BACKGROUND

[0001] Additive manufacturing machines produce 3D (three-dimensional) objects by building up layers of material. Some additive manufacturing machines are commonly referred to as "3D printers." 3D printers and other additive manufacturing machines make it possible to convert a CAD (computer aided design) model or other digital representation of an object into the physical object. The model data may be processed into slices each defining that part of a layer or layers of build material to be formed into the object.

DRAWINGS

[0002] Figs. 1-4 illustrate one example of a build material supply container for an additive manufacturing machine, implementing one example of a joint between the body of the container and the cap.

[0003] Figs. 5-12 present a sequence of views illustrating one example of a process for joining the body and cap in the container shown in Figs. 1 -4.

[0004] Fig. 13 is a flow diagram illustrating one example of a process for assembling a container, such as might be implemented in the sequence shown in Figs. 5-12.

[0005] Fig. 14 illustrates another example of a joint joining a container body to a cap.

[0006] The same part numbers designate the same or similar parts throughout the figures. The figures are not necessarily to scale.

DESCRIPTION

[0007] In some additive manufacturing processes, powdered build materials are used to form a solid object. Particles in each of many successive layers of build material powder are selectively fused in a desired pattern to form the object. Some additive manufacturing machines use replaceable build material powder supply containers. Cylindrical or barrel shaped containers are rotated in the machine to move the powder to inhibit agglomeration and to dispense or receive powder. [0008] In one type of powder supply container, a plastic cap is spin welded into the open end of a plastic container body along a joint at the interface between the two parts. Waste particles created during spin welding along the interface may leak into the body of the container and, therefore, the container must be cleaned of any such contaminant particles before filling with build material powder. In addition, the spin welder must stop with the cap at the desired radial alignment with respect to the body. A new joint has been developed to reduce the risk of weld particles contaminating the container and to relieve the spin welder of the difficult task of cap alignment.

[0009] In one example of the new joint, a plastic“weld” ring clamps the rim on the end of the body to the rim of the cap. The ring is spin welded to the outside of the body rim and to the inside of the cap rim to fasten the parts together. In one example, when the cap is inserted into the body before welding, multiple teeth arranged along the outside of the cap rim bite into and grip the inside of the body rim to keep the cap from rotating during spin welding. The cap is aligned radially with respect to the container body during insertion, not during welding. Any welding waste particles are created away from the interface between the body rim and the cap rim to avoid contaminating the interior of the container.

[0010] Although examples of the new joint are described with reference to a replaceable container to hold build material powder for an additive manufacturing machine, examples are not limited to powder containers, to build material supply containers or to additive manufacturing. Examples may be used for other materials and/or for other uses. The examples described herein illustrate but do not limit the scope of the patent, which is defined in the Claims following this Description.

[0011] As used in this document,“and/or” means one or more of the connected things.

[0012] Figs. 1-4 illustrate one example of a build material supply container 10 for an additive manufacturing machine, implementing one example of a new joint 12 visible in Figs. 3 and 4. Container 10 is structured to hold a powdered build material in a horizontal orientation so that the container may be rotated in the machine to move the build material to inhibit agglomeration and to dispense build material from the container. Referring to Figs. 1-4, container 10 includes a rigid or semi-rigid, generally cylindrical body 14 and a cap 16 that together enclose an interior chamber 18 to hold build material. Body 14 and cap 16 are fastened together at joint 12. Joint 12 is visible Figs. 3 and 4. Body 14 may include a handle 20.

[0013] Build material flows out of and/or into chamber 18 through an opening 22 in cap 16. Thus, cap 16 itself partially blocks the open end of body 14. A valve 24 controls the flow of build material through opening 22. The interior surface 26 of a cylindrical or barrel shaped body 14 is structured to move build material axially toward or away from cap 16 as container 10 is rotated, depending on the direction of rotation, for example with helical raised portions 28, commonly referred as“flightings”, that auger build material along body 14 when container 10 is rotated. Cap 16 is structured to move build material radially toward or away from opening 22 as container 10 is rotated, depending on the direction of rotation, for example with an Archimedes screw 30. In this example, valve 24 includes an auger 32 to move build material axially through opening 22. Auger 32 may include a helical blade 34 that matches the spiral of cap 16 to complete

Archimedes screw 30.

[0014] Auger 32 is keyed to cap 16 or otherwise operatively linked to body 14 so that auger 32 rotates with cap 16 and body 14. As best seen in the section of Fig. 3, valve 24 includes an actuator pin 36 that is pulled out to open valve 24, as indicated by arrow 38, and pushed in to close valve 24, as indicated by arrow 40. Valve 24 is closed in Fig. 3. An o-ring or other suitable seal 42 may be used to seal opening 22 when valve 24 is closed. In a dispensing operation, valve 24 is opened and container 10 rotated in a dispensing direction so that container flighting 28, cap screw 30, and valve auger 32 move build material toward and through opening 22. Also in this example, the exterior surface 44 of body 14 includes a flat part 46. A flat part 46 may be used to orient container 10 in, and align it to, a receiving station in an additive manufacturing machine, as well as help container 10 to remain stable resting on or against a flat surface.

[0015] The open end 48 of body 14 is formed by a circular rim 50. The end 52 of cap 16 is formed by a circular rim 54 that fits inside body rim 50. Rims 50 and 54 are held together with a“weld” ring 56. As best seen in Figs. 3 and 4, ring 56 surrounds body rim 50 and lines cap rim 54. Ring 56 includes a slot 58 formed by a surround 60 welded to the outside 62 (called out in Figs. 6 and 8) of body rim 50, a liner 64 welded to the inside 66 (called out in Figs. 6 and 8) of cap rim 54, and a web 68 that connects surround 60 and liner 64. Welds 70, 72 joining ring 56 and rims 50, 54, respectively, are depicted by a heavier weight line in the figures. As best seen in Fig. 4, welds 70, 72 are made away from the interface 74 between body 14 and cap 16 to reduce the risk of weld waste entering interior chamber 18. In addition, gaps 73 and 75 (called out in Fig. 10) provide space for weld waste to escape to the outside of joint 12.

[0016] An interference fit between weld ring 56 and rims 50, 54 helps form a secure joint 12 and good welds 70, 72. An interference fit may be formed, for example, by making the inside diameter of ring surround 60 less than the outside diameter of body rim 50 at the interface 76 (called out in Fig. 10) between surround 60 and body rim 50 and/or by making the outside diameter of ring liner 64 greater than the inside diameter of the cap rim 54 at the interface 78 (called out in Fig. 10) between liner 64 and cap rim 54. Although a weld 72 between ring liner 64 and cap rim 54 is used in the examples shown in the figures, it may be possible to form a secure joint 12 with just weld 70 between ring surround 60 and body rim 50, where an interference fit is made between ring 56 and rims 50, 54. Also, in the example shown in the figures, web 68 extends continuously around the full circumference of ring 56. It may be desirable in other examples to use a segmented web 68 to connect surround 60 and liner 64 with a series of web segments arranged around ring 56, for example to reduce friction between web 68 and rims 50, 54 during spin welding and to provide additional space for weld waste.

[0017] In this example, multiple teeth 80 arranged along the outside of cap rim 54 bite into and thus grip the inside of body rim 50 to keep cap 16 from rotating during spin welding. Teeth 80 also help accommodate dimensional inaccuracies by penetrating deeper into body rim 50 in the case of more tightly fitting parts or shallower in the case of less tightly fitting parts. As best seen in Fig. 4, cap 16 may include a flange 82 projecting out from the end of cap rim 54 and overlapping a lateral edge 84 of body rim 50 to help position cap 16 axially with respect to body 14 and to cover body/cap interface 74.

[0018] Figs. 5-12 present a sequence of views illustrating one example of a process for joining body 14 and cap 16 at joint 12 in container 10. Fig. 13 is a flow diagram illustrating one example of a process 100 for assembling a container, such as might be implemented in the sequence shown in Figs. 5-12. Reference to the process steps in the flow diagram of Fig. 13 is made in parentheses following the description of the corresponding views in Figs. 5-12. As best seen in Figs. 5,

7, and 9, each section 6-6, 8-8, 10-10, and 12-12 is taken through a tooth 80 on cap rim 54. Therefore, the surface of cap rim 54 in Figs. 6, 8, 10, and 12 is hidden behind tooth 80, and thus is depicted by a dashed line.

[0019] In Figs. 5-8, cap 16 is pressed into body 14 until flange 82 is seated against the edge 84 of body rim 50. (Block 102 in Fig. 13.) Figs. 5 and 6 show cap 16 partially inserted into the open end 48 of body 14. Figs. 7 and 8 show cap 16 fully inserted into body 15 with teeth 80 on cap rim 54 biting the inside of body rim 50 to grip the end 48 of body 14, to prevent cap 16 from rotating during spin welding. (Block 104 in Fig. 13.) Cap 16 is pressed into body 14 until flange 82 is seated against the edge 84 of body rim 50 as shown in Fig. 8.

[0020] In Figs. 9 and 10, weld ring 56 is placed over the ends of body 14 and cap 16 to clamp cap 16 to body 14 between surround 60 and liner 64. Thus, weld ring 56 functions as a clamp clamping cap 16 to body 14. (Block 106 in Fig. 13.)

In Figs. 1 1 and 12, a spin welding driver 88 is inserted into weld ring 56 to engage teeth 86, as indicated by arrow 90, to spin ring 56, as indicated by arrows 92, and simultaneously form welds 70, 72 at interfaces 76, 78, respectively. (Block 108 in Fig. 13.)

[0021] For a build material powder container 10 shown in Figs. 1 -4, body 14 and cap 16 are usually molded plastic. “Plastic” in this context includes composites and reinforced plastics. Also, it is expected that container body 14 usually will be made of softer plastic compared to cap 16 and, therefore, cap teeth 80 on cap rim 54 may bite deeply into body rim 50 to help better prevent rotation while spin welding ring 56. [0022] Fig. 14 illustrates another example of a joint 12 joining a container body 14 to a cap 16. In the example shown in Fig. 14, a gap 90 separates the web 68 of weld ring 56 and the ends 48, 52 of body 14 and cap 16. The configuration shown in Fig. 14 may be desirable, for example, to help prevent friction between the ends 48, 52 of body 14 and cap 16 and ring web 56 during spin welding to form welds 70, 72 and to provide additional space for weld waste.

[0023] 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.

[0024] "A" and "an" as used in the Claims means one or more.