John's Alu Profile build

[Mister Mills]

I totally agree about the rails. Mine came from a salvaged Bisse industrial cnc router. Top quality parts. Budget usually decides @ 3 meters long! I'm going to try and sell my 50W 600x500 laser cutter/engraver so that might help with the proper rail requirement. Doing a check list at the moment and I have everything I need. Says me as I blindly walk into this project. No doubt there will be something missing when I get to that point of" Shit I forgot about that! .
The size will be dictated by the ball screws i have (they came from a Salvaged Datron cnc machine) top notch. The 5 axis setup is really something I would like to do but I will start with 3 and keep the other 2 in mind when doing the new re-design. Good luck with the new base and be sure to post some photos.

[Evengravy]

Planning is in the works for the base, I've been collecting materials here and there as I can source them in the current climate. I've decided against the wall mounted option, when I drew it up in CAD it wasn't really saving me a massive amount of floor space (due to the relatively small footprint of my machine) and I really want to make use of high flow flood coolant so felt a regular horizontal setup would be best.

I've decided to be a bit unconventional with this design as outlined in the images.



The main sides of the structure will be made from concrete based blocks, each measures 140mm(H) x 212mm(W) x 442 (L) and are very strong. These blocks are common here in Ireland and are largely made from a high proportion of granite aggregate along with a minimal amount of concrete as a binder (I'd estimate 15 - 20% concrete/cement) and I hope in this case, given the ratio of granite to cement, that shrinkage will be quite low and vibrations can be minimised too. I've had these blocks for over 12 months now so they should be relatively stable, but time will tell I suppose.

The intention for the main table surface is to cast this from home made glass fibre reinforced ultra high performance concrete. The intention is to cast this as a 75-100mm thick section in one pass by supporting the open section with ply braced from underneath (pre cut in the middle and siliconed at the joint for easy removal). I have sourced and received the glass fibre strands and the superplasticiser which I'll use to minimise the water content required in the concrete mix. I also intend to embed typical steel reinforcements (rebar or mesh or a combination of) I have yet to source those aspects as local steel outlets are closed for the next week or two. Time wise it's likely to be around the second week of June before construction can start, I'm looking forward to it.

For wiring/routing I intend to cast some 30-40mm plastic conduit (sink drainage pipe) into the front section, to allow motor and limit switch wiring to be routed cleanly from the left side to right. Controls box for the steppers and spindle VFD will mount to the exterior of the right hand wall.

I've been experimenting with some cast concrete of late and some alterations in mixes and proportions, likely I'll keep it fairly simple but I'll make some test samples soon to test those out.

The top of the table will be certainly quite rough post concrete casting, so the intention I have is to allow the concrete some time to settle and after that period level the entire table top with a 3mm layer of epoxy to give a nice flat surface to measure from and secondly, to provide some waterproofing. Part of the idea of designing the base this way is to allow sufficient space for a flood coolant capture tank to be housed in the underside of the 'table' and further design some fluid direction system once a tank has been sourced.

I could obviously go the tried and tested route and build the base from steel or aluminium, but I'd like to try this out to see how it goes. It's relatively cheap and if it all goes tits up, well I'm sure I can get a sledge hammer handy enough.