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Aug 02, 2013, 02:11 AM
Wind, hill, ... I'm keen ...
AvB's Avatar

AvB getting a CNC

I’m “coming out” and publicly admitting that I’m getting a CNC machine!

Background: I am a glider nut … heavily into slope and dynamic soaring. I’ve got into composite building in a small way, designing a few homebrews, the most successful being a 1.6m moulded slope/ DS plane called the Scratcho. I have made at least a dozen Scratchos in different layups and weights, and love them. I’m passionate about developing ways to fill moulded wings with various types of solid cores for strength and durability, and my RC Groups build logs over recent years chart lots of experimentation with expanding epoxies, pre-cut foam cores, and expanding polyurethane.

But I’m a total CNC, CAD and CAM newbie. Friends have had some moulds/ plugs cut commercially for some amazingly successful models, but I’ve never been brave enough to go down that route. I’m sure that as soon as I spent 2 grand on cutting moulds, I’d wish I’d designed it differently.

A couple of years ago I got really excited when a mate decided to build a CNC. I hired an experienced CAD guy from our DS fraternity to do the 3D drawings of the Scratcho so that one day we could cut some nice moulds. It didn’t happen. Short story is that Al’s machine is still sitting in his shed 90% built - a totally stalled project! Over many months I then tried to find someone who would help me with cutting moulds cheaply. I could fill most of this page with the dead-ends I followed up.

Meanwhile more of the glider guys were starting to make their own designs, and I could see a number of them hitting the same wall as me. They’d make a prototype, then make a mould from plugs, then they’d want to do it “properly” and investigate CNC, and get scared off by the cost. Paradoxically, although I was reluctant to spend $2K on mould cutting, I felt drawn to spending more than 10x that much to get a machine, just to solve the CNC roadblock!

If I got a machine, I wanted it to be big, so I could cut 2m wings in one span, and so that the machine could be used for other projects by me, my kids or friends. Keep the options open, I reckon. I checked out commercially available machines. Wow. Big, and expensive. And not as accurate as I would want for something that’s going to cut airfoils. And not really rigid enough to handle cutting aluminium. Through one of those “brother of a friend of a friend” things, I heard that a small local engineering firm called Vermec Engineering made quality custom designed CNC’s. Two of us went for a visit, met Justin (the guy who designs and makes them), and in minutes we were awed and overwhelmed with the possibilities. Justin lives and breathes this stuff. His “main” machine is an 1100 x 600 unit, but he designed a big “Special” machine of very solid specs, with a 1200mm X gantry and variable length. He was adamant that this is a seriously strong, rigid, accurate machine. Big solid linear rails. Big servo motors. Gantry side plates of 32mm aluminium, cut to shape and polished like works of art. Vermec has a massive CNC mill, and the parts are perfectly cut from aluminium and steel plates. Justin cuts parts for vintage motorcycles which are sent to enthusiasts all over the globe - and the CNC machine parts show that level of attention to detail and finish. I got a quote and some specs, and the price seemed good.

Anyway … back to reality. A couple of guys gave me some realistic advice. “If you do get into CNC, your hobby won’t be building and flying planes any more! You’ll be full time learning CNC!”. I got the impression that it would be an almost impossible learning curve, laced with problems like noise and unexplained glitches, and I decided not to go ahead.

Some months later a glider mate, Shane, said he had a neighbor (Neil) who had recently got a really amazing new CNC machine but hadn’t used it yet. Shane was going to push this neighbor to get his machine going, and get some moulds cut. He seemed to think it would be a one night job. I lectured Shane about everything I’d learned … it might take months to get the process sorted. Well - by the next afternoon, Shane had the first mould half in his hands. Plus, the accuracy was better than the moulds we’d seen cut commercially. The machine had been super quiet, and they had little difficulty. It has to be said that part of this success was due to involving Sean, who is a CAD expert, to get the drawings working in Neil’s system. And a few phone calls to the guy who sold the machine.

I was gobsmacked. All the negative things flew out the window, and all of a sudden CNC seemed achievable, if you had a machine like Neil’s. I got interested again.

I phoned Justin at Vermec to ask a few questions about the specs of his machine, to compare them with Neil’s. Soon as I started talking, Justin said “that’s Neil’s machine! He’s a really good friend and I built that machine for him!” I asked whether the machine he had quoted for me was similar, and he replied “It’s the same %&*#! machine exactly!

I now knew some new information:
1) That the Vermec machine could produce the quality/ accuracy required,
2) That the whole process didn’t have to be as painful as I previously thought.
3) That it was much quieter than I expected,
4) That the technical support/ training from Justin was amazing,

I ruminated over the idea for a couple of weeks and couldn’t make up my mind. A huge decision. My situation is that we have a big family including a disabled daughter who lives with us and we care for her, so even if I retire we’re always going to be pretty much tied down. So a hobby that I can do at home in between work or domestic duties is a good fit. I am fortunate to have a very supportive amazing wife, plus the cash to throw at it, but I found it a really hard decision. Unlike the bling/ wow/ fun factor of a new plane, I knew getting a CNC machine meant lots of hard work and responsibility! Finally, with no further clarity I decided to go ahead, and placed the order for the machine. It takes at least a month to get various parts from around the world and assemble it, so it’s still weeks away yet but today I dropped in to see the progress and got a few photos.

The other big part of this project is my shed. Although it’s a 6 x 6m shed, with a lifetime of hoarded “stuff”, our bikes, camping gear, tools and (most significantly) gliders and glider building stuff - my shed is crammed to the hilt. It wasn’t a hard decision to rebuild the shed. We have plans in, and the new shed will be a 6 x 9m stud wall design, insulated and sheeted walls (to hang lots of stuff on!). And it has a trussed roof, which provides lots of options for creating big above-ceiling storage. However we still have to get through some nonsensical council regulations first.

This is obviously a huge and potentially very dumb thing to do. I already feel like I can’t keep up with the number of things I want to do, let alone the things I have to do! So apart from the huge cost, the part that scares me most is whether I will get totally overloaded and frustrated with the learning process. I am getting markedly stupider and slower at learning with age! (I’m 52). So I am prepared for the possibility that in a year’s time I may realize that this was an expensive and time consuming mistake.

It’s definitely a move in a new direction. I’m happy for my hobby to shift from building planes to learning CNC, wherever that may lead, and I hope that my creative kids have fun with it too. I’m currently working my way through Rhino CAD tutorials - a humbling experience! My hope is that in 5 or 10 years’ time, I am useful enough with the machine and the software to be able to help other guys out (for a low cost) with their projects, and enjoy it. In the meanwhile, I’m hoping that my other glider obsessed mates head over here for some “shed time” around the machine and we can all learn together. Like a glider CNC club. Sounds fun.

I'll post more photos here as the assembly progresses.
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Aug 02, 2013, 02:28 AM
Auzzie built planks
timbuck's Avatar
Very cool Andrew.. You definitely need a bigger fit all the new molds and plugs..

Along for the ride , I'll bring the pizza

Latest blog entry: More colours
Aug 02, 2013, 03:21 AM
Everything's A Compromise
Larrikin's Avatar
I hate you ....

you know I don't mean that

Aug 02, 2013, 03:56 AM
Thermal Wrangler
DrFragnasty's Avatar
Outstanding. Good luck with it.
Aug 02, 2013, 04:10 AM
Registered User
cleansurf2's Avatar

I've built a CNC hotwire cutter and am struggling with the software side at the moment. The hardware was all scratch build and seems to have been the easier part.
Software I'm using is Mach3 (drives the hardware) and Profilli pro (creates the G-code [patterns] that loads into Mach3). Mach3 seems aimed more at CNC router than hotwire, so it may be easier for your setup. If you have someone available to assist you with your software setup, that will be gold. I can give you copies of Mach3 and Profili if you like. Profili is an airfoil program, pretty sure it can be used for creating G-code for CNC milling of wing moulds. Probably not to the level of Timbos Gizmo type wing (hanging out for my Gizmo ).

Aug 02, 2013, 04:31 AM
Registered User
Wow, that does look like a very solidly built router.
I spent considerable time figuring out things in Cad/Cam, that would have only taken a few minutes for an experienced person to explain. So a Cnc club is a good idea.
Aug 02, 2013, 04:34 AM
There is only DS
airtimeasto's Avatar
Wow Andrew this is a big step dude.
Hope it all goes great for you.
Aug 02, 2013, 04:59 AM
Registered User
Very cool Andrew, I have been planning to build one for some time I got the controller and steppers but then moved. After getting my gararge sorted I may get back I to the project
Aug 02, 2013, 05:04 AM
DS Addict
Soaring Junkie's Avatar
Wow, impressive! Happy to share my 20 years of CAD experience, with the CNC club

Tried Rhino years ago when evaluating modelling/rendering programs for work... didn't work out because we run a fully MAC office, and was PC only.

I use ArchiCAD for everyday cad stuff, but use Cinema4D for the high end renders, as well as Maxwell and have previously used Maya, used for the Pixar movies (expensive and difficult to use). I'm sure Rhino, like most CAD programs these days can import IFC files, good for importing models created in another program.

Aug 02, 2013, 05:05 AM
Wind, hill, ... I'm keen ...
AvB's Avatar
Rick the Mach 3 software comes already set up and tested to work with the machine. They provide quite a bit of training too ... 3 full days training is included with the quote. Plus further help is just a phone call away (and they're only 5 minutes from my place). Yes Profili will create simple wings and moulds or plugs from them - I'm sure I'll be trying that!

Might be worth asking Alex Hewson about your hotwire setup - he uses a CNC hotwire cutter regularly. Or Glenn or Rick at On the Edge, etc.
Aug 02, 2013, 05:09 AM
Wind, hill, ... I'm keen ...
AvB's Avatar
OOOoo, Ooo!! Brent, I think we need to become friends!

I'm using Rhino on Mac ... there's a "Work in Progress" mac version that you can download and trial for free. It seems great.
Aug 02, 2013, 05:10 AM
Auzzie built planks
timbuck's Avatar
I'm glad you chimed in Brent.. I was about to send AVB a message about your stuff. with the cool pics you showed me the other day I'm sure a 3d wing will be a walk in the park for you , compared to a 10 story building ha ha.

Latest blog entry: More colours
Aug 02, 2013, 05:28 AM
Registered User

I found myself learning to use the machine before learning to draw in 3D.
I'm lucky in that a friend of mine is good at CAD and he does the drawing whilst I do the machining. We both end up learning from each project. I try to implement his design and find out what works and what doesn't from the CNC perspective. We are always looking to speed up and simplify the cutting.
I recommend you have a play at 2D first, even then you may need to tweak drawings to get them to work.
Aug 02, 2013, 05:48 AM
Wind, hill, ... I'm keen ...
AvB's Avatar
Good advice, yep thanks. Sean reckons I'll get on top of the CAM and machining eventually, but thinks learning enough CAD to be useful would be a big challenge. However I'd like to learn enough to at least be able to modify things etc. I guess ideally the best situation would be a collaborative team where drawings are done by the guys who know CAD. I have no fixed ideas on this so it will be interesting to see how it pans out.

Some programs like Aspire apparently are much more intuitive and novice-friendly, and I've read of people taking it up and making a fist of it pretty quickly. But I don't think it's the thing to use for blending aerodynamic/ compound curves. I will probably try a trial version at some stage. But as you say, the plan is just to get started with using the machine just to make a straight line in a piece of wood and hopefully go upwards from that! At the moment, I wouldn't know how to turn the thing on.
Aug 02, 2013, 07:46 AM
Registered User
Vectric Aspire is very user friendly. I have version 3.5 and I'm considering upgrading to v4.
I started with Cut2D and Cut3D from the same company so that my have helped me.
Most of the issues I have come across have been duplicate vectors (one, or more, lines drawn on top of each other) or open vectors (two, or more, lines not joined together).
All of these issues (when found) could easily be sorted with almost any CAD package that will work with .dxf files.
I still need to learn how to do my own 3D designs.

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