How to clean up the extruder screw?All of a sudden blackout how to deal with?
How to clean up the extruder screw?All of a sudden blackout how to deal with?
For manufacturing thermosetting powder coatings with extruder, the replacement of coating resin varieties or color varieties, must be clear machine, to prevent interference between varieties of powder coatings, guarantee the quality of products.When extruder machine not thoroughly, the most obvious is the influence on powder coating color, it can be directly observed.In addition, the previous production without flow ping agent type powder coating of fine arts, reproduction without clear clean extruder highlights powder coating, because the material in front of the interference, behind the product to produce coating is easy to produce the ills such as shrinkage cavity.Therefore, when a change in coating resin varieties and designs and varieties, it is very important to thoroughly clean machine.A lot of cleaning machine method for extruder, usually can use the following several kinds:
Resin method of cleaning machine
This method is to use resin, such as polyester resin or epoxy resin machine.This method usually used in cleaning machine of new equipment or extruder use after a period of time, because some material remaining on the screw or the spiral tube gel, material extrusion speed slow, and varieties of color change color color difference is bigger, can use this method.After resin cleaning machine, then use to production of powder coatings with resin, curing agent, or under the condition of curing resin further cleaning machine, when think extrudate clean can be formally put into production.If a change in powder coating of varieties of color difference is small, thorough cleaning machine and not too long, only to production of powder coatings with resin machine can clearly.In order to increase the friction of the resin, which is beneficial to clear the machine, you can add some packing machine.
The resin machine method
This method is to use a certain friction, and easily crushed rice, corn, saws, such as toilet paper, at the end of the heat when extruder to normal after the extrusion temperature, the use of these substances and the friction between the screw and screw tubes remove adhesion on the surface of the screw and screw tubes, rubber compound powder coatings.Experience shows that rice shell of high hardness, the friction is large, compared the effect is more ideal cleaning machine.After cleaning machine in this way, it is necessary to open the screw tubes check cleaning machine, under normal circumstances also need according to the above method is to use a powder coating with the resin again after cleaning machine, to a formal production.
Remove the screw and screw tubes artificial cleaning machine method
This method is to extruder after heated to working temperature, using artificial or automatic release, push the screw to strike removed easily removed material.After cooling in the organic solvent with acetone or cyclohexanone trough soak, when attached to the screw on the melt adhesives swelling, manually remove the attachments.Screw attachments to how much and the soaking time is determined by the thickness of rubber compound.In order to use less solvent and facilitate container seal, with slightly coarse than the diameter of a screw steel pipe or stainless steel tube, one head welding sealing as dip tank can use.From safety considerations, soak screw containers must be put in a cool, away from the fire source and the power of place to store, at the same time mouth sealed to prevent solvent evaporation, and pay attention to safety mark.
If you need a thorough cleaning machine, screw tubes can also after the strike opened, in the artificial method or solvent to clean method to remove adhesion on the inner wall of the screw tubes, rubber compound.In order not to damage the screw and screw barrel surface finish, can't use good things, can only use than the screw and the screw tubes steel soft metal saw blade or steel brush, wipe out the attachments, so as not to damage the screw and screw tubes.
Because the extruder of thermosetting powder coating long retention time in extruder, prone to curing reaction and gel, in become a particle of the coating in the coating powder coating, if there is a cure even extruding machine cannot be started.So before extrusion machine downtime, must use no curing performance, and is no pure resin, curing agent and curing of the resin powder coating material out of the extruder, to prevent these materials remaining in extruder curing reaction.Resin with SAP standard is to ensure that the screw tubes inside can enough remaining in the powder coating material are all introduced screw tubes, prevent the material in the extruder curing for the principle.From extrusion material removal extent, basically can not see the original production of powder coating color standard.
In extruder on production, according to strict procedure with premixed material retained in the extruder of pure resin, when after confirmation of pure resin its clean, can squeeze another material as a formal product.In order to prevent the pure resin into later on the coating product defects in products, clear pure resin and part of the rolling machine in premixed mixture can use right;But it can't bring in fine crushing process in next step.
Extruder in the normal operation of all of a sudden power failure, if not timely the extruder screw tubes inside the material discharge outside, will make some powder coating curing reaction and gel, a long time even serious curing, unable to boot, need electricity heating or gas torch tools such as high temperature heating processing of the material of extruder screw tubes, so easy to damage the equipment., therefore, should immediately turn off after blackout extruder host switch, plate belt by hand or with great artificial rotating mechanical extrusion machine, try to dump the material within the extruder, residue, at least in the screw tubes at the same time, add a small amount of pure resin with some residual powder coating material, because at this time can only using residual heat of extruder, so add the amount of pure resin cannot too much.
If some of the extruder main motor connected directly to the gearbox, and no rocking bar motor turning device, also can increase the cooling water of the cooling system, make the temperature of the extruder screw barrel and screw quickly cooled down, to prevent materials react in the extruder.
