Identify and compensate distortion and stress throughout the entire process including heat treatment and HIP
Distortion due to thermal effects represents the greatest challenge in the field of additive manufacturing. Simufact Additive helps you to calculate displacements and distortions of the finished part, combined with a powerful automatic compensation to reduce them. Receive at an early stage references to the size accuracy of your part.
Simufact Additive supports you to compensate virtual detected distortions automatically. The automatic distortion compensation simplifies, accelerates and improves the distortion compensation of the part.
After the user has set the tolerance range for the deviation, based on the “best-fit method”, the software calculates the deviation from the original component. After three to five iterations steps the user receives a geometry, that meets or even fall under the required deviation between the original and the reference part. Through the iterative compensation, a local „morphing“ is achieved, which effectively suppresses the usual over- and under compensation of previous approaches.
This useful and helpful functionality goes hand in hand with automatic support structure generation.
While the software is calculating the deviation, the user is able to work in parallel in the software in other simulation models.
A simulation across the process chain shows how residual stresses built up in the printing process and how these residual stresses evolve during post processing.
Simufact Additive thus helps to identify typical manufacturing problems:
Avoid these effects by employing Simufact Additive in order to virtually test counter measurements. Changed support strategies, changed manufacturing steps – such as the pre-heating of the base plate – or the orientation of the part can counteract negative effects. The right strategy can be determined quickly and cost-saving by using simulation instead of expensive and time-consuming “trial and error” in a real production process.
Furthermore, the software predicts the reduction of residual stresses during subsequent heat treatment or hot isostatic pressing. Additional distortions, which are caused during stress relief while the part is removed from the base plate or while supports are being removed, can be detected correctly.
Simufact Additive offers flexible options for automated support generation ans optimisation:
Automatically generate and optimise support structures
Based on the part´s CAD, Simufact Additive automatically generates and optimises support structures for the manufacturing processes. Results of the automated support optimisation can be used to perform virtual tests within the software based on Simufact support structures.
The supports delivered by the Materialise support API assist the Simufact Additive user in utilizing more realistic and manufacturing practice-oriented geometrical shapes and provide basic functionality to adjust the structure concerning density and critical part angle. This method provides the best input for build orientation & distortion compensation aiming at the most realistic and accurate build process simulation & optimization results.
The user can transfer the results obtained from the simulation to external software solutions from third-party products such as Materialise Magics, Renishaw's QuantAM or build preparation software for other 3D printers.
Simufact Additive considers orthotropic material properties, which enables a more realistic representation of the support structure stiffness and conductivity. Coarser meshing maintains reliable results with a simultaneous reduction of the required calculation times.
The greatest challenges in the build space are:
Simufact Additive supports you in the component alignment/orientation within the build space with the intuitive assistant functionality.
Users can efficiently position components on the base plate and quickly iterate to optimise the component orientation. Part positioning is very intuitive in the user-friendly interface.
In practice, several geometries are usually arranged and printed simultaneous in the build space. The individual parts can influence each other mechanically and thermally through the base plate. With Simufact Additive, the user quickly and easily models the printing process of several geometries within the build space and identifies how the parts influence each other.
Simufact Additive allows you to compare different options for component orientation and to identify the optimal printing strategy.
The orientation assistant supports the user during the model set up. This feature offers an impressive overall view of the build component orientation, which makes the evaluation and the choice of the orientation more intuitive, easier and faster.
The orientation assistant provides five criteria that can be measured differently:
Users determine the best build orientation by choosing one or more criteria and measuring which criteria are most important to their process. The assistant shows the results of the component orientation in shape of a sphere. The coloured representation (green to red) indicates, how good or bad the component orientation is with respect to the selected criteria. By clicking the sphere, the part automatically turns to the appropriate part orientation. This interactive and intuitive ease of use allows the user to quickly select and instantly visualize the best component orientation. It is also possible to apply this functionality to several parts one by one.
More and more 3D printer manufacturers offer the option of preheating the base plate. Thus, pre heating is becoming more and more a standard. Especially with the use of titanium alloys (ie. . Ti6Al4V), base plate pre heating up to 400 degrees ore more can reduce residual stresses up to 50 percent. (Source: Preheating of Selective Laser Melted Ti6Al4V: Microstructure and Mechanical Properties)
Simufact Additive enables the user to analyse mechanical and thermal influences from the base plate on the part. This is a default setting for simulations with a thermal part. The software does the preheating of the base plate indirectly via the calibration of the mechanical loads, the so-called inherent strains. A more detailed analysis is possible either by a thermal or thermal-mechanical simulation. This feature allows considering the preheating directly in the model and yields to more realistic temperature flows across the height of the build space. Thus, the software enables you to measure better the influence of various parts in the build space during, for example, the so-called nesting. The increased temperature through the preheating leads to lower gradients, slows down the cooling and thus leads to residual stresses and deformation reductions. The preheating increases the temperature which creates lower gradients, slower cooling and thus leads to residual stresses and deformation reductions. The simulation supports the user in evaluating the influence of the base plate preheating on the component properties and deciding whether it makes sense and at which temperature.
Employ Simufact Additive in order to quickly and reliably identify and predict the following manufacturing issues:
During the additive manufacturing process, distortions and residual stresses occur both in the workpieces and in the base plate. The latter can affect the properties of the support structures and the component. Simufact Additive can be used to determine the properties and influences of the base plate during the build process. After simulation of the build process, the unclamping of the base plate from the machine is also considered. Here, the sequence in which the screws are unclamped can have a further influence on the deformation and stress state of the build space and its parts. As a practical application, the user can, for example, determine when the base plate has become too thin and therefore is no longer stiff enough and needs to be replaced.
For the identification of specific manufacturing problems, Simufact Additive offers three methods that support the user during the evaluation of results. They help the user to identify critical areas in the part:
The temporal and spatial tracking of results individual points, the so-called virtual sensors (post particles), enables the user to develope detailed local evaluations.
In many cases, not only the final outcomes are interesting, but also how it has developed until then. For example, how does distortions, stresses and temperatures change during manufacturing processes, by applying new layers, which influences the entire part again and again? A history diagram provides reliable answers.
The colour rendering of the surfaces and internal results by means of sections provides a good overview of the distribution of the results and facilitates the rapid identification of critical extreme points. A more detailed insight into the dependence of the results on their position can be obtained by means of so-called path diagrams. Intermediate results can be easily interpolated automatically so that the meaningfulness of a diagram can be improved with little effort.
The subsequent steps of the printing process such as the stress-reducing heat treatment, cut off and removal of the base plate and support structures and, if necessary, the hot-isostatic-pressing can have significant influences on the quality and accuracy of the part.
You should consider simulating these process steps to achieve print first time right.
Therefore, Simufact Additive not only serves the immediate optimization of the build processes, but also the subsequent processes such as stress relief, cut off and removal of the base plate and support structures as well as HIP. Simufact Additive supports the user to analyse the influence of subsequent steps on the part.
This allows the user to develop strategies for dimensional accuracy across the entire process chain.
The picture sequence shows the gradual reduction of residual stresses within a part during the manufacturing post processing. The result at the end of the simulated process chain is a nearly stress less bracket. The simulation along the process chain makes it possible to optimize the result to the desired result. The parameters of the printing process, heat treatment, cutting and support removal, and HIP can be varied to achieve the desired result.
The heating and cooling of the metal material as the part is build up layer-by-layer leads to internal stresses that should be relieved before the part is removed from the build plate. Otherwise, the part may warp or even crack during the cutting process.
Simufact calculates the results of the heat treatment stress relief process by considering the applied temperature history, the heat dependent material properties and –which is crucial- the creep effects occurring under elevated temperatures and internal loading by residual stresses. By this the stress relief over time can be simulated in detail and still remaining stresses after the heat treatment can be identified. These stresses would influence the stress and distortion state after the cutting process.
If a quick rough assessment is enough also an engineering approach can be chosen in which the stresses are simply assumed to be set to zero. This reduces the overall calculation time and still delivers practically useful results in most cases.
Optimise cutting parameters and compare different cutting strategies with Simufact Additive. Wire EDM and Bandsaw are two methods that are used for this. Note, that the different methods do not make any difference in the simulation.
If you do not have run any a heat treatment or if residual stresses are still present, those will disappear during the cutting process and will lead to further distortions. We advise you to consider cutting history during the simulation process because it always influences the part due to the non-linear material behaviour.
Simufact Additive offers several possibilities to simulate the cutting process of the parts from the base plate as well as the partial cutting of geometries for calibration purposes. In addition to the fast variation to solve all parts in the simulation simultaneously, you can also select predefined sections in x or y-direction at the desired height. If this is not enough, you can define any section concerning direction, length, and height in order to simulate complex section scenarios based on this.
If the support structures are directly removed after the manufacturing process or if still, residual stresses remain in the part after the heat treatment process, the removal of the support structures can result in a new deformation and stress balance. Due to the non-linear material properties, this is in principle dependent on the sequence in which the support structures are removed, so that this can be considered in the simulation.
During the hot isostatic pressing (HIP) the component exposed in a protective atmosphere with high environmental pressure combined with high temperatures. On the one hand, this matches the conditions of an additional heat-treatment-process, but on the other hand, the high environmental pressure should lead to a compression of the porosities in order to increase the strength and lifetime of the component. However, additional distortions can also occur if imbalances (e.g. regarding temperatures, stresses, stiffness) occur in the process.
During the simulation of the HIP-process, as with the heat treatment, Simufact Additive also considers the temporal temperature profile the temperature-dependent material values as well as the creep effects. In addition, the temporal process of the environmental pressure is given. This allows calculating the development of the stress and deformation condition of the component. In addition, the compression of the component from an initial porosity can be simulated with the "hollow sphere" model.
In order to optimise the entire chain of additive manufacturing, Simufact offers an opportunity to run various variants.
The goal must be here an effective and fast optimisation of the entire process chain.
As a user, you often simulate several different variants. With Simufact Additive, you optimise each process step separately on the basis of the previous results. Thus, Simufact Additive shortens the calculation times of the entire simulation.
Simufact Additive compares simulation results with
Simufact Additive allows comparing the simulated deformation of the component directly with the target geometry or with 3D measurement data as a reference. For this purpose, the user positions the simulation result and the reference part relative to each other. This step is performed either manually or automatically using the "best-fit method".
The visual representation of the results on the basis of the surface distances, based on metrological investigations, allows the user to quickly evaluate the results and immediately find out whether the deviations lie within the permissible tolerances.
With Simufact Additive, users can compare simulation results and reference model (e.g., CAD data) by mouse click using "best-fit" positioning. In the best-fit method, the software automatically determines the position at which the deviations are lowest.
The visual presentation of the results, based on measurements, allows the user to quickly assess whether the deviations are within the permissible tolerances.
For this function, Simufact has integrated Hexagon's 3DReshaper technology.
Comparison of the calculated parts with the target design or with 3D measurement data as a reference. The simulated deformations can be viewed relative to the reference geometry. Users measure the actual part and import it into Simufact Additive. This feature allows engineers to compare their results to ensure a more efficient workflow.
Your request will be forwarded to our Global Sales & Support Network that provides best-in-class industry-related application-specific sales and technical services - backed up by qualified local Simufact and Channel Partner experts.
Copyright© 2020 simufact engineering gmbh, part of Hexagon’s Manufacturing Intelligence division.