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View Full Version : BUILD LOG: Vertical fixed gantry. Design & build. (Steel/epoxy)



Greeny
18-08-2013, 03:28 PM
Hello All,
I'm Paul but everyone calls me Greeny.

New poster, but been lurking on and off for quite a while now. I want to build a router for cutting Wood & Ali as a hobby.
Was going to build a Mechmate a few years ago but had to give up my rented workshop, so it got shelved.
Now I intend to build a more "garage friendly" machine as that's the only space available!

Been through a lot of design ideas, looked at alot of designs on here and that american forum etc.
I was recently heavily influenced by Jazz's Vertical router test thread.

My main design philosophy/goals are.
Acccuracy as good I can make it.Over engineer when in doubt.Use the large amount of steel I have in the garage from my aborted Mechmate build. Also some electrical stuff Geckos , Bobs etc i bought.Mixture of Bolting & welding, but restricting welding to non critical areas due to me being a crap welder!

Overall machine size is 1500 wide, 2000 tall & 1350 deep. (I missed most of that off the Dims. Doh!)
Cutting area is 700 x 1580. Z axis travel is ~250mm.
The frame is steel made up of a mish mash of steel i already have.
The large channel is 200x75, most other stuff is 100x50x4 (channel & tube) & 50x50x3 tube.
The moving Y/Z axis which is the width of the bed is made up of 2 100x100x6 tubes with a full back of 6mm plate.
The orange base is epoxy/granite with steel inserts.
I intend to use gauge plate for the mounting plates etc.
Hiwin 30mm rais & carriages (over the top i know, but i have a stash of 6 of em i got cheap a while ago.)
Chinese 20mm ball screws.
For motors, i already have nema 34 3.9Nm steppers & gecko's

Its basically 5 parts. The big Y gantry, the two side frames,top stiffeners, all tied together using the epoxy base.
The moving X axis only has to deal with cutting forces, inertia and friction. Not it's own weight as far a deflection is concerned.
Ditto for the Z.
The only part fighting gravity is the Y. A small mounting plate for the spindle.

Here are some early drawings. I would be most grateful for any feedback & advice.
Don't be shy. You won't hurt my feelings!

Cheers
Greeny

955595609563956495659566

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JAZZCNC
18-08-2013, 04:34 PM
Well must say That's an ambitious first machine.?

Here's what I can add with experience of my machine being vertical.!!

The bottom of the gantry(Were turquoise plate is) will fill with chips if the end is closed so make it open. Also Chips will also collect on the rails so think about some form of shielding to deflect them or build in wipers.

If possible then I'd try to raise it further off the ground and tilt 15deg or so to aid work holding. Being so low it's a pain fastening material lower down also when you need to access material for say flicking small offcuts out the way etc.

With the Gantry raising and lowering in place of a typical Z axis then I'd connect the screws with timing belt rather than using twin motors, you'll keep screw sync much better. This setup will give good strength but will be so much harder to setup regards tramming the spindle. If there's any and by that I mean even the slightest 0.001mm difference in sync between screws you'll get steps when surfacing material.
For this reason I wouldn't use slaved steppers and tie together with belts or use Servo's with encoders and program drives with tiny error values.

Other than these things then it looks Ok but must say again it's very ambitious for a first machine.!!

Oh and why are those screws on the bed so far out.?

Boyan Silyavski
18-08-2013, 05:23 PM
You say you are crappy with welding and here i see a truck trailer:toot:

Greeny
18-08-2013, 10:05 PM
Well must say That's an ambitious first machine.?

Yes, it has kind of got out of control!
Should be fun though, until it starts going pear shaped.

Thanks for the advice on chip protection/clearing and raising/tilting.I hadn't really given either a great deal of thought.
Will ponder more on those.


With the Gantry raising and lowering in place of a typical Z axis then I'd connect the screws with timing belt rather than using twin motors, you'll keep screw sync much better.

I am definitely thinking about one motor for both screws. It seems both the simplest and best way of syncing the screws.
The gap between the screws is ~1770mm. Is this something to worry about with belts?
Is it possible/feasable to have a central motor driving two pulley wheels (one for each screw) so each belt is half the length.(each belt would need a tensioner)
quick & dirty sketchup
9570


Oh and why are those screws on the bed so far out.?
They are slapped on there as i'm unsure about pulley system & the layout for pulley wheels.
There is quite a bit of wiggle room so i should be able to finalise their position soon.

Thanks for the comments an advice
Cheers
Greeny

Greeny
18-08-2013, 10:07 PM
You say you are crappy with welding and here i see a truck trailer:toot:

LOL. yes I think the phrase is "sucker for punishment" :black_eyed:

Hopefully i'll be a slightly less crappy welder at the end !

Cheers
Greeny

JAZZCNC
18-08-2013, 10:44 PM
Oh before I forget your not from Yorkshire are you.? My best mate at school was called Paul Green but he moved away.!


I am definitely thinking about one motor for both screws. It seems both the simplest and best way of syncing the screws.
The gap between the screws is ~1770mm. Is this something to worry about with belts?

No except you'll have to have it made for you, it won't be something you find on the shelf. Most decent bearing/belt suppliers will get you one made. If at the time you have trouble drop me an email and I'll put you intouch with someone who will.


Is it possible/feasable to have a central motor driving two pulley wheels (one for each screw) so each belt is half the length.(each belt would need a tensioner)
quick & dirty sketchup

Yes and infact my first effort with belts was done something like that but in a V shape.
9571

Greeny
18-08-2013, 10:57 PM
Oh before I forget your not from Yorkshire are you.? My best mate at school was called Paul Green but he moved away.!

Strangely I am!
But Whitby in North Yorkshire. I've never moved, so we must be different people. (I will update me profile)


Regarding the belts, that's exactly what i meant. Cheers.
Which would you recommend?
Single long belt, or two shorter ones as per your picture.
Or is it 6 of one & half dozen of the other?

Cheers
Greeny

JAZZCNC
19-08-2013, 12:20 AM
Strangely I am!
But Whitby in North Yorkshire. I've never moved, so we must be different people. (I will update me profile)

Ah was just up road few a weeks ago at friends in RHB.



Regarding the belts, that's exactly what i meant. Cheers.
Which would you recommend?
Single long belt, or two shorter ones as per your picture.
Or is it 6 of one & half dozen of the other?

Well seen has I went with the long version I'd have to say that but really there's nothing in it and I only went with long because it was easier to make covers (Which never got made) . . .Oh there's a tip for you DONT EVEN THINK ABOUT turning machine on until you have finished all you planned to do, you'll never do another thing to it again for least 5yrs if you don't.!!

Greeny
19-08-2013, 09:26 PM
Ah was just up road few a weeks ago at friends in RHB.!A gem of the NE coast. Was in Dolphin for a pint or two just last week!

Thanks for the info on belts, and the warning about finishing before firing up. That definitely applies to me!

I have been thinking about the advice given so far and am now thinking about toning in down a bit. :concern:
Here is a new draft, with quite a smaller footprint, that is simpler, and should be a lot easier to build. As well as cheaper for Rails/Screws etc. which i still have to buy.
Have added M20 ball feet so i can adjust the lean angle.

Cheers
Greeny

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