Y and Z axis set up.....calculations

My existing machine works well milling aluminium, but the Y axis has 25mm unsupported rails, and the Z axis is some obscure setup which needs changing for the better to make the machine more accurate/stronger.

Here is a photo of my machine as it is now....Attachment 11430

The frame is 45mm wide extrusion.

I have been through this with Jonathon and he has helped me a great deal , but I am confused about a few things.
I need a Z travel of 150mm.
I plan to put a 15mm thick alu plate across the entire width of the Y axis and mount 20mm supported rails on top to give me a Y travel of approx 320mm. I want to use new 1605 ballscrews for both axis. Jonathon kindly came up with most of the parts that I require ;

1set 1605-L330mm ballscrew with nut and end machining ( Dimension F needs to be machined to 25mm)
1set 1605-L550mm ballscrew with nut and end machining ( Dimension F needs to be machined to 25mm)

2set SBR20-L320mm rail support
2set SBR20-L515mm rail support
8pcs SBR20UU

Attachment 11436

Plus the aluminium for the Z axis front and back :

320 x 160 x 20mm x1
180 x 160 x 20mm x1

I done a drawing for what I think it will look like, but I cant work out if I have enough Z travel, plus the best way to mount the Z motor ? as there doesn't appear to be enough room for it on the front or back of the Z plates. I might have calculated something wrong or there might be better ways be moving components around.

Diagram : (the longer Z plate being in front of the shorter Z plate)

Attachment 11431


I estimated the Y plate to be 515 x 240 x 15mm

I can grasp the Y travel, thats easy enough.
Any help would be great. Its confusing the hell out of me !

Well sorry this is not much help but I did a drawing in Sketchup of my Z axis, saved the whole assembly as a 'group' which allowed me to move it up and down in relation to the rest of the model and this gave me everything I needed to get the sizes right.

I did use Emachineshop to get it scaled together, but no way of moving it like you did. Thanks for the suggestion, I will take a look.

Attachment 11446

Ok... I think this is ok.. I still dont know where I am going to mount the Z motor , so I have made the Z rear plate the same length as the front one (320mm) maybe the motor will mount on the rear of that, with the ballscrew on the front of the rear plate via pulley / Rails mounting on the front Z plate.

If you get a longer belt for the Z-axis, then surely you could mount the motor in front of, or to one side of the Z-axis?

Quote:

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Originally Posted by Jonathan

If you get a longer belt for the Z-axis, then surely you could mount the motor in front of, or to one side of the Z-axis?

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The motor is too wide to go along side the spindle, and the spindle inc the water pipes and the elec cable doesn't allow enough room for the motor to mount above it unless I lower the spindle and sacrifice some Z movement

Quote:

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Originally Posted by dudz

The motor is too wide to go along side the spindle, and the spindle inc the water pipes and the elec cable doesn't allow enough room for the motor to mount above it unless I lower the spindle and sacrifice some Z movement

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I was thinking put the motor in front of the spindle - i.e about 100mm away from the Z-plate which holds the spindle. You could go with the option you described in post #4. Neither is 'ideal' but both will work.

Quote:

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Originally Posted by Jonathan

I was thinking put the motor in front of the spindle - i.e about 100mm away from the Z-plate which holds the spindle. You could go with the option you described in post #4. Neither is 'ideal' but both will work.

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Hhhmmmm not a bad idea thanks, that maybe the way to go.