FDM DESIGN GUIDELINES - STRATASYS UPRINT SE
The following design guidelines have been created to help you design your part with the FDM 3D printing process in mind. These guidelines are specifically for our Stratasys uPrint SE 3D printer. We use a range of FDM 3D printers, so if you have designed parts specifically for these guidelines, it is important to specify this when requesting a quotation.
The Stratasys UPrint SE Plus can print any geometry, as long as it fits within the maximum build area of 203 x 203 x 152 mm (8 x 8 x 6 in). Larger parts can be printed however your model will need to be split into sections and joined together afterwards using a plastic adhesive / cement.
Layer Thickness (Vertical Resolution)
Changing layer resolution will affect surface finish and build times. Selecting a smaller layer resolution creates a smoother surface finish, but takes longer to build. Layer resolution can also affect minimum wall thickness.
• High - 0.254mm Min. Wall Thickness: (.914 mm)
• Low - 0.330mm Min. Wall Thickness (1.194 mm)
We quote all parts in high resolution as standard, for best print quality.
Based on the vertical resolution listed above, expect a vertical tolerance of +/- 0.2mm. This tolerance is usually at the top of the tolerance band when attempting to print thin sections less than 0.8mm. Although horizontal tolerance is usually better, recommend use this tolerance for all dimensions as build orientation is not always known.
We recommend avoiding wall thicknesses less than 1mm. If a feature in an STL is smaller than 1mm, our 3D print processing software will increase the size of the feature to the minimum wall thickness.
Interior Fill Style (Density)
This establishes the type of fill used for the interior areas of the part. There are three types of model interior that you can choose from:
Solid - Used when a stronger, more durable part is desired. Build times will be longer and more material will be used.
Sparse High Density - This is the default model interior style. Build times will be shorter, less material will be used and the possibility of part curl for geometries with large mass will be greatly reduced.
Sparse Low Density - The interior will be “honeycombed” or “hatched”. This style allows for the shortest build times and lowest material usage but will decrease the strength of the part.
All models will be printed in Sparse High Density as standard. Please advise during quotation if a different density is more suitable.
Factors such as feature strength, build time and surface finish are all affected by build orientation. It is important that orientation is considered to achieve the best result.
Build Speed - Closely related to material use. A lesser amount of support will allow for a faster build speed, achieved by minimising cavities and overhangs. Furthermore, the printer can build faster across the XY plane than it can along the Z axis. Orienting a part so that it is shorter within the modelling envelope will produce a quicker build and minimise cost.
Part Strength - A model is stronger within a layer than it is across layers. Depending upon what features you want your part to demonstrate, we may need to orient your part to have its greatest strength across a specific area. For example a tab that needs to be pressed would be weakest if you are applying pressure across layers.
Surface Finish - How the part is oriented will determine how the surface finish will look and allow the printer to provide the smoothest finish for a specific area. For example, if building a cylinder, orienting the cylinder upright will have a smoother surface finish than building it on its side.
If one of the above features is important to you, please advise during quotation and we will print your model accordingly.
Stepping and Contours
As described above, FDM 3D printing builds in layers, and consequently when building curved surfaces or organic shapes, stepping can occur between layers. This is a limitation of the 3D printing process and in some cases unavoidable.
If this is important to you, please let us know during quotation which faces are visual and we will avoid this as much as possible.
Small text is unlikely to form correctly. For text to form, it will need to have a substantial thickness of around 2mm.
Both internal and external threads can be formed during the FDM process, however for threads to withstand considerable mechanical force or with tight tolerances, we recommend using an alternative method such as press fit inserts or drilling and tapping. Both methods will mean designing the feature with a hole to suit your requirements.
Pins and Thin Extrusions
Narrow pins and extrusions are likely to fail, especially if built across layers. As a rule, pins should be greater than 2mm, however this may be even larger if the length of the extrusion is longer than 4mm.
Holes in FDM parts usually print slightly undersize (rarely more than 0.3mm). Larger holes are usually more accurate the smaller holes. If a tight tolerance is required, we advise printing the hole undersize and drilling to the correct size.
Functional assemblies with moving parts can be 3D printed in one run. To ensure assemblies are formed with support material rather than model material between parts, it is important to leave a gap greater than 0.7mm.
If you have any further questions, please do not hesitate to get in touch using the Contact Us page.