Back to the menu of Technical Information


1.Cleaning methods for injection molding machines



Prev Next


1-1 In case of insufficient Purging with "Basic purging Method(I-2-2)"


This cleaning method is recommended to use when the cleaning method which is already
mentioned in the Basic edition proves to be insufficient.
Especially when an injection molding machine with dulmadge type screw or excessively wear-out
machine come into question, the cleaning of the cylinder itself (grooves of screw and the inside
wall of the cylinder) is hard to be conducted, this method is effective.


Cleaning procedure

1) Move the nozzle backward and purge the
molding material which is left in the cylinder (*)with high back pressure.
  • In case the previous material is left, purging effect may decrease
2) Clean the hopper interior by air blast, etc.
  • In case the pellets, etc. of the previous materials are left, purging effect may decrease
3) Feed required quantity of ASACLEAN.
  • Refer to 2-5 of the Basic edition
4) Let the nozzle touch the mold and meter while applying back pressure.
Back pressure should be at a max. level.Volume to meter should amount to twice as much as the screw diameter.
  • Metering by applying back pressure may cause ASACLEAN leak from the nozzle,when back pressure may not be applied properly. In order to avoid this phenomenon, let nozzle touch the sprue. Beside this, there are ways of using wooden block, aluminum plate and touch plate (solely for this purpose).
5) Soon after metering finishes (**), move the nozzle backward and conduct free shot (***) at high speed.
  • Free shot is more effective than inching (= repeated injection and its interruption).
6) Repeat 4) and 5) above.
 
  • Conduct purging until ASACLEAN fed formerly vanishes

Notes on safety

*) In case no resin is left in the cylinder, don`t revolve the screw. Otherwise, the screw may
rotate disorderly and may touch the inside wall of the cylinder unfavorably.
Revolve at low speed even after feeding molding materials or ASACLEAN .
**) To move the nozzle backward before finishing metering may cause the pressurized
ASACLEAN or resin to gush out. So, "moving the nozzle backward should be made
imperatively after finishing metering".
***) As molten ASACLEAN may be discharged at high temperature and high pressure, use safety device such as nozzle cover, etc. and wear protective gear.

Hints for higher cleaning efficiency

1. Repeated revolution and brief interruption of screw while metering increase cleaning effects.
2. After using mixture of reproducts of pulverized runners (as the powder from them sticks to
cylinder inner walls) ASACLEAN retention in the cylinder for about 5 minutes is effective after metering with full shot.
3. In case cleaning at nozzle site is insufficient or in case of vented machine, refer to 1-2.
4. As regards contaminants (carbonized), refer to the related 3-1.3-2.3-3