El Beast - Initial design phase, comments and critique welcomed!

[Ger21]

Did sb tell you already to rid of that ridiculous Y Hiwin design? Why would you need 2 rails each side? You need one rail and 2 blocks, size 20 which have 100 times the specs higher than your machine can weight or 10x force on them.

I told him that 12 days ago, the first time I saw it.

[Zeeflyboy]

Yeah yeah, just haven't had time to work on that part yet as i've been re-designing the x-axis gantry and the z-axis first.

Boyan - plan was to mount the rail to the 45x90 and then level it to the ecocast plate bed before tightening down all the screws, which would give alignment in the Z-axis. I suppose you are suggesting that the flatness of the extrusion will leave it slightly "wavey" in the horizontal axis?

What about mounting a 20mm ecocast plate to the extrusion and then the rail to the plate, similar to what i'm ending up doing with the X-Axis?

[Boyan Silyavski]

I am speaking about how you would level the long rails that gantry moves on them / Y/- in the Z plane to be on one plane and at the same time to be flat . I am not so worried about the flatness as you say you will be using Ecocast plate.

[Zeeflyboy]

So the plan was to mount the ecocast bed plate, then using a shim between one of the Y-Carriages and the underside of the bed plate I could fasten the screws moving the carriage as I go, which would end up with the rails level to the ecocast bed surface.

The end pieces I have designed a pocket in the back sides to accept the 45x90 extrusions, which keeps the spacing between front and back consistent and (assuming the shop cuts the extrusions square) should keep things squared up too, and was planning on adding a couple of corner brackets to help keep the squareness of the frame acceptable.




So the only thing that can cause significant issues as far as I can see is that I'm effectively relying somewhat on the flatness of the 45x90x1000mmm extrusions to provide the straightness in the horizontal plane. If the extrusions are slightly bent for example then I could get a slight curve when travelling fore/aft in the Y-axis... that would need fairly accurate shimming to get rid of.

Could be an option to get some 20mm ecocast plate to mount to the 45x90mm and then mount the rails to that perhaps?

e.g:

[Zeeflyboy]

Another potential option perhaps would be to re-design around this misumi milled profile? https://us.misumi-ec.com/vona2/detai...689340/?Inch=0

Not sure of the cost or availability however.

[Boyan Silyavski]

Seems alright. I would have done it same way. using straight edge you can make sure all is ok

[Zeeflyboy]

Sorry just to be clear for me - you are saying you would do the levelling the same way with the shim, or the mounting of 20mm plate to the extrusion before mounting the rail, or going with the milled extrusion?

[Zeeflyboy]

yes fair enough, I'm going with a single rail each side.

I like the look of the misumi milled profile - they have it in the 45x90 size i was originally planning. Just need to figure out how to actually buy the stuff and how much it is.

Edit - Father in Law is happy to get it through his company, now just a question of how much dolla!

[A_Camera]

yes fair enough, I'm going with a single rail each side.

It is a good decision. Now just turn them 90 degrees and place them under the table. Squaring will be a problem if you are not doing that. You would also get a more rigid machine if the rails are mounted horizontally.

[Zeeflyboy]

Why do you think it would it be more rigid?

(3) High rigidity in all four directions
Because of the four-row design, the HG series linear guideway has equal load ratings in the radial, reverse radial and lateral directions. Furthermore, the circular-arc groove provides a wide-contact width between the balls and the groove raceway allowing large permissible loads and high rigidity

Personally I think the machine as a whole will be more rigid with the current setup as it allows me to bolt the frame and frame supports to the tool bed for added frame rigidity while keeping the unsupported gantry arm to the minimum length. If I flip the supports 90 degrees and set them up like my current machine then I have an unsupported bed that will flex, and I can't put the cross supports in as they would then interfere with the ball screws... unless I underslung them which would be a mounting nightmare.