New Member and New Build design check

[Procato]

Hi all

Been lurking for years and finally, after many false starts and many redesigns later, have begun a build only to redesign it again. So in an effort to finalise the design and gain some knowledge and tips from the experienced- here's is what I have so far. As you can see, it is an almalgamation of builds and advice gathered on(Stolen from) this website.

I plan to have mill 3d hardwood, softwood and foam sculptures and when the bed is raised I would like it to mill aluminium. it's 1400mmx1000mmx900.

The frame has been mig welded together using 80x80x3.5 and some 50x50x2.5

I had bought some supported round rails a couple of years ago when I first started thinking about building this but unfortunately work got in the way of that build. I had made the decision to use these rails on this build but then, having got this far with the welding, I thought if I'm going to do this, I ought to do it properly. So out with the round rails and in with linear guides and hopefully a substantially 'beefed up' gantry and Z-azis.

So any advice will be very welcome.

I'd appreciate it if any changes to the frame were additive rather than subtractive - I can't face starting from scratch again!



As you see I haven't modelled in any fixings yet and the strange shape of the outside plate on the y-axis is to accommodate another piece of box section if it is needed in the future.

[toomast]

Hello sir!

Gantry certainly looks beefy! What weight do you estimate for it?
It looks like it could handle steel...and little bit OTT for mostly wood? :)
Frame is simple and sturdy.
How will you solve the bed design and work-piece fixing?
I notice 4th axis?

[Boyan Silyavski]

I see a new contestant for the sturdiest build here

The only weak spot that i see at first glance are the corner table connectors. I would additionally brace then in the other direction / L. And this is additive :-)

[Procato]

Hello toomast

Many thanks for your reply.

Now you've got me worried, after some quick guestimation in CAD i think it's going to weight in at about 95+kg - is this too heavy?

Re; bed design -The lack of fixings and fixing holes is misleading - I hope to utilise the same method as Jonathon's, after the rest of the machine is built, I plan to attach a large 20mm-ish aluminium plate to the steel frame of the bed then mill it flat, then mill the slots and finally drill and tap it so that I can screw down aluminium strips to form the T-slots. I realise the t-slots on the outer edges won't be possible with this method so I will probably leave them unmachined.

I think I will be mainly routing highly detailed wooden figurines up to lifesize (in 2 parts) which will be held in the rotary axis on one end and free rotating tailstock at the other. both of these will be bolted down to the bed via the T-slots.

The 4th axis is a doughty drive which I bought a few years ago but I've also got a bargain harmonic drive off ebay the other week which is bigger and stronger and will turn that into the 4th axis. I hope then to mount the dougthy Drive onto the Z-axis to form a 5th axis when needed.

[Procato]

Hi Silyavski

Ha yes as you can probably see I'm hoping to use many of your ideas/designs in my build.

I'm also hoping to be able to mill aluminium moulds for resin infusion of carbon fibre hence the attempt at very rigid design.

Thanks for pointing out this weakness- do you mean something like this?

[Boyan Silyavski]

Yes, exactly that's what i meant.

It would be interesting to see the z axis. Where is the Z ball screw? I can not see it

[Procato]

The Z-axis has been causing me some concern. Do you think there could be a racking issue?
I had thought about putting the ballscrew in the centre of Z-axis pillar with a motor on top but that means either putting a slot nearly all the way down the z-axis pillar which I thought may weaken it too much?
Or making the z-axis twice as long, keep the same amount of travel and put the slot in the top half - this makes a ridiculously long axis.
Or I could add another ballscrew to the other side.
What are your thoughts?