injection molding.

by:INDUSTRIAL-MAN     2019-08-28
Overcome the limitations of all
The demand for precision plastic injection molding systems is unprecedented. growing one.
Production of DVD, audio and data storage devices, electronic transaction cards, precision medical devices, telecom and information processing equipment is one of the fastest growing markets in the world.
In an industry dominated by hydraulic systems, the demand for more precise and energy-efficient
High-efficiency molding technology has promoted
In order to provide a much needed technical upgrade, the electrical \"system has entered a position.
Development of two people
Cincinnati Milacron\'s stage injection device is to make \"all-
\"Electric\" is a viable complete system alternative for hydraulic IMMs.
The current reciprocating screw design is specially developed to reduce the cost of hydraulic machinery.
The screw design allows for simultaneous use in the extrusion stage to melt the plastic and drive the injection piston when pushing the \"shot\" of the melted plastic into the mold.
However, the back and forth movement of the screw constantly changes its effective length, so every time the screw is touched, it damages its ability to homogenize the plastic.
The reciprocating screw cannot travel more than 4-
5 times in diameter.
More things will increase the recovery time and produce products with poor quality.
Designers compensate for the loss of effective length with larger diameter screws to improve throughput.
With the increase of injection volume, the diameter of the screws in the reciprocating device must gradually increase to the extent that it is no longer cost-effective to push the screws forward with the existing mechanical and electrical technology.
When the melt is transferred from the filler to be packed, the standard hydraulic IMM cannot physically brake its reciprocating screws.
Is the compression of molten plastic (melt pressure)
This actually stopped the screw.
The molten plastic is elastic and can actually push the screws back.
In order to overcome this trend of rebounding and ironing plates, the mold often increases the pressure during the packaging phase, thus overfilling the mold.
This could lead to flash-prone molds.
To solve this problem, the hydraulic machinery is compensated with clamping tonnage.
There is no real process control because the mold is full of pressure.
Although it affects the accuracy of the system, by driving the extrusion and injection components from a single hydraulic pump, the adjustment screw greatly reduces the cost of the hydraulic IMMs.
The choice of screw has its advantages;
However, it is not easy to achieve reliable automated production capacity without process control and continuous repeatability.
Energy saving is part of the electric molding technology.
The electric servo is installed on the extruder of the modified hydraulic machine to save energy, and the \"continuous ironing plate\" designed by the screw can be economical and efficient.
Adding a servo system to a hydraulic machine does not change it is still a hydraulic machine.
Although energy consumption and noise can be reduced, the pumping of hydraulic oil and the lack of repeatable process control still exist. All-
Electric IMMs tend to be more expensive than hydraulic, but when a servo drive is added to the hydraulic pump and extruder, it may be replaced by the same price.
It is also possible that the servo-driven pump cannot respond like a fixed pumpspeed motor.
Final result of all combinations-
Electric and hydraulic power may be an energy source.
More efficient machine with characteristic than traditional hydraulic.
The innovative hydraulic machine can share the drive of the extrusion motor and the injection cylinder, using the extrusion screw as the injection piston to reduce the cost of the machine.
This is why the design of the reciprocating screw is more popular. The two-
The stage unit is a departure from the traditional thinking.
It liberates the design of the injection barrel from the plasticization task.
The independent firing chamber allows the use of smaller diameter injection barrels and longer injection itineraries at a given volume, making it easier to produce high injection rates under smaller, more accurate mechanical and electrical drives
Generating injection pressure with smaller diameter screws requires a smaller power, while increasing the stroke to obtain the required volume. The two-
The stage injection device can shoot all its volumes, and does not like to shoot units usually twice its maximum shooting capacity to compensate for the loss of effective length (
Back and forth).
All of Cincinnati mirakon-
Single electric IMMs-
The screw extruder melts the plastic and measures it into the barrel by one of the ports in the barrel.
The extrusion is used as a separate function, and the plasticization rate can be adjusted according to the precise requirements, while the processing screws do not affect any process.
The injection control is much more precise because there is no valve that must be installed before the injection enters the mold.
THT precision lighter side
Electric IMMs have motors that drive injection Pistons.
They are very good in accuracy and repeatability.
The Elektron Technologies division in Milacron, Cincinnati produces the power line series of IMMs, which integrates digital absolute encoders on the motor shaft.
These encoders increase resolution by 64,218 per rotation. The two-
System in two locations
The stage injection unit is capable of solving the increment of 12 micron linear motion. STRESS-
When processing an optical mold, the filling accuracy is essential to maintain the optical quality of the part. Since all-
Electric IMMs do not have to overpack the mold in order to prevent rebound
Back in the past, they avoided over-packaging and this pressure would reduce the optical clarity of the parts.
Ferromatik Milacron, based in Germany, has developed what it calls a DVD and CD forming machine disco line. Two 50-
Tons of media molds were provided to GE Plastic Optical Media Development Center (OMDC)
Research by GE and other stakeholders of OMDC, replicators for validationof-Process Testing.
John sullivan, project leader at OMDC, said: \"The technicians at OMDC will use servotecicdisco machines to evaluate and develop new DVD manufacturing processes that deliver productivity to our customers
\"For example, we will explore the fixture positioning control for processing, which is considered to be the key to shaping the flat stress --free DVD.
With simple control settings, the repeatability of MM 1/100 can be provided, all-
Because it eliminates the mechanical setting, the electric machine will help.
Other inherent variables in the hydraulic mechanical environment.
\"Disco injection devices are customized for the processing of polycarbonate.
Compact machine needs 3.
3 m ground space for class 1000 clean room.
Hydraulic machinery has inherent properties that prohibit the use of clean rooms, mainly involving hydraulic oil.
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