THREADED SLEEVE FOR ASSEMBLING WITH HEAT INPUT IN A COMPONENT MANUFACTURED BY FDM PROCESS

Abstract

A threaded sleeve for assembling with heat input in a component manufactured by FDM process is provided. The threaded sleeve includes a groove along its longitudinal axis. Further, the outwardly facing surface of the threaded sleeve includes a self-tapping thread which is divided into two sections along the threaded sleeve's longitudinal axis. The first section includes a constant pitch diameter and the second area comprises a pitch diameter decreasing along its longitudinal axis. The inwardly facing surface of the threaded sleeve comprises a metric thread. Furthermore, a kit, a system and a method for assembling with heat input the above-mentioned threaded sleeve in a component manufactured by FDM process is provided.

Claims

1. A threaded sleeve (19) for assembling with heat input in a component manufactured by FDM process (37) characterized in that the threaded sleeve (19) has a groove (15) along a longitudinal axis an outwardly facing surface of the threaded sleeve (19) comprises a self-tapping thread having cutting edges (17) and an inwardly facing surface of the threaded sleeve (19) comprises a metric thread (21).

2. The threaded sleeve (19) according to claim 1 characterized in that the self-tapping thread is divided into two sections (2, 4) along the longitudinal axis, wherein a first section (2) comprises a constant pitch diameter (3) and a second section comprises a pitch diameter decreasing along the longitudinal axis and wherein the self-tapping thread's maximum pitch diameter (3) is configured at its first section (2).

3. The threaded sleeve (19) according to claim 1 characterized in that the threaded sleeve (19) comprises ferromagnetic material and/or several grooves (15) along the longitudinal axis and/or an internal hexagon socket (23) and/or a torx socket.

4. A kit comprising a threaded sleeve (19) according to claim 1 and a guide sleeve (25) having a heating coil (27).

5. A system configured for assembling a threaded sleeve (19) according to claim 1 with heat input in a component manufactured by FDM (37) process comprising: a threaded sleeve (19) a guide sleeve (25) a component manufactured using the FDM process (37) characterized in that the inner diameter of the guide sleeve (25) is radially aligned with the self-tapping thread's pitch diameter (3) of the threaded sleeve (19), so that the threaded sleeve (19) is guided in the guide sleeve (25) the guide sleeve (25) is partially surrounded by a heat source.

6. The system according to claim 5 characterized in that the component manufactured by the FDM process (37) has a core hole (35), wherein the guide sleeve (25) rests radially aligned over the core hole (35).

7. The system according to claim 5 characterized in that the guide sleeve (19) has a closure (31) and an insulation layer (33), wherein the closure (31) is displaceable in one degree of freedom through a laterally arranged guide sleeve (25) opening and wherein the insulation layer (33) divides the guide sleeve (25) along a guide sleeve longitudinal axis in an area arranged above the insulation layer (33) and an area located below the insulation layer (33) wherein the closure (31) is located in the area above the insulation layer (33).

8. The system according to claim 5 characterized in that the heat source is a coil (27) placed around the guide sleeve (25) and only the area arranged above the insulation layer (33) is surrounded by the coil (27).

9. The system according to claim 5, characterized in that the guide sleeve (25) is set up to receive the threaded sleeve (19) in an opening arranged in the area arranged above the insulation layer (33), to heat the threaded sleeve (19) and to move the closure (31) into an open position after reaching a target temperature, as a result of which the threaded sleeve (19) is guided into the area located below the insulation layer (33) and is configured to be screwed into the component manufactured using the FDM (37) process by means of a torque-applying tool.

10. The system according to claim 5, characterized in that the torque-applying tool has a sensor which is set up to monitor a parameter selected from the group consisting of temperature, heat input, torque, pressure, feed speed, and rotation speed.

11. A method for assembling a threaded sleeve (19) according to claim 1 with heat input in a component manufactured by FDM process (37), characterized in that a) the threaded sleeve (19) is heated to a target temperature b) the threaded sleeve (19) is screwed into a component manufactured by FDM (37) process using a torque-applying tool, wherein the threaded sleeve (19) is guided.

12. The method according to claim 11 characterized in that step a) is preceded by: a1) a guide sleeve (25) is aligned on a component manufactured by FDM process (37) a2) the threaded sleeve (19) is inserted into the guide sleeve (25) a3) the threaded sleeve (19) is guided on a closure (31) present within the guide sleeve (19) the following steps are between steps a) and b): b1) the closure (31) is moved into an open position b2) the threaded sleeve (19) is guided into a second area of the guide sleeve (25) b3) the torque-applying tool is inserted through an upper opening of the guide sleeve (25) and rests on the threaded sleeve (19).

13. The method according to claim 11 characterized in that the torque-applying tool has a sensor which is set up to monitor a parameter selected from a group consisting of temperature, heat input, torque, pressure, feed speed and/or rotation speed.

14. The method according to claim 11, characterized in that the torque-applying tool, taking into account the monitored parameter, screws the threaded sleeve (19) into the component manufactured by FDM process (37).

15. Use of a threaded sleeve (19) for assembling with heat input into a component manufactured by FDM process (37), wherein the threaded sleeve (19) comprises an outwardly facing surface with a self-tapping thread having cutting edges (17) and an inwardly facing surface with a metric thread (21).

16. The system configured for assembling a threaded sleeve (19) according to claim 5 wherein the self-tapping thread is divided into two sections (2, 4) along the longitudinal axis, wherein a first section (2) comprises a constant pitch diameter (3) and a second section comprises a pitch diameter decreasing along the longitudinal axis and wherein the self-tapping thread's maximum pitch diameter (3) is configured at its first section (2).

17. The method for assembling a threaded sleeve (19) according to claim 11 wherein the-system configured for assembling a threaded sleeve (19) comprises: a threaded sleeve (19); a guide sleeve (25); and a component manufactured using the FDM process (37) characterized in that the inner diameter of the guide sleeve (25) is radially aligned with the self-tapping thread's pitch diameter (3) of the threaded sleeve (19), so that the threaded sleeve (19) is guided in the guide sleeve (25) the guide sleeve (25) is partially surrounded by a heat source.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0142] FIG. 1 schematic illustration of a preferred threaded sleeve

[0143] FIG. 2 illustration of a preferred threaded sleeve while assembling with heat input in a component manufactured by FDM process

[0144] FIG. 3 illustration of preferred a method and a preferred system for assembling a preferred threaded sleeve with heat input in a component manufactured by FDM process

[0145] FIG. 4 schematic illustration of a comparison between a prior art threaded sleeve and preferred embodiments of a threaded sleeve according to the invention with regard to the heat input into an FDM component

[0146] FIG. 5 illustration of two preferred embodiments of a threaded sleeve according to the invention

[0147] FIG. 6 schematic illustration of a comparison between a prior art threaded sleeve and a threaded sleeve according to the invention with regard to the heat input into an FDM component

[0148] FIG. 7 cross-sectional view of a preferred embodiment of the threaded sleeve according to the invention

[0149] FIG. 8 detail view of a groove

DETAILED DESCRIPTION OF THE FIGURES

[0150] FIG. 1 shows a preferred embodiment of the threaded sleeve 19. In particular, the threaded sleeve 19 has preferably two sections 2, 4 on the outwardly facing surface. The entire outwardly facing surface is preferably equipped with a self-tapping thread. The first section 2 is located directly above the second section 4. Further, the first section 2 has preferably a constant pitch diameter 3. This pitch diameter 3 is preferably the maximum pitch diameter of the threaded sleeve's self-tapping thread. The second (lower) section 4 is preferably designed in such a way that the pitch diameter decreases along the longitudinal axis. Hence, the lower section 4 acts like a pointed sleeve and comprises a smallest pitch diameter 11. The inner diameter 9 of the threaded sleeve 19 is preferably constant and a metric thread 21 comprising a constant pitch diameter. The angle of inclination 5 of the self-tapping thread, however, is preferably constant over the entire threaded sleeve 19. The flank width 7 of the self-tapping thread is preferably also uniform and consistent over the entire threaded sleeve 19.

[0151] The following conditions should preferably apply to the pitch diameter:

(1) d.sub.FU≤d.sub.FO
(2) d.sub.FU>d.sub.GH

[0152] The pitch diameter may preferably be variable or constant depending on the height of the threaded sleeve (z). The upper pitch diameters 3 may preferably be constant in order to ensure alignment in the guide sleeve 25 and thus guarantee vertical screwing in.

[0153] The preferred assembling method may preferably be adapted to the angle of inclination 5 of the thread flanks. It is important that no melted material is pressed out of the core hole 35 during screwing in, but that the sleeve is screwed into the softened material at a coordinated rotation speed and feed speed. The thread flank width 7 may preferably be selected so that an optimum temperature distribution is achieved when screwing into the material surrounding the core hole 35.

[0154] The following specifications may preferably be conceivable for the thread flank width 7 and geometry: [0155] i. The thread flank width 7 may preferably be constant, the roughness results from the manufacturing process. Here, the application of 1-4 grooves in the direction z, as described in the document above, must be taken into account to prevent loosening. [0156] ii. Along the thread flanks, a targeted increase in roughness may preferably be possible as an alternative. The melted material then may deposit along the flanks accordingly and hardens. This results in an effect that prevents loosening. [0157] iii. In order to increase the effect from ii., it is conceivable to design the thread flanks with a waviness.

[0158] FIG. 2 shows a preferred threaded sleeve 19 preferably inserted into a component manufactured by FDM process 37. The component 37 is preferably divided into two zones -heat affected zone 1 and unmelted filament 13. The threaded sleeve 19 is preferably inserted into the component's 37 material using the self-tapping thread and cutting edges 17, which causes the heat input zone 1 to melt and change its properties. The molten material is then introduced into the groove 15 of the threaded sleeve 19 and fixes the threaded sleeve 19 in a firm connection. For illustration purposes only, the threaded sleeve 19 is additionally provided with a fictitious slot along the groove 15 so that the inwardly facing surface with metric thread 21 can also be seen.

[0159] A larger number of grooves 15 can result in a stronger connection. In this preferred embodiment, both sections 2, 4 of the threaded sleeve 19 have a constant, equal pitch diameter relating the self-tapping thread. In addition, the first section includes a hexagon socket 23, which allows the threaded sleeve 19 to be screwed into the component 37 using conventional torque setting tools.

[0160] FIG. 3 shows a preferred method and a preferred system for inserting a preferred threaded sleeve 19 into a component manufactured by FDM process under heat input. There are two points in time (a) and b)) shown in the figure. Time a), which precedes time b), indicates that the threaded sleeve 19 is preferably inserted into a guide sleeve 25. The inner diameter of the guide sleeve 25 is preferably matched to the maximum pitch diameter 3 of the threaded sleeve's self-tapping thread so that the threaded sleeve 19 is always aligned correctly. The upper part of the guide sleeve 25 is preferably surrounded by a heating coil 27 or other suitable heat source. This makes it possible to introduce heat preferably via the guide sleeve 25 onto the threaded sleeve 19 or directly onto the cutting edges 17 of the self-tapping thread. Inefficient heating of the threaded sleeve 19 from the inside to the outside is thus eliminated.

[0161] The guide sleeve 25 is preferably additionally equipped with a closure 31, which can be moved from a closed position in an open position. At time a), the guide sleeve 25 is locked by the closure. The preferred inserted threaded sleeve 19 falls preferably onto the closure and is held in the heated area of the guide sleeve 25. When the desired target temperature is reached on the thread flanks, the closure is displaced, and the threaded sleeve may preferably be guided onto the corresponding core hole 35 and can be screwed into the component manufactured by FDM process 37 by applying the desired screw-in torque.

[0162] Below the closure 31, there is preferably located an insulation layer 33 separating the guide sleeve's heated and unheated areas. This results in a temperature gradient along the guide sleeve 25. The lower part, especially the part that is placed on the component 37, should reach relatively cold temperature so that melting by is avoided. If necessary, active cooling can be provided at a suitable point (not shown in the figure).

[0163] FIG. 4 shows a schematic comparison between a prior art threaded sleeve (FIG. 4a) and two preferred embodiments of the threaded sleeve 19 according to the invention (FIGS. 4b and 4c) in terms of temperature input into the FDM component 37 using symbolic temperature gradients. The different threaded sleeves 19 shown are inserted into a core hole 35 (with a diameter D.sub.k), which was machined into the FDM component 37 in a previous step. The two embodiments of the invention (FIG. 4a and FIG. 4b) differ in the design of the thread flanks respectively cutting edges 17, with the threaded sleeve 19 shown in FIG. 4b has tapered thread flanks, while the threaded sleeve 19 shown in FIG. 4c has rounded thread flanks.

[0164] It can be seen that the embodiments of the invention can efficiently melt a much larger area of the FDM component 37 compared to a threaded sleeve known in the art.

[0165] FIG. 5 shows two preferred embodiments of a threaded sleeve 19. FIGS. 5a and 5b illustrate in particular relevant features of two embodiments of the threaded sleeve 19 according to the invention: [0166] the thread flanks provided on the outwardly facing surface of the threaded sleeve 19 are preferably spaced apart by a distance (t) [0167] the thread flanks provided on the outwardly facing surface of the threaded sleeve 19 have preferably a radius (R.sub.K) on the base body of the threaded sleeve 19 [0168] the thread flanks provided on the outwardly facing surface of the threaded sleeve 19 are preferably rounded (R.sub.F) but may also be tapered (cf. FIG. 4b) [0169] the first thread flank provided on the outwardly facing surface of the threaded sleeve 19 is preferably flattened (A) which facilitates immersion of the threaded sleeve 19 in the molten material [0170] there is preferably no thread flank on the lower part (B) on the outwardly facing surface of the threaded sleeve 19 [0171] at least one thread flank provided on the outwardly facing surface of the threaded sleeve 19 is interrupted by one or more groove(s) 29

[0172] All of the named features are aimed at fulfilling the desired functionality—anchoring the threaded sleeve 19 as deeply as possible in the component 37 without causing preliminary damage and increasing resistance to loosening.

[0173] FIG. 6 shows on the one hand a conventional prior art threaded sleeve 19 which is screwed into an FDM component (FIG. 6a) and on the other hand a threaded sleeve 19 according to the invention which is inserted into an FDM printed component 37 using elevated temperatures.

[0174] If FDM-components 37 are screwed using conventional methods (common threads, cold), this inevitably leads to damage to the “microstructure” 39 or the filament coating. Thus, a “predetermined breaking point” is formed on the outer thread flanks (see FIG. 6a; 39), which leads to a reduction in the tolerable load (F.sub.A) on the screw.

[0175] FIG. 6b shows a formation of the homogeneous area around the thread flanks by heat input/melting. As already described in connection with FIG. 2 the component 37 is preferably divided into two zones—heat-affected zone 1 and unmelted filament 13. When the heat affected zone 1 solidifies, a homogeneous area is formed, which can act as an anchorage in the component 37. Comparing both approaches (FIG. 6a vs. FIG. 6b), it becomes clear that the homogeneous bond (heat-affected zone 1) as an anchorage can withstand significantly higher resistance forces against disbonding when stressed by the final screw connection.

[0176] FIG. 7 shows a schematic cross-sectional view of a preferred embodiment of the threaded sleeve 19 according to the invention. This is only a partial view of the threaded sleeve 19, only an upper half of the sleeve 19 is shown in cross section. The inwardly facing surface of the threaded sleeve 19 is provided with a metric thread 21, while the outwardly facing surface of the threaded sleeve 19 is provided with a self-tapping thread comprising cutting edges 17. Furthermore, the preferred threaded sleeve 19 has a groove 15 which has a defined groove depth. The depth is preferably seen in relation to the maximum diameter (major diameter) of the self-tapping external thread. As already described, the groove has a special function which advantageously serves to increase the release torque by allowing molten filament to embed itself in these grooves of the external thread flanks (thread on the outwardly facing surface) and form a material bond there after cooling.

[0177] FIG. 8 illustrates a detailed view of a groove 15 which is preferably milled in a threaded sleeve 19 according to the invention. The groove is formed along the longitudinal axis of the threaded sleeve 19 and has a width 29 of preferably 1 mm to 20 mm, more preferably 3 mm to 15 mm and in particular 5 to 10 mm and a depth a of preferably 0.01 mm to 3 mm, more preferably 0.1 mm to 2 mm and in particular 0.5 to 1 mm. The depth can be measured preferably from the base surface of the threaded sleeve, more preferably from the pitch diameter, and in particular from the major diameter of the external thread. Furthermore, the groove preferably hase two side surfaces 41 and a connecting surface 42 (connects both side surfaces 41), the connecting surface 42 defines the width 29 of the groove.

LIST OF REFERENCE NUMERALS

[0178] 1 heat-affected zone

[0179] 2 first threaded sleeve's section

[0180] 3 pitch diameter of first section

[0181] 4 second threaded sleeve's section

[0182] 5 angle of inclination of the self-tapping thread

[0183] 7 flank width

[0184] 9 threaded sleeve diameter

[0185] 11 smallest pitch diameter in second section

[0186] 13 unmelted filament

[0187] 15 groove

[0188] 17 cutting edge

[0189] 19 threaded sleeve

[0190] 21 internal metric thread

[0191] 23 Internal hexagon socket

[0192] 25 guide sleeve

[0193] 27 heating coil

[0194] 29 groove width

[0195] 31 closure

[0196] 33 insulation layer

[0197] 35 core hole

[0198] 37 component manufactured by FDM process

[0199] 39 damage to microstructure

[0200] 41 side surface of the groove

[0201] 42 Connecting surface of the groove