15 things to know about servo-driven injection machines.
The driving technology of injection molding machine is developing continuously, and the application of servo motor in various fields is more and more extensive.
In terms of cost, performance, maintenance, and training, molders need to know about today\'s servo drives.
In order to better understand the mechanical technology available today, it is important to use a common language for the different driving technologies of modern injection molding machines.
Various uses of servo motors are a complex factor.
This article will discuss and explain the 15 most common terms and concepts involving machine-driven technology, involving costs, performance, maintenance, and employee training. 1. Full-
Electric IMM following the standards of the Plastics Industry Association (formerly SPI), a full-
The electric injection molding machine is at least one of its three main axes (
Clamping movement, injection and metering/plastic enhancement)
Driven by a servo motor.
The remaining three axes (
Nozzle touch, pop-up and mold-
Height adjustment)
The hydraulic system can still be driven.
The most efficient machine can use akinetic-
Energy Recovery System (KERS).
This patented process uses a servo motor as a generator that can collect all the deceleration energy from each shaft and convert it back to electrical energy.
The converted energy is then fed back to the machine and is usually used for heating or control functions. 2.
Hybrid IMM machine, one or more of the three spindles with hydraulic drive, but at least one electric-
The drive shaft is called a hybrid machine.
A common example is a hydraulic machine with a servoDrive metering.
Measurement is the largest energy consumption (
Heating outside the barrel)on any IMM.
So it\'s a wise decision to use at least the servo system
Electric drive for metering.
A hybrid machine is not a machine with a servo
Because all movement is still driven by hydraulic pressure. 3. Servo (driven)
Hydraulic IMM servo-
Drive hydraulic (or servo-hydraulic)
The machine is a hydraulic IMM with a servo motor for driving the hydraulic pump.
These machines usually have a fixed one. displacement-
But it\'s possible. displacement-pumps (
Often DMRC or DFEC)with a swash-plate. 4.
Standard hydraulic IMM with variable
These machines usually have a constant
Speed motor available
Displacement pump with inclined plate, can adjust oil by control
Adjust the volume flow of the pump according to the current demand of the hydraulic system.
If the machine does not move at all, the pump will still be idle and waste energy. 5.
The European plastics industry has developed a system to classify the energy efficiency of IMMs. The Euromap 60.
1 Standard classification machines for certain categories and certain standards have been developed to compare the energy efficiency of similar machines from different suppliers or executing agencies (full-
Electric, hybrid, etc). Servo-driven pump (or servo-pump)
There is no doubt that machines show better energy efficiency than constant machines
Speed motor available
Displacement pump.
Servo motor on servo-
The drive pump machine will only run if the hydraulic system requires oil flow.
There is no movement of the pump during the time when there is no shaft running, so there is no energy consumption of the pump.
Of course, the amount of energy savings depends largely on the point of process for each specific application. Afast-
Circular packaging applications have a lower percentage of energy savings than applications with long cooling times
The speed motor will idle for a few seconds or minutes. Full-
The motor where electric energy is directly converted into kinetic energy has the best energy efficiency because it is not converted from electric energy to hydraulic and then into kinetic energy.
A very rough classification is: * hydraulic machine with constant speed motor: 100% energy consumption;
* Mixing motivation for measuring only full Power: Energy consumption is 75% ~ 80%; * Servo-
Driving pump machine: Energy consumption is 65% ~ 70%; * Full-
Motor: 45% to 60% energy consumption. 6.
Repeatability of Electric
Full hydraulic drive
Repeatability of motor, servo system
At least 10 times higher than hydraulic drivedriven axis. An activeservo-
There is almost no delay in the drive shaft, and the delay in the hydraulic system is inevitable.
The acceleration of the servo drive, especially the deceleration, is also more accurate than the hydraulic driveDrive the machine. Full-
Electric machines also allow immediate production stability due to unnecessary oil preheatingup, and start-
The up is faster after the production timeout.
This is an advantage for full-
Electric Machinery, not servo-driven pump machine. 7.
Noise level-
Electric and servo
The driven pump machine is usually much less noisy than the standard hydraulic machine. Modernfull-
Electric and servo
The driven pump machine should have a noise level around 68 dbA. 8.
The comparison of servo to hydraulic speed and/or acceleration is a matter of intense debate in the industry. Full-
Great acceleration for electric drives-
Much better than pump ramp
In the hydraulic system, it is affected by the compression of the oil and the expanded hydraulic pipe.
The opposite point quoted by some suppliers is that thata has a perfectly designed hydraulic system with accumulators and strategically placed valves that are more spontaneous and flexible than servo systemsDrive the machine. 9.
Complete parallel movement
Electric IMMs typically use a separate servo drive for eachaxis.
This makes these machines very flexible because it allows all axes to be used with parallel motion, which requires measurement during mold opening and pop-up, injection during mold closing, mold opening, etc. Servo-
The drive pump machine and the standard hydraulic machine do not necessarily have such an advantage.
Most suppliers offer a second or even a third pump and hydraulic accumulator as an option. 10.
Hydraulic Design Standard hydraulic machine in the process of idling through the cutting and friction of oil to produce a large amount of waste of heat, which is mainly related to the design and working principle of variables
Displacement Pumps and connectors-speed motor. The servo-
The driven pump machine does produce a smaller amount of heat in the hydraulic system.
In fact, some oil manufacturers operate a special kind of oil.
Heating sequence, keeping the oil at working temperature during production according to the process point, the operating environment of the machine and the process sequence of the specific product/process. 11.
Full cost of machine
Due to the necessary number of electric drives, motors and gears, electric machines are always more expensive than hydraulic machines (
(For example, ball screw, gear box, gear rack)for the former.
However, in many cases, it is easy to calculate the return on investment using energy saving and increasing utilization (
Outbreak time is faster due to parallel movement and less maintenance)
And energy rebates offered by some real estate and energy companies.
Servo-driven pump machine can (
Some suppliers)
Still a little more expensive than standard hydraulic machinery, but as the industry as a whole is vigorously driving servo drive pump technology and even competition between parts suppliers is increasing, allowing for price differences (
Where it still exists)
Narrow to a minimum. 12.
In the case that the hydraulic pump must be replaced, the service of the pump, servo motor, fixed-
Displacement pumps that do not require calibration are faster and easier to change than variables-
Displacement pump. Fixed-
Displacement pumps are usually much cheaper than variable pumps.
Displacement pump.
Although the aservo motor may be more expensive than the constant motor
The speed motor, the mold is more likely to need to be replaced or maintained over time.
Of course, full
Whether it is an electric machine, or there is very little need to handle the maintenance of the pump. The well-
Known Rotex coupling (spider-gear)
Does not exist on the servo-
Driven pump machine
Therefore, there is no need to replace the electric machine.
This is very clear to the maintenance staff of each molding workshop.
In general, modern machines offer better analytical capabilities than their predecessors.
Servo drives can usually be analyzed with easethrough through embedded oscilloscope functions, and some suppliers provide standard additional functions in modern machine control.
This, along with the possibility of accessing a machine through a web service, creates a powerful tool to remotely serve and troubleshoot the machine. Constant-
High speed pump motors generally do not offer this possibility.
Uniform alarm information about servo control-
As the monitoring of the servo drive is more detailed, the drive machine is more accurate. 13.
Oil quality and maintenance of servo system
Driven pump machine, the oil will not be under too much pressure, so the quality of the oil on the standard hydraulic machine will drop slowly.
Of course, it always depends on the process and the degree of movement and shear of the oil;
However, generally speaking, the hydraulic machine will bring more pressure to the oil. Full-
Electric Machinery may not have to process oil at all. 14.
Generally speaking, the complexity of the machine hydraulic machine, whether servo machine
There are electronic, mechanical parts and hydraulic systems. Full-
The motor may have only electronic and mechanical components, which reduces the complexity.
A good electrician can work on the machine without needing to know the hydraulic pressure. 15.
One thing that is easy to forget about the training of maintenance personnel is the training of their own maintenance personnel.
For standard hydraulic machinery, it is recommended to calibrate the hydraulic system once a year.
Better training for employees can better calibrate and identify problems. No pump-
The relevant calibration is required on the motor, so the necessary training for the staff is not so complicated.
These 15 key points and comparisons about local and complete servo
Drive and hydraulic machines are important for evermolder.
With these issues in mind, vendors can help the modders find the best machines for the process they want.
What will you learn?
Term: distinguish between one drive and the other. 2.
Energy efficiency: even with a hydraulic pump, the servo will make a difference. 3.
Repeatability: consider differences in delay, acceleration and deceleration, and changes in oil temperature. 4.
Speed/acceleration: fierce competition between drive types. 5.
Training and maintenance: other factors to consider.
Questions about injection molding?
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Visit the injection molding area.
Marcus Claus is the manager of injection molding machinery at vitman battonfield.
Torrington, Conne.
He received a degree in mechanical engineering from damstadt college in Germany.
He has been in the plastics industry for nearly 20 years in Wittman, ferrotik mirakon and Toyo in Germany, and has joined witterman battonfield in the United States. S. A. in 2013. Contact: 860-496-9603, x198; markus.
Klaustsiwittmann-group. com; wittmann-group. com.
Description: it is becoming more and more common to use servo drives with hydraulic pumps.
It provides considerable energy savings.
Title: constant-
Three Variable speed hydraulic motor-
Displacement pump is an example of a complete hydraulic configuration.
Description: as shown in the figure: injection servo motor.
Speed and acceleration of servo system
The hydraulic drive caused a heated debate.
It is almost certain that the acceleration of the servo drive is greater.
Description: Official Energy
Rating symbol for European map 60. 1.
Description: use a separate servo drive for each machine shaft, allowing parallel clamping and injection movement.
Hydraulic machines can do this with multiple pumps.