cnc question

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the.quass
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cnc question

Post by the.quass » Fri Nov 10, 2017 4:01 pm

Hey guys,
So my Mums partner has just about finished his CNC build. It's not a ski core length long (about 1 metre). I am using Fusion 360. I plan to have two dowels in the spoil board and then have 2 holes in my core stock (bamboo) to align the core. Once one end is done I will spin the core and do the other end.
This isn't going to be as easy as doing it all in one length but I don't have that option at the moment.
Anyone think this is dumb?
Second question. In Fusion, I have ran test cuts using the CAM tab and I have a 3d parallel to get the depth with a 2 d contour at the end to cut it out. Do you guys do it like this?
Thanks David

sammer
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Post by sammer » Fri Nov 10, 2017 11:25 pm

Can't answer the fusion question. but...

I'm not sure why this wouldn't work if your skis were center mounted.
The first generation planer profilers did just that, profile one end then flip it all and do the other. CNC should make it easy.
Just have to figure out set back, and whether you want a flat mounting section.

sam
You don't even have a legit signature, nothing to reveal who you are and what you do...

Best of luck to you. (uneva)

the.quass
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Post by the.quass » Mon Nov 13, 2017 5:48 pm

Hey Sammer,
Thanks for the reply.
I am going to be using 2 different drawings so even if it wasn't centre mounted, It should still work as long as I get my measurements spot on.

Im going to try and do a couple of test cuts soon. The CNC is 2 hours away.

Will let you know.
David

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MontuckyMadman
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Post by MontuckyMadman » Mon Nov 13, 2017 6:16 pm

You dont have to put a hole in the core. Hot glue wrks fine. You can center it with marks.
sammer wrote: I'm still a tang on top guy.

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vinman
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Post by vinman » Mon Nov 13, 2017 6:58 pm

for tool paths, yes 3d parallel and 2d country will work well.

If you just extrude your entire 3d core model a couple mm wider than it needs to be you'll have a little wiggle room on your centering marks. You'll need to be perfect on your 2d contour cuts but this may depend on the type of tip spacer you plan on using.

Like MM said. Hot glue works very well. The better you can hold your cores to the spoil board the more accurate your thicknesses will be.
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the.quass
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Post by the.quass » Tue Nov 14, 2017 2:15 pm

Hi mm and vinman,
Do you Hot glue directly to the spoil board?
Have you ever left tabs in the 2d contour?
I'm keen to see how it goes.
Dc

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vinman
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Post by vinman » Tue Nov 14, 2017 6:22 pm

Yes I hot glue to a spoil board. My vac table is good but I don't get quite enough hold down for my liking while profiling cores, especially with narrower skis. I still use the vac but supplement with hot glue. I may try adding a third vac motor and rebuilding my vac box next season.
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the.quass
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Post by the.quass » Sun Nov 19, 2017 11:36 pm

How do you get the glue to release? Heat?

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chrismp
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Post by chrismp » Mon Nov 20, 2017 12:19 am

You can easily remove hot glue by applying some alcohol along the edges.

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Post by gav wa » Mon Nov 20, 2017 4:33 am

Vac tables need to be made out of a better product than basic unsealed MDF. The stuff with a colored layer, like cupboard type stuff and bench tops, or you need to seal the whole sheet before making it. That stuff is so porous, it's why it works so well as a spoil board.
I am surprised guys need to glue cores down to a vac table, I don't know your exact setup and process but that sounds like there is something wrong there.
Are you using vac pumps or an old vacuum cleaner? You want volume, probably even more than vac pressure.
I use an old vacuum cleaner and I have enough left over suction to run my dust collector off the same vacuum cleaner at the same time. True it works better with a separate vac source for the dust collector but I can get away with it.

It just sounds like you are having major leakage or are using low volume vac sources.

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vinman
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Post by vinman » Wed Nov 22, 2017 4:28 am

I’m using a plenum, sealed with 3 layers of wood glue and an MDF spoil board glued down to it. I fly cut both sides of the MDF prior to flying it down. I have sealed the edges of the spoilboard as well. My cutting surface is 2x8’

I’m using 2 220v vac motors contained in a box with an “air tight� chamber below the motors. This connects with pvc pipes with 4 zones leading to the plenum and spoilboard. I block off as much spoilboard as possible with old translucent top sheet material as possible.

I get decent suction on bigger cores but not enough to be sure things can’t pull up at the ends.

I think it is possible I’m losing vacuum in my chamber. Which is why I’m going to rebuild it this spring. And possibly add a third vac motor...

For now the hot glue ensures my stuff stays down flat to the table.
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gav wa
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Post by gav wa » Wed Nov 22, 2017 6:59 am

You guys are making some sweet rides, so I'm certainly not judging your process, please don't think I am.
Sometimes I'll use a bit of tape on the ends just to help maintain the seal. Your setup sounds sweet, and we all have our own little ways, which adds to the fun. I reckon your hold down is probably even stronger than you think though.

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vinman
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Post by vinman » Wed Nov 22, 2017 5:30 pm

Not offended at all. I often think the same thing, that I shouldn’t need the glue.... but for this season that’s where I’m at. After I get thru my builds this year I’ll try to diagnose and improve the suction on my table. Some of that starts with adding a vac gauge to the system to see how much I am pulling.
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Post by mammuth » Thu Nov 23, 2017 2:55 am

After having some problems too (big machine, dull blades, fast cutting, small parts) i too have the hot glue always beside the machine. Its so quick and easy and gives added safety without headaches especially on non rectangular parts (like molds) ... :)
Tom

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Re: cnc question

Post by ruchika » Fri Jul 19, 2019 4:09 am

Do you Craft glue legitimately to the ruin board? Have you at any point left tabs in the 2d shape?
I'm quick to perceive how it goes.

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