Project priorities...I need some help.

[Azonic]

As I posted in another thread, I have drawn plans for a 5 or 6 axis machine.

I then took the plans and built a (not to scale) model of the machine from cardboard.

The machine will work, I just have the problem of haivng never built a CNC machine...

Where do I start now? I know my gantry will have to support a good deal of weight, torque, and horizontal forces...

So here is the issue...

What spindle do I buy for cutting anything from foam to alum...
What motors and controllers...
What type of bearings, slides, etc...

I know I do not want to buy the motors and such and end up with ones to small.

I do not want to build the gantry and then find out I have to rebuild it as my spindle is to heavy.

I will also need a variety of belts, pulleys, or gear boxes, dual drive axis movement, lathe head, and multiple tools for the spindle..

I refuse to just start buying stuff...

So if this confused state sounds familiar to you...

Give a guy some help will ya?

Thanks!

[ger21]

You say you know it will work, but you don't even know what you need to build it?

You need to do a lot more research before you buy anything. Imo, attempting a 5 axis machine for your first is a recipe for failure. In the 6 or so years this site has existed, I haven't seen a single 5 axis machine built. So finding information on what you need will be difficult, because very few have done it. And again, finding people to tel you what you need will be difficult as well.

What size machine are we taking about here, and what's your budget? And I'm assuming your talking about a moving gantry with a spindle that pivots on 2 axis?

[Azonic]

I understand what you are saying...

As I have been doing my study work I have found the 1.7 million 3 axis machines built from this zone and a hundred others...

Honestly, those are awesome machines, and inspired me to build mine, however, I very rarely do anything simple...

So I thought, 3 axis would not get the design work I wanted it to do.
The 4th axis was the step in the deisgn that set off the whole idea of more axis.

the 4th got me most of what I needed, but the addition of the 5th in the terms of a lathe head was a simple addition to me... (I know I may be wrong)

In terms of what I want to work on it..
minimum requirements is a 2'x2'x2' cube of foam to alum... on the multi axis.
4'x2'x2' on the bed for the 3 & 4 axis work...

I am not as lost as it sounds, and it is not as complicated as it seems..

I know what I need to build it...
Just where to start is the issue...

[lovebugjunkie]

What Cam software have you chosen for your 4 axis work?

[TOTALLYRC]

Originally Posted by Azonic I understand what you are saying... As I have been doing my study work I have found the 1.7 million 3 axis machines built from this zone and a hundred others... Honestly, those are awesome machines, and inspired me to build mine, however, I very rarely do anything simple... So I thought, 3 axis would not get the design work I wanted it to do. The 4th axis was the step in the deisgn that set off the whole idea of more axis. the 4th got me most of what I needed, but the addition of the 5th in the terms of a lathe head was a simple addition to me... (I know I may be wrong) In terms of what I want to work on it.. minimum requirements is a 2'x2'x2' cube of foam to alum... on the multi axis. 4'x2'x2' on the bed for the 3 & 4 axis work... I am not as lost as it sounds, and it is not as complicated as it seems.. I know what I need to build it... Just where to start is the issue...

Easiest way is to build a three axis machine that will have the 4th and 5th added to it once you get the basics up and running. I think that you underestimate what it takes to get a three axis machine up and running.

If you go with a truninon type 4th and a 5th sitting on the trunion it will make the gantry a lot lighter and you won't have the x axis carrying the other 4 axis.

Not to mention the fun and cost of programing in 5 axis unless you are just doing simple positional moves that can be done by hand.

If you know what you need to build it, then where to start is easy. If you need help on where to start, then you don't know what you need to build it, not really. I think what you mean is that you know what you need to build it in broad terms, but its the nuts and bolt that are the tough part.

Since you are woking in foam and maybe alum, an all aluminum frame work should be suitable.
I just noticed that you want 24" in the Z, that alone is going to be difficult because you also need room for components, so the upright could be as long as ~36". This means that you will need to add extra stiffness to compensate for the long lever arm of the z in both the x and y planes.


Of course you left out the most important fact, your budget.
If the budget is $250, forget it.If you say $2-$3k, you will be able to do a nice benchtop machine. If you are shooting for 5 axis, don't start if you are going to skimp on the components.

I can't wait to se the drawings and videos of it working.

Just my random thoughts on your random problem

Mike

[Azonic]

I think you got the point mike...
I am to the point where I need to make desicions of where "the nuts and bolts" go...

I will scan in my original set of "rough" drawings...

Your guess was right, a 36" upright is in order
From a technical stand point, very little will be done in that size range...
But limiting myself does not sound as much fun as building it right the first time...

Budget.. This is not a $250 budget, nor is it an endless budget either...

I do aim to stage into the project. But I have to make all 4 of the original axis work in the original build.

I was aiming for at or around $1000 to build the X,Y,Z portion, with the 4th axis built into the project...

Then move on to making the 4th work, and then adding the 5th axis as a lathe head. during that phase I was intending to make the lathe head mount to a rotating base...

and the point made about cheaping out.. don't worry..
I will build it right or not at all...

I was going to skip building with alum and make a heavy steel frame...
As the X axis needs to carry the 36" tall gantry, the Rotating Y axis, and the dual tower Z axis....

Maybe pictures would help?

[Azonic]

http://www.cnczone.com/gallery/showp...2/limit/recent

[TOTALLYRC]

Originally Posted by Azonic I think you got the point mike... I am to the point where I need to make desicions of where "the nuts and bolts" go... I will scan in my original set of "rough" drawings... Your guess was right, a 36" upright is in order From a technical stand point, very little will be done in that size range... But limiting myself does not sound as much fun as building it right the first time... Budget.. This is not a $250 budget, nor is it an endless budget either... I do aim to stage into the project. But I have to make all 4 of the original axis work in the original build. I was aiming for at or around $1000 to build the X,Y,Z portion, with the 4th axis built into the project... Then move on to making the 4th work, and then adding the 5th axis as a lathe head. during that phase I was intending to make the lathe head mount to a rotating base... and the point made about cheaping out.. don't worry.. I will build it right or not at all... I was going to skip building with alum and make a heavy steel frame... As the X axis needs to carry the 36" tall gantry, the Rotating Y axis, and the dual tower Z axis.... Maybe pictures would help?

Hi Azonic,
very interesting drawings.

A couple of problems with it spring to my mind.

1.moving the Y axis up and down may introduce racking of the Y axis along the plane of the Z axis.
2. Since the Z axis is the y axis carrier, the end of the spindle will either have to project out quite a bit all the time or you will have a tough time reaching the sides or down into pockets.
3.It seems awfully convoluted way of doing what you want.
4.It looks like keeping it rigid is going to be quite a task
5. I am not sure if center driving the x axis will work at 24" wide, but it will all depend on exactly how wide the X axis slides are.

With something this complex and "off the wall" ( no disrespect intended)for lack of a better term, I would build the frame work first, verify that you can actually do what you want, then work on getting motors screws and what not.
This way, you get a feel for the weights and can buy motors to suite, as opposed to trying to lighten stuff for the motors that you have.

All this being said, I would not build the machine in the fashion that you have drawn.

You have seen a million three axis gantry machines built the way they are because they work.

A trunion table can be built out of a rotary table placed on its side for the drive end, a "tail stock" on the other side and a plate between them, The you put another rotary table on the plate at 90 degrees to the first one and all the weight is put on the table where it belongs, not overloading the gantry.
Then the rest of the machine looks like a standard gantry router.

Ifr you choose to go ahead with your design anyway, I will keep watching and try to help where I can.

Mike

[Azonic]

Mike...

My son and I are getting ready to do a "claymation" of the model we have built..

In the model I found a couple issues, similar to what you have described...

The vertical movement works well, however the Y axis movement wants to move the vertical posts. That is not to hard to fix, support built in, second set of rails, etc...

We only have the first 4 axis built... ( we ran out of materials! Lol)

The tool will be on a narrow/long spindle and will reach most places within the limits of the axis movement, the rest comes from the lathe and rotary table.

The center movement of the X axis as you state, may be to much for the size, if so, I will move to dual drive similar to the Z axis movement.

My primary purpose for building it this way is to avoid moving the deck.
For 5th axis movement, I will use the lathe, however
normal work would be done with NO movement of the material, just the tool...

I appriciate the input, and understand what you are saying...
And perhaps it is the road less taken, but that road sometimes has supprises on it!! (even if some are good, and some maybe bad)

[Azonic]

Here is the animated model.
Sorry it is so small. I had to really shrink it down to fit the size limits of the gallery....

I do see a need to further brace the vertical pillars, and add them to the X axis rail...

The X axis does move well with one point of force at the center, however, I may go with dual drives just to prevent any torque...

Add the 5th axis as a lathe head and I am pretty close...

Or am I still way way way off from something that will work when built of quality materials and craftmanship?

[Azonic]

This is the model used for the animation...

Note the Z axis move with it's base as the rail guides for the X axis. The Y axis only has to support the spindle and not the Z axis too...

The Z axis will need dual drives.

The X axis does move well with the force applied at the center, however, I may do dual drives here alos to prevent torque.

The 4th axis (A or W?) works with torque applied to the base through a rod and pulley connected to the motor, and the top moves along a cam follower.

Larger view..

[austin.mn]

I like the enthusiasm and 'can do' attitude....

But honestly there are a lot of lessons to be learned by building a simple machine, and then another, and then another. There are a lot of things that in theory should work great, but in reality don't live up to the promises. One thing to keep in mind is all the accumulated slop. I used to work in a shop that had a couple of 5 axis routers, which worked fine for what we used them for, but you would never be able to do any real accurate work with them once cutting forces were introduced.

One of these days I too would like to build a multi axis machine, but at the moment I am happy to continually make advancements on the simpler 3 axis machines I have.

What kind of parts did you want to make anyways?

Keep up the good work, start small and use the best materials you can afford.