Thermoplastic overmolding system and method

Abstract

The invention relates to a thermoplastic overmolding system and method. The method includes providing a structure including a substrate and a surface having different melting points. The surface has a first melting point. A compound in molten form is overmolded onto the surface. The compound has a second melting point greater than the first melting point. The surface is melted to immobilize the surface to the compound.

Description

Technical Field

[0001] Examples of this disclosure generally relate to thermoplastic overmolding systems and methods, and more specifically to systems and methods for forming thermoplastic fiber-reinforced composite parts. Background Technology

[0002] Some components are formed using overmolding processes. For example, a structure can be overmolded onto a thermoplastic substrate. However, the process used to form such components may not provide the desired bond between the structure and the thermoplastic substrate. Summary of the Invention

[0003] An efficient and effective system and method are needed for overmolding compounds onto a substrate.

[0004] In view of this need, some examples of this disclosure provide a method comprising: providing a structure including a surface having a first melting point; overmolding a compound in molten form onto the surface, wherein the compound has a second melting point greater than the first melting point; and melting the surface to fix the compound to the surface.

[0005] In at least one example, the melting includes melting the surface with a compound in molten form. Optionally (or additionally), the method includes heating the surface to a temperature equal to or exceeding the first melting point.

[0006] In at least one instance, the structure includes a membrane attached to the surface of the substrate. The substrate has a third melting point greater than a first melting point of the surface of the structure. The temperature is greater than the first melting point but less than the third melting point.

[0007] In at least one example, providing the structure includes providing a preform that provides a substrate (the preform may be fiber-reinforced); and attaching a membrane to the substrate, wherein the membrane includes the surface. The substrate has a third melting point greater than a first melting point. The preform may be a carbon-reinforced laminate. The preform may be formed from polyetheretherketone (PEEK). The preform may be formed from polyetherketoneketone (PEKK). The membrane may be formed from low-melting-point polyaryletherketone (PAEK). The membrane may be formed from polyethyleneimine (PEI).

[0008] In at least one example, the membrane is disposed around the entire substrate. Attached Figure Description

[0009] Figure 1 A simplified view of a billet according to an example of this disclosure is shown.

[0010] Figure 2 A simplified front view of a blank arranged between a first mold and a second mold, according to an example of this disclosure, is shown.

[0011] Figure 3 A simplified front view of a first structure formed between a first mold and a second mold, according to an example of this disclosure, is shown.

[0012] Figure 4 A simplified front view of a first structure, constituting between a first mold and a second mold, according to an example of this disclosure, is shown.

[0013] Figure 5 A simplified front view of a compound injection molded onto the surface of a structure according to an example of this disclosure is shown.

[0014] Figure 6 A simplified view of the components according to an example of this disclosure is shown.

[0015] Figure 7 A flowchart of an example method according to this disclosure is shown. Detailed Implementation

[0016] The foregoing summary of the invention and the detailed description of certain embodiments below will be better understood when read in conjunction with the accompanying drawings. As used herein, elements or steps described in the singular and preceded by the words "a" or "an" should be understood to not necessarily exclude multiple elements or steps. Furthermore, reference to "an embodiment" is not intended to be construed as excluding the existence of additional embodiments that also include the described features. Moreover, unless expressly stated to the contrary, embodiments that "comprise" or "have" one or more elements having a particular condition may include additional elements that do not have that condition.

[0017] Figure 1 A simplified view of a blank 100 according to an example of the present disclosure is shown. The blank 100 may be formed as a flat panel 102. The blank 100 has a top surface 104 opposite a bottom surface 106. The top surface 104 and the bottom surface 106 are joined at ends 108 and 110 and sides 112 and 114. As shown, the blank 100 may include one or more openings 116. The blank 100 may include more or fewer openings 116 than shown. In at least one example, the blank 100 does not include any openings. Figure 1 The blank 100 shown is merely an example. It should be understood that the size and shape of the blank 100 may differ from those shown.

[0018] The preform 100 is formed of a material having a melting point. In at least one example, the material is a laminate. As another example, the material is a carbon fiber reinforced laminate. In at least one example, the preform 100 includes a body 118 formed of a polymer and reinforcing fibers 120 dispersed within and throughout the body 118. As an example, the reinforcing fibers 120 may be formed of carbon. As another example, the reinforcing fibers 120 may be formed of a metal such as aluminum. Optionally, the body 118 may not include reinforcing fibers.

[0019] As an example, the material is polyetheretherketone (PEEK). As an example, the melting point of the material can be 695℉ (343℃). Alternatively, the melting point of the material can be less than or greater than 695℉ (343℃).

[0020] As another example, the material is polyetherketoneketone (PEKK). As an example, the melting point of this material can be from 572℉ to 680℉ (300℃ to 360℃). Alternatively, the melting point of this material can be less than 572℉ or greater than 680℉.

[0021] The blank 100 can be formed by stamping. Alternatively, the blank 100 can be formed by cutting, milling, laser ablation, etc.

[0022] Figure 2 A simplified front view of a blank 100 arranged between a first mold 130 and a second mold 132 according to an example of this disclosure is shown. (Reference) Figure 1 and Figure 2 During the fabrication of the blank 100, the membrane 140 is attached to the blank 100. Alternatively, the membrane 140 is attached to the blank 100 after it has been formed. For example, the membrane 140 is disposed around the entire blank 100. As another example, the membrane 140 may be disposed only at a portion of the blank 100, such as attached to the bottom surface 106 of the blank 100. The blank 100 provides a substrate 101, to which the membrane 140 is attached.

[0023] The first mold 130 includes a cavity 150 formed in the lower surface 152. The second mold 132 includes a fluid channel 154 formed through the lower surface 156 and into and through the upper surface 158. The fluid channel 154 may include branches 160 and 162. Optionally, the fluid channel 154 may include a single straight segment. As another example, the fluid channel 154 may include one or more curved portions. The size and shape of the fluid channel 154 may differ from those shown.

[0024] In at least one example, the membrane 140 is bonded to the substrate 101 (provided by the blank 100). The membrane 140 may be coupled to the blank 100 and heated to be fixed to one or more outer surfaces of the substrate 101.

[0025] Film 140 is formed of a material having a lower melting point than the material of blank 100. As an example, the material of film 140 is low-melting-point polyarylether ketone (PAEK). As an example, the melting point of the material of film 140 may be 581℉ (305°C). Alternatively, the melting point of the material of film 140 may be less than or greater than 581℉ (305°C).

[0026] As another example, the membrane material is polyethyleneimine (PEI). As an example, the melting point of the membrane material can be from 340℉ to 490℉ (171℃ to 254℃). Optionally, the melting point of the membrane material can be less than or greater than 340℉ or greater than 490℉.

[0027] In at least one example, the melting point of the material of film 140 is at least 100℉ lower than the melting point of the material of blank 100. Alternatively, the melting point of the material of film 140 may be at least 50℉ lower than the melting point of the material of blank 100. As another example, the melting point of the material of film 140 is at least 200℉ lower than the melting point of the material of blank 100.

[0028] A preform 100 having a membrane 140 thereto connected to it is provided with a structure 170. As described, the membrane 140 is connected to the preform 100.

[0029] Figure 3 A simplified front view of a first structure 170 formed between a first mold 130 and a second mold 132 according to an example of this disclosure is shown. In at least one example, the blank 100 is heated above its melting point before the first structure 170 is formed. This heating can be performed by suspending the blank 100 between two infrared heaters.

[0030] In at least one example, a first die 130 and a second die 132 are configured to stamp a first structure 170, such as by pushing the first die 130 toward the second die 132 in the direction of arrow A, thereby providing form to the first structure 170. The first die 130 and / or the second die 132 may be coupled to an actuator, a vise, etc., to move the first die 130 relative to the second die 132 in the direction of arrow A.

[0031] Heater 172 may be coupled to first mold 130 and / or second mold 132. Heater 172 may be operated to heat first mold 130 and / or second mold 132 during the forming process to facilitate the forming process. Alternatively, heater 172 may not be coupled to first mold 130 and / or second mold 132. Alternatively, instead of heater 172, the illustrated system may be housed within an oven that can provide the desired heating temperature.

[0032] Figure 4A simplified front view of a first structure 170, constrained between a first mold 130 and a second mold 132, according to an example of this disclosure, is shown. (Reference) Figure 3 and Figure 4 The first mold 130 and the second mold 132 are operated to solidify the first structure 170 into the desired shape. Figure 4 The shape of the first structure 170 shown is merely an example. The shape of the consolidated structure may differ from the shape shown.

[0033] After the first structure 170 is fully formed, it may be allowed to cool if necessary. That is, if the forming process involves heating, the first structure 170 may be allowed to cool, for example, to room temperature or the glass transition temperature, but at least below the melting temperature.

[0034] Figure 5 A simplified front view of a compound 180 injection-molded onto the surface of structure 170 according to an example of this disclosure is shown. Compound 180 is formed of a material different from film 140. Compound 180 is formed of a material having a higher melting point than film 140. In at least one instance, the compound is formed of a material having a higher melting point than film 140. The material of compound 180 may have a higher melting point than the material of preform 100. Alternatively, compound 180 may be formed of the same material as preform 100. As an example, compound 180 may be formed of PEEK, and preform 100 (which provides substrate 101) may be formed of PEKK. As another example, both compound 180 and preform 100 may be formed of PEEK or PEKK.

[0035] The melting point of compound 180 is higher than the melting point of surface 171 of structure 170 (the surface on which compound 180 contacts during injection molding). In other words, the melting point of surface 171 (formed by film 140) is lower than the melting point of compound 180. Compound 180 is heated to a temperature that melts compound 180 and injected into channel 154. That is, compound 180 is injected into the channel in molten form. Molten compound 180 flows through channel 154 and contacts surface 171. Because the melting point of compound 180 is higher than the melting point of film 140, the temperature of molten compound 180 must be higher than the melting point of film 140. Therefore, when molten compound 180 contacts film 140, the temperature of compound 180 locally melts film 140 at surface 171, thereby mixing and healing film 140 and compound 180 (such as resin containing compound 180). The operable heater 172 can heat the film 140 to its melting temperature (e.g., below the melting point of the substrate 101) or just below its melting temperature. Alternatively, the heater 172 may not be used, and the temperature of the molten compound 180 provides sufficient heat to melt the film 140, thereby mixing and fusing the film 140 and the compound 180. When the compound 180 cools for a period of time (e.g., one hour or less), the portions of the compound 180 and the film 140 that have mixed together are firmly bonded together, thereby firmly overmolding the compound 180 into the structure 170 in the desired shape.

[0036] Compound 180 may be in molten form (and / or heater 172 may be operable to melt film 140) for a predetermined time period to provide sufficient bonding between compound 180 and surface 171. The predetermined time period may be, for example, 5 minutes, 10 minutes, 30 minutes, or longer. Compound 180 may include reinforcing elements, such as beads or short fibers.

[0037] refer to Figures 1 to 5 The film 140 is miscible with both the preform 100 and the compound 180. For example, PEI is miscible with PEKK and PEEK.

[0038] Film 140 is miscible with compound 180 and preform 100. As described above, in at least one example, preform 100 may be a polymer. Optionally, preform 100 may be a non-thermoplastic structure. As an example, preform 100 may be a thermosetting material, and film 140 may be a thermoplastic film bonded to a thermosetting material. In at least one example, preform 100 may be an epoxy resin, film 140 may be PEI, and the compound overmolded into the film may be PEEK.

[0039] Figure 6A simplified view of component 190 according to an example of this disclosure is shown. Component 190 includes compound 180 (which is bonded to structure 170) Figure 5 The overmolded structure 180' formed (as shown) is formed.

[0040] refer to Figures 1 to 6 Examples of this disclosure provide thermoplastic fiber-reinforced composite parts having a low melting point on a compatible thermoplastic film 140 on its surface. In a second step, a compatible thermoplastic injection-molded compound 180 having a melting temperature equal to or higher than that of the film 140 is formed on the fiber-reinforced part to increase the reinforcement or geometric features of the interface. The fiber-reinforced part can be manufactured by processes such as continuous compression molding, stamping, oven consolidation, autoclave consolidation, or any combination thereof. Examples of this disclosure allow for the use of low-melting-point injection-molded compounds and reduce the risk of deconsolidation of the parent laminate.

[0041] The melting temperature of the overmolded compound 180 is higher than that of the film 140 than that of the underlying laminate (e.g., preform 100 without film 140). Therefore, the fiber-reinforced components are heated at a lower temperature, which provides improved bonding at the interface between compound 180 and film 140 (because a suitable temperature difference conducive to melting the interfacial film can be more easily achieved). Furthermore, low-melting-point materials (such as the material of film 140) typically exhibit improved viscosity (e.g., increased flow), allowing for less complex die design. Additionally, the lower temperature difference between compound 180 and the laminate of preform 100 reduces the risk of deconsolidation of the parent laminate. Moreover, the low-melting-point film 140 allows structure 170 to be welded to other laminates while still retaining overmolded characteristics (such as overmolded structure 180').

[0042] Figure 7 A flowchart illustrating an example method according to this disclosure is shown. References Figures 1 to 7 At 200, structure 170 is provided. Structure 170 includes a surface 171 having a first melting point. At 202, a compound 180 in molten form is overmolded onto surface 171. Compound 180 has a second melting point greater than the first melting point. At 204, surface 171 is melted to mix and fuse surface 171 with compound 180. In at least one example, melting includes melting surface 171 by means of compound 180 in molten form. Optionally (or additionally), melting includes heating surface 171 (e.g., by means of one or more heaters 172) to a temperature equal to or greater than the first melting point. In at least one example, the structure includes a film 140 coupled to a substrate 101 (provided by blank 100). Substrate 101 has a third melting point greater than the first melting point. This temperature is greater than the first melting point but less than the third melting point of substrate 101 of structure 170.

[0043] Furthermore, this disclosure includes examples pursuant to the following terms:

[0044] Clause 1. A method for coating a compound, the method comprising:

[0045] A structure is provided, the structure comprising a substrate and a surface having different melting points, wherein the surface has a first melting point;

[0046] A molten compound is coated onto the surface, wherein the compound has a second melting point greater than the first melting point; and

[0047] The surface is melted to fix it to the compound.

[0048] Clause 2. The method according to Clause 1, wherein the melting comprises melting the surface by means of the compound in the molten form.

[0049] Clause 3. The method according to Clause 1 or 2, wherein the melting includes heating the surface to a temperature equal to or exceeding the first melting point.

[0050] Clause 4. The method according to Clause 3, wherein the structure includes a membrane coupled to the substrate, wherein the substrate has a third melting point greater than the first melting point, and wherein the temperature is greater than the first melting point but less than the third melting point.

[0051] Clause 5. The method according to any one of Clauses 1 to 4, wherein the providing structure comprises:

[0052] A blank is provided, the blank providing the substrate; and

[0053] The membrane is attached to the substrate, wherein the membrane includes the surface.

[0054] Clause 6. The method according to Clause 5, wherein the substrate has a third melting point greater than the first melting point.

[0055] Clause 7. The method according to Clause 5 or 6, wherein the preform is a carbon-reinforced laminate.

[0056] Clause 8. The method according to any one of Clauses 5 to 7, wherein the preform is formed from polyetheretherketone (PEEK).

[0057] Clause 9. The method according to any one of Clauses 5 to 8, wherein the preform is formed from polyetherketoneketone (PEKK).

[0058] Clause 10. The method according to any one of Clauses 5 to 9, wherein the membrane is formed from low-melting-point polyarylether ketone (PAEK).

[0059] Clause 11. The method according to any one of Clauses 5 to 10, wherein the membrane is formed of polyethyleneimine (PEI).

[0060] Clause 12. The method according to any one of Clauses 5 to 11, wherein the connection comprises distributing the membrane around the entire substrate.

[0061] Clause 13. The method according to any one of Clauses 1 to 4, wherein the entire surface has the first melting point.

[0062] Clause 14. A method for overmolding a compound, the method comprising:

[0063] A blank is provided, the blank providing a base;

[0064] The membrane is attached to the substrate, wherein the membrane includes a surface having a first melting point that is different from the melting point of the substrate;

[0065] A molten compound is coated onto the surface, wherein the compound has a second melting point greater than the first melting point; and

[0066] The surface is melted to fix it to the compound.

[0067] Clause 15. The method according to Clause 14, wherein the melting comprises melting the surface by means of the compound in the molten form.

[0068] Clause 16. The method according to Clause 14 or 15, wherein the melting comprises heating the surface to a temperature equal to or exceeding the first melting point.

[0069] Clause 17. The method according to any one of Clauses 14 to 16, wherein the substrate has a third melting point greater than the first melting point.

[0070] Clause 18. The method according to any one of Clauses 14 to 17, wherein the preform is formed from one or both of polyether ether ketone (PEEK) and polyether ketone ketone (PEKK), wherein the film is formed from one or both of low-melting-point polyaryl ether ketone (PAEK) and polyethyleneimine (PEI), and wherein the compound is formed from one or both of polyether ether ketone and polyether ketone ketone.

[0071] Clause 19. The method according to any one of Clauses 14 to 18, wherein the connection comprises distributing the membrane around the entire substrate.

[0072] Clause 20. A method for overmolding a compound, the method comprising:

[0073] A blank is provided, the blank providing a substrate and a surface, wherein the blank has a first melting point, wherein the blank is formed from one or both of polyether ether ketone (PEEK) and polyether ketone ketone (PEKK);

[0074] The membrane is attached to the substrate, wherein the membrane has a second melting point less than the first melting point, and wherein the membrane is formed of one or both of low-melting-point polyarylether ketone (PAEK) and polyethyleneimine (PEI).

[0075] A compound in molten form is overmolded onto one or more portions of the film, wherein the compound has a third melting point greater than the first melting point, and wherein the compound is formed from one or both of polyetheretherketone and polyetherketoneketone; and

[0076] The surface is melted to fix the surface to the compound, wherein the melting includes melting one or more portions of the film by means of the compound in molten form, and heating one or more portions of the film to a temperature equal to or exceeding the first melting point.

[0077] As described herein, examples of this disclosure provide efficient and effective systems and methods for overmolding compounds onto substrates.

[0078] While various spatial and directional terms such as top, bottom, lower, middle, lateral, horizontal, vertical, and front may be used to describe embodiments of this disclosure, it should be understood that these terms are used only with respect to the orientation shown in the accompanying drawings. The orientation may be flipped, rotated, or otherwise changed such that upper is lower, or vice versa, horizontal becomes vertical, etc.

[0079] As used herein, structures, definitions, or elements “configured” to perform tasks or operations are specifically formed, constructed, or adapted in a manner corresponding to the task or operation. For clarity and to avoid ambiguity, objects that can only be modified to perform tasks or operations are not “configured” to perform tasks or operations as used herein.

[0080] It should be understood that the above description is intended to be illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of various embodiments of this disclosure without departing from the scope of this disclosure. While the dimensions and types of materials described herein are intended to define parameters of various embodiments of this disclosure, these embodiments are by no means restrictive but rather exemplary embodiments. Many other embodiments will be apparent to those skilled in the art after reading the above description. Therefore, the scope of the various embodiments of this disclosure should be determined by reference to the appended claims and the full scope of their equivalents. In the appended claims and the detailed description herein, the terms “including” and “in which” are used as simple English equivalents to the corresponding terms “comprising” and “wherein”. Furthermore, the terms “first,” “second,” and “third,” etc., are used merely as labels and are not intended to impose numerical requirements on their objects. Furthermore, the following claims are not defined in an apparatus plus function format and are not intended to be interpreted based on 35 U.SC §112(f), unless and until such claims explicitly use the phrase “apparatus for…” followed by a functional statement without further structure.

[0081] This written description uses examples to disclose various embodiments of this disclosure, including the best mode, and also enables those skilled in the art to practice the various embodiments of this disclosure, including making and using any device or system and performing any incorporated methods. The patentable scope of the various embodiments of this disclosure is defined by the claims, and may include other examples that would occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they have structural elements that are not literal language different from the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A method for coating a compound, the method comprising: A structure (170) is provided, the structure (170) comprising a substrate (101) and a surface (171) having different melting points, wherein the surface (171) has a first melting point; A molten compound (180) is overmolded onto the surface (171), wherein the compound (180) has a second melting point greater than the first melting point; and The surface (171) is melted to fix the surface (171) to the compound (180).

2. The method according to claim 1, wherein, The melting includes melting the surface (171) by means of the compound (180) in molten form.

3. The method according to claim 1, wherein, The melting process includes heating the surface (171) to a temperature equal to or exceeding the first melting point.

4. The method according to claim 3, wherein, The structure (170) includes a membrane (140) attached to the substrate (101), wherein the substrate (101) has a third melting point greater than the first melting point, and wherein the temperature is greater than the first melting point but less than the third melting point.

5. The method according to claim 1, wherein, The providing structure (170) includes: A blank (100) is provided, the blank (100) providing the substrate (101); and The membrane (140) is attached to the substrate (101), wherein the membrane (140) includes the surface (171).

6. The method according to claim 5, wherein, The substrate (101) has a third melting point that is greater than the first melting point.

7. The method according to claim 5, wherein, The blank (100) is a carbon-reinforced laminate.

8. The method according to claim 5, wherein, The blank (100) is formed from polyetheretherketone (PEEK).

9. A method for coating a compound, the method comprising: A blank (100) is provided, the blank (100) providing a substrate (101); The membrane (140) is attached to the substrate (101), wherein the membrane (140) includes a surface (171) having a first melting point different from that of the substrate (101); A molten compound (180) is overmolded onto the surface (171), wherein the compound (180) has a second melting point greater than the first melting point; and The surface (171) is melted to fix the surface (171) to the compound (180).

10. A method for coating a compound, the method comprising: A blank (100) is provided, the blank (100) providing a substrate (101) and a surface (171), wherein the blank (100) has a first melting point, wherein the blank (100) is formed of one or both of polyether ether ketone (PEEK) and polyether ketone ketone (PEKK); The membrane (140) is attached to the substrate (101), wherein the membrane (140) has a second melting point less than the first melting point, wherein the membrane (140) is formed of one or both of low melting point polyarylether ketone (PAEK) and polyethyleneimine (PEI); A molten compound (180) is overmolded onto one or more portions of the film (140), wherein the compound (180) has a third melting point greater than the first melting point, and wherein the compound (180) is formed of one or both of polyetheretherketone and polyetherketoneketone; and The surface (171) is melted to fix the surface (171) to the compound (180), wherein the melting includes melting one or more portions of the film (140) by means of the compound (180) in molten form, and heating one or more portions of the film (140) to a temperature equal to or above the first melting point.

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