves upwards to withdraw from the mold cavity, after the mold cavity is filled with the material, the mold core extends into the mold cavity to extrude the material, the process is repeated, the compacted material reaches the lower part of the outer mold, the heating device heats the material, and the material is gradually melted; forming: and the molten material reaches the shaping die to be gradually cooled and shaped.

Description

PTFE suspension material thin plate extrusion method
Technical Field
The patent relates to a sheet extrusion method, in particular to a PTFE suspension material sheet extrusion method.
Background
The existing extruder can only be used for extruding round pipes generally, and cannot extrude thin plates generally due to difficult feeding and large frictional resistance. Even if it can be extruded with difficulty, it often shows defects such as uneven thickness and poor mechanical properties.
Disclosure of Invention
The patent aims to provide a PTFE suspension material thin plate extrusion method which can extrude a PTFE thin plate with uniform thickness and good mechanical property, and has high production efficiency and low production cost.
In order to achieve the above object, the PTFE suspension sheet extrusion method of this patent comprises the steps of:
filling: placing PTFE powder materials on the tray bottom of a tray; an outer mold is arranged below the disc bottom, and a shaping mold is arranged below the outer mold; the material tray can rotate relative to the outer die and the shaping die; at least one cuboid-shaped die cavity which is communicated up and down is arranged in the outer die and the shaping die, and the width of the die cavity in the left-right direction is larger than the thickness of the die cavity in the front-back direction; the periphery of the lower part of the outer mold is provided with a heating device; a blanking groove communicated with a die cavity inlet at the upper end of the die cavity is formed in the bottom of the plate; a plug for preventing the material from directly falling through the die cavity is placed in the die cavity in advance; the material placed at the bottom of the tray enters a die cavity above the plug through the blanking groove by the rotation of the tray;
pressing: after the die cavity above the plug is filled with materials, the die core moves downwards to extend into the die cavity to extrude the materials in the die cavity, and meanwhile, the plug moves downwards for a certain distance in the die cavity;
refilling and melting: the mold core moves upwards to withdraw from the mold cavity, the material enters the mold cavity through the blanking groove by the rotation of the material tray, after the mold cavity is filled with the material, the mold core moves downwards to stretch into the mold cavity to extrude the material in the mold cavity, the process is repeated, the compacted material in the mold cavity gradually reaches the lower part of the outer mold with a heating device, the heating device heats the compressed material in the mold cavity, and simultaneously the material is gradually melted due to the friction force between the material and the mold cavity;
forming: and (3) gradually cooling and forming the molten material in the shaping mold as the material is pressed down under the mold core, and gradually reducing the temperature of the plate from the lower end of the shaping mold to obtain a continuously extruded sheet.
1.
According to the PTFE suspension material thin plate extrusion method, when the material enters the die cavity, the material placed on the bottom of the plate is pushed into the die cavity through the blanking groove by adopting the scraping device.
The PTFE suspension material sheet extrusion method comprises the following steps that a material tray comprises a tray bottom and a tray edge extending upwards from the periphery of the tray bottom; the scraping device mainly comprises a scraping plate and a cylinder, the bottom edge of the scraping plate is close to the upper surface of the plate bottom, the scraping plate is connected with a cylinder piston rod which crosses over the plate edge on the upper part of the plate edge, and a cylinder body of the cylinder is fixed on a lower template; the cylinder moves to drive the scraper to move back and forth, and the material on the bottom of the plate is pushed into the die cavity through the blanking groove.
In the method for extruding the PTFE suspension material sheet, 2 die cavities are arranged in the thickness direction of the die cavity and are parallel to each other.
In the method for extruding the PTFE suspension material thin plate, the two scraping devices are symmetrically arranged on the central plane of the two die cavities in the thickness direction.
In the method for extruding the PTFE suspension sheet, the following operations are repeated while the tray is rotated, and the sheet is rotated in a forward direction for 3 weeks and then in a reverse direction for 1 week.
The PTFE suspension material sheet extrusion method uses a suspension material sheet extruder which comprises a rack, a lower template fixed on the rack, an upper template connected with the lower template through a guide post, a sliding template arranged on the guide post in a sliding way, and an oil cylinder arranged on the upper template, wherein a piston rod of the oil cylinder is connected with the sliding template; a material tray base is fixed at the upper end of the outer die, a material tray which rotates relative to the material tray base is arranged on the material tray base, and the material tray is connected with a material tray driving mechanism which drives the material tray to rotate relative to the material tray base; and the tray bottom and the tray base are both provided with a charging chute communicated with the die cavity inlet at the upper end of the die cavity.
According to the PTFE suspension material sheet extrusion method, the material tray driving mechanism comprises a motor fixed on the upper template or the lower template, a driving gear connected with an output shaft of the motor, and meshing teeth which are meshed with the driving gear and are arranged on the periphery of the material tray.
According to the PTFE suspension material sheet extrusion method, the motor is fixed on the upper template, the output shaft is connected with the driving gear shaft which penetrates through the sliding template and is rotatably supported on the lower template at the lower end, and the driving gear is fixed on the driving gear shaft.
The PTFE suspension material sheet extrusion method has the extruded PTFE sheet with the thickness of 4.5-5.5 mm and the width of 300-320 mm, the tensile strength of not less than 22MPa and the elongation at break of 280-300 percent.
The beneficial effect of this patent:
the technology is characterized in that after a suspension material (PTFE powder) is compressed into a pre-formed object, the suspension material is heated and melted through a die cavity, then is cooled and formed, and is subjected to heat preservation to obtain a thin plate with uniform thickness and meeting mechanical properties. The specific process is as follows:
filling: the material is placed on the tray bottom, or falls on the tray bottom through an automatic feeding device, and the tray is driven by a tray driving mechanism to rotate, so that the material uniformly falls into a mold cavity.
In order to enable the materials to fall into the die cavity more uniformly, the charging tray rotates reversely for 1 week after rotating positively for 3 weeks, and thus the materials in the die cavity are more uniform.
In order to ensure that the material can reliably fall into the die cavity, the material on the bottom of the plate is pushed into the die cavity through the blanking groove by moving a scraper in the scraping device back and forth.
When the device is used for the first time, in order to prevent the materials in the die cavity from directly leaking out of the lower end of the die cavity through the die cavity, a plug (such as a multilayer braided belt) with certain friction resistance with the inner wall of the die cavity is filled in advance at the lower part close to the inlet of the die cavity.
Pressing: after the die cavity above the plug is filled with the materials, the material tray and the scraping device stop moving, the scraper returns to the original initial position, the die core moves downwards, extends into the die cavity to extrude the materials in the die cavity, prepresses the materials, and meanwhile, the plug can move downwards for a distance in the die cavity.
After which the mould core is moved upwards. And then repeating the processes of filling and pressing, wherein the compacted material in the die cavity gradually reaches the lower part of an outer die with a heating device, the heating device heats the material compressed in the die cavity, and the material is gradually melted due to the friction force between the material and the die cavity.
And (3) gradually cooling and forming the molten material in the shaping mold when the material is pressed down under the mold core, gradually reducing the temperature of the plate coming out from the lower end of the shaping mold, further releasing the internal stress, and finally obtaining the continuously extruded sheet.
When the number of the die cavities is 2, two sheets can be extruded at one time, and the efficiency is higher.
The width direction of scraper blade and die cavity is parallel, and the structure of curb plate is connected to the left and right sides of scraper blade simultaneously, more is applicable to the situation that has two or more die cavities, and it can push the material into the die cavity fast.
When the scraping device has two, the two scraping devices scrape materials in a reciprocating staggered mode (the piston rod of one cylinder stretches out, the piston rod of the other cylinder contracts), in addition, the materials can uniformly enter the die cavity due to the rotation of the material tray, and the obtained thin plate is more uniform in texture.
The PTFE sheet extruded by the extruder has the thickness of 4.5mm-5.5mm, the width of 300mm-320mm, the tensile strength of not less than 22MPa, the elongation at break of 280-.
Drawings
FIG. 1 is a perspective view of a suspended feed sheet extruder;
FIG. 2 is a perspective view of the upper die plate, the lower die plate, the material tray driving mechanism, etc.;
FIG. 3 is a schematic view of the packing state (left cylinder rod retracted, right cylinder rod extended);
FIG. 4 is a schematic view of the packing state (left cylinder piston rod extended, right cylinder piston rod retracted);
FIG. 5 is a schematic view of a depressed state (both the left cylinder piston and the right cylinder piston rod retracted);
FIG. 6 is a schematic view of an outer mold, a sizing mold, etc.;
FIG. 7 is a schematic view of a sizing die, an insulating jacket, etc.;
fig. 8 is a plan view of the blade, the cylinder, and the like.
In the figure, a frame 1, a lower template 2, a guide post 3, an upper template 4, a sliding template 5, an oil cylinder 6, an outer mold 7, a mold cavity 71, a mold cavity inlet 711, an outer mold fixing flange 8, a shaping mold 9, a heating device 10, a heating ring 101, a thermocouple 102, a mold core 11, a tray base 12, a guide rail, a guide rail, a guide rail, guide rail,
Tray 13, tray bottom 131, tray edge 132,
The tray driving mechanism 14, the motor 141, the driving gear shaft 142, the driving gear 143, the engaging teeth 144, the tray drive mechanism,
A charging chute 15,
Scraper 16, scraper 161, rubber substrate 162, cylinder 163, side plate 164,
The heat preservation sleeve 20, the automatic feeding device 21, the blanking port 211, the plug 22, the material 23 and the solid plug 231.
Detailed Description
The method adopts vertical extrusion molding continuous forming, after a suspension material (such as PTFE powder) is compressed into a pre-formed object, the pre-formed object is heated and melted through a mold cavity, cooled and formed, and then the thin plate with uniform thickness and meeting the mechanical property is obtained through heat preservation. The specific process is as follows:
filling: the material is placed on the tray bottom, or the material falls on the tray bottom through the automatic feeding device, the tray is driven by the tray driving mechanism to rotate, and meanwhile, the scraper plate in the scraping device moves back and forth, so that the material uniformly falls into the falling mold cavity.
In order to enable the materials to fall into the die cavity more uniformly, the charging tray rotates reversely for 1 week after rotating positively for 3 weeks, and thus the materials in the die cavity are more uniform.
In order to ensure that the material can reliably fall into the die cavity, the material on the bottom of the plate is pushed into the die cavity through the blanking groove by moving a scraper in the scraping device back and forth.
When the device is used for the first time, in order to prevent the materials in the die cavity from directly leaking out of the lower end of the die cavity through the die cavity, a plug (such as a multilayer braided belt) with certain friction resistance with the inner wall of the die cavity is filled in advance at the lower part close to the inlet of the die cavity.
Pressing: after the die cavity above the end cap is filled with the materials, the material disc and the air cylinder stop moving, the scraper returns to the original initial position, the oil cylinder moves to drive the sliding template to move downwards along the guide pillar, the die core moves downwards to stretch into the die cavity to extrude the materials in the die cavity, the materials are pre-pressed, and the end cap can move downwards for a certain distance in the die cavity.
Then the oil cylinder drives the mold core to move upwards. And then repeating the filling and pressing processes, wherein the compacted material in the die cavity gradually reaches the lower part of the outer die with the heating device, the heating device heats the material compressed in the die cavity, and the material is gradually melted due to the friction force between the material and the die cavity.
And (3) pressing the material under a mold core driven by the oil cylinder, gradually cooling and molding the molten material in the shaping mold, enabling the plate to enter the heat-insulating sleeve from the lower end of the shaping mold, gradually reducing the temperature along with the downward movement of the plate in the heat-insulating sleeve, further releasing the internal stress, and finally obtaining the continuously extruded sheet.
When the number of the die cavities is 2, two sheets can be extruded at one time, and the efficiency is higher.
The width direction of scraper blade and die cavity is parallel, and the structure of curb plate is connected to the left and right sides of scraper blade simultaneously, more is applicable to the situation that has two or more die cavities, and it can push the material into the die cavity fast.
When the scraping device has two, the two scraping devices scrape materials in a reciprocating staggered mode (the piston rod of one cylinder stretches out, the piston rod of the other cylinder contracts), in addition, the materials can uniformly enter the die cavity due to the rotation of the material tray, and the obtained thin plate is more uniform in texture.
The PTFE sheet extruded by the extruder has the thickness of 4.5-5.5 mm, the width of 300-320 mm, the tensile strength of not less than 22MPa, the elongation at break of 280-300 percent and better quality.
The suspended material sheet extruder shown in fig. 1 and 2 used in the method comprises a frame 1, a lower template 2 fixed on the frame, an upper template 4 connected with the lower template through a guide post 3, a sliding template 5 arranged on the guide post 3 in a sliding manner, an oil cylinder 6 arranged on the upper template, and a piston rod of the oil cylinder is connected with the sliding template 5.
Referring to fig. 7, an external mold 7 is fixed on the lower template 2 through an external mold fixing flange 8, the lower end of the external mold 7 is connected with a shaping mold 9, the lower end of the shaping mold is provided with a heat insulation sleeve 20 which is connected with the rack and extends in the vertical direction of the mold cavity, and the heat insulation cotton is filled in the heat insulation sleeve. The periphery of the lower part of the outer mold 7 is provided with a heating device 10; the outer mold and the shaping mold are provided with 2 rectangular mold cavities 71 which are vertically penetrated, the width of the mold cavity in the left-right direction is 310mm, and the thickness in the front-back direction is about 5 mm. The 2 mold cavities are arranged in the thickness direction of the mold cavity and are parallel to each other.
The lower part of the sliding template 5 is connected with 2 mold cores 11 which can extend into the mold cavity.
A tray base 12 is fixed at the upper end of the outer die 7, a tray 13 which rotates relative to the tray base is arranged on the tray base 12, the tray comprises a tray bottom 131 and a tray edge 132 which extends upwards at the periphery of the tray bottom, and the tray is connected with a tray driving mechanism 14 which drives the tray driving mechanism to rotate relative to the tray base; the tray driving mechanism 14 includes a motor 141 fixed to the upper mold plate, an output shaft of the motor is connected to a driving gear shaft 142 passing through the slide mold plate and rotatably supported at a lower end thereof to the lower mold plate, a driving gear 143 is fixed to the driving gear shaft, and engaging teeth 144 engaged with the driving gear are provided on an outer circle of the tray bottom 131.
The tray bottom 131 and the tray base 12 are both provided with a charging chute 15 communicated with a cavity inlet 711 at the upper end of the cavity 71.
The two scraping devices are symmetrically arranged on the central plane of the two die cavities in the thickness direction. Each scraper 16 mainly includes a scraper 161, a side plate 164, a rubber substrate 162, and a cylinder 163. The blade 161 is parallel to the width direction of the cavity (perpendicular to the thickness direction of the cavity); the left and right sides of the squeegee 161 are connected to side plates 164 near the inner side of the disc edge 132. The bottom edges of the scrapers 161 and the side plates 164 are connected to a rubber substrate 162, and the rubber substrate 162 is in contact with the upper surface of the tray bottom. The scraper 161 is connected to a piston rod of a cylinder 163 which crosses over the disc edge 132 at the upper part of the disc edge, and the cylinder 163 is fixed on the lower template.
The automatic feeding device 21 belonging to the prior art is fixed on one side of the upper die plate, and a blanking port 211 of the automatic feeding device is arranged above the disc bottom 131. The automatic feeding device 21 is filled with a material 23, namely PTFE powder. The automatic feeding device 21 is operated, and the PTFE powder falls onto the tray bottom 131 of the tray 13 through the blanking port 211.
Then, filling: the two cylinders are staggered (the piston rod of one cylinder extends out, the piston rod of the other cylinder retracts, see fig. 3 and 4) to drive the scraper and the rubber substrate to move back and forth. While the cylinder acts, the material tray repeats the following actions: rotate forward for 3 weeks and then rotate backward for 1 week.
When the squeegee and the rubber substrate are moved forward toward the cavity, the PTFE powder falling on the bottom of the pan is pushed into the cavity 71 through the chute 15 and the cavity entrance 711.
In order to prevent the material in the cavity 71 from directly leaking out of the lower end of the cavity through the cavity, a plurality of layers of woven tapes having a certain frictional resistance with the inner wall of the cavity are pre-filled as plugs 22 at the lower portion near the entrance 711 of the cavity.
Pressing: after the die cavity above the plug is filled with the material 23, the material tray and the cylinders stop moving, the scraper returns to the initial position (the piston rods of the two cylinders are retracted, see fig. 5), the oil cylinder moves to drive the sliding template 5 to move downwards along the guide pillar 3, the die core 11 moves downwards, the sliding template extends into the die cavity 71 to extrude the material 23 in the die cavity, the material is pre-pressed, and meanwhile, the plug moves downwards for a certain distance in the die cavity.
Then the oil cylinder 6 drives the mould core 11 to move upwards through the sliding mould plate 5. Then, the above-mentioned processes of filling and pressing are repeated, the material 23 compressed in the cavity 71 gradually reaches the lower part of the outer mold 7 having the heating device 10, and the heating device 10 heats the material compressed in the cavity 71 and the material is gradually melted due to the friction force between the material and the cavity.
The materials are pressed down under a mold core driven by an oil cylinder, the molten materials reach the inside of the shaping mold 9 and are gradually cooled and molded, the plates come out from the lower end of the shaping mold 9 and enter the heat insulation sleeve 20, the temperature is gradually reduced along with the downward movement of the plates in the heat insulation sleeve, the internal stress is further released, and finally two continuously extruded thin plates are obtained.
The outer die 7 is fixed with the lower die plate 2 and the rack 1 through an outer die fixing flange 8, and the die core 11 is connected with the piston rod of the oil cylinder 6 through the sliding die plate 5, so that the die core is accurate in positioning, stable and reliable in movement, uniform in die cavity clearance with the outer die, free of clamping stagnation and free of mutual movement. The heating device 10 adopts a far infrared chain type ceramic heating ring 101, a heat preservation device is added on the outer heat dissipation surface of the heating ring, and a ceramic far infrared heating element is arranged inside the heating ring, so that the outer die can be effectively heated quickly and uniformly, and the work is stable.
The feeding adopts an automatic feeding device. The tray 13 is rotated counterclockwise by the driving gear 143 driven by the servo motor 141 to continuously receive the material, and after the tray is rotated counterclockwise for 3 turns, the tray is rotated clockwise for 1 turn (seen from top to bottom). The pair of cylinders drive the scrapers to scrape materials in a reciprocating staggered manner (see fig. 3 and 4), the materials fall under the thrust and the self weight, and after the die cavity and the blanking groove are filled, the two cylinders return to stop positions (see fig. 5). The mould core is gradually pushed and pressed downwards under the driving of the oil cylinder, the dispersed materials 23 are gradually compacted into the solid plugs 231 under the stress of the materials and the extrusion of the four walls. The bottom of the outer die is clamped in a die cavity of the outer die by a plurality of layers of 5mm wide woven belts to provide certain support for materials. The repeated movement of the mold core presses new material at the inlet of the chute and mold cavity into the top of the last section of solid plug 231, causing the material to compact.
The solid plug 231 is pushed to a sintering area with a heating device on the periphery of the outer die, and is subjected to frictional heat with the four walls of the outer die and heat of a heating ring outside the outer die to start melting, and the part which firstly contacts the outer wall of the outer die is gradually melted from outside to inside, so that the solid plug is in a full-melting state. At this time, the mold core needs to apply proper pressure holding of the top solid plug to ensure that the clearance in the molten mass is eliminated and higher melting strength is obtained. Referring to fig. 6, a heating device, i.e., 5 sets of heating rings 101, are installed in the sintering area of the mold, and the heating temperatures of the 5 heating rings are 317 ℃, 378 ℃ and 320 ℃, respectively. Each section is monitored by an independent thermocouple 102 to ensure accurate temperature and thorough material burning.
The thin plate passing through the sintering area reaches the shaping die and starts to enter a cooling stage, the shaping die is additionally arranged at the lowest end of the outer die, the time of the thin plate in the shaping die can be prolonged, the thin plate is prevented from being exposed in the air too early, the thin plate is well supported when releasing internal stress during cooling, and the product is prevented from deforming. The thin plate continuously stays in the heat-insulating sleeve after coming out of the shaping die, and the internal stress is continuously released.
The thickness of the suspension extrusion PTFE sheet is 5.0mm, the width is 310mm, the sampling tensile strength can reach 23.5MPa, and the elongation at break is stabilized at about 290%.

Claims (10)

  1. A PTFE suspension sheet extrusion process comprising the steps of:
    filling: placing PTFE powder materials on the tray bottom of a tray; an outer mold is arranged below the disc bottom, and a shaping mold is arranged below the outer mold; the material tray can rotate relative to the outer die and the shaping die; at least one cuboid-shaped die cavity which is communicated up and down is arranged in the outer die and the shaping die, and the width of the die cavity in the left-right direction is larger than the thickness of the die cavity in the front-back direction; the periphery of the lower part of the outer mold is provided with a heating device; a blanking groove communicated with a die cavity inlet at the upper end of the die cavity is formed in the bottom of the plate; a plug for preventing the material from directly falling through the die cavity is placed in the die cavity in advance; the material placed at the bottom of the tray enters a die cavity above the plug through the blanking groove by the rotation of the tray;
    pressing: after the die cavity above the plug is filled with materials, the die core moves downwards to extend into the die cavity to extrude the materials in the die cavity, and meanwhile, the plug moves downwards for a certain distance in the die cavity;
    refilling and melting: the mold core moves upwards to exit the mold cavity, the material enters the mold cavity through the blanking groove by the rotation of the material tray, after the mold cavity is filled with the material, the mold core moves downwards to stretch into the mold cavity to extrude the material in the mold cavity, the process is repeated, the compacted material in the mold cavity gradually reaches the lower part of the outer mold with the heating device, the heating device heats the compressed material in the mold cavity, and meanwhile, the material is gradually melted due to the friction force between the material and the mold cavity;
    forming: and (3) gradually cooling and forming the molten material in the shaping mold as the material is pressed down under the mold core, and gradually reducing the temperature of the plate from the lower end of the shaping mold to obtain a continuously extruded sheet.
  2. 2. The PTFE dispersion sheet extrusion process of claim 1, wherein: when the material enters the die cavity, the material placed on the bottom of the plate is pushed into the die cavity through the charging chute by adopting a scraping device.
  3. 3. The PTFE dispersion sheet extrusion process of claim 2, wherein: the tray comprises a tray bottom and a tray edge extending upwards from the periphery of the tray bottom; the scraping device mainly comprises a scraping plate and a cylinder, the bottom edge of the scraping plate is close to the upper surface of the plate bottom, the scraping plate is connected with a cylinder piston rod which crosses the plate edge at the upper part of the plate edge, and a cylinder body of the cylinder is fixed on the lower template; the cylinder moves to drive the scraper to move back and forth, and the material on the bottom of the plate is pushed into the die cavity through the blanking groove.
  4. 4. The PTFE suspension sheet extrusion method of claim 3, wherein: the number of the die cavities is 2, the die cavities are arranged in the thickness direction of the die cavity and are parallel to each other.
  5. 5. The PTFE suspension sheet extrusion method of claim 4, wherein: the scraping devices are two and are symmetrically arranged on the central plane of the two die cavities in the thickness direction.
  6. 6. The PTFE suspension sheet extrusion method of claim 1, wherein: when the material tray rotates, the material tray repeats the following actions, and rotates forwards for 3 weeks and then rotates backwards for 1 week.
  7. 7. The PTFE dispersion sheet extrusion process of claim 1, wherein: the suspended material sheet extruder is used and comprises a rack, a lower template fixed on the rack, an upper template connected with the lower template through a guide pillar, a sliding template arranged on the guide pillar in a sliding manner, and an oil cylinder arranged on the upper template, wherein a piston rod of the oil cylinder is connected with the sliding template, an outer mold is fixed on the lower template, and the lower part of the sliding template is connected with mold cores which have the same number as that of mold cavities and can extend into the mold cavities; a material tray base is fixed at the upper end of the outer die, a material tray which rotates relative to the material tray base is arranged on the material tray base, and the material tray is connected with a material tray driving mechanism which drives the material tray to rotate relative to the material tray base; and the tray bottom and the tray base are both provided with a charging chute communicated with the die cavity inlet at the upper end of the die cavity.
  8. 8. The PTFE dispersion sheet extrusion process of claim 7, wherein: the material tray driving mechanism comprises a motor fixed on the upper template or the lower template, a driving gear connected with an output shaft of the motor, and meshing teeth which are meshed with the driving gear and arranged on the periphery of the material tray.
  9. 9. The PTFE dispersion sheet extrusion process of claim 8, wherein: the motor is fixed on the upper template, the output shaft is connected with a driving gear shaft which penetrates through the sliding template and the lower end of which is rotatably supported on the lower template, and the driving gear is fixed on the driving gear shaft.
  10. 10. The PTFE dispersion sheet extrusion process of claim 1, wherein: the thickness of the extruded PTFE sheet is 4.5mm-5.5mm, the width is 300mm-320mm, the tensile strength is not lower than 22MPa, and the elongation at break is 280-300%.
CN202210885561.9A 2022-07-26 2022-07-26 PTFE suspension material thin plate extrusion method Pending CN115122553A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210885561.9A CN115122553A (en) 2022-07-26 2022-07-26 PTFE suspension material thin plate extrusion method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210885561.9A CN115122553A (en) 2022-07-26 2022-07-26 PTFE suspension material thin plate extrusion method

Publications (1)

Publication Number Publication Date
CN115122553A true CN115122553A (en) 2022-09-30

Family

ID=83384986

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210885561.9A Pending CN115122553A (en) 2022-07-26 2022-07-26 PTFE suspension material thin plate extrusion method

Country Status (1)

Country Link
CN (1) CN115122553A (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2242779Y (en) * 1995-05-30 1996-12-18 阜新市红旗塑料机械厂 Vertical plastic thrust machine
CN104400984A (en) * 2014-12-12 2015-03-11 南京肯特复合材料有限公司 Vertical extruder for PTFE pipe
CN104494104A (en) * 2014-12-12 2015-04-08 南京肯特复合材料有限公司 Vertical type extruding machine
CN105729702A (en) * 2016-04-29 2016-07-06 郑州大学 Equipment and method for producing large-size wood-plastic composite boards
CN105835282A (en) * 2016-04-29 2016-08-10 郑州大学 Die pressing device for producing large-size wood-plastic composite board
US20170239868A1 (en) * 2016-02-19 2017-08-24 Broderick Jason Strange Ram extruding thin panels of uhmw polymers

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2242779Y (en) * 1995-05-30 1996-12-18 阜新市红旗塑料机械厂 Vertical plastic thrust machine
CN104400984A (en) * 2014-12-12 2015-03-11 南京肯特复合材料有限公司 Vertical extruder for PTFE pipe
CN104494104A (en) * 2014-12-12 2015-04-08 南京肯特复合材料有限公司 Vertical type extruding machine
US20170239868A1 (en) * 2016-02-19 2017-08-24 Broderick Jason Strange Ram extruding thin panels of uhmw polymers
CN105729702A (en) * 2016-04-29 2016-07-06 郑州大学 Equipment and method for producing large-size wood-plastic composite boards
CN105835282A (en) * 2016-04-29 2016-08-10 郑州大学 Die pressing device for producing large-size wood-plastic composite board

Similar Documents

Publication Publication Date Title
CN217993232U (en) Suspension material sheet extruder
CN111391257B (en) Vertical injection moulding machine for wire plug
CN217993233U (en) Suspension material sheet extruder
US4440702A (en) Method and apparatus for making thin-walled plastic articles
JP5578696B2 (en) Continuous molding equipment for ceramic compacts
CN115339041A (en) Suspension material sheet extruder
CN115122553A (en) PTFE suspension material thin plate extrusion method
CN115157520A (en) Suspension material sheet extruder
CN115366311A (en) Suspended material sheet extrusion method
CN113290241A (en) Powder metallurgy axle bush production forming die
CN111070375B (en) Frozen ceramic slurry 3D printing mechanism
CN110142499B (en) Self-feeding stirring head, self-feeding stirring friction extrusion method and device
CN114425831B (en) Mould pressing device for producing plastic bottle caps
US3748075A (en) Molding apparatus
US3843289A (en) Apparatus for transfer molding thermosetting materials
CN213913649U (en) Compression roller mechanism of calendering granulator
CN114571696A (en) Extrusion molding equipment for sound tube production and sound tube molding method
CN213260665U (en) Continuous forming equipment for polytetrafluoroethylene plate
CN107840561B (en) Glass extrusion type secondary pulling plate forming device and method thereof
CN114619626A (en) Injection molding process
CN116423766B (en) Automobile lamp shell injection mold capable of improving molding precision
CN117382075B (en) Hot-press forming die for drum brake pad
CN219855116U (en) Forming device for activated alumina micropowder green bricks
CN115922877B (en) Automatic forming equipment is used in production of drawing of patterns formula graphite container stove face brick
KR101430717B1 (en) Apparatus for manufacturing synthetic resin sheet and method for manufacturing the same

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20220930