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Wobblycogs
28-07-2012, 05:45 PM
Hi, I've been planning on building a CNC machine for years and I finally think I'm starting to get the time and space to do it. My primary hobby is woodworking so the machine will mostly be working with wood but reading a few posts here I'm starting to get interested in machining some aluminium. My plan had been to build my machine mostly out of MDF but seeing the aluminium profiles a lot of people are using I'm starting to change my mind.

By day I own and run a small business that develops forecasting software which is a fancy way of saying I'm a software developer. I've got a some CAD experience mostly with SketchUp and 3D Studio although I have also had a play with AutoCAD. I've not yet had a tinker with any CAM software so that should be an interesting bit of research. Mechanically I have no formal training but I've built no end of things over the years. A couple of years ago I built my own bench mounted belt sander which I use a fair bit (even if the belt doesn't run quite true :apthy: ).

JAZZCNC
29-07-2012, 11:14 AM
Welcome.

Get the plans drawn and up for us to pull to pieces. . Er mean advise upon. .Lol

Good choice to ditch MDF idea it's only any good for spoil boards and throwing at the dog when it shit's on path..:dog:

If your thinking to cut aluminium then it will need to be built much stronger than you would a purely wood/plastic working machine and you'll need a much better spindle than a basic router can handle so be prepared to spend more money. Routers bearings don't handle the heat and forces cutting aluminium creates and will die quickly if doing lots of it or long jobs.

Post your ideas and ask the questions you think are dumb and between us we'll help you'll build a great machine.

rnr107
29-07-2012, 12:01 PM
Agree with Jazz on this one... Forget MDF, not only because of the strength problems but also it will move with time and therefore lose your precision.
Don't know about throwing it to the dog, I don't have one... LOL... :tongue:

Are you planning on machining sheet material or blocks ? For sheets, a gentry / router type of machine would be best (and easily enough self built) but for blocks you would be better with a milling machine... More robust but not that easy to build, better start with an existing manual mill and convert it to CNC.

Welcome to the party! Enjoy...

RNR

WandrinAndy
29-07-2012, 12:57 PM
Hi Wobblycogs... think I recognise your handle from UKWorkshop.

It seems like your mindset is already transforming as per the norm.

Barely a couple of weeks ago I was simply contemplating how a router table could be redesigned in an upside down kind of way... picked up a few CNC threads on UKWorkshop... and thankfully eventually ended up here.

Just a warning on how this can pan out if you are like-minded... I am now totally consumed by CNC, often only getting to kip when the sun's already up. So much to learn, so little time!

Enjoy the journey!

Cheers,

Wobblycogs
08-08-2012, 11:55 AM
Hi,

The MDF idea has been consigned to the dustbin. I've had a chance to read a few of the threads around here (the FAQ's are good) and it's clear that metal is the way forward. The question now really comes down to steel box section or aluminium profile. I can't weld and don't know anyone that can so aluminium profile is tempting but steel box is so much cheaper. Is bolting the frame together a viable route or would it just result in an incredibly inaccurate machine?

In my minds eye see myself machining sheet materials, I can't imagine that I would be working with wood over 50mm in the Z direction. Certainly the machine I had in mind was of a gantry design.

Andy, yes I'm the same Wobblycogs from UKWorkshop. I know what you mean about getting totally consumed by CNC. Now that I've finally decided to actually build a machine I find myself wandering back here every five minutes to read another thread. I'm wishing I'd done an engineering degree though :-).

JAZZCNC
08-08-2012, 12:20 PM
The question now really comes down to steel box section or aluminium profile. I can't weld and don't know anyone that can so aluminium profile is tempting but steel box is so much cheaper. Is bolting the frame together a viable route or would it just result in an incredibly inaccurate machine?

Ok first welding is easy and with cheap arc welder and just a few hours practice and you'd easily be able to weld good enough to build this frame.!

The welds dont need or want to be long so shorter spot type welds are fine and easy to do. . . .BUT if you don't want to weld then it's still possible to build just has accurate machine using just plates and bolting. It will be far more time consuming but with patience then it will be just has accurate and to some degree more flexable regards alterations and future improvements.
If you have the time then the savings are considerable compared to Alu profile.

What size machine are you looking at building.?

irving2008
08-08-2012, 12:20 PM
Hi,
... I can't weld and don't know anyone that can ...

How do you know you can't? Have you tried? I bought a second-hand stick welder off gumtree (you can get a cheap but usable one on ebay (http://www.ebay.co.uk/itm/Sealey-Power-Welder-150xl-and-a-Box-of-183-Rods-Superweld-/120960963175) for as little as £40), watched a few tutorials on youtube, and some cheap offcuts from the scrappy and taught myself... ok, its not pretty, but it does the job... and practice as they say....

I've also experimented with welding aluminium using a blowtorch and aluminium rods from here: Aluminium Brazing Rods (http://www.aluminiumrods.co.uk/)

JoeHarris
08-08-2012, 01:43 PM
Hi,

The MDF idea has been consigned to the dustbin.

Ha Ha, sound like how I started - MDF and threaded rod with a budget of £500 - I've just spend that on ballscrews and bearings alone!! Good luck and welcome. I'm toying with a combination of alu plate Aluminium Plate - Cut to Order - Aluminium Supplier | Aluminium Stock | Aluminium Warehouse (http://www.aluminiumwarehouse.co.uk/cutting_calc.php), alu profile KJN Aluminium Profile (http://www.kjnltd.co.uk/) and alu box section Aluminium Square Tube | Aluminium Box | Aluminium Warehouse (http://www.aluminiumwarehouse.co.uk/Aluminium-Square_Tube/c120_129/index.html) as I too only have access to limited tools.
Looking forward to seeing some drawings.....

Wobblycogs
08-08-2012, 03:13 PM
When I said I can't weld it wasn't meant I won't or can't learn just that, at the moment, I can't. Part of trying to avoid learning how was a desire to get cracking but as Jazz said it doesn't need to be pretty so I'll add welding to the list of things to learn.

Oooh the machine size question. I've not said anything so far because I suspect I'm making a newcomers mistake of biting off more than I can chew. I'd like a cutting bed of about 1500x1000. One of thing things I want to do is carve / pierce panels for the fronts and sides of cabinets. I could probably get away with a smaller bed but I think that's a good size to aim for.

Can't wait to get drawing some plans but I'm a bit short of time at the moment so you might be in for a bit of a wait until I can post some here. I can't realistically start building the CNC until we've had the workshop built, a process which is really dragging on.