Are there missing layers?

Gaps in the surface are caused by skipped layers. It could be that there was a temporary under-extrusion due to filament issues or the printer rods or bearings are stuck.

Solutions:

This issue can be usually fixed by taking a mechanical check on the 3D printer.

• Do a check-up on your 3D printer: As with every gadget, make sure that everything is screwed in tight. Check if the rods are aligned by switching off the power and gently moving the print head through the X and Y-axis. If it moves smoothly then there is nothing wrong. You can also check for worn out bearings while doing this.
• Keep the joints well-oiled: You can oil your 3D printer’s joints on your own. Prepare the rods by wiping them free of dirt and printing debris. You can then put on a little sewing machine oil. Get a printer control software to move the head through the X and Y axis to cover the whole rod with oil evenly.