Problem with x axis

[nywoodworker]

I have been making some 3 D molding for some doors. After cutting several out I now have a problem with the x axis movement. I have a 4ft of travel on the x axis.

The problem is about 3/4 of the travel on the x axis. The x axis stops. It will jerk left to right and will not move past this point. Not really sure what is going on.

I have :
Switched the x and y cable. The x travel when controlled by the y cable still stops at the same spot.
I have disconnected the x motor. It turns freely in both directions.
I have inspected the gears and see no damage to any of the teeth.
When disconnected I can move the x axis back and forth the full length of the table.
I have moved the x axis to the right the point of the problem. The x movement moves very erratic and jerky after this point. The last few inches of travel of the x axis seems to be OK.

When moving the x axis from right to left it it will move past this point but has some jerky movement.

I can use my cnc machine and everything is working as it should. The problem only happens when I need to use the last 1/4 of the x axis movement.

I need help. Has anyone had something like this happen.
Dave

[martin54]

How wide is your machine? How is it driven ? does it have a single leadscrew on the x axis driving in the centre of the table, if so check the gantry isn't twisting at all, have you checked the screw for damage or anything that may be loose?

[nywoodworker]

The table is 4 ft wide. It only has a single motor to turn the x axis. I have looked and watched as it moves . Their is nothing I can see that interferes with any of the movement. The motor runs smoothly when not connected. I have checked the mounts for the motor. Can't see anything wrong. The problem always happens at the same point of travel.
Dave

[metalworkz]

Have you checked to be sure there is no binding or racking of the slides at that approximate location you mentioned? If driven by a single motor(say in the center), if one of the slides binds it can cause the gantry to rack which will bind the movement. It could be something very minor like a build up of dust etc. in those areas. You did not describe the type of slides used for the movement but a bind could be caused by many other things like alignment, perhaps a bulge or flaw in the slide or perhaps the distance between the slides could be varying. These are just suggestions to help pinpoint the problem but finding it sounds like it will take some close inspection of both the slide mechanisms and even the leadscrew where the bind occurs. When you have time if you can describe the type of slides used, leadscrew, and any other info about your machine like if it is a DIY machine or not it may help someone here to help find the problem.

[garylmast]

If you are using Mach 3, you may check to see if the Limits is set far enough.

[4DThinker]

I'd also check for something that is blocking the X run. I had a student accidentally (or perhaps on purpose) leave a ruler under the bed of the CNC Shark we use where I teach, and no one noticed it until the first project that needed the gantry to move past where the ruler was blocking its movement. A sudden hard stop where least expected. I've also had fine dust (common doing 3D cuts) build up on a rail or threaded lead screw. It would get pushed and piled up at the same spot after running many of the same job, then jam that run on the next project that wanted to go past that point.