• Ensure that the drilled hole for the braille bead is clean of any acrylic debris.
• Make sure the proper braille bit type is being used on the appropriate material type. Ex. using the bit for hard/rigid acrylics on cast acrylic material, or the bit for soft/pliable acrylics on softer materials.
• Try slowing the plunge rate of the drill bit down so that the bit tip will bore into the acrylic material for a slightly longer amount of time, to help ensure the hole is clean.
• Try bumping up the dwell time slightly so that the braille bit spends time in the hole slightly longer to ensure a clean hole.
• Try slowing the plunge rate of the braille bead setter.
• Check that the braille bead setter plunge depth is enough to push the bead all the way into the drilled hole. 
• Check the calibration of the braille bead setter to make sure it is perfectly centered over the drilled hole and not positioning slightly off to the side of the hole. 
• Check that the braille beads are not jamming and are being fed consistently to the tip of the manual braille bead setter.