DE102017201091A1 - Manufacturing method for producing a thermoplastic component - Google Patents

Abstract

The invention relates to a production method for producing a thermoplastic component (1), which comprises the heating, forming, heating, further shaping and cooling of the thermoplastic semifinished product (2) and that causes a foam structure of the thermoplastic semifinished product (2) to collapse.

Description

The invention relates to a manufacturing method for producing a thermoplastic component, in particular for producing a thermoplastic foam core.

For complex sandwich components, hard foam cores are often used in industry, which have to form a thin edge on which the cover layers, which usually consist of carbon fibers or other fiber materials and form the sandwich component with the hard foam core, are brought together. Such a manufacturing method for a sandwich component, for example, in the WO 2016/020252 A1 described.

Such hard foam cores or cores or thermoplastic components are previously produced by machining or by foaming, but this is slow and expensive and therefore expensive.

However, ordinary thermoforming processes are not suitable for the production of such cores, since in the manufacturing process for producing the sandwich components, the edges of a core previously formed by a thermoforming process are deformed again by pressure and temperature. The edge regions, which must be formed tapering point to feed the outer layers together, lose their cohesion in the manufacturing process and therefore do not allow permanent shaping of the sandwich components. In addition, the edge regions in a conventional thermoforming process can not be compressed to the desired and necessary for a flowing, visually appealing transition thicknesses.

The invention is therefore an object of the invention to overcome the disadvantages described above and to provide a method to transform a thermoplastic semi-finished quickly and inexpensively to a thermoplastic component, said predetermined areas to be irreversibly reshaped to make the thermoplastic component dimensionally stable at least in sections.

This object is achieved by the feature combination according to claim 1.

• • Erwärmen zumindest eines ersten Abschnitts eines thermoplastischen Halbzeugs auf eine erste Temperatur T₁, sodass der erste Abschnitt des thermoplastischen Halbzeugs thermoplastisch verformbar ist;
• • Umformen des auf die Temperatur T₁ erwärmten ersten Abschnitts des thermoplastischen Halbzeugs von seiner Ausgangsform auf eine endkonturnahe Form mit anschließendem Beibehalten eines Formzwangs des thermoplastischen Halbzeugs in der endkonturnahen Form;
• • Erwärmen zumindest eines zweiten Abschnitts des thermoplastischen Halbzeugs auf eine zweite Temperatur T₂, bis der zumindest eine zweite Abschnitt einen schmelzflüssigen Zustand aufweist, wobei gilt, dass die Temperatur T₂ größer ist als die Temperatur T₁ bzw. T₂>T₁;
• • Weiterumformen des thermoplastischen Halbzeugs auf die Form des thermoplastischen Bauteils; und
• • Abkühlen zumindest des ersten und des zumindest einen zweiten Abschnitts des thermoplastischen Halbzeugs auf eine dritte Temperatur T₃, wobei gilt, dass die Temperatur T₃ geringer ist als die Temperatur T1 bzw. T₃<T₁.

According to the invention, a production method for producing a thermoplastic component is proposed which comprises at least the following steps:

• Heating at least a first portion of a thermoplastic semifinished product to a first temperature T ₁ so that the first portion of the thermoplastic semifinished product is thermoplastically deformable;
• • Forming of the heated to the temperature T ₁ first portion of the thermoplastic semi-finished product from its initial shape to a final near-net shape with subsequent maintaining a shape compulsion of the thermoplastic semi-finished product in the near-net shape;
• Heating at least a second section of the thermoplastic semifinished product to a second temperature T ₂ until the at least one second section has a molten state, provided that the temperature T _{2 is} greater than the temperature T ₁ or T ₂ > T ₁ ;
• Further molding of the thermoplastic semi-finished product to the shape of the thermoplastic component; and
• Cooling at least the first and the at least one second section of the thermoplastic semifinished product to a third temperature T ₃ , wherein the temperature T _{3 is} lower than the temperature T ₁ or T ₃ <T ₁ .

As a thermoplastic component, a core, a rigid foam component or a hard foam core is understood a component which consists of a thermoplastically deformable material. Likewise, a thermoplastic semifinished product is understood as meaning a starting product consisting of a thermoplastically deformable material.

Cooling can be carried out passively via cooling surfaces or actively via cooling channels. For active cooling, a plurality of cooling channels are advantageously provided, which dissipate the temperature via a heat-storing and heat-transporting medium, such as oil. Advantageous for the active cooling are several oil circuits.

By forming at or near the temperature T ₁ , in particular in the regions with a high degree of deformation, internal stresses arise in the thermoplastic semifinished product. The internal stresses cause the respective areas in which the internal stresses are located to lose the cohesion in the subsequent manufacturing steps for the production of a sandwich component. In order to minimize the internal stresses and to give the thermoplastic component a high dimensional stability, the regions or second portions, which may lose their shape in the subsequent manufacturing steps, are heated to the temperature T ₂ . The thermoplastic material at least partially fuses with each other in these regions or second sections, whereby a possibly present foam structure is collapsed or dissolved. The duration of the heating of the second sections to the temperature T ₂ is preferably less than 120 seconds, more preferably between 10 and 30 seconds. The Duration of cooling to the temperature T ₃ is preferably between 1 and 2 minutes.

The first section extends over at least part of the length of the thermoplastic semifinished product, preferably the entire thermoplastic semifinished product is heated to the temperature T ₁ .

It is also advantageous if the first temperature T _{1 is} in a temperature range of the thermoplastic semifinished product in which the thermoplastic semifinished product is thermoplastically deformable, the second temperature T _{2 is} equal to or above the melting temperature of the thermoplastic semifinished product and / or the third temperature T ₃ below the temperature range of the thermoplastic semifinished product, in which the thermoplastic semifinished product is thermoplastically deformable. Preferably, the temperature T _{1 is} between 210 ° C and 230 ° C, the temperature T ₂ between 260 ° C and 265 ° C and the temperature T ₃ between 80 ° C and 100 ° C.

For the method, it is also advantageous that the thermoplastic semifinished product is formed from a thermoplastically deformable plastic, in particular PET, and that the thermoplastically deformable plastic is present in a foam structure or is formed as a thermoplastic rigid foam.

It is advantageous in a development that the heated to the temperature T ₁ first portion of the thermoplastic semi-finished product from its initial shape by a pressing tool comprising a first and a second pressing tool side, which act on the semifinished with a predetermined force reshaping, on the near net shape Form is reshaped. The pressing tool cools the thermoplastic semi-finished product to a temperature below the temperature T ₁ , wherein the pressing tool preferably has temperature T ₃ .

The first section of the thermoplastic semifinished product with the at least one second section of the thermoplastic semifinished product which is heated to the second temperature T ₂ is advantageously further transformed from the pressing tool to the shape of the thermoplastic component, wherein the predetermined force is maintained or increased. The further forming is carried out after or in parallel with the heating of the second section to the temperature T ₂ .

The at least one second section of the thermoplastic semifinished product is advantageously an outer edge region of the thermoplastic component extending along a longitudinal direction X of the thermoplastic component.

A further advantage is that the at least one second section of the thermoplastic semifinished product is reduced continuously from a first height H1 to a second height H2 by the reshaping and further forming in a width direction Y that is orthogonal to the longitudinal direction X, wherein the second Height is preferably between 5% and 10% of the height H1. The height H2 is advantageously reduced so far that the outer portion separates from the thermoplastic component and a tapered end is formed.

The second height along the longitudinal direction X is also advantageously varied at intervals, so that in the longitudinal direction X sections with differing second heights H2 arise that hold outward portions of the thermoplastic semi-finished by webs on the thermoplastic component and which form the outer edge region of the thermoplastic component and are separated from the outer portions of the thermoplastic semi-finished product. By the webs, the outer portions of the thermoplastic semi-finished product are held on the thermoplastic component and can be removed without additional measures from the pressing tool. The outer sections can be easily separated or broken off from the thermoplastic component by subsequent manufacturing steps.

• • ein quaderförmiges Hartschaumhalbzeug auf die Temperatur T₁ erhitzt und von einem Presswerkzeug umgeformt wird, sodass eine Höhe des quaderförmigen Hartschaumhalbzeugs in seinen außenliegenden Randbereichen in seine Breitenrichtung stetig reduziert ist und
• • das quaderförmige Hartschaumhalbzeug zumindest in einem Bereich der stetig reduzierten Höhe auf die Temperatur T₂ erhitzt und von dem Presswerkzeug auf die Form des thermoplastischen Bauteils umgeformt wird, sodass der Bereich der stetig reduzierten Höhe zumindest zum Teil verschmolzen wird und in eine Längsrichtung des Hartschaumhalbzeugs auf der jeweils außenliegenden Seite des Bereichs mit stetig reduzierter Höhe zumindest Abschnittsweise einen außenliegenden Randbereich des thermoplastischen Bauteils gebildet wird.

It is also advantageous that in the manufacturing process

• • A cuboid rigid foam semi-finished product is heated to the temperature T ₁ and formed by a pressing tool, so that a height of the cuboid hard foam semi-finished in its outer edge regions in its width direction is steadily reduced, and
• • The cuboid hard foam semi-finished product is heated at least in a region of steadily reduced height to the temperature T ₂ and formed by the pressing tool on the shape of the thermoplastic component, so that the region of the continuously reduced height is at least partially fused and in a longitudinal direction of the rigid foam semi-finished product the respective outer side of the region with continuously reduced height is formed at least in sections an outer edge region of the thermoplastic component.

As a result of the abutment of the pressing tool on the thermoplastic semifinished product, the compulsory mold is maintained and the thermoplastic semifinished product is further shaped during or after the partial heating to the temperature T ₂ .

Furthermore, it is advantageous if the at least one second section of the thermoplastic Semi-finished is a along a longitudinal direction X of the thermoplastic component extending central region in which a height of the thermoplastic component is reduced. As a result, ribs and stiffeners can be formed in the central region of the thermoplastic component, which stabilize the thermoplastic component, make it more resilient and enable the connection to further layers in subsequent process steps, without losing the shape of the thermoplastic component.

The features disclosed above can be combined in any way that is technically possible and they do not contradict each other.

• 1 ein thermoplastisches Halbzeug und ein geöffnetes Presswerkzeug,
• 2 ein thermoplastisches Halbzeug in einem geschlossenen Presswerkzeug,
• 3 ein thermoplastisches Bauteil und ein geöffnetes Presswerkzeug,
• 4 ein thermoplastisches Bauteil mit abgetrennten außenliegenden Bereichen eines Bauteils und ein geöffnetes Presswerkzeug,
• 5 ein thermoplastisches Halbzeug,
• 6 ein thermoplastisches Bauteil,
• 7 ein weiteres thermoplastisches Halbzeug und ein Presswerkzeug.

Other advantageous developments of the invention are characterized in the subclaims or are shown in more detail below together with the description of the preferred embodiment of the invention with reference to FIGS. Show it:

• 1 a thermoplastic semi-finished product and an opened pressing tool,
• 2 a thermoplastic semi-finished product in a closed pressing tool,
• 3 a thermoplastic component and an opened pressing tool,
• 4 a thermoplastic component with separated outer regions of a component and an opened pressing tool,
• 5 a thermoplastic semi-finished product,
• 6 a thermoplastic component,
• 7 another thermoplastic semi-finished product and a pressing tool.

The figures are exemplary schematic. Like reference numerals in the figures indicate like functional and / or structural features.

1 shows a front view of a thermoplastic semi-finished product 2 in a pressing tool with a first pressing tool side 11 and a second pressing tool side 12 , The thermoplastic semi-finished product 2 lies between the two pressing tool sides 11 . 12 , wherein still no force through the pressing tool on the thermoplastic semifinished product 2 is exercised. Through the cooling channels 6 still finds no cooling of the thermoplastic semifinished product 2 instead of. The cooling channels 6 are along the surface of the two pressing tool sides 11 distributed at regular intervals to a uniform cooling of predetermined areas of the thermoplastic semifinished product 2 to enable.

2 shows that around the thermoplastic component 1 closed pressing tool. heating elements 7 in the first and the second pressing tool side 11, 12 heat the thermoplastic semi-finished product 2 , whereby the two press tool pages 11 . 12 the thermoplastic component 1 can form. This will be external sections 5 squeezed outwards by the two pressing tool sides and the second section 3 educated.

In 3 is the thermoplastic component 1 after cooling, through in the cooling channels 6 circulating oil from the first press tool side 11 and the second pressing tool side 12 shown separately. At the two outer edge regions of the thermoplastic component 1 are the outer sections 5 still attached over bridges. The bars close to the second sections 3 outward.

The 4 shows an arrangement like 3 , wherein the webs at the two outer regions of the thermoplastic component 2 are severed, eliminating the outer sections 5 of the thermoplastic semifinished product 2 from the thermoplastic component 1 are solved.

A thermoplastic semi-finished product 2 with longitudinal direction X and width direction Y is in 5 shown, wherein the extension of the thermoplastic semifinished product 2 in the longitudinal direction X is not shown to scale.

6 shows the thermoplastic component 1 with its longitudinal direction X and its width direction Y, wherein the thermoplastic component 1 in the second sections 3 or the respective edge regions from a first height H1 to a second height H2 is steadily thinner and the tapered outer edge region 4 forms.

7 shows a thermoplastic component 1 as in but possesses the thermoplastic component 1 in its height reduced central areas 13 , wherein the surface profile of the top and bottom is asymmetrical to each other.

The invention is not limited in its execution to the above-mentioned preferred embodiments. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. For example, the thermoplastic component could have a completely different basic shape.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2016/020252 A1 [0002]

Claims (11)

Manufacturing method for producing a thermoplastic component (1), comprising the following steps: heating at least a first portion of a thermoplastic semifinished product (2) to a first temperature T ₁ , so that the first portion of the thermoplastic semifinished product (2) is thermoplastically deformable; • Forming of the heated to the temperature T ₁ first portion of the thermoplastic semifinished product (2) from its initial shape to a near net shape with subsequent retention of a shape constraint of the thermoplastic semifinished product (2) in the near-net shape; Heating at least a second section (3) of the thermoplastic semifinished product (2) to a second temperature T ₂ until the at least one second section (3) has a molten state, provided that the temperature T _{2 is} greater than the temperature T. ₁ (T ₂ > T ₁ ); Further forming the thermoplastic semifinished product (2) onto the shape of the thermoplastic component (1); and cooling at least the first and the at least one second section (3) of the thermoplastic semifinished product (2) to a third temperature T ₃ , wherein the temperature T _{3 is} lower than the temperature T ₁ (T ₃ <T ₁ ) , Production method according to Claim 1 , wherein the first temperature T ₁ in a temperature range of the thermoplastic semifinished product (2), in which the thermoplastic semifinished product (2) is thermoplastically deformable, the second temperature T _{2 is} equal to or above the melting temperature of the thermoplastic semifinished product (2) and / or the third temperature T _{3 is} below the temperature range of the thermoplastic semifinished product (2) in which the thermoplastic semifinished product (2) is thermoplastically deformable. Manufacturing method according to one of the preceding claims, wherein the thermoplastic semi-finished product (2) is formed as a thermoplastic foam. A manufacturing method according to the preceding claim, wherein the rigid foam is formed of a polyethylene terephthalate (PET). Manufacturing method according to one of the preceding claims, wherein at least the heated to the temperature T ₁ first portion of the thermoplastic semifinished product (2) from its original shape by a pressing tool comprising a first and a second pressing tool side (11, 12) on the semifinished with acting on a predetermined force reshaping, is converted to the near net shape. A manufacturing method according to the preceding claim, wherein the first portion of the thermoplastic semifinished product (2) with the at least one second portion (3) of the thermoplastic semifinished product (2) is heated to the second temperature T ₂ from the pressing tool to the shape of the thermoplastic component ( 1) is further formed, wherein the predetermined force is held or increased. Manufacturing method according to one of the preceding claims, wherein the at least one second portion (3) of the thermoplastic semifinished product (2) is an outer edge region (4) extending along a longitudinal direction X of the thermoplastic component (1). A manufacturing method according to the preceding claim, wherein the at least one second portion (3) of the thermoplastic semifinished product (2) decreases continuously in a width direction Y orthogonal to the longitudinal direction X from a first height H1 to a second height H2, and wherein the second height H2 is preferably between 5% and 10% of the height H1. Manufacturing method according to the preceding claim, wherein the second height H2 is varied in intervals along the longitudinal direction X, so that in the longitudinal direction X sections with differing second heights H2 arise, the further outboard sections (5) of the thermoplastic semifinished product (2) by webs on the holding the thermoplastic component (1) and which form the outer edge region (4) of the thermoplastic component (1) and are separated from the outer portions (5) of the thermoplastic semifinished product (2). Production method according to one of the preceding claims, wherein • a cuboid hard foam semi-finished product is heated to the temperature T ₁ and formed by a pressing tool, so that a height of the cuboid rigid foam semi-finished in its outer edge regions in its width direction Y is steadily reduced and • the cuboid hard foam semi-finished at least in one Area of the continuously reduced height is heated to the temperature T ₂ and formed by the pressing tool on the shape of the thermoplastic component (1), so that the area of the continuously reduced height is at least partially fused and in a longitudinal direction of the rigid foam semi-finished on the respective outer side of the region with a continuously reduced height at least sectionally an outer edge region of the thermoplastic component (1) is formed. Production method according to one of the preceding Claims 1 to 6 , at least a second section (3) of the thermoplastic semifinished product (2) is a central region (13) extending along a longitudinal direction X of the thermoplastic component (1), in which a height of the thermoplastic component is reduced.

Images