Gaps in a 3D Print: What a Service Report Should Record Before Replacing Parts

A printed object with gaps or thin sections may prompt a request to replace the nozzle immediately. But a service team needs more than a suspected part name. Under-extrusion is a description of insufficient material in the print, and the conditions behind it can involve the material, settings, feed path or hardware. A useful report preserves what happened before anyone assumes a cause.

Describe where the material is missing

Photograph the whole object and the affected area, identifying the top, bottom and orientation if these are known. Record whether the missing material appears throughout the print, only on particular walls, or after a certain point in the job. If a layer is missing entirely, describe that observation separately from a general pattern of small gaps. A picture of the finished part alone may not show what occurred during the print.

UltiMaker's under-extrusion support article describes visible signs and discusses multiple contributing factors. Its instructions are written for specified UltiMaker printers, so a different machine requires its own manufacturer's guidance. The appearance described there is a reason to investigate, not proof of a particular failed component.

Keep the job and material evidence together

Identify the printer model, firmware and slicing software version, the print file or revision, the material and the nozzle or print-core configuration as recorded by the operator. Include the settings actually used, rather than copying the current settings after they have been changed. If a third-party material was used, retain the supplier's relevant documentation and label.

Material history can be useful: note when a spool was opened, the storage conditions if known, and whether the same spool was used successfully on a comparable job. Do not claim a material is wet or defective just because it was open. The service provider can decide which additional observations or tests are appropriate for that material and machine.

Build a timeline of changes

Record when the issue first appeared and what changed beforehand: a different material, a software update, a replacement part or a move to another location. A change immediately before a problem is a possible lead, not proof of causation. If a previous print succeeded, preserve its settings and conditions only if they can actually be retrieved.

For example, suppose a print has gaps near its top after a long run. The operator can report the approximate point where the symptom became visible and whether the printer displayed an error. This hypothetical example does not establish that the machine overheated or that the feed path was blocked. The service team may need different information to distinguish those possibilities.

Distinguish observed grinding from its cause

UltiMaker's material-grinding guidance explains that grinding can be associated with a feeder issue or a problem elsewhere in the extrusion path. If the operator observes damaged filament, record its appearance and when it was noticed. Avoid writing “the feeder failed” unless a qualified assessment supports that conclusion.

The same principle applies to a suspected clog. A service record should distinguish a user's description, a technician's inspection and a confirmed repair. Do not dismantle heated components, reach into moving mechanisms or change calibration values merely to make a service request more convincing. Follow the machine's safety instructions and consult an authorized service provider where necessary.

Agree on a controlled follow-up

Ask the service provider what evidence is needed before a test and who is responsible for carrying it out. If a comparison print is approved, document its material, file, settings and outcome. Change only what the approved test requires and record the change; otherwise several simultaneous adjustments can make the result hard to interpret. Do not assume that a successful short print establishes performance for every future material or geometry.

If a component is replaced, retain the part identity, date, technician's findings and the result of the agreed verification. Where the fault remains uncertain, write that it remains under investigation. A record that honestly states its limits is more useful than an unsupported “fixed” label.

Protect customer files during support

Print files can contain confidential designs. Ask whether a simplified sample or a limited set of settings is sufficient before sending a complete model. Use the service provider's approved transfer channel and remove unrelated personal or business information. Retain enough context for the provider to connect a photo, log and file to the same job.

For other service documentation examples, see our articles on measurement references in repair photographs and a first-layer service report, or browse the 3D printer service section. This guide helps organize evidence; it is not a diagnosis or a replacement for model-specific service instructions.