The most comprehensive summary of extrusion die knowledge

1： Definition
Extrusion mold is a kind of forming mold, but its discharging method is realized by extrusion. It is widely used in aluminum special-shaped structures and also in plastic parts. At the front end of the extruder, it is used to make pipes or profiles. In short, a mold is a tool used to shape objects. This tool is composed of various parts. Different molds are composed of different parts. It mainly processes the shape of objects by changing the physical state of the formed materials.
According to the different materials, molds can be divided into metal molds and non-metallic molds.
2： Classification
Metal mold is divided into:
Casting mould (nonferrous metal die casting, iron and steel casting), and forging mould;
Non-metallic molds are also divided into plastic molds and inorganic non-metallic molds.
According to the different materials of the mold itself, the mold can be divided into: sand mold, metal mold, vacuum mold, paraffin mold, and so on.
With the rapid development of polymer plastics, plastic molds are closely related to people's lives.
Plastic molds can generally be divided into: injection molding mold, extrusion molding mold, gas-assisted molding mold, and so on.
Scope of application
Large-scale production of non-sheet metal steel parts - cold heading, die forging, metal die, etc
Sheet metal discharging - hot rolling, cold rolling, hot coil, cold coil
Sheet metal processing - drawing, expanding, bending, punching, blanking
Non-ferrous metals - die-casting, powder metallurgy
Plastic parts - injection molding, blow molding (plastic bottles), extrusion molding (pipe fittings)
Other categories of moulds:
Alloy mould
Sheet metal mold
Plastic mold
Stamping die
Casting mould
Extrusion mold
Die-casting mould
Other moulds
Installation of extrusion die
1 Installation of die head
(1) After the inspection, the qualified die head shall be installed with part 12 first. If there is a transition sleeve (part 15), the transition sleeve shall be installed, and the part 12 and part 14 shall be connected with bolts; Before the final fastening of the two, use a level gauge to calibrate the longitudinal and transverse levelness of the die head (note that it is not allowed to use iron tools to hit the outside of the die head plate during leveling to avoid damage to the positioning system and reduce the positioning accuracy). Screw tightening shall be carried out step by step in order to ensure uniform and reasonable tightening force.
(2) Select the appropriate heating plate (ring) according to the overall dimension of the die head, and fasten it with the die head with screws based on the thermocouple hole position to ensure that the heating plate (ring) is in close contact with the die head.
(3) Plug in the thermocouple and adjust its probe to close to the measuring surface, and connect the heating plate (coil) power plug (note that the voltage of the two should be consistent). The heating of die head shall be carried out in sections. Generally, the temperature of each section shall be adjusted to 140 ℃, and the temperature shall be kept for 30~40 minutes when the temperature rises to 140 ℃, and then the temperature shall be raised to the temperature of normal production.
(4) After the temperature of the die head rises to the preset value, the bolts on parts 16 and 17 and the flange must be tightened again, and the machine can be started only after the fastening is reliable to prevent overflow.
2. Installation of setting mould and water tank
(1) After lifting the setting mould to the setting table (note that the handle is close to the operating surface), first adjust the longitudinal axis of the setting mould to be consistent with the corresponding center line of the setting table using the eye-side method, and then fasten the base plate (part 1) on the setting mould to the setting table through the T-shaped screw on the setting table.
(2) The connection between the water tank and the setting table is the same as that of the setting die; The water tank and the sizing die are positioned with a positioning column (part 3), and connected with each other through the base plate with M10X120 bolts and M10 nuts. Adjust the M10 nut to ensure that the sealing strip of the water tank inlet plate matches the corresponding end face of the molding die.
(3) Connect the air connector and water inlet connector respectively according to the structural diagram of the molding die. The general principle for setting the water and gas connectors is that the front end of each molding die is generally the water inlet connector (the gasket is blue), the middle is the gas connector (the gasket is black), and the end is the water outlet connector (the gasket is red). If the number of water joints of the machine tool is not enough, it can be considered to connect the water inlet and outlet pipes of the middle sections of the mold in series.
(4) Connect water inlet connector, gas connector and ¢ 50 water (gas) pipe according to the water tank structure diagram.
(5) A special vacuum pump shall be used for the first section of sizing die, and the vacuum pump can be used for the rest.
The general operation steps of commissioning are as follows:
(1) Before starting, check whether the temperature control is sensitive, whether the instrument is out of order, and whether the cooling water circuit is smooth. Thermometer, cooling water and other methods are usually used for detection.
(2) The screw, barrel and die head of the extruder shall be heated according to the operating instructions of the extruder. After the temperature rises to the set temperature, it shall be kept for about 10 minutes before starting up, so that the temperature of each part of the machine will be stabilized.
(3) Before starting the machine, be sure to tighten the connecting screws and bolts of each part of the die head while it is hot. Before the material is extruded, the operator shall not stand directly in front of the die to prevent injury accidents caused by bolt or screw breakage.
(4) At the beginning of extrusion, the screw speed should be slow, and then gradually accelerated to prevent damage to the machine parts due to overload during startup.
(5) When starting up, add a small amount of material first and keep the feeding balance. Pay close attention to the torque and other table values when feeding. After the material is squeezed out of the die head and pulled onto the traction equipment, gradually increase the amount of material until the normal extrusion.
(6) At the beginning of traction, there should be a certain distance between the molding die and the die head to facilitate traction. Open the waterway (pay attention not to pour water on the die head, otherwise it will cause abnormal discharge of the die head and lead to material break or die plugging), open the cover plate of the setting die for sections with complex shapes and small cavities and the first mock examination with multiple cavities; After confirming that the extrusion material is plasticized normally, pull the material to the tractor through the set hauling rope. Shorten the distance between the setting table and the die head, cover the cover plate, start the vacuum pump, and when the extrusion speed is basically balanced with the traction speed, observe the profile to normal extrusion, and then reduce the distance between the setting table and the die head to the ideal value.
(7) If it is found that the parison is not formed at the entrance of the setting die or the inner rib is adhered to the inner cavity surface of the profile, a pointed tool can be used to poke several small holes at the part of the parison that is not formed at the entrance of the first section of the setting die or the inner rib, so that the small cavity is connected with the atmosphere. When the parison enters the setting die, it is open, which is convenient to form negative pressure, and promote the parison to adhere tightly to the mold wall of the setting die.
(8) In case of mold blocking (not blocked), immediately move the setting table back or increase the traction speed, or implement the above two schemes at the same time, and then adjust the process to restore normal production. If the above scheme is not effective, the setting table should be moved back immediately, the material should be cut along the setting mould, the moisture in the setting mould should be closed, the traction speed should be reduced, and the profile should be slowly pulled out of the setting mould. If part of the profile is broken in the setting die, the setting die needs to be removed and the residue thoroughly cleaned.
(9) When the machine is shut down, it is generally necessary to add the shutdown material to extrude the production material in the machine, and then shut down the machine and disassemble the die head while it is hot for mold cleaning.
Maintenance of extrusion die
1. Improper handling or cleaning during maintenance and cleaning is one of the main reasons for damage to the mold. Therefore, the disassembly and cleaning of the mold should be completed by professional personnel.
2. Red copper components shall be used when disassembling and cleaning the die head.
3. The assembly surface (sealing surface) of die head can be cleaned with fine oilstone or metallographic abrasive paper.
4. Before the mold is assembled, the runner shall be polished to low roughness with metallographic abrasive paper and coated with a thin layer of silicone ester to reduce gas and water corrosion during long-term storage to protect the runner.
5. During assembly, all bearing surfaces and threads of bolts and screws must be coated with high-temperature grease (7020).
6. When disassembling the setting mould, attention should be paid to avoid collision; The installation shall be arranged according to the sequence number of the molding plate.
7. During the daily maintenance of the water tank, it shall be ensured that there is proper adjustment space on the four sides after the fixed block is installed.
4、 Storage of extrusion die
1. The mould shall be stored in a dry, clean and ventilated warehouse. It is strictly prohibited to store it in the same warehouse with corrosive products;
2. The mold must be cleaned and reassembled after use. Store the oil seal in the warehouse;
3. The mould shall be stored on a special mould storage rack to ensure safe placement and convenient access.