First time build - Steel Frame CNC Router

[examorph]

it will snap your arm like carrot and carry on like it never happened.!!

Ahh, i'm gonna have to get used to keeping a finger on the emergency stop

Cheers for the help guys, will search around locally for suppliers but don't think many will beat the supplier Mike recommended.

[examorph]

Noticed that I might have some difficulty cutting the motor mount slot accurately on the gantry side, so made it a separate adjustable support plate allowing for the Y axis ball screw to sit more central, more adjustment and lets me get started on welding the gantry before getting access to a mill

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I am going to start welding soon and have next to no experience with this so hope you guys can keep me right:

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1. Whats the best way of handeling this, tack up the full frame whilst checking squareness and then weld up fully when happy or do it all in sections?
2. I read on here that short runs are the way to go. Would a 50mm single run along one side of the 50x50 box section be ok or do I do this in two separate runs (25mm)?
3. Are there any parts of the frame I could stitch weld? Maybe the x axis rail support and all of the gantry/side plates? If so, whats the typical size of weld and gap between stitches?
4. Any tips on this/recommended welder settings?

[Davek0974]

Mig? Arc? Tig? What sort of welding?

Yes, always tack up first, when choosing where to weld, always think of contraction - the two sides of whatever you weld WILL be drawn together as the weld cools, no two ways about it, it will happen.

On a box frame I would tack up and check all square, then weld the inside 90 deg angle on opposing corners first. Next I would do the outside edges followed by the two faces. Welding the inner/outer sides first should help resist the tendency of the frame to buckle if the faces are welded first.

Test your settings well on scraps first.

[Davek0974]

Stitch welding is fine, in the right place - if you were welding a plate to the side of a box structure or maybe a corner fillet plate inside the legs, I would stitch, maybe 1" runs. For something like box section legs then seam welding is in.

Think of the stresses the part will encounter, it will help decide how to weld it.

[examorph]

Thanks Davek, I will be using a Mig welder for this. Should have the steel in this week and welding started this weekend.
Will tack up the entire frame and gantry assembly first and check if its all square, once OK I will fully weld/stitch where needed whilst baring in mind contraction.

Is epoxy leveling recommended for a build this size?

[Davek0974]

The chances of it being square when done are slim, treat it as sections and concentrate on getting each section as perfect as possible, whatever method you use there should be a method of tweaking the fit later - my plasma table is 1500 square, it is made up of two side frames bolted together with cross-tubes - i could shim the joints as needed which wasn't in the end but handy still.

The plasma was built in 2mm box section but carefully braced where needed to gain rigidity. I used about 21v / 140A and 0.8mm wire with a tri-mix gas (hobbyweld5) you need to get hot and fast, don't run the power low because it might warp.

Cant help with epoxy, never used it I'm afraid.

[examorph]

Hi guys, came home to find that the linear components had arrived today!! Woohoo

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Seems to be great quality and Fred was a great help, excellent service and I understand now what you all mean by him being a great guy. Will keep these to a side until I get the epoxy and aluminium sorted. Blackburns offered 5754 as the nearest grade to MIC6 and quoted me £85 for 500 x 500 x 20 plate, is 5754 a suitable grade?

Also, steel arrived earlier this week so will be welding this weekend and hopefully have a frame/gantry setup soon.

[examorph]

Steel box section and plate had arrived earlier on in the week:
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Ended up buying a tungsten carbide blade for £80 to cut this as 5 of the 6 local suppliers I visited advised that the machine had a "non-standard" 25.4mm shaft.
Seemed to work fine the first day but when trying to cut the box section the next day, it seemed to require a lot more time/force, I think I may be cutting too fast and wearing out the blade.
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Ended up with a bit extra 100x50 section and too little 50x50 section, I underestimated how much box section it would require and assumed I had more than enough at 7.5m of each. Guess its true what they say about assuming!! Requested price for 1m more of each and changed the design slightly to use the larger box section for the horizontal bracing:
Attachment 17760
Other than the two sections I am ordering, all box section has been cut, but unsure if some of it is still good as I think maybe 3 sections (bed supports and gantry box section) are 3-5mm shorter than what I needed, will this be OK filling up with weld?
Attachment 17761
Was hoping to have it all welded up this week but ended up being a slow start with the few hick ups pushing things back a week
All in all, it was a good experience and even though I had some problems, I enjoyed it and learnt a lot of new things

Some questions I hope you guys could help me with please:

• From what I understand 5754 aluminium is the grade but if specified as tooling plate, would this be OK for use on the Z-Axis without having to face it off?
• As this machine will be moved 3 times (welded in workshop, epoxy leveled in a smaller room for heating and installed in a shed) is it worth welding some adjustable feet to the legs?