cnc profiling core incl sidewalls, trouble sw ripping off

COsurfer · Post by **COsurfer** » Sat Apr 14, 2012 5:37 am

I have tried the happy monkey method. The ptex always pulls away at the ends and rips the Ptex apart. The problem is you cant get the Ptex to have a solid attachment to the wood.

I profile the core and than I profile stock ptex with the same tool path. I than use my table saw to rip the ptex into .5" strips. I resand all bonding edges, flame treat and attach to the core with super thin double stick tape. It Works like a charm and that is the way many manufacturers do it. The only other method is to use a drum sander but you either need a CNC drum sander or have a profile jig.

andi · Post by **andi** » Sat Apr 14, 2012 9:55 am

just tried the other toolpaths, worked sweet as. i even could profile the loose bit of sidewall on my last core!!!!
i was pretty stoked until later some bloody error in my core profiling-toothpath made the core splinter at the tips..actually it also left some bits unprofiled which you could'nt see in the simulation before. F/&%§&% ..
one step fwd, half step back...enough for today..

MontuckyMadman · Post by **MontuckyMadman** » Tue Apr 17, 2012 6:08 pm

Hey A, hope you remember who gave you that one..

COsurfer · Post by **COsurfer** » Tue Apr 17, 2012 7:24 pm

Yes, Montucky. You deserve full credit!

sammer · Post by **sammer** » Tue Apr 17, 2012 8:49 pm

COsurfer wrote:Yes, Montucky. You deserve full credit!

Give that man a medal

sam

MontuckyMadman · Post by **MontuckyMadman** » Tue Apr 17, 2012 10:26 pm

sammer wrote:
COsurfer wrote:Yes, Montucky. You deserve full credit!
Give that man a medal

sam

In all fairness the tape came from iggykinda.

I did put 2 and 2 togather.

I only told one person! Now they all know!!

andi · Post by **andi** » Wed Apr 18, 2012 9:14 am

?? montucky don't get it? what did you give me?

anyway new toolpaths work. so thinking out loud helped me find the solution nearly myself. so i keep whatever medal. hehe.

OnDeck · Post by **OnDeck** » Thu Apr 19, 2012 6:44 am

twizzstyle wrote:I'm convinced a drum sander is the only way to go. I've never had success with a planer either. On the last two pairs I did, I actually did a few passes on the planer just to start, then did the rest of the profiling on my base grinder with the autofeed. .....

This interesting as hell to me. I'm getting brain-melt trying to figure out how you make a jig for it, though!

I feel like sanding the profile will get you the best possible bonding surface.

chrismp · Post by **chrismp** » Thu Apr 19, 2012 10:39 am

twizz, what planer model are you using? just asking because i get great results with my planer.

twizzstyle · Post by **twizzstyle** » Thu Apr 19, 2012 12:23 pm

chrismp wrote:twizz, what planer model are you using? just asking because i get great results with my planer.

Ryobi 13". Even with brand new razor sharp blades, I get great results down to the last few passes. Once the tips are nearing 3-4mm tips, it starts ripping off sidewalls. I use a CNC'd profile board, with skateboard grip tape, and hot glue at the tips to hold the core in place.

When I used my base grinder, like I said first I used the planer and cut down until I was removing material along the entire length of the core. This meant that the correct profile shape was there, just the overall thickness was too much. Then I just kept running it through the base grinder with the autofeed, under the assumption that it was removing a constant amount along the entire length for each pass.

My only hiccup was that the motor on my autofeed (this is my home-built autofeed mind you) would overheat after running for a long time, and just stop. Having the core stop suddenly while doing a pass you can imagine was not a good thing. Only happened a couple of times, and I was able to pull the core out fast enough that it didn't sand in too much of a divot.

I'd buy a drum sander to replace the planer, if they weren't so damn expensive. But since I'm starting construction on my CNC router here very soon, hopefully I can just move to that for everything.

chrismp · Post by **chrismp** » Mon Apr 23, 2012 12:41 pm

twizz, have you tried putting some small wood pieces at the ends of the core as runn-off pieces? SHIF does this to prevent sniping.

here's a pic from SHIF to illustrate:

deepskis · Post by **deepskis** » Mon Apr 23, 2012 2:36 pm

My friends..
These guys seem to have it all figured out

Head Monkey · Post by **Head Monkey** » Thu May 17, 2012 9:21 pm

Haven’t been on in a while, so I’m just seeing this. I also have a problem with the sidewalls coming off while cutting my cores on the CNC machine. It doesn’t happen during profiling for me, which I attribute to the overall method I use of sandwiching the sidewall material in the trench the way I do. But it does happen to me sometimes when cutting out the final shape. Not every time, but most times. I have created a highly technical solution to the problem which has yielded fool-proof results, which I will now share with you…

I use a thin stick of wood and apply pressure by hand to the ends of the sidewall just as the cutter approaches.

Told you it was highly technical

It’s not an automated solution, but it works for my process. If I’m not paying attention and the program runs past that part then I seem to have about a 1 in 4 chance of getting some tear out, but since the sidewall is already profiled at that point I can just glue it back on quite easily.

Hope that helps!

skidesmond · Post by **skidesmond** » Fri May 18, 2012 10:10 am

This has probably been done by somebody in skibuilders but, has anyone taken a wide piece sidewall material and shaped it separately from the core, then rip it to width, then attach to the core? Masking tape might be strong enough to hold the sidewall areas on until the glue dries.

MontuckyMadman · Post by **MontuckyMadman** » Fri May 18, 2012 11:26 am

staples tape chewing gum on my leg all the same works.

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cnc profiling core incl sidewalls, trouble sw ripping off