x,y alignment issue

Dear all,

I am new to the handibot. I managed to cut the example file, draw my own designs in v-carve, and mill the designs on mdf and plywood. But I can not get the cutting done EXACTLY at the x,y location I want them to be at.

If I rerun the same file again on the same piece of wood (just to see if the second time the x,y alignment is still the same) the y-axis is off by a centimeter of more (0.5 ").

Here's what I did: set z axis to 0 by moving the spindle down until it touches the material, press the x,y zeroing button next to the jogging window button, run the file for the first time, when the file finishes I simply rerun the file, without any recalibrations.
Should this work? Or does this fail when the file ends 'unexpectedly', e.g. when I only run the first toolpath from teh file, and not all toolpaths?

Best regards,
Silvia

Silvia,

The position of the cut should definitely be repeatable--stopping in the middle of a cut should have no effect on the home position of the tool...so something definitely isn't working correctly.

First, which generation of handibot are you using? Is it the new Version 2.0 with the wifi "FabMo" controller or the earlier version with the ShopBot 3 control software?

One thing to check is that the tool is able to reach the furthest extents in x and y required by the toolpath. If you open up the toolpath file in a text editor, you'll see a bunch of information in the header, including the maximum extents of the cut in x and y. These numbers should be below 6" in the X and 8" in the Y--to fit into the handibot's cut area. If the tool is trying to travel further then these limits, the spindle will collide with the frame, causing the tool to lose position. You would also notice this during the cut--the motors emit a high pitched squeal when trying to drive past their limits.

It could also be that something else is causing the X or Y motors to bind--check for obstacles around your machine that could be impeding movement. Also manually move the tool around to make sure that it can reach the full range of motion in all axes. Tools will occasionally need a little bit of realignment to run most smoothly and we can troubleshoot that for you.

Let me know what you find and we'll go from there!

Brian

Dear Brian,

Thank you for your quick reply.
The piece I'm cutting is only 150x150 mm large in my design, and when I actually measure it on the work piece it is even a bit smaller. I am sure the tool does not hit any of the end stops.

I am not sure of the version of the hardware... but I run the tool via shopbot 3 control software, as that is what came with the tool on a usb stick, together with the vcarve software.

I ran the same job on the four corners of a square piece of mdf, and on three pieces it is in the same location wrt the corner, in the fourth case it is shifted up by approx. 1 inch.

Best regards,

Silvia

Silvia,

That does sound like an alignment issue with your motors. We've got a couple of quick guides for tweaking motor alignment up on our docs page here: [docs.handibot.com]
[docs.handibot.com]

I think that these will help!

Brian

I follwed the instructions in the manual for x and y axis. Did not do z, as that is not a problem for me.
Made a nice jig so the workpiece is always aligned the same way. Designed a test square of 40x40 mm with its center at 40,40 mm from bottom left corner.
Calibrated z = 0 manually. Then pressed the calibrate x and y axis button. It first asks me about the units that are apparently different now then when I started the tool (I prefer mm in stead of inches), but it asks me this everytime! It proceeds. X is calibrated properly, the tool moves left until it hits the sensor, then it approaches the position x=0 again slowly. In y it does not go to y=0 though! It stops somewhere randomly in space...?
When I cut my square it did so at a much too high y position... (And the left half was left off, maybe too close to x=0?)
I checked that the settings in material are to the datum at bottom left with offset 0,0.
Should I change some settings somewhere in shopbot?

And I have now added the design file of the square, and a picture of the squares it made at the two y heights. In between the first and second one I repressed the x,y zeroeing button, then I jogged down to the bottom left corner with the arrow keys, went one step left and up from the position where the sensors hit the ends, and pressed escape. But is that the way to proceed? How do you make sure it always starts at the same x,y position?

Silvia,

The home position of the tool persists between jobs. Even if it is way off on the other side of the cut area, it will return to it's 0,0 location to start a new job. You don't have to move it back home before starting the next cut.

Looking at your cut file, everything looks fine...but since you're working in mm I wanted to make sure that your tool was set to run in mm. To change this setting, click the blue "?" in the red position window and choose "Access ShopBot Setup"--there's an option at the top to switch to mm.

Brian

My position window gives me a position in mm, but I do not have a blue question mark anywhere. Not in the red window, and not when I open the key pad window. I will attach images of both windows.

Sylvia,

If you're seeing the position listed in mm then it sounds like everything is set up correctly. Just wanted to make sure.

Once you've run the X,Y zeroing routine (this is run from the "Cuts" menu) you shouldn't need to zero the axes between cuts. From your description of pressing the X Y zero button between cuts it sounds like that may be re-setting where "home" is for your tool.

Just to clarify for people who have purchased handibots recently--these commands are for ShopBot 3 software, not FabMo.