Application of MOOG servo control system in plasti

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Application of MOOG servo control system in the field of plastic machines

Moog company (Moog) is a global leader in the design and manufacturing of electrohydraulic servo components and servo systems. William C. Moog, the inventor of electrohydraulic servo valves that appropriately reduce the inlet force (load) and outlet load, was founded in 1951. Products are widely used in aircraft, satellites, space shuttles, rockets and various industrial automation equipment. In the industrial field, the servo control of injection molding equipment and blow molding equipment is one of our important research fields

1. hydraulic servo system:

using DVP (digital velocity & pressure) card and Moog D660 series servo valve can realize the injection process with high accuracy and repeatability. DVP card has the following functions:

◆ closed loop glue injection speed control (with pressure limit protection)

◆ switch from speed mode to pressure mode

◆ pressure maintaining closed-loop control

◆ back pressure closed-loop control during glue injection

this control algorithm is built-in and provides goui software. Closed loop control parameters (P, I gain, etc.) can be downloaded from personal computer to DVP card ROM and stored, or data can be uploaded directly from DVP card

d660 series servo valve adopts servo jet pipe in the pilot stage, which reduces the energy consumption for the benefit of all amputees and improves the robustness of the valve. Because the pilot stage of servo jet pipe has a high undamped natural frequency (500Hz), the dynamic response of this valve is high, and it is widely used in plastic machinery, die casting machines, heavy industry, etc., and shows excellent performance in practice

2. All electric servo system:

as we all know, all electric injection molding machine is a new market trend. Compared with hydraulic press, it has the following advantages:

◆ high repeatability

◆ low operation cost, energy saving up to 50%

◆ less maintenance, easy maintenance

◆ low noise, no hydraulic pollution, suitable for pharmaceutical and other special industries

moog is one of the first professional control manufacturers to enter the all electric injection molding industry, providing partners with DBS, DBM, ds2000 series drives and fastact series motors. Ds2000 driver and fas t AC servo motor have the following characteristics:

◆ the driver can accept any voltage between three-phase, 50Hz, 65 to 506v

◆ set and control AC servo motor or asynchronous motor

◆ the current loop can be configured according to the characteristics of the servo motor, and can be automatically adjusted according to the changes of DC bus. At the same time, it provides b.e.m.f compensation and phase self-correction functions

◆ three digital filters are integrated in the speed loop, with good dynamic performance, etc

blow molding control field:

for hollow products, the control of embryo wall thickness is very important for improving product quality and reducing costs. If the product is not effectively controlled in the process of blow molding, uneven thickness will appear after cooling, and the stress of uneven embryo wall is also different, and the thin position is prone to fracture. After using the wall thickness control system, the mandrel gap can change with the position of the mold embryo, resulting in products with uniform thickness. The impact resistance test shows that the products with uniform wall thickness not only greatly improve the strength, but also save raw materials, shorten the cooling time of finished products and reduce the defective rate

in the field of blow molding control, Moog can provide independent wall thickness control system or whole machine control scheme. The two schemes can be selected according to the actual situation of users

1. independent wall thickness control system:

at present, Moog provides 30-point and 100 point wall thickness controller Digipack, which can be used to control the wall thickness of stock cylinder and continuous blow molding machines

storage tank machines are often used to make larger containers. Digipack controls the opening of the die according to the feedback of the electronic ruler of the storage cylinder. The LCD ordinate displays the position of the storage cylinder, and the abscissa displays the opening of the die. Continuous machines usually have multiple die heads. Digipack controls the opening of the die according to the working cycle time. At this time, the LCD ordinate displays the cycle time, usually taking the cutter action as the beginning of a complete cycle

since the output of Digipack is ± 100mA, Moog g631 series servo valve (mechanical feedback type) can be directly driven without amplifier. Digipack+ g6313005 is also a configuration commonly used by customers at home and abroad, and the system has high stability and accuracy

2. Complete machine control scheme (TMC):

in addition to the independent wall thickness control system, Moog also provides TMC (total machine control) scheme

m400 series controller is essentially a high-performance PLC that can be used in many industries, and the hardware adopts modular structure. In addition to the commonly used digital quantity, analog quantity input and output, temperature module, etc., there is also an expert module m480 dedicated to the wall thickness control of the blow molding machine (this module can also be used as the closed-loop control of mold opening and closing, etc.)

m400 adopts a real-time time multitask operating system, which can define the priority and cycle time of each task, and the real-time performance of the whole system can be optimized

logos (M400) programming software provides a large number of function block functions for plastic machinery control

for temperature control, users do not need to effectively improve the battery energy to write codes, but only need to set some necessary parameters (such as setting temperature, sampling time, alarm temperature). The system can self diagnose and determine according to the parameters to obtain appropriate PID and other parameters

for wall thickness control, the system provides a 128 point wall thickness page, which can add and delete points, and can select the interpolation method between two points (straight line, arc or high-order curve). In addition, continuous type or storage cylinder type can be set according to the machine

for the closed-loop control of position, speed and pressure, the system allows users to set ten curves to optimize the performance of the system

the programming system complies with IEC standards, and allows the use of ladder diagram, instruction table, sequence function diagram without glass fiber reunion and high-level language. And different programming languages can be used for different tasks according to requirements


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