15-08-2013 #41Chaps - i'm dithering about with the gantry quite a bit...can't come up with an approach that i'm happy with yet.
There are several ways to do different and I just drew this quickly to give an idea of easy and strong which go with single screw.
Really how you go about it depends on the job in hand, like in creakys case it was simple but would only really be suitable or woodwork type cutting any harder material like aluminium or if higher accuracy say for fine engraving, by that I mean in brass or Aluminium, PCB's etc where required then this is when weaknesses show thru quickly. . . . Resonance and vibration being the enemy has hollow aluminium box isn't stiff enough.! . . . It's also only works with twin screws and with single screw wouldn't be very good at all.!!
Your problem or complexity/weakness comes from using single screw.!!
[reason I ask is my 4.2mm bit is knakered and I'm looking at replacing it with a taper bit as my chuck is not the best... If m5 is not the way to go I may not bother just now..
Last edited by JoeHarris; 15-08-2013 at 11:17 PM.
On the x-axis I am going to use 2 leadscrews with a single motor.
Ok - i'll draw up a revamped steel gantry...I have a slightly revised approach in mind now...i'll be back with a design for you to tut at later :-p
Ok - I have a gantry drawn up now that i'm feeling much happier about.
Weight as it stands currently is approx 28.5kg...obviously z-axis & spindle etc still need to go on.
Motor mount shown is rough & a guide only.
Leadscrew is guide only.
Teal parts: 75 x 50 x 3 steel box
Green parts: 60 x 5 steel flat bar
Bearing mounts: 15mm ecocast
Front vertical plate: 5mm aluminium plate
End braces: 15mm aluminium plate
Rails are mounted on 50 x 10 aluminium flat bar
Hopefully this is a decent blend of strength, precision/alignment & weight.
Bracing for impact...thoughts?
here's another idea for the ganrty, a bit more expensive solution though as the sides need to be machined/watercut.
so 20mm alu plate reinforced with solid 25mm square bar. 20mm plate all around.
to attach the ballscrew nut, you'll need some sort of hanger or place the ballscrew on top of the linear rails and make it go through the gantry 20mm plate :D
saves material and very elegant .
all criticisms welcomed / encouraged!
what software are you using? it looks interesting.
Last edited by jcb121; 16-08-2013 at 01:18 PM.
Interesting approach - but I think it'll work out a lot more more expensive than the current draft above. As it stands above its about £78 material cost...I can't see that aluminium version being in double figures.
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