Patent Application
20220288853
3D printers convert a digital representation of an object into a physical object. 3D printing includes any of various processes in which material is bound or solidified under computer control to create a three-dimensional object. 3D printing is also commonly referred to as additive manufacturing. 3D printers are often used to manufacture objects with complex geometries using materials such as thermoplastics, polymers, ceramics and metals. In powder based 3D printing, successive layers of a powdered build material are formed and portions of each layer bound or fused in a desired pattern to build up the layers of the 3D object.
The same part numbers designate the same or similar parts throughout the figures.
Metal objects may be printed by selectively applying a liquid binding agent to portions of each of successive layers of metal powder to bind together those portions of the powder corresponding to the solid layer of the 3D object. The binding agent is cured, for example using heat and/or ultra violet energy. The cured object, known commonly as a “green part”, is heated in a sintering furnace to burn off any residual binder and fuse the metal. Polymer objects may be printed by selectively applying a liquid fusing agent to portions of each of successively layers of polymer powder and exposing the treated powder to electromagnetic radiation, causing the treated powder to fuse.
Some of the powder used to print a 3D object may cling to the printed object. The process of removing powder from 3D printed objects is commonly referred to as “depowdering.” Depowdering techniques include vacuuming, vibrating, brushing and air and particle blasting. Different depowdering techniques may be desirable for different types of printed objects. For example, higher intensity depowdering may be used on robust, fully fused objects while lower intensity depowdering may be more appropriate for green parts and other fragile objects.
A new technique has been developed to help select better and more appropriate depowdering processes for a 3D printed object. In one example, a process selector accesses depowdering criteria for the object and a set of depowdering processes, and then automatically selects the process or processes that meet the depowdering criteria. Specific object features and associated depowdering criteria can be used in the selection process. The process selector analyzes an object model to identify features relevant to depowdering and then selects the process or processes that meet the depowdering criteria for the identified feature(s). The object model may represent a green part of a fully fused part, or both. Relevant features may include, for example, material, composition, dimensions, openings, projections and features tagged in the model for depowdering process selection. Multiple different types of depowdering processes may be selected and/or with varying intensities to be performed in a particular sequence to meet the desired depowdering criteria. Depowdering process selection may be executed as part of the development of the object model so that the selected depowdering process(es) may be sent to the user along with, or as part of, the object model. Alternatively, depowdering process selection may be executed by the printer after receiving the object model or by a programmable depowdering unit.
These and other examples described below and shown in the figures illustrate but do not limit the scope of the patent which is defined in the Claims following this Description.
As used in this document, “and/or” means one or more of the connected things; and a “memory” means any non-transitory tangible medium that can embody, contain, store, or maintain information and instructions for use by a processor and may include, for example, circuits, integrated circuits, ASICs (application specific integrated circuits), hard drives, random access memory (RAM), read-only memory (ROM), and flash memory.
Process selector 14 includes the programming, processing and associated memory resources to select a process for depowdering unit 12. A depowdering process selector 14 may be implemented, for example, as part of a 3D modeling system that generates the object model, in an object model analyzer distinct from the modeling system, in a printer controller, or in a controller for the depowdering unit. In one example, process selector 14 is programmed to access a set of object features, a set of selection criteria, and a set of depowdering processes, identify at least one of the features in a digital model of the object to be depowdered, and then, based on the identified feature or features, select a depowdering process that meets the selection criteria. Selector 14 may access the object features, selection criteria and depowdering processes from a local memory or from a remote source. Where a process selector 14 is implemented in the controller for a depowdering unit 12, or otherwise communicates with a depowdering unit controller, then selector 14 may also be programmed to automatically initiate performing the selected depowdering process.
The set of object features may include, for example, material, composition, dimensions, and structures. The set of selection criteria may include, for example, precision and yield. Precision criteria may include, for example, dimensional tolerances for structures such as holes and other recesses or voids, walls, posts and overhangs. Yield criteria may include, for example, a probability of damage associated with each depowdering process. The set of depowdering processes may include, for example, different types of depowdering processes such as vacuuming, vibrating, brushing, and blasting as well as different intensities and durations for the different types of depowdering processes.
In an example, features identified at block 102 are taken from a predefined set of object features 28. “Predefined” in this context means before the identifying is performed. Feature set 28 may be static or dynamic. In this example, object model 24 is analyzed to identify which, if any, object features from set 28 are present in the object model. In an example, object model is analyzed at block 102 to identify features tagged for use in selecting a depowdering process.
In an example, a depowdering process is selected at block 104 based on a predefined set of processes 30. “Predefined” in this context means before the selecting is performed. Process set 30 may be static or dynamic. Process set 30 may include transformation information for each process in the set. Transformation information may include, for example, the precision, yield, and penetration (to clear openings) for a depowdering process. One example set 30 of depowdering processes and associated transforms is shown in the following table, where “UV” means ultrasonic vibration, “AV” means acoustic vibration, and “AIR” means air blasting.
Still referring to
In this example, process selector 14 is implemented in a controller 52 for depowdering system 10. Controller 52 includes the programming, processing and associated memory resources, and the other electronic circuitry and components to control the operative elements of system 10. In particular, controller 52 includes programming to implement a depowdering process selector 14 described above with reference to
As noted at the beginning of this Description, the examples shown in the figures and described above illustrate but do not limit the scope of the patent. Other examples are possible. Therefore, the foregoing description should not be construed to limit the scope of the patent, which is defined in the following Claims.
“A” and “an” as used in the Claims means one or more.
This is a continuation of U.S. application Ser. No. 17/052,012 filed Oct. 30, 2020 which is a national stage of international application no. PCT/US2018/056804 filed Oct. 20, 2018, both incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17052012 | Oct 2020 | US |
| Child | 17827278 | US |
