Hello to you all.

I’m new in the group. I’m from Portugal and I’ve been caught by the “CNC virus”...

I intend to make large scale car models in foam. A starting point, to make very accurate 1/3 scale car models in fibreglass.

I bought a couple of months ago, a little CNC machine from Roland. It’s a MDX20 model, and it has 200x150x65mm working volume. Very small, but very accurate machine. I’m going to use it to make the small items for the model cars, like the head lights, the mirrors, the wheels, etc. It’s capable of milling hard wood, plaster, plastic, aluminium, etc. It’s also capable of 3D digitizing…

But I’m with the problem of the body. Especially by the size of it. I was considering many options, including a spectacular (for me) “enlarging machine” that I’ve invented.

With that, I could start with a 1/24 or 1/18 scale model and then I could make an enlarged model in foam (6 to 8 times bigger than the original) by a mechanical device, with out any electric or electronic device (except for the spindle motor).
This is a very time consuming machine, because it couldn’t work by itself.

The result it’s a not very accurate model, especially because all movements are enlarged 6 to 8 times, including all the errors and the smallest details…
But it’s a good starting point to make the models in 1/3 scale (about 1,5 mt length)

But the main reason of this post is that, after I found this group, and a couple of related links (about home made CNC machines), my thoughts went to build a CNC machine that could make my models in foam, but very much accurate and with other scales also.

My questions are, if anyone can take his time for it, and having in mind that I don’t know almost anything about electronic devices:

Can I actually build a 4 or 5 axis CNC Machine?
How much would the cost be?
Are there any plans or kits to start from?

Can anyone tell me how can I achieve that?

Thanks in advance for the time.

Best regards from Portugal,
Ernesto Freitas

you might be interested in this:

http://www.rainnea.com/cnc_5axisMill.htm there is a gantry too.

Jon

I intend to make large scale car models in foam. A starting point, to make very accurate 1/3 scale car models in fibreglass.

Can I actually build a 4 or 5 axis CNC Machine?
How much would the cost be?
Are there any plans or kits to start from?


This sounds like a very enjoyable project. Welcome, Ernesto, to the group!

Let's take your questions, one at a time.

Of course you can build a 4 or 5 axis CNC machine -- trust me, anyone can do it. How much of the project *you* do will help to determine your final cost.

Let me make the following suggestion. It's often suggested that someone build a small, simple machine first, as a learning experience. You could build a large 3 axis machine, and add the additional rotational axes later, as you gain experience.

The cost is going to be highly variable. Assuming this machine would be used only to cut foam, the loads on the parts would not be very great.

You'll have to tell us what level of accuracy you want, but it should be very possible to make a medium to large sized machine, from commonly available parts, and to do so relatively inexpensively.

If you want to upgrade your parts (for example, manufactured linear rails, rather than something homemade) it'll cost more.

As for existing plans, there are quite a few sets of them, some of which are offered by people on this board. I'll let them respond to this question, specifically.

If you give us some more details about your requirements (what does "very accurate 1/3 scale car models" actually mean, in terms of dimensional errors? +-1mm, or +-1um?) and some more details on the project, I'm sure we can come up with some specifics!

-- Chuck Knight

One of the big hurdles to overcome is the cost of the 5 axis cadcam software. If I were in your shoes, Ernesto, I would shop around and see if there is 5 axis software within your budget.

Thanks for your reply.

In fact +-1mm is more then acceptable.

I can make (or have someone to make it for me) almost all the “mechanical” and structural parts. I only have to get the electronic stuff and learn how to build it up all together…

Of course there is the software problem, but let’s forget that for this moment.

Best regards from Portugal.
Ernesto Freitas

JFETTIG,

Was that build by any plans? I'm just in love by the 5-Axis Gantry Router. It's a dream come true.

Ernesto

You don't need 5 axis, I bet you can do many things you wish with 4 axis or with fixtures, especially in foam.

I made a 5th axis for my mill, had no time to really try it yet, it is also for foam. Check out my site and you will see I make model planes. I also made a digitizer to help copying models etc.

Ernesto, he built it from scratch no plans, the 4th/5th axis are surplus satalite dish turners, the rest is standard router. He uses his own kit of macros in a 3D program I forget the name of. You can get the toolkit from him and join the yahoo group, there is also a free version of the 3D package called gmax, it is limited but you can import from other programs etc.

Cheers,

Graham

Can you please tell me you site?

Ernesto

ooops

www.indoor.flyer.co.uk/5thaxis.htm

In the rainea site, he incorporates two pancake type axises in order to make his birotational head on his z-axis. Where can these items be purchased? or if there is a kit to build it, where would you purchase it?

I would imagine that if he machined it himself, he must have incorporated two stepper motors in the head.(one to control the A axis and one to control the B axis) They would have to be small and use small internal gearing in the pancake-like housing. From the picture, I can see a stepper motor on the head but only one from the angle shown.

Patrick,

http://surpluscenter.com/item.asp?U...atname=electric

Marv

Well, looks like they have discontinued the item. Try this.

http://cgi.ebay.co.uk/ws/eBayISAPI....item=3826181817

hey marv
I tried both links but they seem to be nonworking. This 5 axis router is quite a idea though, I wonder if anyone built one yet?

Surplus Center Sat drives working link here (http://surpluscenter.com/item.asp?UID=2004040510102583&item=5-1440&catname=electric)

gracias

Patrick2by4
From the picture, I can see a stepper motor on the head but only one from the angle shown.

Looks like 2 steppers (C & B) http://www.rainnea.com/tilt-swivel-head.jpg
That is a cool setup!!

I can't find on that site about Tilt Swivel head, is there any place I can buy that stuff ?

can't find on ebay also ... nobody would sell that...

I would love to buy that...
rud

Hi,

I made my 5-axis head from two of the surplus Sat drives,
I machined off the flanges and bolted them together in the most compact configuration that I could find.
I replaced the dc motor and its gearbox with a stepper.

It's actually up on ebay (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=7509162058&rd=1&sspagename=STRK%3AMESE%3AIT&rd=1)just now as I'm upgrading the machine to harmonic drive units (a lot more expensive) if you want to buy one ready-made.
- item no. 7509162058 if that link won't work

I wrote a plugin for 3DS MAX / GMAX that generates the 5-axis G-Code which currently gives you a free basic 5-axis CAM package.

Regards,

Rab

Rainnea CNC (http://www.rainnea.com/cnc.htm)

thank you for pointing out, how come i can;t find it when i search it in ebay.

anyway ... they are in UK, they won;t ship to Indonesia :)

how much you bought it anyway ?


regards
ruddy

Where did you find the sat drives?

ebay,

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=7514383803

Rab,

Rainnea CNC
www.rainnea.com/cnc.htm

Those are the ones I have on the way. I guess I just did't think they were that small after the large diameter is cut.

is it correct it has .5degree backlash ?

The backlash seems to vary between units,

The ones I got had quite a bit of backlash in the reduction gearboxes integrated with the motor.

Rab

Rainnea CNC

how is your harmonic gear ? have you got it ? WIP ?

rud

Hi,
the units are here, I just need to machine up motor adaptor and mounting plates

Rab

What do they look like? Any pics?

yeah any pictures ?
i wonder how big it is ?
how much you bought it and where ? ebay ?

I bought mine quite expensice US$ 200 1:50 ratio.

rud

what kind is yours for $200?Any pics of that one?

here it is

Who makes that one? Do they have a smaller one?

well the problem is I do not know what brand it is.
I saw smaller than this but longer.

I need short for my 4-5 "spindle" axis.

it's japan made, the bearing brand says NSN or something, defenetly not NSK.

if anyone knows who made it let me know, I just want to disassable it but I need the drawing to do that, don't want to damage the bearing.

rud

Where did you see them? What site?

i was in singapore, it's where I got mine from.
I don';t think he sell it for public.
rud

http://www.harmonicdrive.de/en/2_3_1.htm

I paid £400 for a pair of new, old stock, size 20, 50:1 ratio

Rab

Any progress on your new head?

I'm busy making the body frame , the head going to be the last.

check this out
http://www.5-axis.com/

does anyone has any clue what''s inside ?
any idea how to make it ?
any drawing ?
does they use harmonic gear ? I don't think so.

they said it's servo driven.

rud

Calico, Cool Link! Did you notice in the videos that they didn't do any actual cutting? (Just followed the Cutting path/Contour, of a part already cut) I want to see chips Fly! :)

Ernesto,

Most of the clay/foam mills I have seen in design studios are 3-axis horizontal arm type machines. GM has machines made by Tarus... maybe a google search can yield some pictures. Basically, there is a track in the floor that runs beside the car (front to back). On this track is a tower (Z axis) and from that tower a horizontal arm that runs cross-car (Y axis).

The spindle is a seperate router looking thing. It is set to different angles - so the software creates different files depending on the angle. Only one side of the car is done at a time. They have the luxury of having a machine on each side, but you may have to rotate the model or have a duplicate floor track.

Just my two cents.

Henry

http://www.tarus.com/styling

This site is well worth the visit. While I am here, is there anyone that has any experience with 5 axis that could spend a little time with us here. I have several questions and need some input from someone who's been there.

Mike

Mike, what type of experience? I've ran 5 axis machines for almost 10 years, and still currently run one.

Shoot away with the questions, and I'll try my best to muck them up.

Hey Dustin,
Knowing you like I do I am tempted to take this off forum but I have looked so hard to find some 5 axis info lets leave it here and maybe everyone can benefit.

First I want you to know I am not nuts. I want to build two 5 axis machines! :idea: I want to build a really small one but I also want to build a fairly large envelope machine too. Like the starter of this thread I want to carve car parts or full bucks from foam or mdf. Nothing any harder than that. Due to the size of the parts I need this thing to move right now! With that in mind it needs to be light weight and stiff. So how do I do it? (nuts) :D Ok enough of the emoticons!

What I am after is a machine that can carry a spindle that will handle as large a bit as possible and still be nimble. I plan to use good linear ways with belt drive for the x,y and z. I am curious if a stepper will give enough holding torque to keep a 4th and 5th axis in place while machining mdf at 3-500 ipm?
I will machine it faster than that if I can come up with all the right compontents.

I would like to build the b/c rotary and yoke out of aluminum honeycomb and carbon fiber for stiffness and the ligthness. Do you think this will work? If so co you have any pics of a yoke head that I could get some specs from?

Mike

ps on the small machine, I am certain the composite I described will work. I just need to design that little yoke thingy!

Mike, by the sound of things it seems like you are hoping to build a machine and get seriously into carving other people's projects? i.e. more than just to carve your own present automotive project? I know you've probably already thought this through but if it's just for your project wouldn't it be cheaper to get someone to carve your job for you? I must say that I was pretty impressed with your idea of a simple 3 axis stepper powered unit where you just change the plane that it is working on. (i.e. left side vertical, top horizontal, etc.) I guess the limitation of your idea and mine (carving each plane and then joining (screwing) the planes together) is that the more rounded or flowing that a project is, the more difficult it would be for this type of machine.

p.s. Has anyone got any idea of what one of those heads from http://www.5-axis.com/ costs? Just curious that all.

Hi Skippy,

I think I can build a light weight machine cheaper than I can have the part machined. I believe there is also a good market for this type thing. The accuracy doesn't have to be what GM or Ford would require because these guys are still going to do a lot of hand work on their buck/plug. Dab would be the one to give an idea of how expensive (hrs) it would take to carve a whole car body, but that is not all the story. The door jambs need to be carved the glass flanges where the sealant rubber will go has to be machined. Of course all those things would require additional time but would be much simpler for the machine than an individual having to do it all by hand.

Mike

edited to add: I haven't given up the idea of the manually indexable z axis. The problem with it though is that when you need to cut the door jambs it may not work. The undercuts on the rear of the car would not be possible and probably lots of other areas I haven't even thought of.

Turmite,

I am thinking 3-500 inches/minute to be allot faster then is possible for a light weight machine. I am in the process of making a 4x4x4 machine to do scale work right know and the I will move up to the big boy. I will probable use the same x head and drive on the big one and just make x and y bigger.
I am thinking of making a large rotary table for the big machine and axe the fifth, but just a thought right know.

Mike

Hi guys,

I was browsing through and see that a few posts back the discussion was on harmonic drives. I picked some up last week off of eBay-$200/unit. They were manufactured by Harmonic Drive Technologies (www.harmonic-drive.com). These are 120:1 reduction. I've attached some pics and a drawing from the web site showing their recommended drive-a toothed belt.

Lance

mikejkd you may be correct but I can cut at 300 ipm in foam right now with a much heavier machine than I am considering build plus I plan to use belt drives with this one, which mariss says is faster than screws or r&p.


lance are you selling those harmonic drives? If so lets talk consider one or two of those on that other deal. :)

Mike

Hi, I´m in a simililar project like Ernesto. (Sorry for my poor english)
My machine is only on paper for the moment, it´s a big gantry mill (3metersX - 2mY 1m Z) for foam patterns used in lost foam die casting. I think I will need 5 axis, and in this point I´m not sure to go on. This is what I planned at the moment.
Rack and pinion, with 1/4 reduced by timing belts with 5 Nm torque steppers. I´m thinking to put the 5th ahis on the table, to make it easyr, but I,m not sure. Like Ernesto asked, Who has built a cheap and simple 5 axis?
Kind regards from Argentina

I can live with 1mm accurancy.

check this site, it has a veeeeery large foam mill

http://www.hsm-modal.com/

just use rotarty table units, the more compact the better, what baffles me is the offset of the router not being directly under the rotating axis in the rienai router, i presume the cad toolpath generators allow for this oddness

I have plans to make my router a 5 axis.
Yes you can get two rotary tables, but that fun is that? My idea is fairly compact. It should be rock solid too.
50mm preloaded roller bearings, two of them for each rotary axis.

I have some 40mm angular contact bearings I will be using to add another rotary axis anyways. Tricky part I see is coping with backlash