labelMaxWidth: Number

Sets the maximum width of label after which it gets wrapped or clipped depending on whether labelWrap is set to true (default) or false.

Default: Automatically calculated based on the length of label.
Example: 4, 20, 100 etc.

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
 axisX:{
   labelMaxWidth: 20
 },
 .
});
chart.render();