CNC Router V1.0 (For Cutting Multiple Materials)

[biketrialsdave]

Thanks Jazz! I had thought of something similar but was afraid monting the ballscrew like that would cause problems. Is the general idea of the gantry sides to keep them as short as possible? Well not the sides, but the distance between the top and bottom profile carriages on the X axis?

[JAZZCNC]

Thanks Jazz! I had thought of something similar but was afraid monting the ballscrew like that would cause problems. Is the general idea of the gantry sides to keep them as short as possible? Well not the sides, but the distance between the top and bottom profile carriages on the X axis?

Yes if you want the best possible strength then you want short stubby sides but this is only really required if you want to cut hard materials most of the time. Gantry height just needs to be high enough to provide support to the Y/Z axis and resist Twisting/flexing. With this design the height of the gantry supports and takes the full load of the Z axis bearings with just the ballscrew and motor above the gantry.
The red machine in the pictures is twin ballscrew driven and this cuts aluminium no problem with resoanable quality of finish but it's not designed to do this all the time and it would eventually take it's toll on the machine, where has with woods etc it will happily cut 24/7.

With regards to the ballscrew at the rear then IME it hardly makes any difference unless wanting to cut hard materials with deep DOC. Which in this case then you'd want a stronger gantry design. For all wood and lighter aluminium use then it's no problem at all, if it was I wouldn't be using this design.!

To be honest if your wanting to cut all materials then you have to lose something somewhere. If you build for cutting the hardest materials then you need strength and weight, this comes at the cost of speed unless you increase the strength of motors etc and this costs cash.
This is wasteful if your only ever going to cut hard materials 5% of the time. So IMO you get a much better machine if you target the main use and design for the optimum doing this.! . . . Jack of all trades works but truely is master of none and you have to accept this other wise you'll be sadly dissapointed.!

[biketrialsdave]

Finally feeling like I may be going in the right direction now! (*awaits comments saying I'm not* =P).

There's just enough room to mount the X axis motor on the inside of the gantry.

[JAZZCNC]

Won't need that top piece it's only adding weight and expense.

[biketrialsdave]

Thought you might of said that! Now removed.

I am looking to mount the motor on the inside of the gantry but I'm going to need a long motor shaft or a pulley with a long hub length to get through the 20mm plate and out the other side with enough length. Any suggestions?

[biketrialsdave]

It looks as if it will be easier to mount the X axis motor on the outside of the gantry plate (See below). If I wanted to mount it on the inside and still use the FK bearing block then the shaft would be too short to mount a pulley.



I am now looking at the Y axis ballscrew mounts in a little more detail. In the screenshot below how is the bearing mount attached to the steel box section? (Does anyone have a link to this build thread btw?)



I assume that there's another piece of welded steel plate on the end of the box section? As below?



While I am on the subject of the "end plate", I assume some sort of adjustment will need to be built in to allow movement in the Z axis as if I use the epoxy method on the box section then it's going to add some height?

Dave

[biketrialsdave]

Yet more questions... this time about welding and distortion.

What is the best technique to use to minimize distortion? I assume I should tack weld each side of the box section before doing full fillet welds? Do I need to do any kind of stress relief to the joint after? I am only practicing at the moment. Picked up an Evolution Rage 3-S to cut some box section and purchased an auto darkening helmet =)

I've also ordered one of these, which I hope will help:



Dave

[biketrialsdave]

I am now looking at the Y axis ballscrew mounts in a little more detail. In the screenshot below how is the bearing mount attached to the steel box section? (Does anyone have a link to this build thread btw?)



I assume that there's another piece of welded steel plate on the end of the box section? As below?



While I am on the subject of the "end plate", I assume some sort of adjustment will need to be built in to allow movement in the Z axis as if I use the epoxy method on the box section then it's going to add some height?

Dave

Is anyone able to answer any of the above? It would be great if there was a link for the red router listed?

Cheers,

Dave