- About me
- A university trained Professional Mechanical Engineer, registered in the Province of Ontario, Canada.
A wire and cable manufacturing engineering specialist with over 35 years hands on experience.
- Hello again Mohammad and thank you for the resolution of your rough insulation issue.
It never dawned on me that you would be having such a basic or fundamental problem as precure in the extruder barrel as it was my belief that you had much experience in the manufacture of a saline-grafted, moisture cross-linkable polyethylene system.
It just goes to show just how dangerous an assumption can be.
- From Dan Heidel
"Memory alloys can have their atoms arranged in two different atomic lattice arrangements. All metals have different atomic arrangements they can take on but usually they have stable ranges that are separated by very large temperature variations. With the memory alloys, the amount of energy required to shift lattice arrangements is very low.
When you bend them, the physical force triggers the lattice rearrangement wherever the metal is being compressed or stretched (forget which) which give the metal a tremendous ability to reversibly bend.
Some memory alloys just snap back to the original shape when released. I had a pair of glass frames years back that were like this. You could wrap the arms of the glasses around your finger like a corkscrew and they would snap back to the original shape as soon as you let go.
This particular alloy requires a small temperature shift to go back to the original lattice configuration. Tossing the metal into hot water triggers it and it goes back to the original configuration."
I also understand that because of the above,"memory free" steel wire is very stable over very large temperature variations as per the above definition. Thus it is the converse.to the above definition.
- We assume that you are manufacturing a one-shot, three component, saline-grafted, moisture cross-linkable polyethylene system consisting of a proper (Density Please!) XLPE base compound rated for the appropriate voltage, a catalyst master batch approved for use with the base compound and a color concentrate fully compatible with the two other components..
We are however unclear on your statement "masterbatch extruders" as this tends to conflict with a one-shot.extrusion process.
If you are getting a rough surface after extrusion, make sure of the following points: (This is most appropriate for a "one-shot" XLPE colored insulation.)
]1) That the components have been properly sealed before use and that all the components are completely dry.]
]2) That all components are within their shelf lives,and that all have been stored in accordance with the directions on the packages and on the materials sheets.
]3) That all components are all dried before extrusion n accordance with the directions on the packages and the materials sheets.
]4) Gravimetric mixers must be used at the extruder hopper so that all components become an exact concentration mixture by weight and then are precision mixed. Do this at the extruder hopper so there is no random compound segregation by the hopper loading system. Seal or discard any mixed material that was not used in the run. (Left over)
]5) The die must have a land or bearing appropriate to the density of base XLPE material you are using.
These items should resolve your Vinyl Silane XLPE extrusion problem.
- This was sent by to me by Mr Mohammad Zaree
We started extruding XLPE on LV cables and we have problem with it. It occurs in most of the sizes.
The outside surface of the insulation become rough after coming out of the cooling water in all the colors..
We tried to adjust most things but nothing worked. We changed the temperature zones, exchanging the master batch extruders with the insulation extruders,but no improvement.
The problem still remains. If some one could help us we would be really appreciative.
- Hello Jonathan,
Here are a couple of suppliers of composite polyester-aluminum foil shielding tape for power cable applications. We are unclear whether you are looking for helical or longitudinal applications. You must talk with these people to ensure you are getting exactly what you need.
HOWAR Equipment Inc. (Distributor)
499 Edgeley Blvd., Unit 12
For all Commercial and Technical inquiries:
Chase Global Operations Center
295 University Avenue
Westwood, MA 02090
- Hello Amar,
When you preheat PVC pellets you must be very careful to make sure the pellets do stick together in the extruder hopper and bridge the throat of the hopper. Many use vibrators on the outside surface of the hoppers (Air or Electric) to prevent bridging inside the hopper. Experimentation is necessary to prevent pellet compaction that could make the problem worse
It would seem to me that you are at the limits of the extruder to properly extrude this particular PVC compound. You neglected to tell us what kind of extruder screw are you using but care must be used there as well as burning by shear is always a potential issue.
We suggest that you start communicating with Rosendahl as follows:
Rosendahl Nextrom GmbH
8212 Pischelsdorf, Austria
Phone: +43 3113 5100
Fax: +43 3113 510059
Provide them with the model number serial number of the extruder and the information on the screw.
Provide them with the data sheet for the compound you are using and your speed limitation issues.
Please note that 200 meters per second is 39,370 feet per minute which is inordinately fast so we think you have made an error describing the line speed. Please double check.
- Hi Thomas,
I have fiber feeds into my house but the optical signal is converted into a digital electronic signal and fully distributed inside the house with CAT 6 cable (Internet, Television, 3 Telephone circuits). The fiber cable outside is strictly optical and is buried. It is fed directly from a heated pedestal in front of my house and then onward to a very large node about 3/4 mile away. I cannot see the requirement for fiber distribution inside the house. In an industrial building, the fiber cable can routed to an exchange or distribution point inside the building. Then CAT 6 cable could be used.
A CAT 6 cable containing two optical fibers should be a fairly simple thing to manufacture for indoor use so long as the fibers are well protected (Fully mechanically insulated.) from micro-bending (Signal attenuation.) by the insulated wires and that the cable is carefully installed to eliminate sharp bends and over tension. These issues will will also result in fiber signal attenuation.
An outside fiber drop wire is much more complicated because there is a temperature - attenuation window that must be addressed and the fibers must properly protected from bending and vibration. A CAT 6 cable is not required.