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Ragging

Ragging

“Ragging” describes a print defect in which cured or partially cured resin forms thin, shelf-like structures that hang horizontally from a print. These structures, also called “flaps,” can detach from the part during printing.

Once these flaps are floating in the resin tank, they can block the laser’s path and cause print failures in subsequent layers. Ragging occurs when diffused laser light spreads the cure area beyond the appropriate limits for each layer outline.

Visual symptoms

  • Flaps of cured or partially cured resin on the print that degrade the overall cosmetic aspects of the print
  • Thin flakes of cured or partially cured resin from the print floating in the resin tank, which may or may not cause a print failure

Common causes

Any of the following factors, or a combination of them, can cause ragging in prints:

  • Expired resin
  • Debris/clouding/damage in the resin tank
  • Contaminated optical surfaces
  • Restricted resin flow due to improper model orientation or overly dense supports

Troubleshooting steps

Successful troubleshooting identifies symptoms and systematically narrows down the root cause of an issue. Follow the troubleshooting steps below to check for possible causes, beginning with the most likely cause of the print defect.

Note:

Make sure that your firmware and PreForm versions are up to date. To check your printer’s firmware version, refer to the support article Checking the firmware version for Formlabs SLA printers. To update your PreForm version, refer to the FAQ article How do I update PreForm?.

Step 1: Check the resin’s expiration date

Parts printed with expired resin may have poor surface finish and exhibit rashing and ragging. Formlabs resins last for 12 to 24 months in the resin cartridge, depending on the resin type. Learn more about resin lifetime and storage to determine if your resin has expired.

Step 2: Check the resin tank

Any damage or debris in or on the resin tank can block the laser at that location, preventing the resin directly above it from curing. Inspect the inside and underside of the tank for dirt, dust, and/or fingerprints. The bottom of the tank must be clean for the best print results.

Form 2Formlabs LFS printer (Form 3 or later)
  1. Inspect the resin tank for debris with a scraper.
  2. Remove any failed prints and cured resin with the scraper, being careful not to gouge or cut the elastic layer at the bottom of the tank.
  3. Filter the resin to remove any contamination or cured resin.
  4. If using Resin Tank LT, skip this step. Inspect the elastic layer of the standard resin tank for clouding. Severe clouding means a standard resin tank needs to be replaced.
  5. Inspect the acrylic tank window on the underside of the resin tank for dirt, dust, cured resin, or fingerprints. Clean it with Formlabs recommended steps and supplies.
  1. Inspect the resin tank for debris with the tank tool.
  2. Remove any failed prints and cured resin using the tank tool.
  3. Alternatively, remove any failed prints and cured resin by printing a cleaning mesh.
  4. Filter the resin to remove any contamination or cured resin.
  5. Inspect the flexible film at the bottom of the resin tank for scratches or wear. Excessive wear means the resin tank needs to be replaced.
  6. Inspect the underside of the flexible film for dirt, dust, or fingerprints. Clean it with Formlabs recommended steps and supplies.

TIP:

Keep resin tanks clean and well-maintained between prints for reliable and successful printing.

Step 3: Check the optical window

Any contamination, dust, or debris on the printer’s optical surfaces can cause the laser light to diffuse or weaken, resulting in a print failure. Contamination is most likely to occur on an exposed optical surface in the printer.

Form 2Formlabs LFS printer (Form 3 or later)
The optical surface most likely to be contaminated is the glass optical window beneath the resin tank that protects internal components from contamination.
  1. Inspect the optical window on the Form 2 or for contamination.
  2. Follow the instructions in the support article Cleaning the glass optical window (Form 2). If streaks are difficult to remove, contact Formlabs Support or your authorized reseller.

The optical surface most likely to be contaminated is the glass optical window, which sits atop the Light Processing Unit (LPU).

  1. With the printer plugged in and powered on, tap the wrench icon to access the Settings screen, then tap Maintenance > Motor Moves. The Motor Moves screen appears. Tap and hold Left (<) to move the LPU housing to the middle of the printer cavity. Other controls on this screen fully sweep the LPU housing across the printer cavity and control the build platform carriage.
  2. When prompted by the touchscreen, disconnect the power cable before continuing with maintenance.
  3. Inspect the optical window for contamination.
  4. Follow the instructions for cleaning the glass optical window.
  5. If streaks are difficult to remove, contact Formlabs Support or your authorized reseller.

Notice:

Follow the optical surface cleaning guides exactly. Failure to follow instructions could damage the printer.

Step 4: Check for restricted resin flow

On the Form 1+, and to a lesser extent on newer Formlabs SLA printers, restricted resin flow can cause ragging. “Resin flow” describes the liquid resin’s movement throughout the resin tank during the print process.

Restricted resin flow can occur during the peel process or resin dispense attempts, oftentimes due to either improper model orientation or overly dense supports on the model.

Check additional instructions on orienting models and adding custom supports manually in PreForm.

  • To resolve improper model orientation in PreForm, manually reorient the model so that the longest axis is parallel with the front of the printer.
    • On a Form 1+, the parallel orientation allows resin to flow downstream during the peel process, which lowers the right side of the tank.
    • On a Form 2, the parallel orientation, while less critical, also aids with resin flow in the tank.
    • On a Formlabs LFS printer (Form 3 or later), the orientation of the part does not have a significant effect on the flow of resin within the resin tank.
  • Both the part and the build platform displace resin when the printer lowers them into the resin tank. Overly dense supports trap resin, restricting resin flow in the tank and causing ragging. To resolve overly dense supports using PreForm:
    1. Use the Support tool to manually reduce the number of supports on the part.
    2. Reorient the part manually to reduce the number of supports generated.

Contacting Formlabs Support

If the troubleshooting steps above do not resolve the print failure, contact Formlabs Support or your authorized reseller.

To help us provide the fastest and most effective response to your issue, please follow these steps:

  1. Upload diagnostic logs
  2. Serial name of the printer
  3. Troubleshooting steps attempted
    • Example: “I reoriented the model in PreForm. I inspected the resin tank and did not notice any damage, clouding, or debris.”
  4. Resin formulation and lot number
  5. Layer thickness
    • On a Form 2: Tap the queue icon on the home screen. The Jobs screen appears.
    • On a Form 3/Form 3B or Form 3L/Form 3BL: Tap Queue on the Home screen. The Queue screen appears.
  6. Relevant FORM files
    • If available, attach FORM files of the model to the support request.
  7. Previous attempts to print the part and any successful prints
    • Example: “I printed the file part2.form three times previously. The first and second were successful. The third one failed.”