Need Help!- Alignment problem

[boboxx]

Hello guys,
I just terminated my Joes hybrid look alike. This is my first built and it when fairly smoothly.

I ran my first part tonight, I was pretty excited event dough it did not come out as nice as expected… as you can see from the picture attached, I’m having some sort of skewing problem on my Y axis, I have double check everything and it should be ok but it’s not!! Anyone know where I should start looking? Both sides are the same…





Thanks

[ger21]

If the part you cut is a parallelogram, then your gantry is probably out of square.

[boboxx]

yes it is... what would be the easiest way to square it out?? I just used my 30 year old carpenter (was my grandfather) square to square it up... I know I can use the 3,4,5 rule but it won’t be precise enough....

[joecnc2006]

Machine looks very much like my CNC 4x4 Hybrid from gantry rail down, I suppose you built it from seeing the many machine completed now, a skew problem has not arised as of yet with people building the machine.

Use the Router bit to square the machine up, mark the lines with the square on the table and jog the machine to each side, then rotate the leadscrew manually on that side until it is on your square line, then lock the motors into place.

We have quite a few machines built already with great success, when they were following the plans. Plus allot of support on the forum. We have 4 others in Canada building the machine already

Hope you are able to get the machine running the way you want, It is a proven design and robust, not to mention flexible.

Joe

[Richster]

Yes if you're ending up with a parallelogram then the X and Y axes are not at 90deg to each other as previous posters have mentioned. Another similar way of resolving which worked for me is to mark the 4 extreme corners using the router bit. Measure the diagonals - any non-squareness between x and y will give an enlarged error here. Basically you want to adjust one side of the gantry until the two diagnoal measurements match.

Good luck...

[ger21]

Mount home switches on each side and let mach3 square it with a homing command.

[joecnc2006]

Originally Posted by ger21 Mount home switches on each side and let mach3 square it with a homing command.

I think if the motors are slaved, then mach3 will shut down that axis when it hits one of the homing switches, not sure as i do not have home switches on mine.

Joe

[boboxx]

ha thanks guys, this is all good info :c) I don’t have homing switches yet as I didn’t not really how to align the ends of my 2 rails on my Y, plus I wanted to have a touch probe and would not have enough inputs to support all of them on a single board. I will have a look again tonight.. I'm sure i will be able to do something with all the recommendation that were given.
I hope it works out, the machine is sweet, I just have 2 slaved 260oz motors on my Y and 1 260 on my Z and a 280 on my X, this was a kit from Probotix. The table is about 36x48 and I can jog at 90IPM…
The cost of the table was a little under 1100$ including the Bosh trim router. I have not bought or followed joe’s built plan, plus this is my first machine so I can understand that I might have issue that payed members would not have! Joe, by the way this is a really nice machine and should be really easy to build using the pans as mine was still fairly easy without plans. Some inspiration was taken from the first and second generation of the 4x4 hybrid and some other bits and piece here and there from other machine I have found here on CNC central hope you don’t mind guys :c)


Thanks
Christian

[ger21]

Originally Posted by joecnc2006 I think if the motors are slaved, then mach3 will shut down that axis when it hits one of the homing switches, not sure as i do not have home switches on mine. Joe

Joe, Mach will home each side together (they'll move towards the switches together), but each side will trigger it's switch separately, allowing the axis to be squared to the switches. There is also an option to home them together to a single switch.

[boboxx]

ha ok that is good to know but then I still have the same problem, how could I make sure that both of my switch are equal???

[M250cnc]

I can use the 3,4,5 rule but it won’t be precise enough....

Bob that statement is incorrect.

I am planning a router at some stage and this concentrated the mind in how to square the machine.

The next point is your square is that correct ?

The next problem i can see in the design of an axis that is slaved, in that you may lose steps on one motor of the pair then you will be out of square again. And you will need to be able to readily reset the machine back square.

So now the fix, cut some strips of MDF say 2" wide x 1/2" thick. These will need to be long enough to do the 345 over the longest length of your machine.

You will then parallel to the edge of the strips put in accurate holes at the centres of your correct 345 dimensions these will need to be dowelled together. It will not matter that the machine is out of square at this stage.

You will then have the correct 345 triangle for setting your machine you could set the homing switches to achieve this using your jig.

HTH
Phil_H

[jcoats]

I really like your computer cabinet ... great for use in the shop!