Router build

[Blackrat]

sand with a 1500kgm3 will add 60kgs to the gantry :S

an idea ....

[JAZZCNC]

sand with a 1500kgm3 will add 60kgs to the gantry :S

an idea ....

How do you work that out.? What size boxsection are you using and how long.?
Looking at your pictures of design the box section looks like approx 120 x 80 and not much more than 1mtr long (and your proportions are wrong 120x80 won't have square internal rad they will be approx 5mm.)

So according to solid Works, I've just took the volume of the internal of 120 x 80 x 5 x 1mtr length rectangle section and working on 1470kgM3 which is the closest material I could find in Density which happens to be Melamine resin. The density comes out at 11.29kg per 1mtr length. That's just the internal volume not the Steel.

The same volume with Unfilled Epoxy comes out at 8.45Kg but that's without any filling which you would need. SO I reckon Epoxy/sand or gravel mix would end up weighing much more.!

[Blackrat]

150x100x4 1600mm wide

if you go to the bottom of the materials list, you can specify your own material so you dont need to look for a similar material with the density you require ...

the epoxy is only 10mm thick ... working as a sandwich between the two layers of steel

[JAZZCNC]

150x100x4 1600mm wide

Why so Big.? . . . . You'd be better off using smaller size with thicker wall.! . . . Besides Your Gantry design is the weak link here not the material.

To me your focusing on the wrong areas of the build and not looking at the Basic design and foundation. Without good foundations best resonance handling material in the world don't mean diddly squat.!!

Another thing to ask your self is do you really need massive strength.? Silyavski (Boyan) machine is a credit to him but IMO it's massive OTT for anything but aluminium. SO Unless your mostly cutting aluminium do you really need to go that far.? . . . . Like every thing in life Strength comes at a cost in both monetry and performance terms so why waste both if your only using 100% of it 2% of the time.?

All round machines are great but they take much more to build so they do it well and even then they NEVER do it has good as a Machine specificly designed and optimised for that sole purpose.
Remember a good design is built just strong enough to perform it's role with enough safety margin to ensure reliabilty and anything more is waste.!

[Blackrat]

i want to cut fast ... i cant sit around all day watching the machine scrape about ....

so what would you recommend to cut 2400x1200 MDF minimum ... my initial design was 76x76 tube which was too small ... so 150x100 is too big ...

im not too bothered on non critical design details right now , if the radii is 5mm or 6mm its not gonna make a difference to the whole concept .... when i receive the steel i can measure what the exact detail is and amend the drawing to be sure any bolts/nuts/washers dont sit on the radius of the tube

[Boyan Silyavski]

I don't see why you would not push this build just a bit up and finish with aluminum cutting machine. I mean a very nice aluminum cutting machine.

I am in the process of making now exactly the same working area machine and one of the ideas is to cut Aluminum precisely. Ignore the third bearing blocks in the middle everywhere.

By pushing a bit up, i mean on the long axis 2510 screws from china and rotating ball nut . I am not expert here, before some time Dean told me not to go RP if i want precision cuts. You would not believe how comparably cheap are 2x 3m / screw + nuts, for what they will offer.

2x 100x100x4 for the gantry , 100x100x3 for sides , front and back. All rest cross sections could be 80x80x3

just received 7x6m 100x100x4mm which i will use on all machine. 500eur with transport here in Spain. So basically my design uses 42m of main material. It doesn't matter if you make it on the floor or raise the legs, its the same.

i am expecting from my machine 20000mm/min, servo driven 1:1.5 , with very good resolution. That at 3000rpm of the servos. Not that they can not be driven at 4500rpm. There were panasonic servos at ebay, that have the same torque up to 6000rpm. that should be pretty frightening though

if you want fast, and heavy you will drive it AC servo, yes? Not that it can not be step driven, though i cant imagine what i would feel if it looses steps when i am doing 2m ali sheet

[JAZZCNC]

i want to cut fast ... i cant sit around all day watching the machine scrape about ....

so what would you recommend to cut 2400x1200 MDF minimum ... my initial design was 76x76 tube which was too small ... so 150x100 is too big ...

Ok well if your wanting to cut fast then your concerns are not just strength.? Your main concern will be spindle power and tooling.
You Can build the machine like a tank but ultimately the spindle power and tooling will dictate the speed you can cut at. Any machine using 100x100 steel section for the gantry will more than match most spindles that would be attached to a DIY machine.

Building a successful machine is about balance. No point wasting money on expensive servo's, ballscrews and massive steel structure etc if your going to attach a 1.5Kw spindle at the sharp end.! . . . . . Equally no point attaching 10Kw ATC spindle if the machine is flexing like a jelly fish. The results while differant in practise will still be the same.? . . . Disappointing.!

Balance is required so you need to define what your going to cut with the machine and be realistic regards the feeds/speeds/DOC. Everything needs to match and suit to get a balanced machine and this is where it gets hard and expensive to achieve with a Jack of all trades machine. Esp if your chasing speed.!!

Edit:

so what would you recommend to cut 2400x1200 MDF minimum ... my initial design was 76x76 tube which was too small ... so 150x100 is too big ...

I never said 76x76 would be too small and 80 x80 would make a decent gantry if design was good so I wouldn't be too concerned using that size section provided it had decent wall size. . . BUT . . Your box on box with no bracing and open ends isn't a good design IMO so I'd be looking to change things in this department.

[Blackrat]

wahoo

my rails and servo kit has arrived

but now to finalize the design to get building