Scalable / Adaptable Gantry Router

[ynneb]

Andy, I must say I am smiling at what you have done.
Firstly, I remember you telling me how you were going to build your machine out of Mecano ( I said i liked a guy who was prepared to try new things, while thinking I didnt hold much hope for it) Then you were going to make it out of an old Triton work bench, I was thinking, yeh I am glad this guy has dropped the mechano idea. At least he has a better chance with the triton, but still not the best idea.

Then we discussed welding and glueing of you metal frame. I hated the glue idea.
I see you have settled for bolts. I have previously offered for you to take my welder, the offer is still open.

Its fun to see your progress, because I can see how you have considered many options and you project has evolved greatly over time. When you are finished, I am sure you will look back with fondness over the time you spent thinking and considering options for you machine. Its a head ache in the mean time though, but your progress is going well.

Keep up the good work.

[andy_ck87028]

Benny

Thanks for your very kind remarks.

And thanks for repeating your offer over the welder.

Much appreciated and I will most probably be taking it up.

I'll hopefully pop over soon and who knows Santa might have a beer with him

Andy

[Pat2000]

Hey just catching up with yer thread Andy... interesting... looks good! I'm interested in that Z axis when you get there, thanks for the PM enjoy the heat you lucky Auzzies.

Pat

[andy_ck87028]

I've thought of two innovations this afternoon that I will be incorporating into my machine.

Thought I'd report on them as they might be of interest to others.

Large Z Travel

From the pictures below, even though the pictures aren't that clear, the router is a long way down from the y rail. The ideal place for the router cutter has to be as close to the x and y plane as possible as the further the distance away from those planes , a) the greater the risk of vibration, b) inaccuracies caused by increased moment c) greater wear on parts and d) accelaration/deceleration problems caused by the gyro affect of the router.

The problem is that if you want large travel on the z axis, the greater that distance can become. Furthermore, if the head assembly is designed for a 6" Z, then the normal place for cutting will be at the bottom of the travel which is the worst place from a design efficiency point of view.

So, my answer to this problem is 1) keep the x plane as close to the y plane as possible, 2) have the normal cutting position for the z immediately below the x y plane 3) still allow for 6" z travel and 4) have a variable height cutting table. When the 6" Z is called for....... lower the cutting table.

Modular Head assembly

From the pictures you will see four vertical angle irons within the triangular frame. Try to visualise that as two components, 1) a self contained box (called Z assembly) and 2) a triangular head frame. The box then goes within the head frame.

Earlier today, I was thinking about structural rigidity of that entire assembly and realised that with the Z assembly being a self contained box, then a) I would ensure that assembly is rigid, b) alignment is then managed purely as a positioning issue of the box assembly within the head frame (assuming the box itself is square) and c) I can easily remove the Z assembly if I need to replace the tool attachment.

To achieve that, I would need to ensure the ball screw is attached to the head frame as distinct from the Z assembly.

Effectively what I am describing is the separation of each sub assembly into discrete parts and then ensuring that the purpose of each sub assembly is clearly defined.

Hope those thoughts are of interest.

Cheers

Andy

[andy_ck87028]

No other pictures at this stage but plenty of effort.

Many false starts but still having fun.

Have bought 3 of these Nema 34 637oz steppers and they are coming back from O/S in my wife's suitcase (I'm not popular!)

I've just bought my z axis bearings , have got my Z axis shafts (from a scanner), have just bought 5 metres of timing belt and a couple of pulleys.

Have bought a toroid.

New phase of building has just started.

X linear rails built, y linear rails built, trucks assembled.

Having fun

Hope to be finished by Xmas !!!!!

Andy

NB Thanks for the patience almost everyone has shown in coping with my often inane questions. ... just wait when I can't get the b----y thing working

[andy_ck87028]

Well 18 months later and the machine is now manufactured.

I am now going through the process of aligning and tightening; bedding down, etc.

I have also just got me a camera

So, I thought that I would show some pictures that will reveal the detail of my design.

The two pictures attached are one of the carriages that sit on the X axis. Attached to the carriage is the sub assembly that the y rails are bolted to.

More pictures soon.

[andy_ck87028]

Oh yes.......

Some of the earlier pictures of the head assembly are now history. Bin fodder!!

I'll get some pictures up of the finished version soonish

Andy