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- 3-3 Effective Way of Cleaning with ASACLEAN® Pre-overhauling
- In
conventional ways of molding machine overhaul, the screw is pulled out
of the cylinder and cleaned perfectly with a screw cleaning machine
or by various other means, while the inner wall of cylinder is no more
than scrubbed with a brush or cloth and therefore is not always adequately
cleaned. Cleaning with ASACLEAN® prior to overhauling
of molding machines enhances the efficiency and effectiveness of the
overhaul, as described below.
1. Precautions for safe, effective overhaul
- 1. ASACLEAN® type selection
- (1)For cleaning injection molding machines, use inorganic-filled,
high-detergency Type newEX.
(2)For cleaning extruders, use unfilled Type newE first in order to avoid filler passage through the die, and after removing the die, clean the cylinder again-this time with Type newEX.
(3)For cleaning the extruder cylinder and screw only, use Type newEX from the beginning.
- 2.Operating temperature
- Avoid the use of temperatures over 300°C.
- 3.Personal protection
- Wear protective gear (safety glasses, protective gloves) to prevent
thermal burns and other injuries.
2. Cleaning and overhauling procedures - (1)Fully discharge from the cylinder the molding material used
in the preceding run, as you do in purging for color change or resin
change.
(2)Check the cylinder temperature setting (the molding temperature of the preceding molding
material). If it is over 300°C, lower the setting to 300°C or below, then feed ASACLEAN®.*1
(3)After making sure that the preceding material has been replaced with ASACLEAN®, stop
feeding ASACLEAN® and discharge.*2
(4)Turn off the cylinder heater and, when the cylinder temperature has lowered to approximately
220-230°C, extract the screw. (If the temperature is too high, the extracted screw is sticky ;
if too low, screw extraction is difficult.)
(5)Give finish-cleaning to the cylinder and screw.
- *1 : For vented molding machines, feeding a small amount of ASACLEAN®through
the vent as well enhances the effectiveness of cleaning.
*2 : When cleaning an extruder, extrusion speed should be kept low until ASACLEAN® discharge from extruder head, and as soon as ASACLEAN® discharge has started, increase the extrusion speed. WhenASACLEAN®becomes no longer discharged, continue operating the extruder without load for 2-3 minutes to completely squeeze out residual ASACLEAN®.
3. Effects of ASACLEAN® Use
- (1)Deposits on the cylinder inner wall, which are hard to remove by
manual cleaning, can be removedalmost completely. The machine can thus
be restarted after no more than manual finish-cleaning.
(2)Deposits on the screw have also been removed almost completely, and in addition ASACLEAN®adhesion to metals is low. Therefore, finish-cleaning can be done, by merely scrubbing with a brush.
(3)Consequently, labor and time required for overhaul can be substantially reduced, and the rate of
rejection due to contamination can be also be lowered by a considerable degree.
(4)If the extracted screw is to be heat-treated :
Without ASACLEAN® cleaning-the screw surface may be corroded with acidic products of resin
decomposition, depending on the type of resin.
With ASACLEAN®cleaning-such corrosion can be prevented because such resin has been replaced with ASACLEAN®.
4. Overhaul and ASACLEAN®
At most molders, molding machines are overhauled from time to time to ensure the machine interior is clean enough to produce contamination-free moldings. As overhauling requires considerable time and labor, however, we propose the following for increased efficiency.
Step 1 :Reduce time required for overhauling, by conducting a pre-overhaul cleaning with ASACLEAN® according to the procedures and instructions described herein.
Step 2 : Skip overhauling and operate the machine after ASACLEAN® cleaning only, by way of trial.
Step 2 is ideal but may be impractical in some cases. So start with Step 1, then move on to Step 2 in feasible cases.