hello everyone
i need to bulid a 15mmx12x1m carbon tube
how can i do it
from what i need to bulid the mandrel
i need instruction
thank you
harel
Get an aluminium mandrel
Release it with a semi-perm or wax
Lay carbon over the top
Compact with shrink wrap tape
Cure at whatever temperature, eg 100C
Remove once cured
Place in a bucket of ice water and mandrel slides out
I have wondered about this as well, Does the aluminum shrink enough to make for easy removal? I would assume a longer piece may be harder to release? What about a larger diameter like 3"?
hello to you
its to big
Larger diameters work better than small ones. The more aluminum you have the more shrinkage there is when you chill it.
I prefer to cure the part under heat. This causes the mandrel to expand while the composite is curing. You will then have you even more clearance when you chill the mandrel.
The mandrel needs to be very true. If there are undulations in the surface then you can have issues with removal.
Yea all that makes sense, Does the mandrel need to be solid? I fully understand the shrink and growth deal… I have seen a large shaft cooled with liquid nitrogen and a drum the shaft was being installed in heated…In the ambient temp state there was almost a 1/4" difference in the two pieces!
I am just wondering if a thick walled pipe would work for this over a solid mandrel.
Sorry to thread jack here!
Preferably hollow, so you can heat it by aiming a heat gun in it.
Does anyone have any pictures of this being done? And maybe a finished product? Would be interesting to see!
I was making 2" elipse tube with vacuum infusion on aluminum mandrel. Mandrel(aluminum tube vas proccesed in conical shape on 3m of length there was 0.08 degrees of conus) First of all CNC proccesing on lathe is crucial to achive perfect straight mandrel and also polishing was done on CNC lathe. Because I needed elipse shape later also the CNC press brake was used to achive propper shape of my mandrel. I was using QZ-13 silicone separator, CF was cured at 140 degrees celsium and when cured I used liquid nitrogen released into the aluminum mandrel and with some hidraulycs 3m long carbon fiber tube was in my hand.
It’s quite a job arround those long CF tubing…
As SLADIC mentioned, anything is possible with the right tooling. If you have a hydraulic pulling system, you don’t have to do any cooling, as long as your tool is true. You can do a rope/strap wrap around one end that tightens as you pull, and secure the far end on something. You can also add a flange to the end you are pulling for better grip. This way, you can have a round or oval tube. It also helps to have a ever so slight draft in the mandrel. Because once you start pulling, your mandrel vs. tube gap increases.