We have seven tips when buying a PVC injection molding machine from Machine specification to Safety maintenance:
- Machine specification and model
- Mould size and design
- Temperature control
- Injection speed and pressure
- Servo motor and hydraulic system
- Corrosion protection
- Safety maintenance
Machine specifications and models
Choosing the right injection moulding machine starts with evaluating its specifications and model.
Each machine has unique features that must be matched to your project needs.
Mould size and design
Ensure that the size of the mould matches the machine’s capabilities by considering the mould size, clamping force, and injection capacity.
Also, the mould should be designed to avoid sharp corners or abrupt changes to prevent PVC material degradation.
Temperature control
PVC is a heat-sensitive material, so the temperature needs to be strictly controlled during the injection process.
Mould temperature should usually be kept between 30℃ and 60℃ to reduce product deformation and improve production efficiency.
Meanwhile, the screw temperature should be controlled between 170°C and 190°C to prevent PVC from overheating and decomposing.
Injection speed and pressure
Proper control of injection speed and pressure is essential to prevent material decomposition.
Normally, the injection speed should be increased gradually according to the filling of the mould to avoid cracks and shrinkage marks.
Servo motor and hydraulic system
Selecting a machine with a highly responsive hydraulic system can support fast injection speeds and rapid mould opening and closing movements.
Servo motor technology ensures precise control of the injection process, resulting in quality products and minimised waste.
Corrosion protection
Due to the corrosive nature of PVC, machine screws and nozzles need to have good corrosion resistance and are usually made of stainless steel or chrome plating materials.
Safety Maintenance
Ensure that the machine is well equipped with safety measures.
Such as a good ventilation system to deal with the toxic gases released when the PVC is melted, and regular maintenance to extend the life of the machine.
By taking all these factors into consideration, you can choose the right PVC injection molding machine for your needs, thereby increasing productivity and ensuring product quality.
Tips of PVC injection moulding machine temperature
Temperature control is one of the crucial factors in the PVC injection moulding process.
We have 6 tips for this:
- Melt temperature
- Mould temperature
- Nozzle temperature
- Injection pressure and speed
- Back pressure and cooling
- Other considerations
Melt temperature
The melt temperature of PVC usually ranges from 140°C to 190°C, and sometimes up to 200°C. The melting temperature of PVC can be as low as 1.5°C to 1.5°C.
However, must take care to avoid decomposition of the material.
In practice, melt temperatures are usually set between 170°C and 190°C to ensure that the material melts well and has good flow properties.
Mould temperature
Mould temperature is generally controlled between 30°C and 60°C to prevent premature cooling and curing of the PVC material in the mould, which may affect product quality.
Proper control of the mould temperature helps to reduce product deformation after moulding and improve the dimensional stability of the finished product.
Nozzle temperature
The nozzle temperature is usually 10-20°C lower than the barrel temperature.
This ensures that the molten PVC can enter the mould smoothly without leakage or freezing.
Injection pressure and speed
The injection pressure can generally reach 150 MPa.
And the injection speed should be adjusted according to the specific situation to avoid material degradation and ensure the moulding quality.
Back Pressure and Cooling
The back pressure is set between 50 and 100 psi, and the cooling process requires a cooling water system to control the mould temperature to ensure that the PVC cools and cures uniformly in the mould.
Other Precautions
Due to the heat sensitivity of PVC material, the retention time of the material in the barrel should be as short as possible during the injection moulding process.
And use special PVC injection moulding machine and screw design to improve the moulding efficiency and product quality.
The quality and productivity of PVC injection moulding can be effectively improving by precisely controlling each of the above temperature parameters.
What are the tips for corrosion protection on PVC injection moulding machines?
The TIPS of corrosion protection measures for PVC injection moulding machines need to consider from several aspects.
We suggest focusing on five aspects
- 1.PVC injection moulding machine injection unit material selection
- 2.PVC injection moulding machine injection unit surface treatment
- 3.Maintenance and care
- 4.Environment control
PVC injection moulding machine injection unit material selection
The use of bimetallic PVC injection molding machine units is an important measure to prevent corrosion.
Especially in the production process may produce corrosive by-products or in a humid environment for a long time downtime.
Bimetallic materials have good corrosion and abrasion resistance and are suitable for use in moulds that are subjecting to high pressures and long running times.
PVC injection moulding machine injection unit surface treatment
The application of anti-corrosion coatings or the use of vapour phase corrosion inhibitors (VCI) on the surface of the screw barrel of a PVC injection moulding machine is an effective method of corrosion protection.
These coatings or inhibitors can prevent corrosion from occurring during storage or idling of the mould.
Maintenance and servicing
Regular machine and tool maintenance is an important measure to extend the life of the equipment.
This includes inspecting and replacing wear parts, as well as keeping equipment clean and dry to minimise the potential for corrosion.
Environmental control
In the production process, humidity and temperature must keeping as much as possible to avoid corrosion caused by environmental factors.
For example, humid operating or storage conditions may lead to condensation, which can accelerate the corrosion process.
Through the above measures, the service life of PVC injection moulding machine can be effectively extended, and the stability and safety of its production process can be ensured.
Tips for purchasing servo PVC injection molding machine
We have five tips when buying servo PVC injection moulding machine:
- The choice of servo control system
- Energy saving and efficiency
- Optimisation of process parameters
- Automation and intelligence level
- Screw design and material selection
The choice of servo control system
Servo control system is the key to improve the precision and energy saving effect of injection moulding machine.
The servo motor-driven constant pressure pump hydraulic system used by Haichen has fast response, high precision control and good energy saving effect.
Energy saving and efficiency
It is very important to choose a PVC injection molding machine with high efficiency and energy saving features.
Servo energy-saving control systems can improve energy efficiency by automatically regulating pressure and flow in a closed loop.
At the same time, the use of servo motors can reduce energy consumption and extend equipment life.
Optimisation of process parameters
In the PVC injection moulding process, parameters such as injection temperature, injection pressure, injection rate and injection time have a significant impact on the mechanical properties of the final product.
For example, better mechanical properties can obtaining when the injection temperature is 185°C, injection pressure is 80 MPa, injection rate is 60 g/injection s and time is 5 seconds.
Auto
mation and intelligence level:
Select the injection moulding machine with advanced automation function.
Such as the use of PLC servo system and touch screen control of the equipment, can improve production efficiency and ease of operation.
Using embedded industrial control computer and servo motor computer combination of control systems can improve the overall control accuracy and product quality.
Screw design and material selection:
The design of Haichen PVC special injection screw needs to consider the pressure field, shear stress field and velocity field during the plasticising process in order to optimise the metering section parameters.
Suitable screw design can improve plasticising efficiency and moulding quality.
When selecting a servo PVC injection moulding machine, should to pay attention to its control system, energy-saving performance, process parameter settings, automation level and screw design.
Haichen ensures that you get high quality products and high productivity with high quality PVC injection moulding machines.
