Hollow-profile Composite Technology

Abstract

The invention relates to a process for producing a composite component having at least one functional element composed of at least one cylindrical hollow profile and at least one plastic to be introduced into the hollow profile by means of specific injection molding methods.

Claims

1. A process for producing a composite component by a) providing an injection mold having at least one openable cavity and a mold dimension (A) in closure direction and a mold dimension (B) at right angles to the closure direction of the mold and a cavity circumference (UW) corresponding to the circumference of the cavity in the region of mold dimensions (A) and (B), and at least one secondary cavity, b) providing at least one hollow profile in the form of a hollow cylinder having i) the hollow profile circumference (UH), the wall thickness (S), the external diameter (C) and the longitudinal axis (L), ii) at least one bend with angle (W) and iii) at least one perforation 2 along its longitudinal axis (L), and in unbent regions of the hollow profile iv) having a ratio of external diameter (C) to wall thickness (S) in the range from 5:1 to 300:1, where the external diameter (C) in the region of the mold contact surfaces (K) is greater by a range from 0.1% to 5% than the mold dimension (A) and is less by a range from 0.1% to 5% than the mold dimension (B), and v) the figures for external diameter (C) are based on 90° viewed in the direction of the longitudinal axis (L) of the hollow profile, and vi) the hollow profile circumference UH=C.Math.π corresponds to the cavity circumference (UW) of the at least one injection mold cavity in the closed state, and vii) the mold contact surfaces refer to the sealing surfaces of the mold in the closed state with the hollow profile, c) introducing the at least one hollow profile into the at least one cavity of the injection mold, d) closing the at least one cavity of the injection mold and compressing the hollow profile at its mold contact surfaces in closure direction of the at least one cavity, e) injecting plastic into the interior of the hollow profile and simultaneously filling the at least one secondary cavity via the at least one perforation 2 in the hollow profile, f) expressing excess plastic through at least one of the two lateral openings in the hollow profile by injecting gas or fluid or a combination of the two, g) cooling down the plastic melt introduced into the hollow profile and into the secondary cavity in e), and h) removing the finished composite component from the injection mold and optionally removing sprues, with the proviso that the figures for mold dimension (A), for mold dimension (B) and for cavity circumference (UW) in process step a) relate to regions of the injection mold in which unbent regions of the hollow profile lie, and the hollow profile is based on metal or on a composite.

2. The process as claimed in claim 1, wherein the at least one perforation (2) is introduced before, during or after process step b) in the form of at least one hole or bore from the outside into the wall of the hollow profile at positions where at least one functional element is provided.

3. The process as claimed in claim 1, wherein the bonding of a functional element simultaneously fashioned by means of injection of plastic into the hollow profile to the hollow profile is assisted by additional measures.

4. The process as claimed in claim 3, wherein the measures comprise the introduction of beads, holes, bores into the hollow profile wall or the application of additional anchoring elements.

5. The process as claimed in claim 1, wherein the metal used is steel, aluminum or alloys of aluminum.

6. The process as claimed in claim 1, wherein the hollow profile has a circular or elliptical cross section, where an elliptical cross section varies by not more than 10% from a circular cross section.

7. The process as claimed in claim 1, characterized in that wherein the hollow profile has a wall thickness (S) in the range from 0.1 to 10.0 mm.

8. The process as claimed in claim 1, wherein the hollow profile has a longitudinal axis (L) in the range from 60 to 2000 mm.

9. The process as claimed in claim 1, wherein at least one material from the group of metals, alloys, thermoplastics and thermosets is used for production of the hollow profile.

10. The process as claimed in claim 9, wherein the metals used are steel, aluminum, magnesium, titanium, tin, zinc, lead, silver, gold, brass or alloys, and the thermoplastics used are polyamides, polyalkylene terephthalates, polyethylene, polypropylene and polyvinylchloride, and the thermosets used are epoxy resins, crosslinkable polyurethanes or unsaturated polyester resins.

11. The process as claimed in claim 10, wherein the polyamide used is nylon-6 and the polyalkylene terephthalate used is polybutylene terephthalate or polyethylene terephthalate.

12. The process as claimed in claim 10, wherein a thermoplastic with at least one reinforcer is used.

13. The process as claimed in claim 12, wherein the hollow profile used is a thermoplastic-based composite in which the reinforcer is based essentially on weaves or scrims of fiber mats.

14. A composite component comprising at least one hollow profile in the form of a hollow cylinder and at least one bend, the inner walls of which have been coated with plastic, having at least one functional element cohesively bonded to the hollow profile at discrete bonding sites via the plastic within the hollow profile, wherein the hollow profile has a diameter/wall thickness ratio in the range from 5:1 to 300:1.

15. The composite component as claimed in claim 14, produced by a) providing an injection mold having at least one openable cavity and a mold dimension (A) in closure direction and a mold dimension (B) at right angles to the closure direction of the mold and a cavity circumference (UW) corresponding to the circumference of the cavity in the region of mold dimensions (A) and (B), and at least one secondary cavity, b) providing at least one hollow profile in the form of a hollow cylinder having i) the hollow profile circumference (UH), the wall thickness (S), the external diameter (C) and the longitudinal axis (L), ii) at least one bend with angle (W) and iii) at least one perforation (2) along its longitudinal axis (L), and in unbent regions of the hollow profile iv) having a ratio of external diameter (C) to wall thickness (S) in the range from 5:1 to 300:1, where the external diameter (C) in the region of the mold contact surfaces (K) is greater by a range from 0.1% to 5% than the mold dimension (A) and is less by a range from 0.1% to 5% than the mold dimension (B), and v) the figures for external diameter (C) are based on 90° viewed in the direction of the longitudinal axis L of the hollow profile, and vi) the hollow profile circumference UH=C.Math.π corresponds to the cavity circumference (UW) of the at least one mold cavity in the closed state, and vii) the mold contact surfaces refer to the sealing surfaces of the mold in the closed state with the hollow profile, c) introducing the at least one hollow profile into the at least one cavity of the injection mold, d) closing the at least one cavity of the injection mold and compressing the hollow profile at its mold contact surfaces in closure direction of the at least one cavity, e) injecting plastic into the interior of the hollow profile and simultaneously filling the at least one secondary cavity via the at least one perforation (2) in the hollow profile, f) expressing excess plastic through at least one of the two lateral openings in the hollow profile by injecting gas or fluid or a combination of the two, g) cooling down the plastic melt introduced into the hollow profile and into the secondary cavity in e), and h) removing the finished composite component from the injection mold and optionally removing sprues, with the proviso that the figures for mold dimension (A), for mold dimension (B) and for cavity circumference (UW) in process step a) relate to regions of the injection mold in which unbent regions of the hollow profile lie, and the hollow profile is based on metal or on composite.

16. The composite component as claimed in claim 14 in the form of a bodywork part.

17. The process as claimed in claim 1, wherein the at least one perforation (2) is introduced before, during or after process step b) in the form of multiple holes or bores from the outside into the wall of the hollow profile at positions where at least one functional element is provided.

18. The process as claimed in claim 10, wherein a thermoplastic with one or more reinforcers are used in amounts in the range from 10 to 400 parts by mass per 100 parts by mass of the thermoplastic.

19. The process as claimed in claim 13, wherein the fiber mats are glass fiber mats based on longitudinal glass fibers or continuous glass fibers.

20. The composite component as claimed in claim 16, wherein the bodywork part is a cross-car beam, front end, engine bearing, stabilizer, 2-point link, 3-point link, shock absorber, crash element, fender support or pedal.

Description

[0202] Particularly preferred embodiments are described with reference to the figures that follow, with the composite component always being one formed from a hollow profile (1) in the form of a hollow cylinder with at least one bend and a plastic coating applied to the inside (7) of the hollow profile (1), and the hollow profile (1) having at least one functional element (3) connected directly to the plastic coating introduced by means of GIT or FIT or a combination of GIT and FIT on the inside of the hollow profile via at least one perforation (2) in the hollow profile (1).

[0203] FIG. 1 shows an unbent section of a hollow profile (1) for use in accordance with the invention in the form of a hollow cylinder having a center axis (L), the external diameter (C), the wall thickness (S), a perforation (2) and the hollow profile circumference UH.

[0204] FIG. 2 shows a hollow cylinder to be used as hollow profile (1) with a bend having angle (W) along its centre axis (L) and a perforation (2).

[0205] FIG. 3 shows a composite component of the invention, based on a hollow profile (1) according to FIG. 2 with a molded-on functional element (3) and the mold contact surfaces (K) on the hollow profile (1).

[0206] FIG. 4 shows the cross section of an injection mold to be used in accordance with the invention of the contact surfaces with the mold half (4) and the mold half (5) in the closed state. The mold dimension (A) is 0.1% to 5% smaller than the external diameter (C), the mold dimension (B) is 0.1% to 5% greater than the external diameter (C), and the cavity circumference (UW) is equal to the hollow profile circumference (UH); where: UH=C.Math.π.

[0207] FIG. 5 shows the cross section of an injection mold to be used in accordance with the invention with the mold halves (4) and (5) in the open state at the mold contact surfaces with inserted hollow profile (1) and its inner surface (7) that is to be coated by spraying with plastic. (6) represents mold closure direction. For the hollow profile circumference: UH=C.Math.π. The mold dimension (B) is 0.1% to 5% greater than the external diameter (C).

[0208] FIG. 6 shows the position of a hollow profile (1) to be used in accordance with the invention at the mold contact surfaces on closure of the mold when the hollow profile (1) comes into contact for the first time with the mold of the invention having the mold halves (4) and (5). At this time, a mold gap (8) is still open.

[0209] FIG. 7 shows the position and shape of a hollow profile (1) to be used in accordance with the invention of the mold contact surfaces with respect to the mold of the invention having mold halves (4) and (5) when the mold is completely closed. The hollow profile 1 with the original external diameter © is/has been compressed at the mold contact surfaces (K) into the mold cavity with the mold dimension (A) and the mold dimension (B).

[0210] FIG. 8 shows the section of a hollow profile (1) without a bent section that is to be provided prior to process step b) in accordance with the invention, but with a circular perforation 2 for the purpose of molding on at least one functional element (3).

[0211] FIG. 9 shows an alternative embodiment of FIG. 8: an unbent region of a hollow profile (1) having a rectangular perforation (2) which is to be provided prior to process step b). The short sides of the rectangular opening are crimped inward in order to assure improved form-fitting with the plastic to be injected into the hollow profile (1) in process step e).

[0212] FIG. 10 corresponds essentially to the representation in FIG. 8 and shows a circular perforation (2), the edge of which is crimped inward, in order to assure improved form-fitting with the plastic to be injected into the hollow profile (1) in process step e).

[0213] FIG. 11 corresponds essentially to the representation in FIG. 8 and shows a circular perforation (2), the edge of which is crimped outward, in order to assure improved form-fitting with the plastic to be injected into the hollow profile (1) in process step e).

[0214] FIG. 12 shows the region of a composite component without a curved section, based on a hollow profile (1) having a circular perforation (2) and a molded-on functional element (3). After the injection of the plastic and the blowing-out of excess plastic with gas in process step f), an inner plastic coating (11) remains within the hollow profile, i.e. on the wall of the inner surface (7).

[0215] FIG. 13 shows the region of a composite component without a curved section, based on a hollow profile (1) having a circular perforation (2) and a molded-on functional element (3). After the injection of the plastic and the removal of excess plastic with gas in process step f), an inner plastic coating (11) remains within the hollow profile, i.e. on the wall of the inner surface (7). The molded-on functional element (3) is also blown out according to the representation in FIG. 13.

[0216] FIG. 14a shows a hollow profile 1 with four bends and numerous perforations (2).

[0217] FIG. 14b shows a composite component of the invention, configured as a dashboard crossbeam based on a hollow profile (1) according to FIG. 14a with four bends and six molded-on functional elements (3), of which (3i) represents a securing element to the A pillars (left and right), (3ii) represents a brace to the bulkhead, (3iii) represents a securing element for the steering column, (3iiii) represents a brace to the center console with integrated receptacles for infotainment and climate control system, and (3iiiii) represents a mount and receptacle for glovebox and airbag.

EXAMPLES

[0218] The following parameters are employed for a GIT process in process step f) in experiment V1 on a tubular test injection mold in the form of a hollow profile with Durethan® BKV30 (30% by weight of glass fiber-reinforced nylon-6 from Lanxess Deutschland GmbH, Cologne) as plastic to be used in process step e): injection pressure around 700 bar spec., melt temperature 280° C., mold temperature 80° C., injection rate up to 150 mm/s, cycle time 94 sec.

[0219] Gas injection parameters: gas injection delay 3.5 sec., blow out mold at 80 bar for 3 sec, hold gas pressure of 175 bar for 45 sec., gas pressure drop over 20 sec.

GIT Process Procedure Steps:

[0220] 1. Gas introduction delay [0221] 2. Blow out molding at set pressure [0222] 3. Buildup/release of gas hold pressure [0223] 4. Maintain gas pressure [0224] 5. Release gas pressure [0225] 6. Remove pressure from molding

[0226] Experiments V2, V3, V4 and V5 were conducted on a tubular test mold manufactured in the same way as in V1 in the form of a hollow profile with Durethan® BKV30 (30% by weight of glass fiber-reinforced nylon-6 from Lanxess Deutschland GmbH, Cologne) as plastic to be used in process step e) by the WIT process with the WIT process procedure steps of: [0227] 1. Buildup of water pressure up to the inlet valve. [0228] 2. Introduce water pressure into the molding at set pressure [0229] 3. Buildup/release of water hold pressure [0230] 4. Maintain water pressure [0231] 5. Release water pressure [0232] 6. Remove water from molding

TABLE-US-00001 TABLE 1 Maximator WIT plant settings: WIT WIT WIT Experiment 2 Experiment 3 Experiment 4 Experiment 5 Shots 1-10 Shots 11-25 Shots 26-45 Shots 46-82 GIT Melt Melt Melt Melt Experiment 1 temperature temperature temperature temperature 20 shots 285° C. 290° C. 290° C. 290° C. Time Time Time Time Time Pressure in Pressure in Pressure in Pressure in Pressure in in bar sec. in bar sec. in bar sec. in bar sec. in bar sec. 1 0 2.5 50 4 50 4 50 4 50 4 2 250 0.5 50 2 50 2 50 2.5 50 2.5 3 250 2.5 200 1 200 1 200 1.5 200 1.5 4 150 0.5 200 10 200 10 200 10 200 10 5 150 30 0 1 0 1 0 1 0 1 6 0 0.5 0 25 0 25 0 25 0 25 7 0 15 Wastewater start from step 6

[0233] Tab. 1 shows the experimental settings of pressure and pressure profile in the pressure generation unit (from Maximator) for water injection and for gas injection.

TABLE-US-00002 TABLE 2 Core Delay time in sec. pull Function V1 V2 V3 V4 V5 Pressure 1 Large 0.5 1 1 1.5 1 40% blowout (56 bar) cavity 2 Small 1 1.5 1.5 2 1.5 40% blowout (56 bar) cavity 3 Sprue 35 25 25 25 25 100%  gate (140 bar)

[0234] Tab. 2 shows the experimental parameters of hydraulic pressure (<Pressure>) and time (<Delay time>) for the actuation of the core pulling systems that control the 2 blowout cavities and the sprue gate.

Materials Used:

[0235] Material 1: Durethan® KU2-2224/30 H2.0, Pt.30CD4C0560; Fb.900116 [0236] Material 2: Durethan® KU2-2224/30 H2.0, Pt.30CD2N0630; Fb.901510 [0237] Material 3: Durethan® KU2-2224/30 H2.0, JADE 3576 B

[0238] Material 1 was compared in the GIT and WIT methods. Materials 2 and 3 were compared with one another in the WIT method. Table 1 describes the assignment of materials to the respective experiments under Comments.

Comments on GIT Settings:

[0239] Variation in the set parameters for the GIT plant did not bring any improvement in the inner surface of the GIT tube. It was possible to run a fully automated cycle with uniform quality.

Comments on WIT Settings:

[0240] The shortest cycle time was achieved with the WIT setting for V5 of the experimental protocol. Gate formation at the distributor was much rarer with the materials from V3 and V4. There was no observation here of material rejected as a result of large separate gas bubbles. It was possible to run a fully automated cycle.