Hello Martin,
spectre07 is indeed correct in asking about the size and make-up of the aluminum conductor and the polymer being extruded but here are a couple of points to be aware of:
- Regardless of the wire size, if you want adhesion no doubt to reduce shrinkback, you need to have the conductor clean as there is residual oil on both single and stranded conductors from both drawing and stranding.
- Generally speaking, the smaller conductor gage sizes such as 22 or 24 AWG with Tefzel insulation use tubing, usually with vacuum. (Figure about 1600 feet per minute for this process.) The PE, PP and PVC polymer insulations are generally pressure extruded at much higher speeds. (Figure 4,000 feet per minute to say 7,500 feet per minute depending on the polymer, conductor size and extrusion equipment.) I am not sure what the best cleaning solution is today. Western Electric used to use liquid Freon at their high speed extrusion lines but this is no longer allowed of course. Perhaps others will advise us what is used. Whatever that solvent is, it must be safe and leave no residual chemicals on the conductor surface.
- Larger stranded conductors for products such as line wire can be both tubed and pressure extruded. Generally speaking an in-line natural gas or propane furnace is installed at the front of the extrusion line. This first burns off the oil from the surface of the conductor.
There is also machinery that cleans wire at various speeds but each one may or may not be appropriate for aluminum wire at your particular conductor size. You will have to research this yourself.
- Cable Consultants Corporation Primary Wire Wipe. This machine is designed to clean non-ferrous solid or stranded wire from 18 to 30 AWG at speeds up to 8000 FPM.
www.cableconsultantscorp.com/primary.htm
- The PlasmaCLEANER is a plasma treatment machine designed for surface cleaning or deoxidation on ferrous and non-ferrous wires, tubes or strip.
www.plasmait.com/index.php?page=5
- DynaPower Inc. markets its patented ultrasonic and electrolytic cleaning systems to the wire manufacturing industry.
www.dynapowerinc.com/
- GEO-Reinigungstechnik GmbH provides in-line, portable, semi and fully automatic washing systems for wire.
www.geo-reinigungstechnik.de/index.php?article_id=1&clang=1
- Vapor Blast Manufacturing Company manufactures and sells its liquid honing equipment.
www.vaporblast.com/
Kindest Regards,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com