1rst build, time to do next step

[Gytis]

HI,

this is my almost finished CNC machine model,
bed is from the aluminum extrusions (heavy) 90 x 45 and 45 x 45, it will cost me about 800 eu + delivery?, only for the extrusions!
overall dimensions (bed) is 1590 x 1250 x 590 mm.

[JAZZCNC]

Wow your really making that harder and more expensive than it needs to be.? Also has a flaw.?
First I'd use Steel for the frame and save 600eu.!! . . but that's not what I mean here.?

Orientate the side profiles on there edges and you'll gain strength and be able to do away with those aluminium braces and the 2 long middle profile, then Extend the 3 uprights to meet top rail.
Put the ball screws on the outside and make drop brackets part of gantry sides, sides will be shorter than drop bracket, less material,weight,money. Easier to setup and adjust screws/motors has they are more accessible. Then you can line the inside walls doing away with the slot and stop crap hitting the screws completely.!! . . . . Your way has a BIG flaw in that it will allow chips into the sides, still hitting screw and eventually filling up the sealed cavity.
You'll be constantly cleaning it out and believe me it won't take long to fill the void between middle profile and slot. Chips spray in a linear direction off the cutting tool and that Gap is in direct firing line so you'll be surprised just how much disappear thru it.!. . . . Kid you not Bet I could fill that gap with alu chips within 3weeks and that's allowing for sizeable percentage not hitting slot gap.!!!!

One other thing.?. . . If those bed supports are 45x45 then I think you'll find there not strong enough at that length and allow bed to potentially bow in centre when cutting or plunging. My suggestion is to put 2 or 3 45x90 on there edge for main supports and make rest up with 4x45.

Sorry to keep pulling at your designs but with experience these things just jump out at you and I'd feel shit if didn't mention them, then at later date you came back and said wished I'd done this or that which I'd spotted.!!

[Gytis]

Hello,

OK..., this is me second attempt to make a strong frame, but this time not so expensive.
Frame from the steel box 60x40x4mm all round, steel will cost me about 180£ (6 x 7.5m), it's a big savings compared to aluminum.
just a little bit worried for the welding work, but I'll try and we'll see what happens

Wish me good luck

frame size 1600x1180x600 (x,y,z)

[Jonathan]

The way you've mounted the bed looks a little weak to me. The bed box section could rotate about the fixing 'rails', so the end fixity is poor, which means the bed itself will sag more when a weight is placed upon it. You could instead bolt the bed frame directly to the machine frame.

[Gytis]

The way you've mounted the bed looks a little weak to me. The bed box section could rotate about the fixing 'rails', so the end fixity is poor, which means the bed itself will sag more when a weight is placed upon it. You could instead bolt the bed frame directly to the machine frame.

I was thinking about that, bolt bed directly to the frame
but then I have to make the bed a very accurate, This means that zero play between the bed and frame
I chose the easy way, the bed pulls out like a drawer and can have a few mm error

[JAZZCNC]

the bed pulls out like a drawer and can have a few mm error

No BAD idea it will resonate and will show in the quality of cut.

You don't need to make the bed tight fit just have few mm gap and put the angle brackets so they fasten to the insides of steel uprights. Make the side guards out of flexible rubber or plastic like Damp course fasten to bed sides and at top rail so it travels with bed and the brackets will be underneath out of way and accessible from out side.

Then you just surface the sacrificial board on the bed to bring parallel to machine.

[Gytis]

Hi,

quick update,

received yesterday parts for the Z axis from JAZZ CNC
well.., what I can say.., he is a real man !
I'm impressed with the quality and accuracy of the parts! Thank you Dean!

My next step will be steel frame construction , I waiting for the chop saw speed regulator (I want to drop RPM of my saw) and welding mask .
I hope to see you soon?!

[JAZZCNC]

Hi Gytis,

Looking good just couple of things which will help, you may have seen me post it on other threads has I seem to be repeating my self quite a it now more folks are taking to steel.!!

Make the top rail bolt onto plates, much easier for setting rails parallel and on same plane.

The connection of bed to frame looks a little weak and could flex. I'd just bolt straight to frame with angle brackets. It will also be very heavy so I'd consider having some way to help assist with the lifting, IE Acme lead screw or Large pitch Threaded rod.

Would make the sides separate bolt on sides and have the green frames separate structures, would also make the triangle braces on green ends longer so they support frame further down.
Having separate sides will make assembly easier with flexibility to adjust any error out like getting square and vertical. Also will come apart for moving or if you sell it.

Secret to good DIY is lots of adjustability.!!