NordicCNC's build log

[NordicCnc]

Y-axis design

- 1600mm long, 160x80 (heavy) Item profiles will be used for the sides, onto which the linear rails are mounted. Travel length is approximately 1400mm.
- 1065mm long, 160x80 (heavy) Item profile is used for the front.
- 1065mm long, 80x80 (heavy) Item profiles will be used between the 160x80 side profiles. The base frame profiles are mounted together with front/end plates and 80x80 angles.



- The plates onto which the guide carriages and the ball screw nut housing are mounted are separated from the gantry. The purpose is to allow some adjustment later when squaring the gantry. It will also separate the aligning process of the Y-axis ball screw and linear rail from the gantry squaring process. This will make the aligning easier.
- 20mm HIWIN linear rails with wide guide carriages.
- 2010 ball screws, 1500mm long, with BK15/BF15 bearings.
- Double Delta 400W servo motors with a 2:1 reduction, to limit ball screw RPM. 20T and 40T timing pulley's will be used. Preferably with taper-lock mounting.
- Same servo motor brackets, BK/BF bearing spacers and ball screw nut housing concept are used as in the X-axis. Commonality and re-usability is the goal here.




- The spindle will have a 100mm overhang at when the Y-axis is at the end of the table. The purpose is to be able to mount work pieces vertically, for dovetail machining.



- The table surface I am not sure about yet. Either I will install a HDPE sheet or and MDF spoil board.
- The complete machine will later be mounted to a sturdy metal bench/frame. Adjustable feet will be used.



Originally I intended to have the Y-axis linear rails side mounted, to make the footprint as small as possible and to protect the rails from dust and chips. I was informed that alignment is significally harder with side mounted rails, which is why the rails are now top mounted.

[JAZZCNC]

Ermm to me by arranging the profiles at the top of the 160 side pieces your wasting 80mm of height that could be used to lower the gantry height and increase stiffness or keep as it is and gain clearance.
The gain in having the motors under the bench isn't worth wasting stiffness, also moving the motors to the outside will shorten the belt length.

Also, the slightly elevated sides put the rails up higher and stop debris from hitting them directly and building up against the rail.

[NordicCnc]

Ermm to me by arranging the profiles at the top of the 160 side pieces your wasting 80mm of height that could be used to lower the gantry height and increase stiffness or keep as it is and gain clearance.
The gain in having the motors under the bench isn't worth wasting stiffness, also moving the motors to the outside will shorten the belt length.

Also, the slightly elevated sides put the rails up higher and stop debris from hitting them directly and building up against the rail.

Those are some extremely good points..

By moving the motors to the outside of 160x80 profiles, the belt lengths will be shorter and I will be able to move the 80x80 profiles down 80mm. This in turn will decrease the needed height of my gantry sides by 80mm while also protecting the Y-axis rails.

There is no doubt, I will make those changes. Maybe I could even change the sides to 200x80 and be able to make the gantry sides even lower! Now it starts to turn into a raised gantry design. The drawback will be that it becomes more difficult so access the machine table from the side, when e.g. fastening the workpiece.

Thanks JAZZ!

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[JAZZCNC]

The drawback will be that it becomes more difficult so access the machine table from the side, when e.g. fastening the workpiece.

Yep there's always going to be some trade off with design like this, you just have to decide which is most important to you.!

[NordicCnc]

Yep there's always going to be some trade off with design like this, you just have to decide which is most important to you.!

Yes.

If I think about it, side loading would not be too complicated with only 200mm raised gantry sides. You can still reach for all the clamps quite well and large wooden sheets can be loaded from the front.

The purpose of the high gantry sides was exactly for that reason, to simplify side loading. But now when analysing the problem closer, this will probably not have any impact to me at least.

Time to modify the design... again!

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