PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Hi Kerry,
Seeing the excess epoxy after the long infusion was not a pretty
sight...I figured that would result in a total waste of 6 hours of
work and materials...
What a nice supprise to be able to use the part...
Original weight of the dry fibers was 79 grams and the finished
part was 124.8 grams...and only about 0.035" thick...
We have 2 CF tubes and 1 CF plate to make after which I will
start doing the programming of the CNC router to cut the parts.
Figured I'd wait till all of the CF is done as the programming
will hopefully go quicker with doing it all at once...
That leaves the mounting dovetail in aluminum yet to be designed, the
collimation knobs, secondary spider adjusters that hold the
outer edges of the CF spider ends, and a few other bits and
pieces....
I can see the end in sight.
Best Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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Sky Captain
Scope Builder
Reged: 11/07/04
Posts: 5743
Loc: Seattle Washington
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Quote:
Seeing the excess epoxy after the long infusion was not a pretty
sight...I figured that would result in a total waste of 6 hours of
work and materials...
Thank goodness you were able to salvage the piece and make it work.
BTW, when you get geared up for making CF tubes, can you build me a tube 9" diam. by 27" long?  
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Equipment Overload!
Kerry.
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Kerry, let me finish this beast and redo the Primary Baffold without wrinkles and I'll think about making you a tube...
But for your 8 inch visual...it would really be a waste as you are focusing manually...CF is best for CCD...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Knocked out the second Spider today...
In testing for vacuum leaks we found the problem of yesterday...
First the brass barb was full of cured epoxy, so we cleaned it out and tried again...
Still no vacuum to the mold  now what ???
Remove the barb and take the whole resin trap out of the vise holding it in place.
Looking behind the pipe threaded area was about 1/2" thick cured epoxy...drilled out and we have a strong vacuum flow again
Pic showing good infusion and no dry spots or puddles of cured resin like yesterday.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Here are both composite Carbon/Aramid Spiders ready to be machined.
The one on the right is todays and weighed 120.5 grams compared to yesterdays at about 125 grams...not too bad, considering the lack of vacuum flow yesterday
I'll see about trying to get the CAM package to output some Gcode so that we can try a test cut this afternoon/tomorrow depending on how much I remember about programming...it's been several months 
--------------------
A few I enjoy,
and a few more in the works ;<)
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Sky Captain
Scope Builder
Reged: 11/07/04
Posts: 5743
Loc: Seattle Washington
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Looks great Preston.
Are you going to do a test cut, maybe on the aluminum skin from the mold?
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Equipment Overload!
Kerry.
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Hi Kerry, I programed the Gcode this afternoon and did some air cuts...for some reason, after finishing it wants to go -1 inches or below the total surface...
I'll trial the pattern on luan ply and once it is acceptable will go with a 5 ply of 5 oz Carbon Fiber for a test...
Once confirmed, we'll indicate one of the Spider halves and cut out the inside triangles first...then, screw in some hold downs and cut the outside...filp it around and repeat...
If all goes well, we might have them done tomorrow afternoon...
Spent 2+ hours on what would now take 15 minutes getting back up to speed with the CAM program that gives the instructions to the CNC router...I need to do this more often... 
Cross your fingers that tomorrow goes well...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Ok, I spent all day farting around with the software Mach3 and finally posted a question on the Mach Forum...
The router works, but I was trying to get the Homing to work to be able to replicate all of the operations...
No such luck yet
Hopefully tomorrow I'll get an answer or try again to do without...
No progress today...
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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awallin
member
Reged: 04/01/08
Posts: 24
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Looks like you have a layer of kevlar (aramid) in there. My experience is that it's very very hard to cut or sand kevlar. Usually you just take away the epoxy and leave a fuzzy mess of kevlar fibers.
If you are able to cut the kevlar cleanly I'd be interested in what kind of cutter and feed/rpm you are using.
Anders
PS. Once you are done with Mach and want a real cnc-control, take a look at EMC2 www.linuxcnc.org 
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Quote:
Looks like you have a layer of kevlar (aramid) in there. My experience is that it's very very hard to cut or sand kevlar. Usually you just take away the epoxy and leave a fuzzy mess of kevlar fibers.
If you are able to cut the kevlar cleanly I'd be interested in what kind of cutter and feed/rpm you are using.
Anders
PS. Once you are done with Mach and want a real cnc-control, take a look at EMC2 www.linuxcnc.org
Hi Anders,
Yes, I do also have linixcnc and a Fagor control which is great...the linixcnc is not as well documented yet and Mach so far seems to be easier to get answers to a likely problem with the 15000 users out there...
As to the Kevlar, I purchased carbide bits made just for cutting this material at $25 each...cheap in the whole realm of things...if they work, I'll post the info tomorrow...
Today, we got the Homing to work nicely thanks to Hood in Scotland...thanks HOOD!!!!!!!!!!!!!!
We have a couple of more little issues and then will likely be cutting test parts from thin veneer wood first tomorrow and then doing carbon fiber test, before doing the carbon/aramid fiber spiders...
Hopefully, pictures tomorrow...
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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So finally we are getting somewhere...
CNC router is working and here we are cutting the
support form and hold down fixture made of MDF.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Closeup of the 1/4 inch bit used to cut the carbon/aramid fiber sandwich...running at 21,000 rpm with a feed rate of 21 IPM and doing multiple passes with a step down helps to get a clean edge with the aramid on the inside...differant teeth are contacting as we step down in 0.050" steps totaling 5 steps...
Just using one pass without stepping down leaves a suzzy edge in places...hit or miss.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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VARTM carbin/aramid composite clamped to the support/hold down jig ready for cutting.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Inter triangles have been cut out already and we are routing the outer edge of the first side.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Screen shot of our Mach3 CNC control while cutting the outside of the spider.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Close up showing the cross hairs in the V at the right end of the spider indicating the bits location.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Final cut on the outside of the second side...
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Front view of finished carbon/aramid spider.
--------------------
A few I enjoy,
and a few more in the works ;<)
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PrestonE
scholastic sledgehammer
Reged: 04/29/05
Posts: 817
Loc: Houston,Texas
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Inside of the spider showing the 3/8 inch radius curve that will fit around the 3/4 inch carbon fiber tubes.
Total weight of one spider is 43 grams or just under an ounce and a half...
Now we are cooking 
And I am SO glad to have this part behind me...finish the second one tomorrow...
Hope you have enjoyed this little adventure.
Regards,
Preston
--------------------
A few I enjoy,
and a few more in the works ;<)
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BluewaterObserva
Post Laureate
Reged: 05/18/04
Posts: 4763
Loc: Zuni Mtns, NM
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Man.. The pics are saaweeetttt.. Keep them comming.
I want to personally thank you for sharing this project with us here in such detail. A look into "what it really takes" such as this is really rare.
I learned two things so far... I will take them as life lessons...
1. I'm not building an RC anytime soon if ever
2. Carbon fiber is way cool stuff. I am surprised more people are not DIY'n with it. I mean fiberglass these days is done by just about any hack. I wonder if Carbon Fiber may get to the same point eventually?
I come here everyday just so I can just to check on this thread!!!
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