Clod Loop injection Machine Commissioning & Testing
Introduction
This document provides guidance for the commissioning and testing clod loop injection moulding hardware, injection system & control software
Caution: Plea ensure all instructions and guidelines regarding safety and normal operation of the machine referred to in the installation and normal operation provided by the manufacturer of the machine.
Caution: It is the responsibility of the commissioning / testing technical team to ensure safe installation and initial operation of all systems of the injection moulding machine. Any person operating this equipment must be fully qualified and undergone comprehensive training. All documentation regarding the machines safe installation and operation provided by the machine manufacturer must be read and understood before the machine installation / operation of the machine.
Caution: in order to prevent injuries from the machine and damage to the machine ensure enough caution and professional understanding is applied towards the tup of the machine.
Additional Information:
For further information, parts, rvice, or latest information related to the full installation and operating of this equipment etc, contact the Equipment Manufacturer.
1.Pre-Commission / Testing Checks
1.1.M achine
1.1.1.C heck that the machine is installed per the manufacturers instructions and that proper
湖北卫视回放
guarding and safety precautions have been obrved.
1.2.F acilities & Ancillary Equipment
1.2.1.A ll facilities and equipment required to conduct moulding / machines trials should be available
< Appropriate Power Supply, Compresd Air Supply, Mould Temperature Control; Hot
Water, Chilled Water, Normal Water with appropriate connections. Clod loop Material
Dryers & Dehumidifiers.
1.2.2.A n appropriate mould should be lected, installed in the machine and allowed reach specified
temperature.
1.2.3.R esin should be allowed sufficient time in the hopper / dryer to reach specified moisture levels
prior to beginning the machine t up and initial checks.
1.2.4.O perators should be provided by all necessary equipment, safety and otherwi to safely
operate the equipment.
2.Machine Set-up & Testing
2.1.Calibrate screw bottom reads zero
Check that the screw bottom or zero point, switch the cycle to manual with low pressure and bring the screw full forward. Check the screw position reading: It should be zero. If not, recalibrate the position nsor.
2.2.Check: Screw Drift, Shot-Size & Position Cut Off consistency
With the machine cycling, check that the screw is not moving as the mould is opens, ejection / re-loading and then closing the screw should not move. Note the position of the screw at the end of screw
recovery, this should be identical on every shot. Check that the machine is switching from first to cond stage as the screw hits the t cut off position (assuming cut off is via stroke position). Variation should be less than 0.05 mm. If the machine fails any of the tests, the shot size is fluctuating beyond
acceptable levels.
2.3.Load Compensation Checks
C hecks the machine’s ability to keep fill time constant by adapting to viscosity changes, such as
temperature cycles, resin lot changes, colour changes, and other normal process variations.
Start up the machine following your normal procedures, making sure you are operating with an
appropriate Delta P and switching from first stage to cond stage via stroke position. Make short sh
ots by reducing Second-Stage Pressure as low as possible while leaving some time on the hold timer.
Select three injection velocities, low, med and high. At each in turn, note the fill time and pressure at transfer to make this 90-99% full shot. The fill time is FT1 and the pressure at transfer is PK1. Now, either manually or in automatic cycle using screw decompression before screw rotation, pull the screw back (without screw rotation) to the exact same position ud to make your 90-99% full part. That is, you have a shot of air, no plastic in front of the screw. Before you make this air shot, make sure you can easily dig out a very short shot. Now, on mi- or fully automatic cycle, shoot air into the mould and note the fill time and pressure at transfer. This is FT2 and PK2. The fill time should be the same, with a
薛立significantly reduced pressure at transfer. The following equation calculates the machine’s load
nsitivity:
(FT1 – FT2) ÷ FT1) ÷ (PK1 – PK2) ÷ 1000) × 100 = % error/1000 psi.
The percent error should be near zero; slightly negative is ideal. If the error is greater than +5% error are not properly load compensated. Test at three different injection velocities—slow, medium, and fast. If your machine pass this vere load-variation test, it will keep fill time constant during production.
2.4.Velocity Linearity
Caution: Before beginning this test, make sure short shots can be ejected easily. If shorts cannot be easily ejected you will have to u cond-stage pressure to finish filling the part.
The purpo of this test is to compare a machine’s t velocity with what is actually achieved. To get good data, it’s recommended that the shot should be at least 60% of the barrel capacity. If you are using less than 40% of barrel capacity, do not u that mould for this velocity linearity test, as the
results may be uless.
In normal production mode using normal procedures to begin production making full parts. Lower the cond-stage, or pack and hold, pressure as far as the machine will allow. At whatever velocity is currently t on the machine’s controller, this should make a short shot. If not, adjust the position transfer to make a part that is short but at least 80% full.
Make sure the machine is running under velocity control and you have an appropriate Delta P. Now increa the t injection velocity in reasonable (safe) increments until the machine is t to the
fastest injection velocity allowable. As you increa the velocity, you may have to adjust the position transfer to ensure you are making short shots, and double check that you are still under velocity
control with an appropriate Delta P. Once at the fastest allowable velocity, adjust the position
transfer to make a 99% full part.
Once you are making 99% full parts under velocity control, you can start taking data. Note the actual “screw start position”—don’t go by the t shot size and decompression or suck back, if any. Then note the cut off or stroke transfer position and the fill time (to within 0.01 c). Without changing
anything but injection velocity, reduce the t velocity from as fast as the machine can go to nearly a
s slow as the machine can go. Make sure you are transferring on position and not time; that is,
make sure the overall injection timer has enough time on it to allow you to reach the transfer
position. The parts may change in size but do not readjust shot size or position transfer during the test.
Set up the data table to look like Table 1 and if you want, graph the data as shown in Fig. 1. To
calculate the actual velocity, subtract the cut off or transfer position from the actual screw start
position and divide by the fill time. Becau this method includes the initial inertia to get the screw up to speed, expect the fastest actual velocities to be only 85% to 95% of the t velocities.
Shot Set Velocity种豆芽
小车司机mm/c.
Fill Time c.
Actual Velocity
mm/c.
% of Set Velocity
1 2 3 4 5 6 7 8 9
10
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安全事故案例11
12
Note: At high velocities actual being a bit slower then t is to be expected becau of inertia. If the data shows actual velocities hitting a maximum and levelling out this test has failed.
防溺水手抄报大全图片保密工作管理制度2.5.Switchover Respon from First to Second Stage
Switchover respon is the pha of the cycle is the critical stage where the first stage of filling the part to 90+% full ends and the cond stage (pack and hold) begins.
Try, check two methods, 100 parts each method:
5.1.1. Rapid Transfer
Rapid transfer from first to cond stage, very little plastic has to be delivered to the cavity, the rapid drop of plastic pressure in the nozzle does not over pack or accentuate the rapid development of cavity pressure. If this method does produce consistent parts the performance of the screw’s check ring is suspect.
5.1.2.Slow, Velocity Controlled Pack
Requires a three-stage moulding process, the filling or first stage gets the part 90+% full. Second Stage, packing is velocity controlled to slow the cavity-pressure development and ends when the cavity pressure reaches a level previously found to produce an acceptable part. Once this cavity pressure is achieved, the machine transfers to holding (third stage) to keep all the plastic in the cavity and hold the part to specified dimensions. This method will compensate for viscosity
variations and any leakage of the check ring.
Data Recording:
