3D Printing Material: Rigid Polyurethane CLIP (DLS) Resin
On this page you will find all of the information, hints, and advice you’ll need to create an object with Sculpteo’s Rigid Polyurethane resin material. By the end of this page you will understand:
- Our 3D printing process for Rigid Polyurethane
- Finishing options
- Overhang and support considerations
- Successful modeling processes
- Technical specifications on the material
Rigid Polyurethane Resin material
Our Rigid Polyurethane resin material creates 3D printed objects from a base of photosensitive polymer liquid. That liquid is then solidified by UV light layer by layer to create a rigid and highly detailed prints which are comparable to injection molded plastics. Rigid Polyurethane is very stiff and strong with material properties that outperform ABS plastic and rivals Nylon. This material is perfect for mechanical parts that needs to be tough, heat-resistant, and abrasion-resistant.
RPU is certified by the UL 94 HB flammability classification for a more secured use.
Processing times and pricing
The printing price of your design is calculated automatically the moment it is placed online. As you modify your object you will note that the price changes automatically. The pricing is based on a series of factors, including: volume of material used, size of object, and multiple other factors. To see your price in just a few clicks you just need to upload your file .
We estimate our Rigid Polyurethane prints will be shipped 6 days after the order is placed. In some outstanding cases, the print can take more time to be shipped - this usually depends on the volume of prints being processed. The exact shipping estimate will be given upon checkout.
Delivery time should be added to processing time and depends on the delivery option you choose .
Rigid Polyurethane 3D prints are created through CLIP (DLS) process. CLIP stands for Continuous Liquid Interface Production. CLIP (DLS) is a photochemical process that carefully balances between light and oxygen to rapidly produce parts. It works by projecting light through an oxygen-permeable window into a reservoir of UV curable resin. As a sequence of UV images are projected, the parts solidifies and the build platform rises. Your design goes through multiple steps before arriving at your object:
- Model transferred to 3D printer
- Object is 3D printed
- Support removal
Before printing your object you must create a 3D model using a program dedicated to 3D modeling. Your 3D model details are prepared with specific supports depending on the shape of your 3D file. Then this new 3D file is sent to our 3D printers and arranged within the next available batch. For Rigid Polyurethane prints, that batch will be done in one of our printers by Carbon3D.
The 3D print itself is carried out layer by layer within a batch of photosensitive resin. A sequence of UV images are projected, hardening the liquid with a high level of accuracy. The process of fine layer polymerization is repeated until the object is finished.
After the photopolymerization is completed, the objects are detached from the build platform and the supports are carefully removed. The object is then cured with heat in an oven. The curing completes the polymerization so the part achieves its final material characteristics.
Polishing can be performed upon customer’s request. After removing the supports, the part is gently sanded to remove most of the support marks.
Uses and maintenance
Parts printed with CLIP (DLS) are much more like injection-molded parts than objects produced with other 3D printing techniques. CLIP (DLS) produces consistent and predictable mechanical properties, creating parts that are smooth on the outside and solid on the inside.
Rigid Polyurethane is our stiffest and most versatile polyurethane-based resin. It performs well under stress, combining strength, stiffness, and toughness. These properties make RPU particularly useful for consumer electronics, automotive, and industrial components where excellent mechanical properties are needed.
We remove the support structures for you during our post-processing steps, but the surfaces where the supports structures come in contact with the part will be visible but can be sanded and finished by a technician upon request. This means there are considerations you should keep in mind during the design of your part to facilitate not only the successful construction of your part, but also the removal of support structures and the finishing of your surfaces.
There are multiple finishing options available through Sculpteo:
- Raw: Supports are removed from the model. Support scars/bumps will still be visible.
- Polished: Supports and support scars/bumps are removed.
Rigid Polyurethane resin material is adapted to at-home post treatment. Thus, you can easily make your own finishes on your object: polishing, painting, varnishing, and more.
Overhang and support considerations
Sculpteo technicians will make the ultimate choice regarding orientation and support. As is the case in many 3D printing processes, there are likely features on your part that require support to print properly. Supports are removable structures placed along your part that hold up overhangs and help anchor features of your model to the platform . They can be bars, with tapered tips, trusses, lattices, but all aim to improve your part's final properties and printability. These kinds of features include overhangs, small angles and floating structures. Due to the nature of the CLIP (DLS) process, the support structures are built from the same material that the part is constructed with and are therefore physically bonded to the final printed part.
The following sections will help you to understand why specific features require support and how those supports may impact your part. Once you've developed a solid understanding of support structures, you will be able to make smart design decisions to reduce the need for support and optimize your part for the best possible product. Like DLP and SLA, CLIP (DLS) requires the use of support structures to enable generation of overhanging features, shallow angles, and detached bodies.
Overhangs are the parts of your structure that extend past the bulk of your part into free space. An excellent example of an overhang that requires support is a cantilever beam or plate, which is anchored at only one end to your part. As the part is printed, an unsupported cantilever will sag and deform, ruining your feature and resulting in a failed print. A properly supported cantilever beam will print with accuracy and rigidity!
Your part is printed layer by layer, from the bottom to the top. Depending on the orientation of your part in the printer, it can be necessary to add supports to avoid the overhang effect. Beware of the features of your model that would be printed before the parts supposed to attach them to the rest of the part: as they can't be printed in free space, they will need supports.
You may not have any cantilever features on your part, but that doesn't mean you can get away with-out using support! Small angles, definitely anything less than 40 degrees, also need to be supported. This is because each layer can only slightly overhang the previous layer else sagging will occur. When you have a small angle, larger portions of the new layer extend beyond the bounds of the previous layer. This extended surface can't support itself, and must be supported by a secondary structure.
Access to support
It's also imperative to remember that these supports need to be able to be removed! The support removal process, as mentioned above, is a physical process where a technician will use snips to carefully remove the structures from the part surface. Keep this in mind when designing your part, and try to design your part such that areas that need support are accessible!
Many part designs have surfaces that are visually or functionally important. These surfaces print the best when they aren't attached by any supports, and print the best when facing against the direction of the build. If it's within your design scope, try and build all your important surfaces facing the same direction.
As a final word on support and orientation, the orientation in which the part is printed is critical to the success of the build. It will impact how and where supports are generated on your part, with the goal being to minimize the support necessary for a successful build. Use these considerations to inform your design and make the best part possible for the CLIP (DLS) process. Sometimes, your first shot at design for 3D printing doesn't always turn out perfect. Don't worry about it too much! Our technicians will review every model for printability and evaluate it for the CLIP (DLS) process. If they find an issue with your model, they will work with you to find a solution. However, the final decision of how to best orient and support your part is left in the hands of our skilled technicians. Remember -design is an iterative process, and it might take a few tries to get it right.
|Layer thickness||100 µm|
Our printer by Carbon3D allows us to print with a layer thickness of 100 µm or 0.1 mm. In consequence, it is important that your prints are exported with the highest quality possible. This will avoid any sort of triangulation during the print - though keep in mind your file cannot be greater than 50mb.
|Maximum size||200 x 180 x 110 mm (7.87 x 7.08 x 4.33 in)|
With CLIP (DLS), parts are limited by the area of the build platform and the height the platform can travel to. If you need to build something larger, you'll have to print your design in several parts and assemble it later. Check out our tips regarding Minimum Clearance and Spacing.
Use wall angles above 40 degrees: Wall angles above 40 degrees don’t need to be supported. Printing self-supporting parts is faster and uses less resin thus shorter lead time for delivery. It also eliminates the step of removing the supports.
Avoid sharp angles, use curved corners: Gradually curving forms, are well-suited to CLIP printing. If your starting design has sharp angles, try to smooth the design. You can add fillets, bars, and ribs to support and smooth 90° angles.
Keep in mind that our solidity check tool does not detect physical aberrations such as floating parts, unstable position, parts supporting too much weight relative to their thickness, etc. Particular care must be given to the geometry of your design and the most stressed parts must be thickened.
Part accuracy and tolerance
The CLIP (DLS) process is very reliable, but the parts it produces are susceptible to shrinkage and other sources of variation in the part.
It is important to note that accuracy and tolerance are dependent upon the material you select, and these values may change respectively. Furthermore, as a tolerance is tighter in the XY place, you should consider placing features that require a higher degree of tolerance facing the same directions. This way, when the build is prepared, the part orientation can be selected to place these features in the XY plane.
The CLIP (DLS) process is capable of printing with the above 95% of features falling within a +/-0.1mm tolerance in the XY plane and +/-0.4mm in the Z direction.
Minimum Thickness and Geometry
|Minimum wall thickness||1 mm|
Recommended thickness for certain structural features will vary based on their specific nature. For example, a vertical wall 5 cm in height will be somewhat flexible if it is printed at a thickness of 1 mm, but rigid if it is printed at a thickness of 1.5 mm.
The walls of your object must be thick enough to support the weight of the object without breaking under its own weight. We recommend designing your model with the material's minimum design standards located in “Tips & Tricks.” This resolution holds true for short walls on the order of 2mm protruding perpendicular to the build direction (XZ and YZ planes) as well as in the XY plane. As it is the case with any thin or small feature, anything with a high aspect ratio (long and thin) will be fragile and need to be supported by other design features (ribs or fillets) or removable support structures. When designing thin/small features, keep the aspect ratio 1:4 to minimize distortion. For the upper limit, try to design your walls no thicker than 1cm as bubbles may develop.
Moreover, tall and large parts have a tendency to warp and must be supported to maintain rigidity throughout printing process. Warping can be caused by heat, vacuum forces, and thin walls. For larger parts, 0.5mm may not be enough to avoid warping depending on the cross sections.
Make walls thicker than 1 mm: Walls thinner than 1 mm are difficult to print and are best avoided. It is possible to add a support structure to maintain stability. For example, if you are modelling a bust of a person, you can attach thin aspects of the design like the ears in more places around the model’s head. Doing that will avoid cantilevered and easily breakable elements in the final print.
Make walls and solid blocks of resin thinner than 10 mm: As parts thicker than 10 mm may suffer from heat-related distortion and bubble formation, try to avoid printing block-like models. However, by hollowing out solid areas and adding supporting 3D lattices, you can convert blocky designs into ones more suitable for CLIP (DLS) printing.
Keep cross-sections below 50 mm: We are able to design models as small as 1 cm3 as small parts are light and therefore resistant to being deformed by gravity. We can print parts longer than 50 mm in the z-axis, but we try to avoid designs with cross-sections larger than 50 mm because they may distort during printing.
|Minimum Etching Detail||0.5mm|
|Minimum Emboss Detail||0.5mm|
A detail’s minimum precision is mainly determined by the resolution of our printers. However, during the cleaning process, a fine layer of detail can also be lost. In order for a detail and text to be visible we recommend following our recommended sizes at the very least. It is possible to go to a minimum etching and embossing detail of 0.1 mm but visibility will decrease. To ensure details will be visible, their width should be at least as big as their depth.
Minimum Size of the text
The smallest resolvable text is 8 point (which equals to 11 pixels or 2.9mm), in both recessed and protruding features. In some instances, especially in the XY plane, font sizes smaller than 8 point may be possible but run the risk of losing detail due to over-curing, the unintended resin of curing across a feature.
Enclosed and Interlocking Volumes
|Enclosed parts ?||No|
|Interlocking parts ?||No|
|Minimum clearance||0.6 mm|
Objects printed in Rigid Polyurethane can be printed to be assembled. As long as a width of at least 0.6 mm is left between the different parts of the object.
The resin does not allow for the hollowing of your object. For this reason, the option is not available during checkout.
For the same reason, it is not possible to create an empty cavity within a closed Rigid Polyurethane resin object. If the object were hollowed, the 3D printer would add support elements in the empty space which would be impossible to remove and trap uncured resin inside. Those elements run a high risk of breaking as the object is handled and releasing uncured resin.
|Files with multiple objects ?||No|
It is not possible to upload a file to be printed in resin with multiple objects.
Multiple objects and clusters
It is not possible to print a 3D file containing several objects, that's why we cannot accept files that contain clusters of multiple objects . However, don't worry, this doesn't mean you'll pay more for your multiple objects: to reduce the 3D printing cost, we set up a different price calculation as soon as you order two or more objects with CLIP (DLS).
To get more information on our additive manufacturing service, you can contact our qualified sales team.
Rigid Polyurethane CLIP (DLS) Resin
|Impact Strength||J/m||21 - 23|
|Young's Modulus||MPa||1700 - 2200|
|Tensile strength||MPa||42 - 47|
|Elongation at break||%||90 - 120|
|Glass Transition Temperature||°C||80|
|Heat Deflection Temperature||°C||70|
For more information about Rigid Polyurethane resin's specifications, refer the following document:
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