DE102009024789A1 - Molded part e.g. z-bar for front end carrier, production method for motor vehicle, involves mutually molding textile feeder in injection mold with thermoplastic melt, and fixing feeder in injection mold before molding by fixing elements - Google Patents

Abstract

The method involves mutually molding a textile feeder (1) e.g. linen fabric, in an injection mold with a thermoplastic melt. The textile feeder is fixed in the injection mold before molding by fixing elements e.g. slide clamps. The textile feeder in the injection mold is deformed by closing the injection mold. An insert element is provided between fiber strips (2, 3) of the textile feeder and/or in the injection mold before molding of the textile feeder. The insert element is pressed and/or rotated by a spike connector between the fiber strips of the textile feeder.

Description

The The invention relates to a method for producing a molded part made of fiber-reinforced thermoplastic by injection molding, in particular a molding for a vehicle.

• – Herstellung mindestens eines Textileinlegers aus nicht konsolidiertem Hybridgarn aus thermoplastischen und aus (an)organischen Verstärkungsfasern,
• – Vorwärmen des mindestens einen Textileinlegers auf eine Temperatur nahe dem Schmelzpunkt der thermoplastischen Fasern vor oder beim Einbringen des mindestens einen Textileinlegers in eine Spritzgießform,
• – Umspritzen des mindestens einen Textileinlegers mit einem Thermoplasten bei einer Temperatur oberhalb der Schmelztemperatur der thermoplastischen Fasern, wobei diese im Wesentlichen vollständig aufgeschmolzen werden,
• – Abkühlung und Entnahme des Exterieur- oder Interieurteils.

In the DE 10 2006 040 748 A1 Such a method for the production of exterior or interior parts of motor vehicles made of fiber-reinforced thermoplastics by injection molding is proposed. The method comprises the steps:

• Production of at least one textile inlay of unconsolidated hybrid yarn of thermoplastic and of (inorganic) organic reinforcing fibers,
• Preheating the at least one textile inlay to a temperature close to the melting point of the thermoplastic fibers before or during the introduction of the at least one textile inlay into an injection mold,
• Overmolding of the at least one textile inlay with a thermoplastic at a temperature above the melting temperature of the thermoplastic fibers, these being substantially completely melted,
• - Cooling and removal of the exterior or interior judgment.

Of the Invention is based on the object, an improved method for producing a molded part from fiber-reinforced thermoplastic by injection molding.

The The object is achieved by a method solved with the features specified in claim 1.

advantageous Embodiments of the invention are the subject of the dependent claims.

at the process according to the invention for the preparation a molding of fiber reinforced thermoplastic by Injection molding is the textile insert in an injection mold encapsulated on both sides with a thermoplastic melt.

By the double-sided encapsulation of the textile insert is this after insoluble in the curing of the thermoplastic melt connected to the thermoplastic. Opposite from the state the technique known unilateral back injection of textile inserts This will result in a defective composite adhesion of the textile inserter on the thermoplastic and a partial or complete Removal of the textile insert from the thermoplastic advantageous avoided. At the same time is ensured by double-sided encapsulation, that the textile insert in the desired position in the Tool and thus remains in the later part and not by unilateral force application due to a one-sided injection back is moved.

Further Advantages, features and details of the invention are described below based on embodiments with reference to drawings described.

there demonstrate:

1 a top view of a textile insert,

2 a longitudinal section through a textile insert,

3A to 3G schematically longitudinal sections through an injection mold with two mold halves and a textile insert at various stages of fixing and extrusion coating of the textile insert in the injection mold, and

4 schematically a plan view of a textile insert and a metal bushing, which is pressed by means of a piercing mandrel between fiber strands of the textile insert.

each other corresponding parts are in all figures with the same reference numerals Mistake.

1 shows a plan view of a textile insert 1 made as a fabric of first fiber strands 2 and second fiber strands 3 is trained. The first fiber strands 2 parallel to each other, the second fiber strands 3 are perpendicular to the first fiber strands 2 and are intertwined with these. Such a textile insert 1 is for example a canvas fabric. As an alternative to the illustrated and described fabrics, other technical textiles, for example in the form of a fabric, knitted or knitted fabric, can be used with the same advantages.

2 shows a longitudinal section through the in 1 illustrated textile insert 1 ,

The fiber strands 2 . 3 For example, from hybrid yarn and / or so-called fiber rovings, for example based on metallic fibers, glass fibers, carbon or aramid fibers, formed for thermoplastic. They may be fully, partially or not consolidated or impregnated.

From the textile insert 1 becomes by the procedure according to invention described in the following by encapsulation of the Textileinlegers 1 made a molding, for example, a reinforced, so-called soft carrier or a Z-strut for a Frondendträgerausführung a vehicle.

The 3A to 3G show schematically longitudinal sections through an injection mold S and a textile insert 1 in various successive stages of fixing and overmolding the textile inserter 1 in the injection mold S.

The injection mold S has two mutually corresponding tool halves 4 . 5 on, which each as dowel pins, clamping hooks, clamping slide, spring strips and / or fixing needles formed fixing 6 . 7 exhibit. Here are the first fixing elements 6 in a first tool half 4 arranged and from this in the direction of the second tool half 5 extendable. Second fixing elements 7 are in the second tool half 5 arranged and out of this towards the first tool half 4 extendable. The fixing elements 6 . 7 are preferably independently of each other by means of electric motors and / or hydraulically and / or pneumatically controllable or automatically by the plastic melt in the extrusion process movable. Further, the second tool half 5 movable and can close the injection mold S on the first mold half 4 to and to open the injection mold S of the first mold half 4 be moved away.

3A schematically shows an insertion of the textile insert 1 in the injection mold S. In this case, the injection mold S is opened so far that the textile insert 1 between the two tool halves 4 . 5 can be inserted. The insertion of the textile inserter 1 in the injection mold S is preferably carried out automatically by means of a gripper, for. B. a clamping gripper or needle gripper, which is mounted on a linear or multi-axis robot. In this case, the textile insert 1 be inserted directly into the injection mold S, or are first stretched in a clamping frame, which is then inserted into the injection mold S, or initially in a removable three-dimensional recording tool insert, z. As a narrow shell, inserted and fixed there and therein the injection mold S are supplied.

After inserting the textile insert 1 the injection mold S is closed by the second mold half 5 on the first tool half 4 to be moved until the textile insert 1 , as in 3B shown between the two tool halves 4 . 5 is trapped. This will make the textile insert 1 transformed into its final form.

After forming the textile insert 1 becomes the second tool half 5 , as in 3C shown by about half the thickness of the molded part to be produced from the first mold half 4 moved away. In this case, the first fixing elements 6 from the first half of the mold 4 extended until their textile-side ends the textile insert 1 to the second tool half 5 to press.

Then the second tool half 5 , as in 3D shown another piece of first tool half 4 moved away until her distance from the first tool half 4 the thickness of the molded part corresponds. In this case, the second fixing elements 7 from the second half of the mold 5 extended so that their textile fabric-side ends of the textile insert 1 or into it and the textile inlay 1 through the fixing elements 6 . 7 between the two mold halves 4 . 5 is fixed, but of each mold half 4 . 5 separated by a gap. This will make the textile insert 1 advantageously held in its desired position, so that it is not moved from this position in the following encapsulation. The textile insert 1 can through the fixing elements 6 . 7 and / or additional clamping elements, for example controllable or automatically movable by the plastic melt strips, slats and / or clamping hooks, also be stretched.

After fixing the textile insert 1 be the gaps between the textile insert 1 and the tool halves 4 . 5 by means of spray nozzles 8th . 9 with a thermoplastic melt 10 injected and thus the textile insert 1 overmoulded, as in 3E shown. In this case, the textile insert 1 also in the spaces between the fiber strands 2 . 3 be injected. Due to the pressure sensitivity of conventional textile inserts 1 For example, a low pressure injection molding method for overmolding is preferably used. The spray nozzles 8th . 9 For example, are designed as a needle valve nozzles and it is z. B. uses a cascade control, so that the melt flow course gently for the textile insert 1 (Avoidance of unwanted injection, ejection of the fibers, local positional shift) is regulated.

Subsequently, or even during the overmolding, as in 3F shown before curing the thermoplastic melt 10 the fixing elements 6 . 7 back into the respective tool half 4 . 5 drove, for example, each independently before each other from the thermoplastic melt 10 be reached, the retraction is triggered by fast response pressure and / or temperature sensors. This can advantageously the entire textile insert 1 both sides with thermoplastic melt 10 to be overmoulded. Alternatively, it is also possible the fixing 6 . 7 in such a way that they automatically from the thermoplastic melt 10 be moved, which advantageously significantly simplifies a process control described above by means of sensors.

When the thermoplastic melt 10 all or at least partially cured, the injection mold S, as in 3G shown, opened and that from the over-molded textile inlay 1 removed existing molding. In this case, the fixing elements 6 . 7 be used advantageously for ejecting the molding. Subsequently, the molding can be reworked if necessary.

In the basis of the 3A to 3G described embodiment, the thermoplastic melt 10 , as in 3E shown schematically, by means of two spray nozzles 8th . 9 at the same time on two different sides of the textile insert 1 injected sprues. In alternative embodiments, more than two spray nozzles 8th . 9 can be used for injection and / or the gate marks can be on the same side of the textile insert 1 are then, in which case the thermoplastic melt 10 through breakthroughs and / or between the fiber strands 2 . 3 through to the other side of the textile inserter 1 is injected. Furthermore, the molded part during encapsulation of the textile insert 1 by appropriate design of the injection mold S with functionally relevant structures, eg. B. with reinforcing ribs provided.

The textile insert 1 can be prefabricated prior to insertion into the injection mold S, ie that it is already cut to the finished target shape, so that no reworking on edges of the molded part is more necessary. However, it can not be pre-assembled, ie it has an excess of its edges. This can advantageously simplify its handling, for example a simpler fixation of the textile insert 1 allow, but requires a post-processing of the molding. Furthermore, the textile insert 1 also be partially prefabricated so that it has oversize in certain places to facilitate handling.

With at least partial prefabrication of a non-consolidated textile insert 1 this is preferably welded to an edge at which it is cut, z. B. laser welded. A consolidated textile inlay 1 For example, it is punched and / or cut by means of a water jet for prefabrication.

Furthermore, the textile insert 1 preferably before, during and / or after being placed in the injection mold S heated. This facilitates in particular its subsequent deformation in the injection mold S, cf. 3B , through the tool halves 4 . 5 ,

For example, the textile insert 1 heated prior to insertion into the injection mold S on a conveyor belt in a separate furnace by heat convection and / or by thermal radiation, such as infrared radiation, to a certain target temperature. In particular, the textile insert 1 during transport to the injection mold S are heated. The heating of the textile insert 1 is preferably carried out during a predetermined period of time, which particularly preferably with a transport time for the transport of the textile insert 1 matches the injection mold S.

Heating can also be on spotlights, z. As infrared radiator, carried out, which are integrated in the gripper. Here is the contact surface between the support surface of the gripper and the textile insert 1 be kept as small as possible, in order to reduce or even avoid Verkiebungen and cold bridges. Alternatively or additionally, the textile insert 1 be heated by heat conduction by means of the gripper, wherein a bearing surface of the gripper is heated as a kind of heat plate inductively to a certain surface temperature.

Furthermore, the textile insert 1 alternatively or additionally be heated in the injection mold S, for example, after the closure of the mold halves 4 . 5 by heat conduction to the textile inlay 1 , These are the textile insert 1 facing surfaces of the tool halves 4 . 5 at least in some areas variotherm (by inductive mold temperature control) to a certain mold surface temperature, which is, for example, depending on the matrix material of the plastic melt between 80 ° C and 270 ° C, heated.

The textile insert 1 can also be heated in several steps before and / or after insertion into the injection mold S. For example, the textile insert 1 heated by infrared radiators during transport to the injection mold S to a certain first target temperature and then during and / or after the transfer of the textile insert 1 to the injection mold S additionally heated by the infrared radiation and the tool surface to a second target temperature. In this case, the tool surface temperature is preferably higher than the temperature of the gripper to better transfer of the textile insert 1 to allow the injection mold S and in particular a bonding of the textile insert 1 to avoid on the gripper surface. In this regard, the gripper may also have a coating, in particular an insulating coating, on the gripper surface.

A simplified variant of the method provides fixed instead of extendable fixing 6 . 7 in front. In this variant, the textile insert 1 by means of fixation elements fixedly arranged in the injection mold S or a pick tool insert 6 . 7 fixed and, if necessary, tensioned. When overmolding of the textile inserter 1 with the thermoplastic melt 10 becomes the textile inserter 1 from the fixed fixing elements 6 . 7 held in the desired position. This also creates vacancies (not with thermoplastic melt 10 filled areas of the textile inlay 1 ) on the molding. These vacancies are preferably arranged in anyway required breakthroughs in the molding.

Another variant of the method sees automatically movable fixing 6 . 7 in front. In this variant, the textile insert 1 by means of fixing elements which can be moved automatically in the injection mold S or in the take-up tool insert 6 . 7 fixed and, if necessary, tensioned. In this case, the automatically movable fixing elements 6 . 7 from the thermoplastic melt 10 pushed away when they are reached by this. Thus, the whole textile insert 1 (without vacancies) with thermoplastic melt 10 molded.

As automatically movable fixing elements 6 . 7 For example, spring-mounted conical shaped clamps are suitable. Prior to the encapsulation, such a tensioner is used as a tensioning element and fixing element by means of a spring bias a compressive force on the textile insert 1 which exerts this from a surface of a tool half 4 . 5 pushes. The compressive force of the tensioner is preferably so great that the textile insert 1 remains in the desired position remains at melt flow. When the thermoplastic melt 10 a clamping point at which the tensioner the textile insert 1 touched, reached, the tensioner is through the thermoplastic melt 10 due to its conical shape from the textile insert 1 pressed away. Thus, the clamping point is complete with thermoplastic melt 10 molded.

Additionally or alternatively, a spring-mounted clamping bar as an automatically movable fixing 6 . 7 be used. The clamping bar is at a certain angle, z. B. 45 °, to the gap between the tool halves 4 . 5 and the melt flow direction inclined. The compressive force of the inclined clamping bar is preferably so large that the textile insert 1 remains in the desired position remains at melt flow. Upon arrival of the thermoplastic melt 10 At a clamping point of the clamping bar is the inclined clamping bar through the thermoplastic melt 10 due to their inclination and shape from the textile inlay 1 pressed away. Thus, the clamping point is complete with thermoplastic melt 10 molded.

Another variant of the method provides for a controlled melt flow at opposite gate points. In this variant, the textile insert 1 without fixing elements 6 . 7 or only at the edge of the textile inserter 1 with fixing elements 6 . 7 or a tenter. The gate marks for the thermoplastic melt 10 are located on both sides of the textile insert 1 , The thermoplastic melt 10 is simultaneously on both sides of the textile insert 1 injected. By the simultaneous double-sided encapsulation and the two-sided uniform course of the thermoplastic melt 10 becomes the textile inserter 1 of itself in the middle in the gap between the tool halves 4 . 5 positioned. Thus, a double-sided uniform loading of the textile insert 1 guaranteed. The injection of the thermoplastic melt 10 preferably takes place from the inside to the outside to wrinkle-resistant textile inlay 1 to avoid. Also in this variant is the whole textile insert 1 (without vacancies) with thermoplastic melt 10 molded.

The mentioned variants can also be combined, wherein the textile insert 1 from fixed and / or controllable movable and / or automatically movable fixing 6 . 7 and / or fixed on both sides melt flow fixed and / or clamped.

Furthermore, the above based on the 3E described single-stage encapsulation, in which both sides of the textile insert 1 be overmolded at the same time, also be replaced by a two-stage overmolding, in which the two sides of the textile insert 1 be back-injected one after the other. In this case, the injection mold S, for example, designed to be rotatable at least in parts. After inserting and deforming the textile insert 1 First, a first side of the textile insert 1 with thermoplastic melt 10 back-molded. Thereafter, the injection mold S is rotated and the one-sided over-molded textile insert 1 if necessary, reheat again. After that, the second side of the textile insert 1 back-molded.

4 schematically shows a plan view of a textile insert 1 and one as a metal bushing 11 executed insertion element. The metal bush 11 is by means of a piercing spike 12 between fiber strands 2 . 3 of the textile inserter 1 pressed.

The metal bush 11 is for example provided with an internal thread for receiving a screw and is advantageously integrated for the transmission of large tightening torques of the screw in the molding. It is preferred after inserting the textile insert 1 in the injection mold S and after its heating, but before the encapsulation of the textile insert 1 between fiber strands 2 . 3 , pressed. This has the advantage that the heated textile insert 1 soft and therefore easy to work, leaving the metal bushing 11 easy between the fiber strands 2 . 3 is depressible. The piercing spike 12 is shaped accordingly, for example, with a tip whose longitudinal section is a traktrixartige contour has or is spherical, so that they are the fiber strands 2 . 3 gently push aside without damaging it. The piercing spike 12 is through the metal bushing 11 guided and is pulled out after the encapsulation of the textile insert from the molded part. The impressions of the metal bush 11 before overmolding the textile insert 1 advantageously avoids additional process costs, for example, by pressing the metal bushing 11 would arise in the molding and / or punching a hole in the molding after its production. The metal bush 11 is also preferred as a fixing element 6 . 7 for fixing and / or tensioning the textile insert 1 used.

The metal bush 11 is designed, for example, as a special bush with an undercut, so that a cross-sectional area in a middle region of the metal bush 11 smaller than at their ends. The metal bush 11 becomes during the encapsulation of the textile inserter 1 also with thermoplastic melt 10 molded. As a result, it is after the curing of the thermoplastic melt 10 anchored positively in the molding. The cross-sectional reduction in its central region advantageously prevents the metal bushing from slipping out 11 from the molding. The thermoplastic melt 10 gives the metal socket 11 additional hold in the textile insert 1 ,

Alternatively, the metal bushing 11 designed as a standard socket (without undercut). This is the metal bushing 11 except with the piercing spike 12 still with a hold-down, the cross-sectional area of the cross-sectional area of the metal bushing 11 excels in the textile inlay 1 pressed and then together with the hold-down with thermoplastic melt 10 molded. After curing the thermoplastic melt 10 prevents the hold down slipping out of the metal bushing 11 from the molding.

In a further alternative variant, a metal bushing 11 used with an external thread. By means of the piercing spike 12 will the on the stinging thorn 12 located metal bush 11 in the textile inlay 1 screwed. Turning the metal bushing in 11 protects the fiber strands particularly advantageous 2 . 3 of the textile inserter 1 because there are no vertical forces on the fiber strands 2 . 3 Act. After fixing the metal bush 11 in the textile inlay 1 become the metal bushing 11 and the textile feeder 1 with thermoplastic melt 10 molded. The piercing spike 12 becomes after the overmolding of the metal bushing 11 unscrewed. The external thread prevents the metal bushing 11 after curing the thermoplastic melt 10 slipping out of the metal bushing 11 from the molding. Advantageously, the metal bush 11 while an external thread in the form of a left-hand thread.

In a further alternative variant, in particular for a thin textile insert 1 , becomes a metal bushing 11 made of sheet metal with an open at least one point and preferably structured outer wall used. The metal bush 11 becomes so in the textile inlay 1 arranged that it does not protrude beyond this, so that there functional elements flush with the textile insert 1 can be connected. After fixing the metal bush 11 in the textile inlay 1 they and the textile inlays 1 with thermoplastic melt 10 molded. The thermoplastic melt 10 gives the metal socket 11 additional hold in the textile insert 1 in particular by the structuring of the outer wall of the metal bushing 11 , The piercing spike 12 is after the encapsulation of the textile insert 1 and the metal bush 11 from the metal bush 11 withdrawn or unscrewed with internal thread. The opening in the outer wall of the metal bush 11 prevented after curing of the thermoplastic melt 10 advantageous slipping out of the metal bushing 11 from the molding.

1

textile depositors

2

first tow

3

second tow

4

first tool half

5

second tool half

6

first fixing

7

second fixing

8th

first nozzle

9

second nozzle

10

Thermoplastic melt

11

metal bushing

12

spike

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102006040748 A1 [0002]

Claims (6)

Method for producing a molded part from fiber-reinforced thermoplastic by injection molding, wherein a textile insert ( 1 ) in an injection mold (S) with a thermoplastic melt ( 10 ) is sprayed over, characterized in that the textile insert ( 1 ) in the injection mold (S) is encapsulated on both sides. Method according to claim 1, characterized in that the textile inlay ( 1 ) before encapsulation in the injection mold (S) by means of fixing elements ( 6 . 7 ) is fixed. Method according to one of the preceding claims, characterized in that the textile insert ( 1 ) in the injection mold (S) by closing the injection mold (S) is deformed. Method according to one of the preceding claims, characterized in that before and / or in the injection mold (S) before the encapsulation of the textile insert ( 1 ) at least one insertion element between fiber strands ( 2 . 3 ) of the textile inserter ( 1 ) is pressed and / or rotated. A method according to claim 4, characterized in that the at least one insertion element by means of a piercing spike ( 12 ) between fiber strands ( 2 . 3 ) of the textile inserter ( 1 ) is pressed and / or rotated and the piercing spike ( 12 ) after encapsulation of the textile inserter ( 1 ) is pulled out of the molding and / or unscrewed. Process for producing a molding for a Vehicle according to one of the preceding claims.