The precision of a component is vital for using it in industry and mechanical engineering. The question is, which dimensions are necessary and which tolerances are demanded simply out of habit because it is feasible in conventional manufacturing? Furthermore, at which point do the advantages of an optimised topology from additive manufacturing outweigh the disadvantages?
In production processes in industry and mechanical engineering, nominal dimensions, tolerance values and ISO standards ensure that series components have the required dimensions. Exact values must be adhered to for components and assemblies, in constant quality with every batch produced. This is possible with additive manufacturing. However, it is important that the differences in the production process are considered. In 3D printing, printing is done from a CAD file, i.e., normally without an associated drawing. Therefore, all tolerance values and other important dimensions must be included directly in the print file. As an alternative, the drawing can be supplied with the order, but in this case an indication of the required tolerances is necessary, to make the processing easier.
But be careful: Before placing an order, check which tolerances are actually required! Does a workpiece really have to meet precise tolerances in the micromillimetre range in all dimensions for the required application? Or do you simply order the 3D printed part within these tolerance values because that is how you know it from conventional CNC production? Perhaps a topology-optimised component with slightly lower accuracy will be of greater benefit in use than the conventionally manufactured assembly? 3D printing is perfect for producing components with complex surfaces and undercuts. Consider this topic and give it the necessary attention during designing a component!
If you convert a CAD file into a 3D print file such as .stl or .stp, please note that the grid model (triangulation) is at least 0.01 mm so that the resolution is sufficient for production.
Further information :
The following tolerance values are adhered to at Jellypipe. If other values are required, please enquire or provide the information when ordering.
| Technology | Material group | ISO value | Tolerance value |
| Selective Laser Melting SLM | Metals | 2768, medium | |
| Stereolithographie SLA | Resins | +/- 100 – 150 µm | |
| Fused Deposition Modeling FDM | Plastics | +/- 0.2 mm |
Please note that all required values are supplied in the 3D print file. If this is not sufficient, please enter an "individual request", enclose the PDF drawing and mention in the text the important values that must be strictly adhered to. By doing so, you avoid misunderstandings during printing.
Check here how to place an individual request on the Jellypipe platform: Individual Request
In 3D printing, the terms tolerance, accuracy, precision, and resolution are used as follows:
Accuracy: detail of a CAD file
Accuracy is about whether the 3D printed part exactly matches the dimensions in your CAD file, i.e., how big the deviations are.
Precision: reliability of the additive manufacturing process
Precision refers to the repeatability when components are printed several times. Example: How many of the 3D printed parts exactly match the required values when the same part is printed in a series of 1000 parts.
Tolerance: scope for deviation
How much is the margin for deviations? In which cases does the 3D printed component still perfectly fulfil the functionality with deviations? An example: A mechanical assembly that will be constantly moving must be produced more precisely than an additively manufactured case made of plastic.
Resolution = how thin the individual layers may be
The height of the individual layers a 3D printer produces components with. FDM printers can print layer heights of 0.1 mm without any problems. SLA printers produce with a layer height of ~ 25 µm.
We are convinced, that this information will help you to get exactly what you need. If you have any questions, please do not hesitate to contact one of our Solution Partners.
Jellypipe
