For the PVC molding machine, normally we are talking about UPVC pipe fitting injection molding machine.
There are 2 kinds of PVC: soft-PVC and hard-PVC. The hard PVC is for the pipe. While the UPVC Pipe is made by the extruding process and its fitting is through injection molding process.
Raw Material: UPVC
The melted UPVC has high viscosity and poor fluidity. And the state of raw material will be resin granule or powder.
Injection Molding Success Request:
– The injection molding for the pipe fitting, it requests core pullers, 1-3 sets even more.
– Measuring the melting temperature accurately.
– Viscosity melted plastic requests more power for the screw shear.
Customized machine will be applied normally:
– Extend the housing to cover the mold core puller, so that the maximum platen may be used fully.
The molds with core pullers are in different directions. For installation of these molds, some factories keep the machine saft door open. But this has seriously violated the basic safety operating principles of the machine. On the other hand, using the machine without extending the housing, one or two grade upper is needed just for the safe door close well, like the following one:
– Install the fan to measure temperature accurately
– Increase the screw motor capacity to drive the viscosity melted plastic.
The screw motor may be upgraded one level or even two levels to increase the output.
The hydraulic motor which is applied as the screw motor normally. The bigger hydraulic motor with higher cost. Nowadays, more and more servo motor is applied as the screw motor.
For more information, please check the section in the following page:
CUSTOMIZED MACHINE ‘s ELECTRICAL PLASTICIZING OF INJECTION UNIT
-Other machine features
Some molds have the unscrew function, so the hydraulic motor to drive is needed. The point is this device is installed per mold or instaledl on the top of the machine platen.
These two options are as followings:
As for the question that how the motor is connected to the machine hydraulic system, you should consult with the machine manufacturer.
PVC
Injection Molding Machine
Let’s take a look at our PVC Injection Molding Machine.
Including the PVC Pipe Fitting Production Line.
PVC Machine
Pipe Fitting Injection Molding Machines
The melted PVC with high viscosity and is easy to decompose. And the decomposition has a corrosive effect on iron. Tekwell’s Pipe fitting injection molding machines with special plasticizing parts and temperature control systems, includes
- Screw& barrel set special for UPVC
- Screw with chrome-plating, high corrosion resistance
- Barrel with cooling fans to adjust the temperature of melting UPVC material
- Special design for screw structure(UVPV powder)
- Optimized design for machine safety door – Upgraded hydraulic motor with high torque
- Upgraded motor and pump
- Multi core pullers
Tips For Production Parameters Setting
1
Melting temperature: ranging from 185-205℃
The exact melting temperature of UPVC can be known from the smoothness of the injected material. If the material is rough and uneven after injection, it proves that the material is not uniform (insufficient plasticization), indicating that the set temperature is too low; if there is foam and a lot of smoke after injection, it indicates that the temperature is too high.
2
Injection speed
It must be slow, otherwise excessive shearing will degrade the material.
3
Back pressure
It is determined according to the molding cycle time. The screw surface speed should not exceed 0.15-0.2m/s.
4
Injection speed
It is up to 150bar, the lower the better, usually 5bar.
Retention time
At a temperature of 200 °C, the retention time of the barrel should not exceed 5 minutes at most. When the temperature is 210 ℃, the barrel retention time cannot exceed 3 minutes.
Brief Introduction
PVC
The melted PVC with high viscosity and poor fluidity. Even if the injection pressure and melt temperature are increased, the fluidity does not change much. In addition, the molding temperature of the resin is very close to the thermal decomposition temperature, making it difficult to mold.
1. Treatment of plastic: with water absorption less than 0.02%, no need to dry it. If dry, put them into a dryer at 80°C for 1-1.5 hours.
2. Percentage of recycled material is no more than 20%.
PVC Pipe Fitting Moulds
PVC Pipe Fittings
