A part production method

Abstract

The present invention relates to a production method that enables the production of polymer matrix materials used in the manufacture of automotive parts at different thicknesses and foaming ratios using chemical foaming and core retraction methods.

Description

[0001] A Part Production Method

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a method for producing automotive parts with different thicknesses and foaming ratios using polymer matrix materials and chemical foaming and core retraction techniques.

[0004] PRIOR ART

[0005] Traditional injection molding methods are widely used in the production of parts with consistent thickness and mechanical properties from polymer matrix materials. However, these methods do not offer the flexibility to achieve different thicknesses and foaming rates during the flow of the material within the mold. Standard processes are often inadequate for producing parts with complex geometries or requiring regional density variations, as they typically involve a fixed core structure and movement limitations. The application of chemical foaming additives in traditional methods is generally uncontrolled, and it is difficult to achieve variable foam density in specific areas of the part. This situation limits the possibility of reducing the product's weight and optimizing its durability characteristics. Furthermore, if the additives are not homogeneously distributed in the mold, the final product may exhibit surface defects and mechanical weaknesses. Because material homogeneity cannot be achieved during the integration of material content and additives, the final product quality decreases, which in turn reduces production efficiency. Furthermore, the positive impact of standard methods on environmental sustainability is limited. In terms of cooling, conventional molds typically have a fixed cooling duct system, which leads to uneven cooling in different areas of the part. The development of internal stresses negatively affects the mechanical performance and long-term durability of the part.

[0006] As a result of research conducted on the current state of the art, R&D work must be carried out on existing techniques to develop more flexible, efficient, and environmentally friendly methods that enable the production of polymer matrix materials with different thicknesses and foaming ratios.As a result, all abovementioned problems have made it necessary to make an improvement in the relevant technical field.

[0007] OBJECT OF THE INVENTION

[0008] The present invention aims to eliminate the abovementioned problems and to make a development in the relevant technical field.

[0009] The primary object of the present invention is to present an innovative production structure that enables the production of parts with different thicknesses and foaming ratios from polymer matrix materials using chemical foaming and core retraction methods.

[0010] Another object of the present invention is to provide a method that meets different thickness and density requirements in the production of automotive parts with complex geometries.

[0011] Another object of the present invention is to reduce the weight of parts using a chemical foaming method, while also ensuring that durability and mechanical properties are maintained.

[0012] Another object of the present invention is to ensure the production of parts with high surface quality and mechanical strength by controlling the even distribution of the material within the mold and the homogeneous cooling processes.

[0013] Another object of the present invention is to minimize internal stresses after molding through core retraction and multiple cooling ducts.

[0014] BRIEF DESCRIPTION OF THE INVENTION

[0015] The present invention is a method used in the production of automotive parts so as to fulfil all aims mentioned above and will be obtained from the following detailed description. Accordingly, to enable the mold (A) with at least one core to produce parts with different thicknesses and foaming ratios using the chemical foaming and core retraction method, it comprises the following process steps, respectively:

[0016] a) Fixing the mold (A), A plate (7), B plate (8), and C plate (6) in their starting positions to adjust the temperature, pressure, and material dosages in the injection system (H),b) Melting the polymer matrix material at a temperature range of 150-300°C to achieve a homogeneous structure,

[0017] c) Activating the pins (5) to secure specific areas and ensure the formation of different thickness zones,

[0018] d) Injecting the mixture obtained into the mold (A) consisting of plate A (7) and plate B (8) in the B process step,

[0019] e) Fixing plate C (6) which is fixed inside plate B (8) in its starting position, f) Controlling the material inside the mold (A) using temperature and pressure sensors,

[0020] g) Closing the injection gate (4) after a t period of time, the material is injected into the cavity to ensure that the material is distributed into the desired voids within the mold (A),

[0021] h) Maintaining active injection pressure to ensure material solidification, i) Moving the C plate (6) backward in time t+1 and locking the same when it reaches displacement values of 1-5 mm,

[0022] j) Repositioning and re-checking the operation of the pins (5) to secure specific areas and ensure the formation of different thickness zones, k) Starting the foaming process with chemical additives, and forming bubbles in areas that do not come into contact with the steel walls, l) Continuing the chemical foaming process in the moving areas (10) so as to ensure that different thicknesses and foaming ratios are achieved in the final part,

[0023] m) Activating the cooling ducts (20) to ensure the material's temperature drops below 30-80°C and the foaming process entering its final stage, n) Hardening the final part when the foaming process and material expansion are complete,

[0024] o) Eliminating the back pressure and injection pressure,

[0025] p) Withdrawal of pins (5) and releasing plate C (6),

[0026] q) Removing the final part from the mold (A).

[0027] In a preferred embodiment of the invention, it comprises an inert gas-based foaming agent to initiate chemical foaming in process step i.

[0028] In another preferred embodiment of the invention, it comprises individual or combinations of polyethylene (PE), polypropylene (PP), polycarbonate (PC), and acrylonitrile butadiene styrene (ABS) selected as the polymer matrix in process step b.BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 shows a cross-section of the front perspective view of the injection mold.

[0030] Figure 2 shows a schematic view of a part production method.

[0031] Figure 3 shows a cross-section of the internal structure of the injection mold from a detailed front perspective view.

[0032] Figure 4 shows a cross-sectional view from the detailed front perspective of the Heating Unit, Heating and Cooling Control Unit, Heating Element, Heating and Cooling Circuit, and Cooling Duct structures.

[0033] The figures are not required to be scaled and the details which are not necessary for understanding the present invention may be neglected. Moreover, the elements that are at least substantially identical or have at least substantially identical functions are shown by the same number.

[0034] DESCRIPTION OF THE REFERENCE NUMBERS IN FIGURES

[0035] A. Mold

[0036] E. Extruder

[0037] K. Housing

[0038] H. Injection System

[0039] 3. Valve passage

[0040] 4. Injection Path

[0041] 5. Pin

[0042] 6. C Plate

[0043] 7. A Plate

[0044] 8. B Plate

[0045] 9. Hydraulic Mechanism

[0046] 10. Moving Region

[0047] 11. Separation Plane

[0048] 12. Pusher Plate

[0049] 13. Control Unit

[0050] 14. Pusher

[0051] 15. Cavity

[0052] 16. Heating Unit

[0053] 17. Heating and Cooling Control Unit18. Heating Element

[0054] 19. Heating and Cooling Circuit

[0055] 20. Cooling Duct

[0056] 21. Material Feeding Units

[0057] DETAILED DESCRIPTION OF THE INVENTION

[0058] In this detailed description, A Part Production Method of the present invention is described by means of examples only for clarifying the subject matter such that no limiting effect is created.

[0059] The present invention relates to a method for producing automotive parts made from polymer matrix materials with varying thicknesses and foaming ratios through chemical foaming and core retraction.

[0060] Traditional injection molding methods have several limitations, including homogeneous thickness and low design flexibility, inadequate chemical foaming control, material and energy inefficiency, lack of control in cooling and solidification processes, difficulties in producing complex structures, and uniform mechanical properties. These methods do not provide sufficient performance in the production of automotive parts that require different thicknesses and foaming ratios. It offers optimized thickness and foaming ratios in different areas of the part with the help of the chemical foaming and core retraction mechanism, while providing an environmentally friendly and economical production method through the use of recycled materials. It offers a technically and environmentally superior solution with innovative features such as energy and material savings, controlled cooling processes with cooling ducts (20), and the production of complex structures with movable pins (5).

[0061] The mold, whose schematic view is given in Figure 2, is detailed in cross-section in Figure 1. The process of producing automotive parts with different thicknesses and foaming ratios using chemical foaming and core withdrawal methods consists of the following elements integrated / assembled into the injection molding machine (H): Mold (A), Extruder (E), Housing (K), Valve passage (3), Injection path (4), Pin (5), Plate C (6), Plate A (7), Plate B (8), Hydraulic Mechanism (9), Moving Region (10), Separation Plane (11), Pusher Plate (12), Control Unit (13), Pusher (14), Cavity (15), Heating Unit (16), Heating and Cooling Control Unit (17), Heating Element (18), Heating and CoolingCircuit (19), Cooling Duct (20), Material Feeding Units (21). The connected valve passage (3) within the mold (A), which is the main structure that determines the final form of the product and consists of fixed and movable parts for shaping the material, is a structure that controls the flow of material inside the mold (A) and precisely regulates the moments when the flow starts and stops. In the plastic injection process, this is a critical transition point where the molten polymer material is transported into the cavity (15) and the material flow is terminated. The injection path (4) receives the molten polymer material from the injection machine and connects it to the cavity (15). The injection path (4) ensures even distribution of the material into the mold (A) and controls the flow of the material. The housing (K) is the cylindrical structure through which the molten material is conveyed and directed during injection, ensuring a homogeneous flow by keeping the material temperature under control. The single or multi-screw extruder located inside the housing provides both the mixing of the material and the advancement of the material from the housing (K) to the mold (A). The cavity (15) is the area where the final form of the material is formed and is directly related to the injection path. The shape in the cavity (15) is obtained by correctly closing the mold (A). Plate A (7) is the fixed part of the mold (A), providing structural support. Plate B (8) supports the movable part of the mold (A), providing stability and alignment during the opening and closing of the mold (A). It ensures the smooth joining of the mold (A) halves and the stability of the mold (A). In this process, the separation plane (11) ensures correct closure by defining the connection line of the fixed and movable mold (A) parts.

[0062] Cooling ducts (20) and heating and cooling circuit (19) are activated to ensure that the material is distributed and solidified homogeneously in the mold (A). Cooling ducts (20) remove heat from inside the mold (A), ensuring even cooling of the material and preventing the formation of internal stresses, thereby increasing the mechanical strength of the final product. The heating and cooling circuit (19) optimizes the fluidity of the material and its placement in the mold (A), keeping temperature variations under control. Material feeding units (21) ensure that the polymer matrix material is transferred to the injection system (H) in the correct amount and continuously.

[0063] Heating unit (16) maintains the fluidity of the material by keeping the temperature inside the mold (A) at a certain level. This unit ensures homogeneous distribution within the mold (A), allowing the material to take shape evenly. This is especially important for the material to move smoothly within the mold (A) during the production process. Theheating process ensures that the material acquires the desired properties by maintaining temperature balance inside the mold (A). The heating and cooling control unit (17) monitors and regulates the temperature fluctuations of the mold (A). The heating and cooling control unit (17) minimizes temperature fluctuations of the material, thus ensuring a more stable production process by controlling temperature changes. The heating element (18) increases the fluidity of the material by providing the necessary temperature to the mold (A), thus making the forming process efficient. The heating and cooling circuit (19) balances the mold (A) temperature and reduces the formation of internal stresses during cooling, which increases the mechanical strength of the product. The cooling duct (20) ensures that the material cools quickly and in a controlled manner. It ensures that the material solidifies homogeneously and increases the mechanical strength of the final product. It helps the product achieve the desired physical properties by reducing internal stresses during cooling.

[0064] Plate C (6) and pins (5) play an important role in creating complex geometries and different thicknesses. Plate C (6) enables the material to expand and form different thicknesses in the moving regions (10) of the mold (A) by performing the core retraction movement. The pins (5) enable the creation of detailed geometries by keeping the moving regions (10) fixed. The hydraulic mechanism (9) controls the moving parts such as the mold (A) and pin (5). It enables the material to take the desired form during processing by moving them with high precision. The coordinated operation of these structures makes it possible to obtain different density and thickness characteristics on the product as desired.

[0065] In the final stage, the pusher plate (12) and pusher (14) come into play during the process of removing the solidified product from the mold. The moving region (10) refers to the part that moves when the mold (A) is opened to remove the part. These structures ensure that the product is removed from the cavity (15) without damage. During all these processes, the control unit (13) regulates parameters such as temperature, pressure and timing inside the mold (A). The separation plane (9) defines the connection line of the fixed and movable mold (A) halves. This plane ensures that the mold halves (A) close and open correctly. The final part is the end product obtained as a result of the injection molding process. The part will have the desired shape, thickness, and specifications.Core retraction plays a critical role in shaping materials with varying thicknesses and foaming ratios during the production of automotive parts. This method is performed by plate C (6) located inside mold (A). During injection, the material is injected into the mold and the plate C (6) is initially fixed. However, after the t+1 time, plate C (6) begins to retract, and this movement causes the material to expand and become thicker in certain areas of the mold cavity.

[0066] The core retraction process allows the material to spread toward the moving regions (10), thereby helping to create the desired thickness variations. The retracted core allows for greater expansion and foaming only in certain areas of the material, resulting in both dense and lightweight regions within the part. This allows the mechanical properties of the part to be optimized. Furthermore, this process, which works in conjunction with the chemical foaming process, increases flexibility in the design and production of the material. Core retraction allows for a more efficient structure and improved performance in the final part.

[0067] The method for producing automotive parts made from polymer matrix materials with different thicknesses and foaming ratios using chemical foaming and core retraction is as follows:

[0068] Step A Material Preparation:

[0069] In the material preparation process, thermoplastics such as recycled or virgin source or bio-based polyethylene (PE), polypropylene (PP), polycarbonate (PC), and acrylonitrile butadiene styrene (ABS) are preferred. The mixture is prepared by adding 25-100% by weight of the main polymer material and 2-25% of other additives, including foaming agents. These components are melted in an extruder at a temperature range of 150-300 °C to form a homogeneous structure, making them suitable for injection molding.

[0070] Mold systems and plates are fixed in their predefined positions.

[0071] Step B: Mold Injection Process:

[0072] The prepared homogeneous mixture is injected into the mold (A) system, consisting of plate A (7) and plate B (8), while the flow of the material is precisely monitored with temperature and pressure sensors. The injection process begins with the material being conveyed into the cavity (15) via the valve passage (3), while the temperature is maintained between 150-300°C to preserve the optimal fluidity properties of the material.At the same time, by fixing the injection pressure in the range of 75-175 MPa, the material is ensured to fill the cavity (15) homogeneously and the surface quality is high. The valve passage (3) is the duct that ensures the smooth transfer of molten plastic material from the injection molding machine to the cavity (15).

[0073] Step C Securing the C Plate:

[0074] Plate C (6) inside mold (A) in injection system (H) is fixed to a specific starting position at the beginning of the injection process. This fixation process is carried out to ensure that the material in the cavity (15) is evenly and homogeneously distributed. Fixing the plate C (6) ensures that the material is correctly directed during injection and evenly distributed to each section. Thus, it regulates the flow of the material and prevents the formation of unwanted air pockets or flow problems in the cavity (15). This step improves the quality of the final part, and by ensuring homogeneous filling, especially in products with complex geometries, it enhances the efficiency of the production process and the durability of the product.

[0075] Step D Closing of the Injection Path (4):

[0076] The injection path (4) is left open to ensure that the material is distributed homogeneously into the cavity (15) during the injection process, but it closes at the end of time t, thus playing a role in limiting the movement of the material inside the mold (A). This closing process allows the injection pressure to control the material flow and prevents the material from being undesirably distributed within the mold (A). Closing the injection path (4) ensures that the internal cavities of the mold (A) are properly filled and the material takes the correct shape. In addition, closing the injection path (4) creates the environment necessary for the material to start cooling, because the material inside the mold (A) is fixed and further flow is prevented. This process helps ensure that the final shape of the part is smooth and flawless.

[0077] Step E Maintaining Active Injection Pressure:

[0078] Maintaining the injection pressure is a critical step to ensure the material is properly placed in the mold (A). This pressure ensures that the material completely fills the cavity (15) and spreads evenly in every area. Pressure also controls the flow of the material within the mold (A), ensuring smoothness and uniformity of the surface, thus preventing molding defects and gaps. The shape of the part is stabilized by continuing to applypressure while the material is still in its liquid state, and as the material cools, it contributes to the formation of a homogeneous structure. This process improves the mechanical properties of the final product while also ensuring compliance with aesthetic and functional requirements. The hold pressure is selected to be 50-70% of the injection pressure.

[0079] Step F The retraction movement of Plate C:

[0080] At the end of the T+1 period, plate C (6) starts to retract, and this movement allows different thicknesses to be formed in certain areas of the material (A) in the mold. The displacement of the plate C (6) is adjusted in the range of 1-5 mm; this adjustment plays a critical role in achieving the desired thickness differences in the part. As the C plate (6) is retracted, the material expands in accordance with this movement and has thicker regions, while the material density increases in thinner regions. This process allows for the achievement of different thicknesses and mechanical properties, in accordance with the part's design. In addition, this movement during the flow and shaping of the material helps to reduce internal stresses within the mold (A) and promotes more stable solidification of the part.

[0081] Step G Activation of the Pins (5):

[0082] Pins (5) fix specific areas in the injection molding process, enabling the formation of the desired thicknesses in these areas. This fixing process ensures that the material is correctly oriented within the mold (A) and that a homogeneous distribution is achieved in each area. The movement of the pins (5) plays a critical role in ensuring the geometric accuracy of parts with different thicknesses, as this allows the material flow inside the mold (A) to be directed in a controlled manner and prevents unwanted deformations. As a result, products with smooth surfaces and accurate formations are obtained, conforming to the specified thickness values in each section of the part.

[0083] Step H Initiation of the Chemical Foaming Process:

[0084] Chemical additives added to the mixture, such as foaming agents like citric acid, nitrogen, or sodium carbonate derivatives, initiate the foaming process. These additives cause foaming by releasing gas within the material. In areas not in contact with the steel walls, bubbles form due to the effect of this gas, and the material expands in these areas. This expansion helps to lighten the part and achieve better mechanical properties, whilealso creating gaps in the part's internal structure. The foaming process makes it possible to achieve the desired properties, especially in parts requiring different thicknesses and weights.

[0085] Step I Cooling Process:

[0086] Cooling ducts (20) are activated to ensure that the material is brought below critical temperatures. These cooling ducts (20) ensure that the material is cooled quickly and efficiently, guaranteeing that the part solidifies homogeneously. The critical temperature range has been determined as 30-80°C, as this range provides ideal conditions for material optimization and complete solidification. With the help of the cooling system, this process allows the material to achieve the desired mechanical properties and increases production efficiency.

[0087] Step J Continuation of the Chemical Foaming:

[0088] In moving regions (10), while the chemical foaming process continues, the expansion of the material and bubble formation continue. In moving regions (10), foaming ratios are adjusted between 10% and 40% to provide customized foaming according to the needs of each area. Low foaming rates result in a denser and more durable material, while high foaming rates help to lighten the part and create internal voids. This control optimizes the mechanical properties and weight of the part, ensuring that the desired thickness and lightness values are achieved in the design.

[0089] Step K Solidification and Freezing of the Structure:

[0090] Once the foaming process and material expansion are complete, the material begins to solidify completely. Cooling occurs in a controlled manner throughout the part, thus preventing the development of internal stresses and optimizing the mechanical properties of the final product. This stage ensures that the desired shape and structure of the part are fixed, making it possible to proceed to the final steps of the production process.

[0091] Step L Pressure Relief:

[0092] The part is allowed to rest firmly inside the mold (A) by terminating the back pressure and injection pressure. This step ensures that the material inside the mold (A) remainsstable without deformation due to any external influences, and helps the part to fit its shape perfectly. Relieving the pressures allows the material to complete its solidification process and dissipates the internal stresses within the mold (A), thus ensuring a high quality final product. This process is necessary to ensure the part can be removed properly.

[0093] Step M Release of Pins (5) and Plate C (6):

[0094] When the pines (5) are retracted, certain areas in the mold (A) are fixed, so that the part can be removed from the mold (A) smoothly. At the same time, plate C (6) is released and moved out of the mold (A), which allows the part to be easily and undamagedly removed from the mold (A). This process ensures that the material inside the mold (A) takes its exact shape and that the part is removed from the mold (A) smoothly without any deformation. Thus, the production process is completed and the final part is removed from mold (A).

[0095] Step N Removal of Part (A) from Mold:

[0096] The final part is removed from the mold (A) after all processing steps are completed. The protection scope of the invention is specified in the claims and cannot be limited to the description made for illustrative purposes in this brief and detailed description. It is clear that a person skilled in the art can present similar embodiments in the light of the above descriptions without departing from the main theme of the invention.

Claims

CLAIMS1. A method used in the production of automotive parts so as to enable the mold (A) with at least one core to produce parts with different thicknesses and foaming ratios using the chemical foaming and core retraction method, characterized by comprising the following process steps, respectively: a) Fixing the mold (A), A plate (7), B plate (8), and C plate (6) in their starting positions to adjust the temperature, pressure, and material dosages in the injection system (H),b) Melting the polymer matrix material at a temperature range of 150-300°C to achieve a homogeneous structure,c) Activating the pins (5) to secure specific areas and ensure the formation of different thickness zones,d) Injecting the mixture obtained into the mold (A) consisting of plate A (7) and plate B (8) in the B process step,e) Fixing plate C (6) which is fixed inside plate B (8) in its starting position, f) Controlling the material inside the mold (A) using temperature and pressure sensors,g) Closing the injection gate (4) after a t period of time, the material is injected into the cavity to ensure that the material is distributed into the desired voids within the mold (A),h) Maintaining active injection pressure to ensure material solidification, i) Moving the C plate (6) backward in time t+1 and locking the same when it reaches displacement values of 1-5 mm,j) Repositioning and re-checking the operation of the pins (5) to secure specific areas and ensure the formation of different thickness zones, k) Starting the foaming process with chemical additives, and forming bubbles in areas that do not come into contact with the steel walls,l) Continuing the chemical foaming process in the moving areas (10) so as to ensure that different thicknesses and foaming ratios are achieved in the final part,m) Activating the cooling ducts (20) to ensure the material's temperature drops below 30-80°C and the foaming process entering its final stage,n) Solidifying the final part when the foaming process and material expansion are complete,o) Eliminating the back pressure and injection pressure,p) Withdrawal of pins (5) and releasing plate C (6),q) Removing the final part from the mold (A).

2. Method according to claim 1 , characterized by comprising an inert gas-based foaming agent to initiate chemical foaming in process step i.

3. Method according to claim 1, characterized by comprising individual or combinations of polyethylene (PE), polypropylene (PP), polycarbonate (PC), and acrylonitrile butadiene styrene (ABS) selected as the polymer matrix in process step b.

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