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View Full Version : So what to do with this profile?



Rogue
23-09-2012, 11:14 PM
There's a bunch of alu profile sitting around, waiting to be attacked with a compound mitre saw. It's a job lot of 45x45 bits and pieces I got last year so a design limitation was that I want to work with what I have for the base frame. The minimum area I want is A4-size, this set up should give me 340mm x 300mm give or take a few whiskers, with 130mm of Z travel depending on a few choices later on. Footprint is 590mm x 790mm and I'm pencilling in another 10mm for the protruding pulleys. Access from the side of the workpiece is admittedly limited but I can live with front access.

6955

The plan is for the motors to be "inside" the frame, with an external pulley system. Let's add some alu plate with a few holes to show how I envisage that. This was the secondary reason why I had the extra pillar at the rear of the frame instead of an angled support, in order to support the plate that will hopefully hold the motor & pulley for the X axis. The primary reason was because my compound mitre saw doesn't seem to like angles that aren't 45deg. The angled supports going forward are there because I kept looking at pics of Z-axisisis and thinking "they look like some heavy beggars stuck out a good way from the gantry, that thing'll tip over!"

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The profile at the bottom is split by the profile that makes up the gantry legs. With the X motor plate already providing some bracing I thought it might be nice to run an extra bit of plate along the bottom. I quite like the "banded" look, I can only hope it has some practical effect. It might not be obvious but there is a similar band running across the back at the height of the X motor mount plate.

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While I think the X-axis plates are well supported here, the Y-axis plates are spanning 590mm, 500mm of that is unsupported. Would 20mm aluminium be able to provide sufficient bracing for the machine while also holding the motor and the business end of the screw?

And just because the "in-thing" is vertically orientated mills, here's this one orientated suchly. Footprint drops from 590mm x 790mm (600mm x 800mm with pulleys) down to 590mm x 500mm (600mm x 510 with pulleys).

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I was considering a while back using a folded sheet of alu as a "wrap around" to brace it, leading to what I affectionately refer to as "the Bat mask". Because it looked a bit like Batman's mask. From... a certain angle. And mindset. Umm...

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The X motor plates and forward angled braces would still be added, leading me to wonder if the benefit of the Batmask would be superceded by the 20mm plate banding. Or we could add it all in together, leading to what I affectionately refer to as "the Robocop". Because that was the music playing in my head at the time. All together now... dum dum de dummm dummm, dum dum de dummm...

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Are there any issues that leap out immediately? I would prefer some crossmembers at the bottom (needing only 410mm length of profile, requiring a 5mm v or semicircle cut into them to give the ballscrew clearance) but I think there may not be room with the motor, ballnut etc. I don't have any lengths of 590mm so I can't run a crossmember completely from one side to the other.

Edited to add: forgot to mention, but for the x axis I plan a "c"shaped system, with profile rails mounted on the top and bottom of the gantry, not on the face.

Rogue
25-09-2012, 10:03 PM
6958

While I think the X-axis plates are well supported here, the Y-axis plates are spanning 590mm, 500mm of that is unsupported. Would 20mm aluminium be able to provide sufficient bracing for the machine while also holding the motor and the business end of the screw?

I suppose along with this question I should also add my tapping question, as it fits better into this thread. These 20mm-thick plates will be butt-jointed. I was hoping to use the same size bolts everywhere (M10x1.5) but I'm wondering if they will be suitable for fitting endways into the 20mm plate. Would anyone have any recommendations?