CNC Routing One Piece Wing Ribs

[JBMoore]

As far as the paper plot not matching the plastic.......
The only way to get a completely accurate wing print is to plot it out from the dimensions using AutoCad or a similar program.
If you take the original and make a copy, the copier will one time make it 99.99% and the next time 100.99%; hence, the discrepancy.

Jeff Moore

[mmarien]

Jeff

True. I read a few stories about making the jig on a paper plot only to find out that it didn't measure properly once they had it laid out so I expected the difference. In my case, the paper print was from the same AutoCAD drawing as the plexiglas jig drawing. The printer I used was only 11x17 so I had to piece it together. I also found that the printer didn't print true. I plotted a series of lines with one inch spacing along the top as a control for the print. I scaled the plot in AutoCAD to get the print to scale true and when I pieced it together I made sure the distance between spars measured properly.

Didn't matter as when I took it to my hanger the change in humidity changed the size of the paper. It didn't change the plexiglas jig though. It measures properly between the spars even though the paper doesn't anymore. The paper plot was simply to show the pattern so it works even though it's a bit off scale.

[cfrasers]

Hi Murray,
Did you buy your CNC Router online, or do you have a retail outlet that you can visit.
cheers
Fraser

[mmarien]

Fraser

Bought it on eBay. Came from China but only took three days to get here. Search for 6040Z on the net. There is lots of information on the 3040 and 6040 routers, both from China. I found a place in my hometown that sells CNC routers but they were a little more expensive. If you want local support then purchasing it locally may be a good option. Search for CNC Piranha. It's a lot more sophisticated than the 6040Z.

You will also need some software and there is a bit of a learning curve. I'm more handy with a keyboard and mouse than hand tools but it still took some effort to learn about CNC. There was no documentation with the router so I used the Internet to figure it out. I have AutoCAD and use it to do the initial drawings as I'm familiar with it so drawing the parts wasn't a problem. I found a program called CamBam that can convert the AutoCAD drawings into a 3D part and produce the gcode. The third bit of software is called Mach3. It's what interprets the gcode and controls the CNC router. I was making parts within a week but it took a few more weeks to get familiar enough to stop burning the wood and melting the plastic.

It won't cut chromium steel. It's limited to wood and plastic. Some guys are using it to cut aluminum. I know the guys here want to try and cut their aluminum panels with it. I think it will pay for itself in time saved by the time I finish the Hatz.

I got tired of it taking up all my bench space and spewing chips and dust all over the place so I built a special table for it:

20160406_162745 Small.jpg

[cfrasers]

Murray,
Thanks for your comments and info regarding your CNC purchase. After doing some research here (Australia) , purchasing on EBay and a steep learning curve is probably the best option for me also.
I had originally intended to get all the wood parts laser cut. The cost of that alone would go a long way toward paying for a machine such as yours.

I haven't as yet located anyone selling these small CNC's locally. So I will do some more research and probably go the EBay route.
In the meantime I will follow your build and ask questions.
Thanks Fraser

[mmarien]

Hey no problem. If you do purchase a CNC router all the parts I made have gCode files. As long as you are using the same size bit, you can just use the same gCode file to cut your parts. gCode works on any CNC router.

The time consuming part was redrawing the rib in AutoCAD. I found a formula for the Clark Y airfoil and overlaid it over a copy of the plan. The spars are 25" apart and the other pieces have to fit between the top and bottom airfoil so I just filled in the rest. I changed the nose and tail pieces slightly from ideas I got from this forum. I also made most of the the gussets round. Once the rib was drawn I used it to create the gCode files for the router.

[BravoCharleyWindsor]

Glad to see this thread still going after being a way for a while. I picked up a Logan 825 lathe, Enco 6x26 mill back, cutoff saws, and lots of tooling in January for a good bargain. But its been a project (ongoing still) getting it all cleaned and setup. I'm still hoping for a CNC router. An acquaintance has a full sixe (for 4x8 sheets) but obviously even a small CNC is very practical. Based on the comments here and other factors I do agree now that truss build would be best as per plans, but even that still allows for gaining efficiency via CNC use.

[cfrasers]

Hi Murray,
Just a quick question about your CNC router.
What power rating is the spindle in watts is please and are you still happy with its performance cutting wise.
I am looking at what's available on the web here, some from Sydney & some direct from China.
3 different power ratings on the spindle are available, 800w, 1500w & 2200w.
Cheers

[mmarien]

Mine is 1500 watts, 220 volts. It's water cooled. I think the 800 watt is 120 volts and not water cooled. I'm not sure I needed the 1500 watt spindle for what I'm doing. Just cutting wood and plastic. I don't have any previous experience.

I have a guy that worked in a CNC machine shop coming to look at mine this week. He's looking for something for hobby work. I'll ask him about the spindle ratings and what he's considering.

[cfrasers]

Thanks Murray,
From your pictures it looks like yours cuts the quarter ply without any difficulty. I was thinking 2200 watts is a bit of overkill for what I intend using it for, be good to hear what your friend reckons.
Cheers