Cars and consumable industry for injection products quality request, so more and more strictly for injection molding process also presents puts forward new requirements, seamless surface, shorter period and high precision injection molding - the three challenges, need for injection molding formulate a special cooling technology, become mould temperature control is an efficient solution.
Change mould temperature control tools
Change mould temperature control means mould temperature not remain unchanged, but an injection cycle, according to the definition of temperature curve is controlled. Inject, temperature and the temperature of the material injection almost as tall, After injection mold needs rapid cooling down to the material fast-curing. Therefore, the use of this technology, it is possible to produce no streamline, deformation of high-gloss surfaces of plastic parts.
There are many techniques can achieve change mould temperature control, if use two cooling loop (steam/water or oil/oil), liquid cooling and induction heating combination, infrared heating and liquid cooling combination, or with the heating elements electrothermal heating and liquid cooling combination, and the dynamic CPH high-performance ceramic mold temperatures precision control technology or two circular temperature control.
Injection molding dynamic temperature control realization needs open close to mould outline of temperature in a quick slots, heating and cooling. Considering different thickness, and everywhere in different areas of the workpiece, heat conduction in different ways. The cooling channels throughout the mould cavity or approximates to the cooling process adjustment, the more accurate. Premise is every cooling channels have their own temperature control. For smaller tools, the channel is located in cavity of 1.5 mm below. Big mould halves established according to the outline of the tool, need to open a long temperature control channels.
Closed chamber temperature control
Change mould temperature control with a short period of time requirements certain degree, but this kind of conflict photogenic conflicted by like "segmentation tools temperature control" new technology to solve. Use these techniques, the cooling channels will be very close to the mold cavity, can be in the mould structure and implementing 3d channels get ideal cooling channel configuration.
Temperature control by measuring near the cavity from mould temperature or to measure the temperature of cooling fluid backflow realization. Usually adopts thermocouples or resistance thermometers, if use PT100 as sensor, the temperature of the measuring current, and the information transfer to a controller, then you adjust each channels in coolant flow. Control measures are injected steam or hot water heating, cooling water. The temperature control type greatly improve surface quality and significantly reduce cycle time.
Valve technological innovation
Proportional electromagnetic valve new development make multi-loop parallel operation temperature regulating circuit implementation. These valves advantage lies in its use of the magnetic bearings, and friction-free through special forms of spring avoid stick-slip effect. This can be reflected by excellent record, including the most important response sensitivity (of final value 0.1% of), the smallest reversal errors and excellent regulation performance. New electromagnetic valve measurement range for 1 0, which makes it can adapt to even very slight temperature changes, such as by the corrective actions caused very slight change.
Used to measure the workpiece cooling process of decisive test value is returned temperature and the water flow, it helps in absolute reliable and accurate manner to adjust cooling fluid amount. The most advanced sensors in 100 to detect changes between 300 milliseconds, control valves in 0.3 to 1 seconds adjust flow. Impeller sensor is especially suitable for, because their small frame size and excellent response time.
Actuator project
Valve choice depends on the flow and cooling fluid level of pollution. If high velocity and pollution liquid, recommends the direct effect on the valve. If temperatures as high as 180 ℃, pneumatic operation of On/Off or regulator is appropriate. According to the loss of heat, if you want to control valve opening time, then in injection molding cycle cooling stage adopts the on/off control temperature or pulse cooling.
For low velocity and clean cooling liquid, such as has the central water treatment equipment, and water temperature under 90 degrees centigrade, servo hydraulically electromagnetic valve is very good.
For depends on workpiece properties of more or less cooling, adopt multi-channel temperature control, use pneumatic - valve, direct action or servo booster electromagnetic valve, provides an obvious advantages. Their crack opening can quickly at 0 to 100% between regulation. This dynamic regulator technology makes it may, according to the workpiece predefined temperature curve. Swiftly realize temperature regulating protection and enhance valve durability. Using pneumatic control valves, the nominal diameter is not popular with fluid pressure restrictions. Usually it's range from 4 to 20 millimeter, or even higher. To adjust the specific crack open degree, need a supplement of electronic control. This is through pulse adjust proportional regulator (PWM) to realize. Relative to the normal process type control valves, this is a by combination valves positioning control auxiliary locators control valves. It adjusting processing valve piston to specific crack opening.
Distributed mould temperature control
Usually, integrated process system includes a flow sensor, proportional valve and flow controller. The controller and decisive role within the system, because it must be able to handle different sensor signals, such as temperature, pressure or traffic, and must be able to pneumatic and electric control system of communication.
Its most important features are: temperature regulation; Pressure control; Flow control; Control On/Off solenoid valves, proportional valve, the process type control valve and electric control valve, Input normal sensor signal (standard signal 4 to 20mA, frequency, PT100); For set point with 4-20mA and central control unit communication, processing value feedback. According to the selected applications (flow, temperature or pressure control) easy configuration, Memory most valves and sensor data. ECONTROL also can finish a press 1/16DIN standard perforated panel form, and can be integrated into the existing control cabinet. Distributed mould temperature control system is simplified control machines, allowing them to focus on their own correct task.