suggestions on core materials for this job??

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#1

I have an enquiry to produce lightweight dish shaped mouldings almost like a big carbon fibre satellite dish.

I was wondering about the core materials available and if you guys have any suggestions as what the best processing method would be?

Both sides have to be A1 perfect with minimal post finishing work. They are 50cm diameter and need to be 6-8mm thick.

I have only used nomex cores before and they wouldnt be suitable for this project. I have the option of using either prepreg over a core in a split mould or infusion/RTM but I guess cores would be different.

Perhaps something like divinicell?! :slight_smile:

#2

what are the specifications for this project? does it need to be light weight? there are many different closed cell foam companies you can use for infusion, all can have channels cut in to them for infusing. depending on how much your dish curves you may have some trouble keeping the material down before bagging. there are many heat forming closed cell foam cores availible. why cany you use honeycomb? worried about print though? honeycomb works great with prepregs, but I have never used foam core with prepreg, I am guessing a higher gsm film adhesive would work good though

#3

They havnt specified any parameters as far as weight goes however I didnt really want to use nomex core as far as the cost goes and also its not the easiest thing to process and confrom around corners.

It has to have no open ends where moisture can get in and needs several holes machining in it for post bonding inserts in.

Up to 500 units per year. slots and holes are machined in afterwards.

I was thinking maybe make a seperate mould where I can inject a foam in to make the core. Then prepreg over this and layup in metal male/female mould + pop in hydraulic heat press to cure.

#4

ha, big enough drawing? Yea if I was you I would go prepreg too, its alot faster, easier and more repeadable. you may be able to inject the foam in after the skins have been cured, eliminating a first step of preforming/casting the core. just a thought

#5

yeah dont know why that turned out so big :smiley:

I suppose I could join the skins together then inject the foam, its just another operation though to machine a joint line and bond everything.

Guess either way the high temp tooling for prepreg is going to run into many thousands.

Tricky one, would rather go the prepreg route. Some testing with foam is in order 1st though!

#6

whats the diameter of this? and what is it for?

#7

Funny you should bring this topic up:

We used 1/4" x 1/4" core for our solid 2ft dishes, and 3/4" x 1/4" for the segmented 4ft dish.

1 layer of 120 FB prepreg for the surfaced for a good sanding layer, 2 layers of 5oz plainweave carbon, core, 2 layers of carbon, and another layer of 120.
Used corefill adhesive to hold the core on during debulking (else, there is NO way you will get that core to stay in a compound curve like a dish), along with spar locations, and around the outside edge of the dish.
Mounting ring was a 4-6layer 120 and carbon half donut, mounted on the back with

ask any questions you might have

#8

what about SORIC 6mm core?

#9

I say get a bunch of core material and do testing on it. Same layup, same size. Weigh them, and do strength testing on them.

#10

finally tracked down the british distributor of lantor soric. Its an infusion type core which could work well for this. Sample is on its way for me to try out :slight_smile:

#11

had the rep around with samples for airex cores today. Tried some airex C52.60 core and am quite impressed. It cuts on our cnc laser a treat and then we can press mould the preform at 100deg C and it stays put in that shape with no crease lines.

The only problem is infusion wise it doesnt have flow channels in it so I would have to mould the skins then sandwhich the preform core inbetween and stick it all together.