Printed parts can unintentionally warp, or curl, at different points in the 3D printing process:
- During the print job,
- Immediately after the print job, or
- After post-processing.
Warping During Print
In DLP 3D printing, resin is cured by UV light. The transition from liquid to solid results in internal stresses. If the internal stresses are not handled properly, part warping can occur.
Wall thickness is a major contributor to warping. The internal stresses from the resin's curing process can cause the parts to shrink and expand, leading to surface and internal cracks.
Wall thicknesses of 2.0 mm to 10.0 mm are printable without special considerations. If the walls are thinner than the recommended size, consider redesigning the part in your CAD software.
See Minimum Features.
Parts are subject to suction force during the printing process. If a part has a large flat surface parallel to the build platform, then the suction forces increase exponentially.
Angle the part by 10-20 degrees away from the build platform to reduce the surface area per layer.
Use Adequate Supports
DLP 3D printing requires a strong foundation because each layer is built on top of the previous one. In a bottom-up 3D printer, parts are printed against gravity.
Printing parts without support, directly on the build platform, provides a strong foundation. However, the burn-in distorts the part by forming a lip across the bottom surface.
Tip: The Burn-In adheres parts to the build platform by prolonging the initial exposures of the print job. This setting is automatically applied in Envision One RP Software.
When printing a heavy part, always use supports with thick contact tips. This reduces the risk of the new layer detaching from the previous layer, causing a print failure.
Parts with overhangs or unsupported areas must have adequate supports to hold up the part.
Warping During Wash Cycle
Wash Times and Cleaning Agents
Always follow the recommended wash times during post-processing. Always use the cleaning agent validated for your specific material.
Many ETEC materials are washed in 99% Isopropyl Alcohol (IPA). When parts are over-exposed to IPA, they absorb the IPA and swell, causing warping. This warping may be immediately visible or it may develop over time.
Most wash times with IPA are between 2-3 minutes and never exceed 5 minutes. For best results, follow the guidelines.
Parts must be completely dry before post-curing.
A glossy part surface indicates:
- Leftover IPA, or
- Uncured resin.
Dry parts with compressed air followed by convection/static drying. If you still see a glossy finish:
- Spray IPA on the glossy areas.
- Immediately dry the part with compressed air.
Tip: A matte surface finish signifies a dry, clean part.
Warping After Post-Cure
Always follow the recommended washing and curing procedures. Incorrect washing and post-curing can result in dimensional or mechanical variation. Warping is a possible defect associated with incorrect washing and or curing.
- Material Cure Times PCA 2000
- Material Cure Times PCA 4000
- Material Cure Times Otoflash
- Material Cure Times UVCA 3000