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Problem X Axis

Posted: Tue Apr 24, 2012 8:48 pm
by nio
Hi again..
i've got almost the shapeoko working, but when i make straight lines in the X axis, at the beginning of the X axis the pen touches the paper, but from the middle to the end of the X axis doesn't touch, about 0.4/0.6 mm aprox above the paper...

I've tried to unmount the X and mount again, but the problem is the same...

Any idea how do i fix it??

Thanks

Re: Problem X Axis

Posted: Tue Apr 24, 2012 9:40 pm
by RedOko
Looks like its the relationship between your X-axis and the actual drawing plane/board.

I suggest just adding a piece of shim to lift one of the side to make it parallel. Check your Y-axis too.

In actual machining they actually mount a wide (big diameter) mill to mill the bed flat in relation to the axis. They have an actual term but I forgot :?:

Luis

Re: Problem X Axis

Posted: Tue Apr 24, 2012 10:55 pm
by nio
Hi Luis,
i was trying to level the bed, but probably it was not the best calibration :)...
i'm going to try leveling again adding pieces of shim and test it...

Thanks for the tip..

Re: Problem X Axis

Posted: Wed Apr 25, 2012 2:40 am
by Enraged
The best way to level it is to actually cut it with the Shapeoko itself. This can take quite a bit of time with a small end mill, but if you make a Gcode program to do it for you, you can just run the program every time you replace the spoilboard.

Problem X Axis

Posted: Wed Apr 25, 2012 1:23 pm
by lasershark1
RedOko wrote:In actual machining they actually mount a wide (big diameter) mill to mill the bed flat in relation to the axis. They have an actual term but I forgot :?:
Making your bed? ;)

Re: Problem X Axis

Posted: Wed Apr 25, 2012 1:34 pm
by edwardrford
lasershark1 wrote:Making your bed?
Nice!

Actually if I'm not mistaken, it's called facing. Generally one would use a fly cutter to perform such an operation. Read the 'fly cutter' section of the (now) infamous Milling Cutter entry on wikipedia: http://en.wikipedia.org/wiki/Milling_cutter#Fly_cutter

I've searched for a fly cutter with an 1/8" shank and have yet to locate one. If anyone were to run across such an (awesome) item, please post it in the 'useful links' section and please create a corresponding wiki entry.

-Edward

Re: Problem X Axis

Posted: Wed Apr 25, 2012 2:17 pm
by RedOko
@lasershark :lol:

So it will be "Facing your Bed" .

With a dremel it will be a lot of trouble just to face the sacrificial bed(1/8 shank). I rather get an almost flat mdf board and just shim the frame until I get it almost level with the board. I'm planning of replacing the end plates with some misumi extrusion and and make a frame/bed that I will try to get almost parallel to the axis. That way I will just have to clamp a sacrificial board and indicate the actual part and just do some shimming.

Re: Problem X Axis

Posted: Wed Apr 25, 2012 3:51 pm
by Tom Smith
Why not set up a system much like that used for restaurant tables? ie. Attach the ShapeOko to the spoilboard/table via bolts that are fixed on the board, but adjustable via the ShapeOko (or vice versa) so that a few twists of the bolt raise or lower the respective corner of the frame. I don't have a drawing, but with the appropriate T-nuts, etc, this should be pretty easy to rig up.

Re: Problem X Axis

Posted: Thu Apr 26, 2012 4:54 am
by sandro
Shims only work if the spoilboard is flat. If it's bowed, cupped, or twisted there won't be a way to shim it level.
My guess is that people really want precise results the board will need to be faced.

Re: Problem X Axis

Posted: Thu Apr 26, 2012 12:06 pm
by orcinus
A bizarre idea - why not use a glass plate as a bed?