Description:TITLE
METHOD AND SYSTEM FOR MACHINING SEATLESS PISTONS WITHOUT LOCATION REFERENCE

FIELD OF INVENTION
[0001] This invention relates to piston manufacturing, specifically an advanced method and apparatus for precisely machining seatless pistons without using a traditional location seat as a process reference. The invention utilizes high-pressure die-casting (HPDC), precision CNC machining, and advanced measurement techniques to achieve high-accuracy machining without requiring a conventional location seat. The present embodiment is particularly relevant to the automotive, lawn & garden, and aerospace industries, where this method improves manufacturing efficiency, reduces material waste, and enhances the structural integrity of pistons, making it ideal for high-performance internal combustion engines.

BACKGROUND
[0002] Piston manufacturing has traditionally relied on machining a location seat to serve as a process reference for subsequent operations. This reference seat is a designated feature that ensures proper alignment and positioning of the piston blank during machining. While effective in maintaining consistency, the location seat introduces several drawbacks, including additional material usage, increased machining complexity, and higher production costs. In the context of modern internal combustion engines, where efficiency, weight reduction, and precision are crucial, the conventional method of using a location seat presents significant limitations.
[0003] One of the primary concerns with traditional piston machining is the additional weight introduced by the location seat. Internal combustion engines are designed to operate efficiently, and any excess weight in reciprocating components, such as pistons, directly impacts fuel consumption and engine performance. A location seat adds unnecessary mass to the piston, increasing the overall reciprocating weight and affecting the engine’s power output and efficiency. By eliminating the need for this reference feature, significant weight reduction can be achieved, leading to improved engine performance and lower fuel consumption.
[0004] Additionally, conventional piston machining has an increased number of manufacturing steps. The process of creating a location seat requires extra machining operations, which add to production time and cost. Once the seat is formed, multiple machining steps depend on this reference point, further extending the manufacturing cycle. This complexity affects throughput and increases the likelihood of dimensional inaccuracies due to multiple repositioning and fixture changes. The dependency on a fixed reference seat restricts the ability to optimize machining operations for higher efficiency and flexibility.
[0005] Furthermore, the conventional approach of machining pistons with a location seat limits design adaptability. Automotive and industrial engine manufacturers continuously seek advancements in piston geometries to improve thermal efficiency, durability, and combustion characteristics. The requirement for location seat constraints design modifications, particularly in skirt height variations, optimized weight distribution, and novel piston profiles. The inability to make rapid design changes without reconfiguring machining setups hinders innovation in piston manufacturing.
[0006] Manufacturing methods that rely on creating a location seat are associated with higher material waste and energy consumption. Gravity die-casting (GDC), which is widely used for piston production, requires thicker walls to accommodate the location seat. These thicker sections contribute to excessive material use, increasing casting weights and longer solidification times. Additionally, GDC operates at higher temperatures than alternative casting methods, resulting in greater energy consumption and higher carbon emissions. A more efficient manufacturing approach should aim to optimize material utilization while reducing energy requirements to support sustainable production practices.
[0007] To address these challenges, there is a need for a more efficient and precise piston manufacturing method that eliminates the requirement for a location seat while maintaining or exceeding the accuracy levels achieved in conventional machining. A machining system that allows direct processing of the piston blank without requiring a predefined reference seat can significantly streamline manufacturing operations. Such a system would rely on advanced alignment techniques that enable precise positioning of the piston blank throughout the machining process, ensuring high accuracy without needing a fixed reference point.
[0008] Eliminating the location seat makes manufacturing pistons with thinner walls, optimized geometries, and improved weight distribution possible. This approach enhances fuel efficiency and engine responsiveness and reduces material costs and machining time. Additionally, casting technologies such as high-pressure die-casting (HPDC) offer improved dimensional accuracy, reducing the need for excessive machining allowances and further contributing to overall process efficiency.
[0009] The present embodiment provides a novel method and system for machining seatless pistons, offering a streamlined and cost-effective alternative to traditional machining processes. By integrating precision alignment techniques and advanced measurement systems, the invention ensures that pistons are machined accurately while eliminating the drawbacks of using a location seat. This advancement represents a significant improvement in piston manufacturing, supporting the development of more efficient, lightweight, and high-performance internal combustion engines.
SUMMARY
[0010] The present embodiment introduces an advanced method and system for manufacturing seatless pistons, eliminating the need for a location seat traditionally used for process referencing. This method ensures superior geometric accuracy, optimized weight distribution, and enhanced fuel efficiency by leveraging high-precision machining techniques, including high-pressure die-casting (HPDC), coordinate measuring machine (CMM) monitoring, and multi-axis CNC machining.
[0011] According to an embodiment of the method, a piston blank undergoes a series of machining operations to achieve the final shape and functional attributes. Rough and fine machining processes like size turning, ring grooving, and head facing are performed to shape the piston and drill necessary oil holes in the G-pin boss to facilitate lubrication. An embodiment includes executing lock pin drill, fitting, pressing for secure component assembly, and performing circlip grooving and bore chamfering to refine its dimensions to meet stringent tolerances. Preferably, advanced techniques such as bore burnishing, oval turning, and ultrasonic cleaning are employed to enhance the piston's surface finish and overall quality. Preferred embodiments integrate real-time monitoring systems, including CMM, to ensure dimensional accuracy is maintained throughout the manufacturing process without needing a location seat.
[0012] Additionally, the use of high-pressure die-casting (HPDC) provides several advantages over conventional gravity die-casting (GDC), such as reduced material waste, improved dimensional accuracy, and lower carbon emissions. The elimination of the location seat not only simplifies the machining process but also reduces the overall weight of the piston, contributing to improved engine efficiency and fuel economy.
[0013] Furthermore, an embodiment includes an automated system for handling pistons between machining stations, ensuring precise positioning and consistency. The entire process is optimized through a control unit that adjusts machining parameters in real time based on feedback from the measuring systems. The use of simulation software further enhances the efficiency of the manufacturing process by optimizing machining strategies before actual production, minimizing errors, and reducing material waste.
[0014] By implementing these advanced techniques, embodiments disclosed offer a highly efficient, cost-effective, and environmentally sustainable alternative to traditional piston manufacturing methods. This innovative approach significantly improves the accuracy, quality, and performance of seatless pistons, making them ideal for modern high-performance engines.

BRIEF DESCRIPTION OF DRAWING
[0015] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope. The disclosure will be described and explained in detail in the accompanying drawings.
[0016] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims after the specification. The foregoing and other aspects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
[0017] FIG. 1 illustrates seatless and conventional pistons with varying skirt heights.
[0018] FIG. 1a illustrates a piston without a location seat
[0019] FIG. 1b illustrates a cross-sectional view of a piston without a location seat with a different skirt height.
[0020] FIG. 1c illustrates a cross-sectional view of a piston with location seat
[0021] FIG. 2 illustrates the differences between conventional pistons with location seats and the new stratified piston / seatless piston design.
[0022] FIG. 2a depicts the stratified piston / seatless piston design.
[0023] FIG. 2b depicts the upside-down view of the stratified piston / seatless piston design
[0024] FIG. 2c depicts conventional piston design.
[0025] FIG. 2d depicts conventional piston design showing the location seat.
[0026] FIG. 3 (3a and 3b) shows the step-by-step machining process flow for producing a seatless piston.
DETAILED DESCRIPTION
[0027] For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Such alterations and further modifications in the illustrated system and such further applications of the principles of the invention as illustrated therein would be contemplated as would usually occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The system, methods, and examples provided herein are illustrative only and are not intended to be limiting.
[0028] The present embodiment will now be described in greater detail with reference to the accompanying drawings, which illustrate exemplary embodiments of the method and system for manufacturing seatless pistons. These drawings are provided for illustrative purposes and should not be interpreted as limiting the scope of the invention.
[0029] FIG. 1 effectively highlights the key structural and functional differences between a conventional piston with a location seat and an optimized seatless piston design. The figure demonstrates how the seatless piston enhances weight efficiency, machining precision, and overall engine performance while simplifying manufacturing.
[0030] FIG. 1 illustrates a comparative view of a conventional piston with a location seat and a seatless piston, as shown in FIG. 1a. The conventional piston includes a location seat, which is a reference point during machining operations such as turning, ring grooving, bore machining, and head facing. While this location seat helps ensure alignment and machining accuracy, it introduces several disadvantages, including increased material usage, added weight, and restricted design flexibility. The additional weight affects engine efficiency by increasing reciprocating mass, while the extra material contributes to higher production costs and machining complexity. A fixed reference seat also limits the ability to optimize piston geometries, particularly in skirt height, weight distribution, and combustion chamber configurations.
[0031] In contrast, the seatless piston, as depicted in FIG. 1a and FIG. 1b eliminates the need for a location seat, offering several advantages. By removing this feature, the piston achieves a significant reduction in weight, which enhances engine efficiency and fuel economy. The absence of a location seat also simplifies the machining process, reducing the number of necessary machining steps and lowering both production time and cost. Additionally, the seatless design allows for greater design flexibility, enabling manufacturers to optimize piston geometry for improved combustion efficiency, durability, and performance. Furthermore, with no need for excess material to form a reference seat, the casting process is more efficient, reducing overall material waste and lowering carbon emissions. FIG. 1 visually highlights these differences, demonstrating how the seatless piston provides a superior alternative to conventional piston designs in terms of weight, cost, and manufacturing efficiency.
[0032] FIG. 2 highlights the structural improvements achieved by eliminating the location seat. The seatless piston is lighter, structurally optimized, and easier to machine, making it ideal for high-performance internal combustion engines. The figure clearly demonstrates how removing the location seat enhances piston efficiency, reduces machining steps, and contributes to material savings.
[0033] FIG. 2 provides a detailed structural comparison between a conventional piston and a Stratified/seatless piston, emphasizing the differences in weight distribution, wall thickness, and overall dimensions. As shown in FIG. 2c and FIG. 2d, the conventional piston design requires extra material to support the location seat, leading to thicker walls and increased mass. Additionally, the overall length of the piston is more significant, which increases inertia and negatively impacts engine dynamics. The need for a location seat also makes bore machining more complex, as alignment constraints must be managed throughout the machining process.
[0034] In contrast, the stratified/seatless piston structure in FIG. 2a and FIG. 2b demonstrates a more optimized design with thinner walls and reduced overall mass. The absence of a location seat allows for a shorter piston skirt, reducing reciprocating weight and improving engine performance. Direct bore machining without relying on a fixed reference simplifies the manufacturing process while maintaining high precision. By eliminating unnecessary material, the seatless piston contributes to more efficient machining, lower production costs, and a more environmentally sustainable manufacturing process. FIG. 2 visually represents these benefits, showcasing how the seatless piston design enhances efficiency, machining accuracy, and structural optimization compared to traditional piston manufacturing methods.
[0035] FIG. 3 (FIG.3a & b) illustrates a step-by-step machining process flowchart for manufacturing a seatless piston, detailing the sequential operations involved in achieving a high-precision piston without using a location seat as a reference. The process begins with Step 302, providing a piston blank, which is typically produced using high-pressure die-casting (HPDC). This casting method ensures minimal machining allowances, reduces material waste, and improves the dimensional accuracy of the raw piston blank.
[0036] According to an embodiment, once the piston blank is prepared, the machining sequence starts with rough turning 304, which removes excess material to establish the preliminary piston shape. The process continues with next step 306, size turning, ring grooving, and head facing, where the outer diameter (OD) is machined, grooves for piston rings are cut, and the piston crown is faced to achieve the desired profile. Following this, in step 308, oil hole drilling in the G-pin boss is performed to ensure adequate lubrication, which is critical for minimizing friction and wear during engine operation.
[0037] According to an embodiment, the next step 310, involves rough and fine machining of the Gudgeon pin (GP) bore, ensuring high accuracy and proper fitment. The piston then undergoes lock pin drilling, fitting, and pressing in step 312, followed by step 314, where circlip grooving and bore chamfering refine the edges and assembly features to ensure a precise and secure fit during final assembly. These steps contribute to the structural integrity and durability of the piston.
[0038] To further enhance the surface finish and mechanical properties, bore burnishing is performed in step 316. This process improves bore smoothness, reducing friction and increasing wear resistance. Subsequently, in step 318, burr removal is conducted to eliminate sharp edges and machining irregularities, ensuring quality and safety. In step 320, the piston undergoes oval turning, a crucial step in achieving the final piston profile, optimizing weight distribution, and ensuring dimensional precision.
[0039] In the final stages of the process, stamping for identification is carried out in step 322, allowing for traceability and part recognition. In step 324, the piston undergoes ultrasonic cleaning, removing contaminants such as machining residues, oils, and dust to maintain a clean and defect-free surface. In step 326, the final inspection and quality control process utilizes measurement-based positioning techniques, such as coordinate measuring machines (CMM), to verify dimensional accuracy before the piston is approved for assembly or shipment.
[0040] FIG. 3 provides a comprehensive overview of the seatless piston machining method, illustrating how each step is precisely executed to maintain accuracy, efficiency, and consistency. The figure highlights how the absence of a location seat simplifies machining operations, reduces material waste, enhances manufacturing speed, and results in a lightweight, high-performance piston suitable for modern internal combustion engines.
[0041] The present invention relates to a method and system for machining seatless pistons without using a location seat as a reference, thereby improving manufacturing efficiency, weight optimization, and machining precision. The invention eliminates the conventional location seat, which has traditionally been used in piston manufacturing for alignment and positioning during machining operations. By removing the need for a fixed reference seat, the invention allows for a more streamlined, flexible, and cost-effective manufacturing process while maintaining high precision and structural integrity.
[0042] This innovative machining method involves a series of carefully designed precision machining steps that ensure the accurate and efficient production of seatless pistons. The method integrates high-pressure die-casting (HPDC) for blank production, multi-axis CNC machining for turning and finishing, automated positioning techniques for precision alignment, and real-time measurement systems for quality control.
[0043] According to a preferred embodiment, the manufacturing process begins with the provision of a piston blank, which serves as the foundation for all subsequent machining operations as shown in step 302. Unlike conventional methods that require additional material to accommodate a location seat, the present invention utilizes high-pressure die-casting (HPDC) to produce a high-precision piston blank with minimal machining allowances. HPDC is selected over traditional gravity die-casting (GDC) due to its ability to create net-shape components with tighter tolerances, reduced porosity, and superior surface finish. This method significantly reduces the amount of excess material that needs to be removed during machining, leading to greater material efficiency and shorter production times.
[0044] Additionally, HPDC enables the formation of thinner walls in the piston blank, contributing to overall weight reduction without compromising structural integrity. By eliminating unnecessary material associated with the location seat, the piston blank is optimized for enhanced weight distribution and better engine dynamics. Further, the casting process ensures uniform metal flow and consistent mechanical properties, reducing defects and the need for extensive post-casting treatments. The use of HPDC over GDC also results in lower energy consumption, reduced material waste, and lower carbon emissions, making the process more environmentally sustainable.
[0045] According to an embodiment, the dimensional accuracy of the HPDC piston blank is crucial for maintaining tight tolerances during machining. Since the casting is already produced with near-final dimensions, the subsequent machining operations require minimal material removal, ensuring a more efficient and cost-effective process. By using a precisely cast blank, embodiments disclosed eliminate the dependency on a location seat for alignment, replacing it with precision machining and measurement-based positioning techniques to achieve superior accuracy and consistency. Thus, the HPDC piston blank forms the ideal starting point for the advanced seatless piston machining process, ensuring optimized performance, reduced waste, and improved manufacturing efficiency.
[0046] According to an embodiment, once the high-pressure die-cast (HPDC) piston blank is prepared, the machining process begins with rough turning, which is the first step in shaping the piston to its desired form. Rough machining of the piston, step 304 involves the removal of excess casting material to establish the preliminary geometry of the piston, ensuring that it is ready for more precise machining operations. Unlike conventional methods that rely on a location seat for alignment during machining, this process eliminates the need for such a reference, instead employing precision positioning techniques to secure and orient the piston blank accurately.
[0047] A preferred embodiment of the method includes Rough turning that focuses on achieving a uniform outer diameter (OD) while maintaining the structural integrity of the piston. The goal is to minimize machining allowances, ensuring that subsequent fine machining steps require minimal material removal. By removing only the necessary amount of material at this stage, the process reduces tool wear and increases machining efficiency, leading to cost savings and improved production throughput.
[0048] According to an embodiment, following rough turning, the piston undergoes size turning, ring grooving, and head facing to refine its shape further. Size turning helps in establishing the final outer contour of the piston as shown in step 306, ensuring it meets the required dimensional specifications. Ring grooving involves cutting precise grooves into the piston to accommodate piston rings, which are critical for sealing the combustion chamber and ensuring efficient engine performance. Head facing is performed to smooth and level the piston crown, preparing it for subsequent finishing processes.
[0049] Thus, by eliminating the location seat and adopting precision alignment techniques, rough machining is streamlined and optimized, allowing for greater flexibility in piston design and improved weight distribution. The combination of rough turning, size turning, ring grooving, and head facing ensures that the piston is accurately shaped while maintaining structural strength and dimensional consistency, setting the foundation for subsequent high-precision machining operations.
[0050] According to an embodiment, after the rough machining phase, the piston undergoes precision drilling and bore machining to ensure proper lubrication and accurate fitment of the gudgeon pin. These operations are critical for ensuring smooth piston movement, reducing friction, and enhancing overall engine performance.
[0051] A preferred embodiment of the method includes oil hole drilling process mentioned in step 308, which results in creating precisely positioned oil passages in the gudgeon pin (G-pin) boss. These holes facilitate adequate lubrication to minimize wear and friction between the gudgeon pin and the piston during high-speed engine operation. The drilling process must be highly accurate and consistent, as improper placement or misalignment of these oil holes can lead to insufficient lubrication, increased friction, and premature component failure.
[0052] Following oil hole drilling, the gudgeon pin (GP) bore machining step 310 is carried out to achieve high dimensional accuracy for the pin fitment. This step involves two machining phases—rough and fine bore machining:
[0053] According to an embodiment, Rough GP Bore Machining removes excess material from the bore to bring it closer to the final dimensions and ensures that the bore is cylindrical and structurally sound before fine machining. Fine GP Bore Machining involves precision cutting to achieve the final bore diameter with tight tolerances. This ensures that the gudgeon pin fits securely, preventing excess play or misalignment and also provides a smooth surface finish, reducing friction and wear over prolonged engine operation.
[0054] Since this machining step occurs without a location seat, advanced alignment and positioning techniques are employed to ensure consistent bore concentricity and precise hole placement. Eliminating the location seat allows for greater design flexibility, enabling the manufacture of pistons with optimized geometries and weight distributions. With high-precision oil hole drilling and GP bore machining, embodiments disclosed enhance lubrication efficiency, reduce mechanical losses, and ensure the structural integrity of the piston, leading to improved durability and high-performance engine operation.
[0055] According to an embodiment, after the gudgeon pin bore machining is completed, the next crucial step 312 is lock pin drilling, fitting, and pressing in the seatless piston manufacturing process. This operation is essential for securing the gudgeon pin in place, ensuring that it remains firmly positioned during engine operation while preventing any unintended movement or rotation within the bore.
[0056] According to an embodiment, the method includes lock pin drilling, where precise holes are created at predefined locations in the gudgeon pin boss area. These holes serve as receptacles for the lock pins, which act as mechanical retainers for the gudgeon pin. The drilling process must maintain strict alignment and depth accuracy, as any deviation can compromise the structural integrity of the piston or lead to loose pin fixation, potentially causing engine damage over time. Once the holes are drilled, the lock pins are fitted into position. These pins are typically made from hardened steel or other wear-resistant materials to withstand the high-stress conditions inside the engine. The fitting process ensures that the pins are properly seated within the drilled holes, maintaining precise alignment with the gudgeon pin bore.
[0057] Finally, pressing the lock pins into place using a controlled force application is performed. This pressing operation ensures that the pins are firmly embedded within the piston structure, providing long-term stability and preventing any axial displacement of the gudgeon pin during operation. The pressing process is carefully monitored to prevent over-compression, which could lead to deformation of the piston material or affect the functionality of the gudgeon pin assembly.
[0058] The architecture of the embodiments disclosed takes a unique approach once all primary machining features of the seatless piston have been machined, the process advances to the final machining and finishing operations. These steps are essential for achieving precise dimensions, superior surface finish, and optimal performance characteristics necessary for high-performance internal combustion engines.
[0059] According to an embodiment, the initial stage of final machining includes step 314, which involves circlip grooving and bore chamfering. Circlip grooving involves machining precise grooves inside the gudgeon pin bore to accommodate circlips, which securely retain the gudgeon pin within the bore. This step ensures that the pin remains firmly positioned during engine operation, preventing axial movement. Bore chamfering follows, where the edges of the bore are beveled to remove sharp transitions, making assembly easier and reducing the risk of stress concentrations that could lead to material fatigue or cracking.
[0060] Embodiments disclosed include step 316, which is bore burnishing, a surface finishing process that enhances the inner bore’s smoothness and durability. This process is crucial for reducing friction and wear between the gudgeon pin and the bore, extending the lifespan of both components. Bore burnishing involves cold working the bore surface using precision rolling tools, which compact the material and improve surface hardness, reducing the likelihood of premature wear during engine operation.
[0061] Following bore burnishing, step 318, burr removal is conducted to eliminate any sharp edges, machining debris, or excess material that may have formed during previous operations. The removal of burrs ensures a smooth and defect-free surface, preventing any issues during piston assembly and operation. This step is particularly important in maintaining consistent tolerances and ensuring that the piston does not suffer from microfractures or performance inconsistencies due to residual machining imperfections.
[0062] Embodiments disclosed include step 320, oval turning, where the outer profile of the piston is precisely shaped to achieve its final dimensions. Oval turning is crucial in ensuring optimal weight distribution and mechanical balance, which directly impacts engine efficiency, combustion stability, and reduced vibrations. The machining process is highly controlled, ensuring that the piston maintains tight tolerances for skirt shape, clearance, and overall geometry, optimizing its performance for high-speed engine applications.
[0063] Additionally and alternatively, after the completion of final machining and finishing operations, the piston undergoes marking, cleaning, and quality control inspections to ensure that it meets the highest standards of precision, durability, and performance. These final steps are crucial for ensuring traceability, contamination-free assembly, and compliance with dimensional and functional requirements.
[0064] Embodiments disclosed include step 322, which is marking or stamping, where essential identification details are permanently engraved on the piston. This marking process typically includes part numbers, batch codes, manufacturer information, and production dates, allowing for easy traceability throughout the piston’s lifecycle. The stamping ensures that each piston can be tracked back to its production batch, facilitating quality assurance, warranty tracking, and compliance with industry regulations. In an alternate embodiment, marking may be performed using laser engraving, mechanical stamping, or other precision marking techniques, ensuring that the information remains legible and durable even under extreme operating conditions. This step plays a crucial role in ensuring proper inventory management, product verification, and after-sales support in case of performance analysis or recalls.
[0065] A preferred embodiment of the method includes ultrasonic cleaning, step 324, for ensuring a completely contamination-free component before final assembly. During machining, oil residues, metal shavings, fine dust particles, and machining coolants may remain on the piston surface. These contaminants must be thoroughly removed to prevent operational issues, premature wear, or damage to engine components. Ultrasonic cleaning is performed using high-frequency sound waves in a specialized cleaning solution that effectively dislodges even the smallest particles from the piston surface and internal cavities. The process ensures that the ring grooves, gudgeon pin bore, and oil passages are completely free from residual machining debris, allowing for proper lubrication and smooth engine operation.
[0066] Additionally and alternatively, some cleaning processes may include a vacuum drying stage to ensure that no moisture or solvent residues remain on the piston surface, further preventing oxidation or corrosion before the piston is packed or installed.
[0067] According to an additional embodiment, the last step 326, is final inspection and quality control. This process ensures that every piston meets the strict dimensional tolerances, surface finish requirements, and structural integrity standards required for high-performance applications. The final inspection involves advanced measurement and verification techniques, including Coordinate Measuring Machine (CMM) Inspection – Which ensures dimensional accuracy by verifying outer diameter, ring groove depth, gudgeon pin bore alignment, and skirt profile with high-precision scanning. Surface Roughness Testing – Confirms that the bore surface, piston skirt, and ring grooves meet the required smoothness specifications to reduce friction and wear. Weight and Balance Check – Ensures that the piston meets the required weight specifications, optimizing engine balance and efficiency. Visual and Manual Inspection – Performed to detect any scratches, burrs, or other surface defects that could compromise performance. After passing all final quality checks, the piston is either packaged for shipment or directly transferred to assembly lines for integration into an engine.
[0068] The present embodiments offer significant improvements over conventional piston manufacturing methods by eliminating the need for a location seat while maintaining high precision, weight efficiency, and production accuracy. One of the primary advantages is weight reduction, as the removal of the location seat leads to a lighter piston, reducing reciprocating mass and improving engine efficiency and fuel economy. Additionally, the machining process is simplified, as the elimination of the location seat removes unnecessary machining steps, leading to reduced cycle times and lower production costs. By integrating high-pressure die-casting (HPDC) with precision machining techniques, the invention ensures minimal material waste, making the process both cost-effective and environmentally friendly.
[0069] Embodiments disclosed comprise another key advantage, which is the enhanced dimensional accuracy achieved through advanced positioning and measurement-based alignment techniques, which allow for precise machining without relying on a fixed reference seat. This ensures that critical features such as the gudgeon pin bore, ring grooves, and oil holes are manufactured within tight tolerances, improving the structural integrity and durability of the piston. Furthermore, the flexibility in design provided by the seatless piston approach allows for customization of piston geometries, skirt profiles, and weight distributions, enabling better optimization for high-performance internal combustion engines.
[0070] Additionally, the adoption of HPDC in the initial blank production phase further enhances material efficiency, as it results in reduced machining allowances, lower casting defects, and improved surface quality, which directly translate to lower energy consumption and reduced carbon emissions compared to traditional gravity die-casting (GDC) methods. Additionally, surface finishing processes such as bore burnishing, ultrasonic cleaning, and final quality control inspections ensure that each piston meets the highest durability and performance standards before final assembly.
[0071] Thus, by incorporating manufacturing technologies, precision machining techniques, and automated inspection processes, this invention provides a superior alternative to conventional piston machining. The combination of reduced weight, improved efficiency, enhanced accuracy, and increased sustainability makes this seatless piston ideal for next-generation high-performance engines, ultimately contributing to better fuel economy, lower emissions, and enhanced engine longevity.
[0072] Since various possible embodiments might be made of the above invention, and since various changes might be made in the embodiments above set forth, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not to be considered in a limiting sense. Thus, it will be understood by those skilled in the art of metallurgy and materials science, piston manufacturing, and more particularly, methods and apparatuses for the precision machining of pistons without the use of a traditional location seat as a process reference, that although the preferred and alternate embodiments have been shown and described in accordance with the Patent Statutes, the invention is not limited thereto or thereby.
[0073] The figures illustrate the architecture, functionality, and operation of possible implementations of systems according to various embodiments of the present invention. It should also be noted that, in some alternative implementations, the functions noted/illustrated may occur out of the order noted in the figures.
[0074] The terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0075] The present invention and some of its advantages have been described in detail for some embodiments. It should be understood that although the system and process are described with reference to the method and system for machining seatless pistons without location reference, they are highly reconfigurable and may be used in other systems as well. It should also be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. An embodiment of the invention may achieve multiple objectives, but not every embodiment falling within the scope of the attached claims will achieve every objective. Moreover, the scope of the present application is not intended to be limited to the embodiments of the process, machine, manufacture, and composition of matter, means, methods, and steps described in the specification. A person having ordinary skill in the art will readily appreciate from the disclosure of the present invention that processes, machines, manufacture, compositions of matter, means, methods, or steps presently existing or later to be developed are equivalent to and fall within the scope of, what is claimed. Accordingly, the appended claims are intended to include processes, machines, manufacture, and compositions of matter, means, methods, or steps within their scope.
, Claims: CLAIMS

1. A high-pressure die-casting (HPDC) machining method for manufacturing a seatless piston, the method comprising:
machining a piston blank;
removing excess casting material by performing rough turning on the machined piston blank;
shaping the outer diameter OD by performing size turning, ring grooving, and head facing of the machined piston blank;
performing oil hole drilling in the G-pin boss to facilitate lubrication of the machined piston blank;
performing rough and fine GP bore machining to ensure accurate bore dimensions of the machined piston blank;
executing lock pin drilling, fitting, and pressing of the machined piston blank, for secure component assembly;
performing circlip grooving and bore chamfering of the machined piston blank to refine edges;
bore burnishing the machined piston blank to enhance bore surface finish;
removing burrs from the machined piston blank to eliminate sharp edges;
executing oval turning on the machined piston blank to achieve the final piston profile;
performing stamping for identification or branding; and
conducting ultrasonic cleaning for contamination control.
2. The method of claim 1, wherein high-pressure die-casting (HPDC) is used to produce the piston blank, ensuring improved casting quality and higher geometric accuracy.
3. The method of claim 1, wherein the rough turning process is executed with automated tool path adjustments, optimizing material removal rates and reducing machining time.
4. The method of claim 1, wherein the size turning, ring grooving, and head-facing operations are performed in a single machining station, minimizing setup time and improving alignment accuracy.
5. The method of claim 1, wherein the oil hole drilling in the G-pin boss is conducted using a high-speed drilling system with automated depth control, ensuring consistent lubrication channel dimensions.
6. The method of claim 1, wherein the rough and fine GP bore machining is carried out using a precision-controlled boring tool to maintain strict dimensional tolerances and surface finish quality.
7. The method of claim 1, wherein the lock pin drilling, fitting, and pressing process utilizes automated positioning and hydraulic or pneumatic pressing mechanisms to ensure uniform pin insertion and secure fitment.
8. The method of claim 1, wherein the circlip grooving and bore chamfering are performed using specialized carbide cutting tools to achieve uniform groove depth and chamfer angles for optimal assembly compatibility.
9. The method of claim 1, wherein the bore burnishing process is executed using a roller or diamond burnishing tool, improving surface hardness, reducing friction, and enhancing wear resistance.
10. The method of claim 1, wherein the burr removal process includes automated brushing, deburring, or vibratory finishing techniques, ensures a smooth surface free from machining defects.
11. The method of claim 1, wherein the oval turning operation is dynamically adjusted using real-time measurement feedback to achieve optimal weight distribution and precise skirt profiling.
12. The method of claim 1, wherein the stamping for identification or branding is performed using laser engraving or deep etching technology, ensuring permanent and high-contrast markings.
13. The method of claim 1, wherein the ultrasonic cleaning process is followed by a vacuum drying stage to eliminate moisture retention and prevent oxidation before final inspection.
14. The method of claim 1, wherein HPDC casting allows for reduced machining allowances, thereby improving material efficiency and minimizing machining time.
15. A high-pressure die-casting (HPDC) machining system for manufacturing a seatless piston, the system comprising:
a high-pressure die-casting (HPDC) unit configured to machine a piston blank;
a rough turning station for removing excess casting material efficiently;
a size turning, ring grooving, and head-facing unit for shaping the outer diameter (OD) of the machined piston blank;
an oil hole drilling station designed to create lubrication passages in the G-pin boss of the piston blank;
a GP bore machining unit configured for rough and fine machining of the gudgeon pin bore to achieve precise dimensions;
a lock pin drilling, fitting, and pressing unit for secure component assembly within the piston blank;
a circlip grooving and bore chamfering station for refining edges and improving assembly fitment;
a bore burnishing system to enhance bore surface smoothness and wear resistance;
a burr removal mechanism for eliminating sharp edges and ensuring a defect-free surface;
an oval turning system for shaping the piston to its final profile;
a stamping station for engraving identification or branding marks on the piston; and
an ultrasonic cleaning unit for removing machining residues and ensuring contamination-free surfaces.
16. The system of claim 1, wherein the high-pressure die-casting (HPDC) unit is integrated to produce the piston blank, ensures uniform material distribution and reduces casting defects.
17. The system of claim 1, wherein the rough turning station includes a high-speed cutting tool with adaptive feed rate control, optimizing material removal and extending tool life.
18. The system of claim 1, wherein the size turning, ring grooving, and head-facing unit operates to perform in a single machining station, allowing precise machining of complex piston geometries.
19. The system of claim 1, wherein the oil hole drilling in the G-pin boss is conducted using a high-speed drilling system with automated depth control, ensuring consistent lubrication channel dimensions.
20. The system of claim 1, the rough and fine GP bore machining is carried out using a precision-controlled boring tool to maintain strict dimensional tolerances and surface finish quality.
21. The system of claim 1, wherein the lock pin drilling, fitting, and pressing module features an automated alignment system to ensure consistent positioning and uniform pressure application.
22. The system of claim 1, wherein the circlip grooving and bore chamfering station employs real-time feedback sensors to detect and correct deviations in groove depth and chamfer angle.
23. The system of claim 1, wherein the bore burnishing system is configured with adjustable pressure settings, allowing controlled surface enhancement based on piston material composition.
24. The system of claim 1, wherein the burr removal unit includes a robotic arm with precision-guided deburring tools, ensuring defect-free surfaces without manual intervention.
25. The system of claim 1, wherein the oval turning system incorporates a measurement device for continuous in-process monitoring and real-time correction of ovality deviations.
26. The system of claim 1, wherein the stamping module features programmable depth settings, enabling customization of branding and traceability markings.
27. The system of claim 1, wherein the ultrasonic cleaning system uses multi-frequency transducers to optimize contamination removal while preserving fine surface details.
28. The system of claim 1, wherein the HPDC unit and machining stations collectively enable reduced machining allowances, improving material efficiency and minimizing energy consumption.