Automotive stamping service manufacturer China automotive metal stamping with TS16949 quality system2021-08-02T13:22:05+01:00
-Low cost customized production of automotive stamping parts to your satisfaction
Sipxmach is invested by Chongqing Hegao Automotive metal stamping Co., Ltd in 2008. And is proud to offer high quality, cheap price cutting-edge component to a wide range of clients in the automotive field.
Sipxmach have the ability to handle the any size of production and capacity to manufacture sheet metal components with highest standards. It’s no wonder that automotive leaders have trusted sipxmach metal stamping for their sheet metal stampings with their automotive custom stamping parts more than 10 years.
Sipxmach manufactures a wide range of precision metal stamping for the automotive industry – from precious automotive stamping parts to large-gauge steel parts. Sipxmach understands the importance of affordable and durable in making custom auto stamping parts. The expenses you paid for a quality new part will cause less faulty or damaged. We provide you with every production details you want in the stamping proccess for your business.
We produce stamping products, always adhere to the implementation of the three inspection:
First inspection. Before production, check mould and material, check stamping machine and employee safety wear condition.
Production inspection. During production, spot check product quality, pay attention to the safety and stability of the stamping process and health.
Last inspection. At the end of production, check product stacking and transfer, confirm machine power off and cleaning.
Contact us today if you’re in need of automotive stamping services. We’ll work with you directly from start to finish until the job is done to your standard of satisfaction.
Car internal stamping parts. In automotive parts, some parts can be used directly after stamping. Appearance and structure stamping parts. The other part after stamping also need to go through welding, or mechanical processing, or paint and other processes to become a part of the car.
The classification of automotive stamping parts and body structure:
In medium and heavy vehicles, most of the covering parts, such as the body outer plate, and some load-bearing and supporting parts, such as the frame, carriage and other auto parts are stamping parts.
Material selection for automotive stamping parts
Automotive parts production using a large number of cold stamping process. Used in cold stamping steel plate and steel belt is the main steel, account for 72.6% of the vehicle steel consumption of cold stamping material close relation with auto stamping parts production.
The stand or fall of material not only decides the performance of the product, more directly affect the product quality, cost, service life, and the rationality of the design of the production and the difficulty, so reasonable choice material is an important and complex work.
Selection principles of materials:
Can meet the performance requirements of auto parts.
Good physical and chemical properties of materials.
Automotive Stamping Components
Sipxmach Metal Stampings is an expert to manufacturing precision automotive metal stamping parts& engine parts, chassis stamped parts with various metal materials and alloys.
When you choose Sipxmach Metal Stampings for your automotive needs, you will always enjoy:
TOP QUALITY PARTS -When choosing a sheet metal fabrication supplier, first should consider always the stable quality. We are an ISO 9001 and TS16949 certified metal fabricator, and we use uncompromising quality practices in the manufacturing of all our components. Sipxmach Metal Stampings is also ROHS compliant.
SERVICES THAT EXCEED VALUE -You choose us and present your criteria, then few times confirm during automotive stamping parts production. Your goods will reach you efficiently.
We can produce components in all shapes, sizes and forms. We do different sizes and shapes automobile stamping parts from small quantity to batch production. Our presses are from 5T to 800T, we and can use larger presses if the future value of your order can meet our standard.
You can choose the following materials: Hot rolled steel, cold rolled steel, stainless steel, galvanized steel, spring steel, aluminum and copper.
Capable of stamping parts including thicknesses of 0.01 in. to 0.2 in. and tolerances of +/-0.005 in.
Automotive Stamping Capabilities include punching, blanking, embossing, bending, flanging and coining. Low to mass volume production offered. Value added services such as assembly, welding, riveting, plating, coating and heat treatment provided.
COST SAVINGS SOLUTIONS
– Contact our technology department to discuss your project from first step of prototyping samples to batch production about your automobile stamping parts. Saving you money by providing innovative, cost-effective solutions is our responsibility.
We understand that the automotive stamping industry demands strict tolerances, and we have worked to create components for multiple vehicle systems and sub-systems for a wide range of vehicle types together with several internationally renowned automobile and motorcycle brands.
Sipxmach Co.,Ltd is an Trustworthy Automotive Stamping Company
We have served the automotive industry by simplifying the metal stamping parts fabrication. We provide our customers with the information they need in a way that is simple and direct to minimize complications. We suggest the most cost-effective project solution for customers or make some testing for their potential plans before start the project.
Aside from the automotive market, all other metal stamping parts are also available. We are a full-service diversified fabricator of gaskets, seals, tapes, and precision die cuts.
Our comprehensive custom metal stamping services and special designed stamping dies can meet any and all specifications you may have. If you need automotive stamping, contact us our project engineer to learn more about our quality products and services. Now our stamping parts have exported to Germany, American, Holland, Italy, Russian. All our products are 100% completely with ISO9001 or TS16949 quality certification. We are committed to serving you with optimal solution for all your kinds of metal stamping parts from all over the world. No matter your parts need polishing, zinc plating, powder coating, painting or other treatment all are no problem.
Automotive stamping as an important thin sheet metal component forming method, Sipxmach will give you our best and professional suggestion. Contact us we will work with you with free from the start of the project to your final drawing finished, after that we will give our best price for you to decide choose us or our competitor to produce the sheet metal forming parts.
Automobile stamping defect and quality control
Understand the automobile stamping
By applying external force to plate, pipe and profile by press and mold, the material can produce plastic deformation or separation, so as to obtain the designed shape and size.
Plastic processing (or pressure processing) is divided into stamping and forging.
Car trunk structural parts
Structural reinforcement for car
Automotive stamping parts according to the quality grade, divided into:
Exterior parts. Fine stamping parts requiring coating or polishing and painting
Internal parts. Internal structural parts are the main, not directly exposed to the air. The main requirement is high performance stamping parts
Quality control of automobile stamping
“3S inspection” of automobile stamping parts:
Self-inspection In the process of production, the operator himself completes the quality inspection of the products in this process
Substitute inspection The operator checks the finished quality of the product from the previous process, and whether it meets the processing quality requirements of his own process
Special inspection Full-time inspectors check whether the quality of materials meets the processing requirements, and at the same time check the quality characteristics of any process in the whole process
Common defects in automobile stamping
Automotive stamping parts’ defect level
A defect 1
A defect 2
1. Defective parts that can’t be accepted by customers, whose shape or size exceed the tolerance range. Finally scrap the parts.
Internal injury. Visually, the material becomes thinner, less than 70% of the material thickness. Usually, the old staff can easily judge the material thickness according to their experience.
Cracking. Visually, a cracking point or fault zone is found.
3. Cause Internal injury is common in R Angle, due to stretch denaturation and thinning, resulting in internal injury. In severe cases, cracking occurs. Hidden damage and cracking will reduce the strength of the stamping parts.
4. Preventive measures Maintain mould regularly, keep mould and product clean and lubricate.
B defect 1
B defect 2
1. A surface defect that can be seen or felt. Need rework.
Material Plate or mold surface dirty, after blanking burr, etc.
Equipment The suction cup of the servo machine is dirty and the table of the press machine is sundry.
3. Preventive measures Keep clean
C defect 1
C defect 2
1. Can not directly see, but by the method such as oil stone can found the surface concave and convex point or burr. Should better be corrected.
2. Judge Apply oil or oil stone to determine the severity of surface defects. Hemp point ≤5, burr ≤1.5mm.
Material in processing is not clean
The production environment is dusty and sandy
Mold tool edge wear
4. Preventive measures
Strengthen mold and material cleaning and maintenance work, record and analyze the problems
Inspect and clean equipment before use
You can create a closed job environment
Maintain tool edge according to frequency
What is Automotive Stamping Quality Control
The automotive industry is one of the largest industries that require an efficient car body stamping process. The automotive stamping companies require complex processes and also make use of complex body stamping equipment. This complex technology has completely changed the manufacturing process of vehicles. Therefore, cars are produced at a faster rate, which is while automotive stamping companies continually seek to balance the high demands with quality and innovation. In the increasing automotive metal stamping companies, manufacturers of precision metal stamping tools must be able to produce and deliver parts with zero defects and comply with the changing industry standards. Due to the high competition in the automotive stamping industry, automobile companies have continually emphasized the need to put quality in place in all aspects of production and service delivery. This, therefore, births the importance of quality management in the automotive metal stamping industry.
One of the processes in automobile production requires body stamping. The metal body stamping process involves the use of dies and punches, shape or bend sheet metal parts. The car body stamping processes often used in the automotive industry include bending, blanking, embossing, coining, punching, etc. For all these processes, quality has to be put in place. Quality among automotive metal stamping companies is now an effective strategy to remain competitive. The quality in which automobile manufacturers produce and deliver services is important to remain competitive in the industry.
1.2, The Basic Concept of Automotive Quality Management Information
Total quality management in automotive stamping companies refers to the culture, attitude, and organization that a company strives to produce high-quality products and services that meet customers’ expectations. Originating in the 1950s, its popularity has increased since the 1980s, and its quality management concepts have been used by automotive companies such as Ford Motor Companies, General Motor Companies, Toyota Motor Company, etc. Total quality management involves customer focus, continuous improvement, use of quality tools, product design, supply quality, etc.
Customer focus- This is the first and most important concept in quality management. The quality of any product is reduced if it does not meet customers’ needs. The customer focus the concept also means that clients’ needs must be met and exceeded. But first, a company has to decide what those needs are. Within the automotive industry, quality must satisfy and overcome client’s expectations. The purpose is to identify that the client’s needs are met. Total quality management admits that a perfectly built product has no value if it does not meet the client’s expectations. This is why it is said that the quality level is granted by customers. In any case, it is not easy to determine what the client wants, because the taste and preferences change. Also, a client’s expectation varies from one client to another. For example in the automotive industry, the preference changes fast, from small cars to four-wheel-drive vehicles and then back to small cars. The automotive stamping companies must gather information through market studies, research groups, and client meetings. In the automotive industry, the benefits of applying this principle are the following:
Increased revenues and market quotas obtained through flexibility and a quick answer related to the market opportunities.
Increased effectiveness regarding the use of the organization resources in order to increase client’s satisfaction.
The improvement of the client’s loyalty degree results in continuous business interactions.
The practical application of this process will lead to:
Researching and comprehending clients’ needs and expectations.
Ensuring that the organization’s objectives are correlated with clients’ needs and expectations.
Communicating the needs and expectations within the organization.
Measuring the clients’ satisfaction and acting according to the results obtained.
The systematic management of the relation with the clients.
Continuous improvement- Automobile manufacturers understand that customer’s expectations are always changing and typically rising as quality management begins to yield results. It is important to remember that when customers are assessing quality, they are not simply comparing the products and services to the previous year but to other companies serving their needs. Total quality management is mainly concerned with improvement in all work, from high-level strategic planning and decision-making to detailed execution of work elements on the shop floor. It also stems from the belief that mistakes can be avoided and defects can be prevented. It leads to continuously improving results, in all aspects of production, as well as continuously improving capabilities, people, process, technology, and machine capabilities. Continuous improvement does not only deal with improving results but more importantly with improving capabilities to produce better results in the future.
One of the approaches that automobile manufacturers use for continuous improvement; the plan-do-study-act (PDSA) cycle and describes the activities a company needs to perform in order to incorporate continuous improvement in its operation. The circular nature of this cycle shows that continuous improvement does not end. The first step in the PDSA cycle is to plan. Manufacturers must evaluate the current process and make plans. Automobile manufacturers must evaluate the current process and make plans based on what they find. They must document all procedures, collect data, and identify problems. This information should then be studied and used to develop an improvement plan and specific measures to improve performance.
Do the next step in the cycle is implementing the plan. During the implementation process, automobile manufacturers should document all changes made and collect data for evaluation. Study, the third step involves studying the data collected in the previous phase. The data are evaluated to see whether the plan is achieving the production goals established in the planning phase. Act, the last step in the cycle is to act on the basis of the results of the first three phases. The best way to achieve this is to communicate the results to other members of the company and then implement the procedure if it has been successful. Manufacturers should note that this is a cycle, the next step is to plan again. The main benefits of applying this principle in the automobile industry are:
The alignment of the improved activities at all levels, with the strategic intentions of the organization.
The flexibility to react rapidly at the occurrence of the opportunities.
The application principles will lead to:
The existence of a continuous performance improvement.
The assurance of adequate training on the use of tools and equipment for continuous improvement.
The establishment of specific objectives that is able to guide the continuous improvement and of certain actions that are able to provide performance improvement follow up.
Employee empowerment– Employee involvement evolved out of the business’s need to improve performance. The impact of human resources in the automotive company depends on the empowerment given to them. In total quality management, the role of workers is different from what it was in the traditional system. Workers are empowered to make decisions relative to quality in the production process. They are considered a vital element of the effort to achieve high quality. Their contributions are highly valued and their suggestions are implemented. In order to perform this function, workers are given continual and extensive training in quality measurement tools.
Product design– Providing a design that meets customer’s needs is a critical element in building a quality product. Unfortunately, this can be more difficult than it sounds because most customers provide general descriptions, such as “safe”, “tough”, or “sleek”. The automobile manufacturers must translate these generalizations into specific technical requirements. A useful tool for translating the voice of the customers into specific technical requirements is quality function deployment. Quality function deployment is also useful in enhancing between different functions such as marketing, operations and engineering. Quality function requirements begin by identifying important customer requirements which typically come from the marketing department. These requirements are basically scored based on their importance and scores are translated into product characteristics. Evaluations are made of how the product compares with its main competitors relative to the identified characteristics. Finally, specific goals are set to address the identified problems Quality Function Deployment (QFD) enables automobile companies to view the relationships among the variables involved in the design of a product, such as technical versus customer requirements. This can help automobile manufacturing companies analyze the big picture—for example, by running tests to see how changes in certain technical requirements of the product affect customer requirements. An example is an automobile manufacturer evaluating how changes in materials affect customer safety requirements. This type of analysis can be very beneficial in developing a product design that meets customer needs, yet does not create unnecessary technical requirements for production. The three important production system objectives are productivity, flexibility and quality. In traditional production system design, the sole objective was productivity in terms of cost-per-unit or workers-hours-per-unit. Recently, the value of flexibility has been recognized and often takes an explicit role in production system design.
Process management- According to total quality management, a quality product comes from a quality process. This means that quality should be built into the process. Quality at the source believe that it is far better to uncover the source of quality problems and correct it than to discard defective items after production. If the source of the problem is not corrected, the problem will continue. Quality at the source exemplifies the difference between the old and the new concepts of quality. The old concept focused on inspecting products after they were produced or after a particular stage of production. If an inspection revealed defects, the defective products were either discarded or sent back for reworking. All these cost the automobile company money, and these costs were passed on to the customers. The new concept of quality focuses on identifying quality problems at the source and correcting them.
Manage supply quality- Most total quality management does not involve the company alone but extends to the outside supplier. Suppliers who meet the automotive company’s needs help the company meet their customer’s needs. In many cases, as long as suppliers meet preset quality standards, materials are accepted without inspection, which helps to speed up the overall production process. Therefore, total quality management does not only involve the products and service quality but the systems and processes put in place to achieve them, as well as consistency in the product and service delivery. The main benefits of managing supply quality include:
Increased ability to create value for both parties.
Flexibility and speed of the common answer to the market changes or the clients’ needs and expectations modification.
The optimization of cost and resources.
The application of this principle will lead to:
The establishment of relations able to balance the short term profits with the long term considerations.
The use of expertise and resources together with the partners.
The identification and selection of the key suppliers
The establishment of common development actions and of certain improvement activities.
The suggestion, encouragement and recognition of suppliers’ improvements and accomplishments.
The total quality management process has four main components: quality planning, quality control, quality assurance and quality improvement. The quality management process involves knowledge, skills, techniques, tools, and systems that define, visualize, measure, control and report the processes.
Quality information from customers is an important measure in quality decision making, quality planning, and quality control. An automotive manufacturing industry’s quality information influences the process of quality formation and quality assurance. In an automobile company, manufacturing management of the process quality information is an important link to quality control. It is important that defects and deviations are discovered early to ensure that quality control is carried out effectively. The quality in manufacturing engineering refers to the manufacturing process quality and the design requirement through the production process. The product involves the workers, technology, equipment, raw materials, test method and the environment. From these, the main manufacturing engineering qualities reflect product quality. The manufacturing process has six quality processes: The man (man), machine and equipment (machine), raw materials (material), processes, detecting methods (methods), and environment (milieu). These factors can be classified into 5M 1P. Managing quality involves controlling all the factors. All these must be present to ensure customer satisfaction.
Chapter 2: Automotive Stamping Process in Automotive Industries
The recent competition in the automotive stamping companies has led to high demands in productivity improvements at the same time, reducing the cost of productions. Automobile manufacturers are changing their strategy of operation. Manufacturers no longer adopt the ‘simple washer attached to a complicated fender, all in-plant stamping facility’. Car manufacturers now produce a large number of automotive stamping parts on their own. Automotive companies produce approximately 50 critical panels per model of a car in-house, which would require about 150 dies. The criteria for the panels to be manufactured in-house differ from company to company. The stamping plants of the automobile manufacturers produced in house are the following:
External panels such as fenders, bonnet, decklid, roof, side panels, doors. Some of these panels are sets for the left and right sides of an automobile.
Internal mating panels such as bonnet inners, decklid inner, or deck inner deciding subassembly quality.
Dimensionally critical inner panels are complicated either because of their complex shape or severe draw conditions. They include floor pans, dash panels, etc.
Automobile manufacturers prefer to procure medium and small size panels from specialized external suppliers depending on their availability and capability to meet specific requirements. Some automobile companies prefer specialized companies to produce and supply each part. This then makes them focus on assembly operations, leaving out specific technology relating to manufacturing, such as machining and pressing to a separate supplier or company.
Metal stamping processes continue to develop and improve with new technology. Not only does the manufacturing process benefit from increased end-to-end automation, but the stamping machinery is also becoming more advanced. One popular advancement is the use of electromagnetic tools. These devices can better interact with sheet metal by using electromagnetic forces to precise position the sheet metal. Electromagnetically assisted tools can both make more intricate, complex forms and reduce material waste by narrowing the margin between stamps.
There are three popular types of metal stamping presses used for automotive and other industrial parts. They include:
Mechanical presses, which have a mechanical flywheel powered by a motor.
Hydraulic pressures, which have pressurized fluids that control the pressure and application of force on a work piece.
Mechanical servo presses, which use only motors and no mechanical flywheels.
All three press types can work with automated systems, such as automatic feeders, to increase efficiency and production speed.
Automatic feeders send coiled or blank sheet metal through the presses to create a fast run.
Metal stamping presses and dies can work with many different metals to create diverse parts.
Some of the most commonly used metals in stamped automotive parts include aluminum, copper, and steel. Each metal has unique attributes that make it ideal for certain applications.
Aluminum: Manufacturers use aluminum for visible parts and details because of its attractive appearance and lightweight. Automotive metal stamping companies can also easily form alloys with aluminum and other metals to make stronger or more durable varieties.
Copper: This metal resists corrosion, is ductile, has an attractive finish, and is affordable. Automotive stamping companies can also choose copper for environmentally conscious customers; the metal is easy to recycle and reuse.
Stainless Steel: This metal resists corrosion and rust because it has a makeup of at least 11% chromium. Not only does it have increased durability, but it also has a lustrous, attractive surface.
Steel and Steel Alloys: Steel alloys come in many different varieties, such as mild steel, high-strength steel, and specialized steel that can be used to create a variety of durable parts.
The materials used for car panels must have certain characteristics in order to meet up several industry challenges. Such challenges include rationalization of specifications for learner inventory, improved formability for reduced rejection rate and better quality. Higher Strength Low Alloy Steels of thinner gauges are getting preference for weight reduction and the resulting better fuel economy. Other quality characteristics under demand are higher yield stress (strength), toughness, fatigue strength, improved dent resistance as well as corrosion resistance in materials used for body panels for improved durability and reliability.
In order to achieve high-quality automotive body panels without failures during stamping, the strip steel must be ductile. The numerical values of the strain hardening exponent (n-value), the plastic anisotropy (r-value), and the forming limit diagrams for the sheet steels provide the index of formability of the panels. Strain hardening to some extent improves dent resistance. Strain gradients in pressings are not to be unduly severe causing splitting and other related problems. To maintain the shape after the forming operation, minimal ‘spring back’ and high ‘shape fix abilities are also essential. As the panels are welded to shape the body structure with various arc/resistance welding operations, the weld ability of the materials in use is very important. Finally, the specific roughness levels (textures) of the steel used for skin panels must be consistent and reproducible. Most of the steels used in car body stamping applications are aluminum-killed steels of about 0.7 to 0.9 mm thickness.
The stamping of sheet metals can be described as the process of changing the shape of the sheet metal blank into a useful shape in the plastic deformation state, using a die and a mechanical press.
The car body stamping process commonly used in the automotive industry include blanking, drawing, piercing, forming, notching, trimming, hemming, etc. Blanking prepares the initial approximate form of the part in a flat sheet. Drawing is usually the first process carried out to attain desired depth-related form. Piercing, notching, hemming, are the processes that involve the product design related specific applications.
The trimming removes the extra material on the periphery of the panel provided for blank holding during the drawing process. The decision on trim line is very important and becomes deciding factor to obtain a good draw.
The purpose of this metal stamping process is to be able to produce formations of any shape and size desired out of the metal sheet. The stamping process is common with the automotive industry because each car is made up of many parts made from steel. Examples of car parts made with this process are the outer car panels like hoods and fenders. In an automobile manufacturing process, about 60% to 70% of the metal parts are processed by plastic forming.
Blanking uses dies that are specific to the automobile part that needs to be produced. It is necessary that the shape of the panel has the same part design. The blanking line is able to produce about 60 pieces in a minute. Rectangular, trapezoidal, or curved shape blanks can be created with some panels and can be produced by shearing machines. Oscillating shear is used for flexibility in blank preparation, it has a stroke rate of 100 per minute. This means that a single shearing line can be used for several press lines. A blanking line includes coil handling, decoiler, flattener, feeder, blanking press, and stacker for blanks.
As the batch size gradually reduces, the coil may be withdrawn before it can be used.
Tailored blanks basically refer to welding different blanks together to form complex panels. Different joining processes such as laser welding, spot welding, or mesh-seam welding are used to form tailored blanks. These processes save materials and achieve better material strength. Two or more pieces of the same and different materials are welded into a single blank before automotive stamping parts. The use of expensive materials that are stronger, thicker or coated stock can be reduced with the use of tailored blanks. Separate stamping of more expensive materials followed by welding would mean multiple dies, multiple operations, assemble and checking fixtures.
A combination of different thick or thin strengths results in weight reduction. For instance, in the stamping of a motor compartment rail, the original plan was to manufacture about 2mm thick stock across the length. After a finite element analysis, it was decided to use two blanks that have 0.8mm front part rail and the rest at 2mm. It resulted in unit blanks weight saving up to 3.4kg in galvanized steel and 1.3kg in vehicle weight with no loss of rigidity and safety aspects. Splitting the complicated panel into more than one piece would result in a better yield from the coil stock. With the addition of laser welding of the two halves before stamping, it saves over a million mass-produced panels for an automobile manufacturer. In a door inner, the 0.81mm and 1.83mm thick galvanized pieces meant there is no need for a hinge and mirror reinforcement. Also, the need for fourteen dies, weld fixtures and check fixtures were also eliminated. Tailored blanks automatically cut down the tolerance stack and improve a car’s dimensional accuracy. A conventional door inner’s assembly accuracy covers a tolerance in the thickness of steel and tolerances associated with stamping, piercing, and spot welding reinforcements. When there are no reinforcements, accuracy is improved. With laser welding of blanks, the dimensional variation of hole location in the door panels was reduced from +/- 0.5 to +/- 0. 075mm. For the body side panels of the Toyota model of cars, 5 straight-cut pieces of mild and high strength low alloy galvanised steel were laser welded. The material yield was reduced from 65% to 40%, the number of dies required was reduced from 20 to 4. Apart from saving materials, tailored blanks have additional advantages such as reinforcement elimination, weight saving, and aesthetics. In preparing a tailored blank, laser welding blanks provide three distinct three advantages:
The narrow weld seam on galvanized sheet enables corrosion resistance throughout the heat-affected zone.
Ductility is greater compared to other welding processes.
A laser weld seam is stronger than the base material. The joint between the blanks appear smooth and reduces the chance of die wear in the forming process.
It is important that automobile manufacturers note that the tailor blanks demand stricter control of the edge quality, butt-joint pressure and other laser welding parameters, such as the welding power, speed, depth of focus, beam alignment, etc.
Mesh sheet welding is another process used to prepare tailored blanks. It is a form of resistance welding where blank sheet metals are overlapped slightly, driven between two electrode wheels under pressure, welded by electric current. As the overlapping blank sheets may vary in thickness, planishing wheels usually follow the welded electrodes to cold work the welded joint to less than 10% of the original thickness. The mesh seam welding is used for longish panels.
Automobile manufacturers have accepted scrap levels of 40% or more as standards for the technical requirements for blank holding stock in a draw operation. Tailored blanks have contributed to the growth of the cost-conscious automotive industry.
Deep drawing is one most commonly used metal forming techniques in an automotive metal stamping company. The drawing of automobile panels is also a demanding process. The deep drawing process begins by placing a flat sheet metal on a forming die. The sheet metal is then held in place via a compressive force exerted by a blank holder, which controls the sliding of the sheet metal during the drawing process. The punching tool then moves down to the workpiece, causing it to deform. The metal flows into the die cavity to create the final shape, which is typically hollow and open on one side. The term “deep drawing” refers to shapes produced by this method, as they often have depths that exceed their diameter. The ‘quick approach- quick return’ motion curve of the outer slide ensures better productivity.
The blank holder clamps the blank between the draw ring and the hold-down unit and is decisive for the quality of the draw. If the hold-down force is too low, the blank will develop wrinkles in the flange of the drawn parts.
Due to the punching nature of the drawing tool, deep drawing is best suited for hollow cylindrical or box-shaped objects. Shapes with straight, tapered, or curved sides can be produced, based on the type of punching tool.
The versatility of the deep drawing process can be utilized to create products ranging from everyday household items such as aluminum cans, kitchen sinks, and baking pans, to industrial components such as fire extinguishers, automotive parts, and plumbing fixtures.
This forming method is used in any application that requires the mass manufacture of metal products with hollow axisymmetric geometries.
The automotive industry is well known for its heavy reliance on deep drawn stamping services to create various automobile parts and components.
This industry maintains a constant demand for components that are high-strength and leak-resistant.
Deep drawn automotive components benefit from strain hardening during the moulding process, and as such, are ideal for automotive uses. Strain hardening increases the strength properties of the metal, which makes it more durable in harsh automotive applications.
Also, since deep drawn parts are created from a single sheet of metal, the final component contains no seams, which can be susceptible to leaks.
Some common deep-drawn auto parts include exhaust mufflers, engine mounts, body mounts, jounce bumpers, pins and connectors.
Stretch forming is a metal forming process that simultaneously stretches and bends a selected material over a machined form, called a die, to form a part with one or several different curve radii. This process produces perfectly curved parts with smooth, wrinkle-free contours.
Metals have a fundamental mechanical property called elasticity: their ability to return to their original size and shape after being stretched by an applied load, but only up to a limit. If a sufficient load is applied, the material reaches its elastic limit or yield point, where it will permanently deform. Elasticity and yield point properties are different for each material. These properties are essential factors to consider when stretch forming.
Like a rubber band, when a metal part is stretched, but the yield point is not exceeded, it will return to its original length when the pulling load is released. If sufficient force is applied to exceed the yield point, the part will be permanently lengthened or formed to the desired curve if formed over a die. This loaded state where the tension applied exceeds the yield point but does not break the part is a semi-plastic loading zone where stretch forming occurs.
There are two basic types of stretch forming equipment: longitudinal and transverse. Longitudinal equipment stretches the work piece along its length. Transverse equipment stretches the work piece along its width.
Stretch forming used in automotive panels provides advantages such as 15 to 20% of the smaller blank size and elimination of turnover after the draw. For example, in hood stamping, little stretching occurs in the corners. During stretch forming, measurable deformation occurs over the entire material surface.
In an automobile manufacturing process, about 60% to 70% of metal parts are processed by plastic forming. The metal forming process is used to form various car body panels, car part support, engine exhaust pipe and muffler, hollow camshaft, oil pan, engine cradles, frameworks, structures horizontal beam, etc.
Chapter 3: Quality Information Flow of Automotive Stamping Workshop
As an automobile manufacturer, your goal is to achieve the quality that can be defined, verified and reproduced again and again.
According to ISO 9000:2015 section 3.6.2, quality is “the degree to which a set of inherent characteristics of an object fulfills requirements.”
In the manufacture of automobile parts, the purpose of quality control (QC) is to not only prevent defects but also ensure that the parts are made to design specifications and will function properly.
A good quality control program also helps to keep manufacturing on time and on budget. It also helps to avoid product safety and reliability issues that can add to costs, result in product recalls, or cause problems that pose risks to users or consumers.
In a stamping workshop, there are two quality information processes, they are internal and external quality information. These internal and external quality information flows of a stamping workshop established in the basis for understanding the stamping workshop, specific work process, the existing quality control mode, specific work process, the existing quality control mode, and the grade of stamping workshop quality information.
3.1, The External Quality Information Flow of the Stamping Process
In the external quality information flow, the first link of the workshop is the suppliers, body workshop, assembly workshop, the quality department, and manufacturing. Each department has different information and interaction.
The quality information of the sheet metal is the major information interaction between the stamping workshop and the suppliers. Suppliers provide quality information on sheet metals to the stamping workshop for a smooth production process. However, at the stamping stage, if the information is not clearly stated, the inspection section will return the material to suppliers.
The metals sheets that pass through the inspection section will be sent to the manufacturing or the stamping section to make stamping pieces. The quality department has a Standard Inspection Process (SIP) that confirms the sheet metal quality in the last section of the stamping workshop. This section examines stamping parts before they are stored in the warehouse for further processing. If quality defects are found, the sheet metals are either returned or repair carried out. If the products do not pass from 3*2 inspections, it results in wastage. The products that pass the SIP inspection will be kept in the warehouse.
3.2, The Internal Quality Information Flow of the Stamping Process
The internal process of the stamping, workshops involve opening the materials, deep drawing, scrap edge, punching and reshaping processes. The product from the stamping workshop needs to pass through workshop inspection and confirm with SIP materials that pass through the inspection and pass the quality inspection is sent to the welding workshop, the unqualified materials are repaired and rechecked until they are qualified.
The materials will be opened at the opening material section to check for defects. Each batch is then measured in terms of material aspect ratio and size thickness. The measurements and results are filled in plate quality record cards. Workers at the punching production line will check the workshop equipment and record the information in the Total Productive Maintenance (TPM) inspection table.
In the stamping workshop, all quality activities the workers’ responsibilities involve checking information and repairing them as the case may be. All this information are managed in the internal workshop, the SIP checks the information sent by the workshop and quality department. The TPM examination information shared by the workshop and the manufacturing department. The plate quality information shared by the supplier and the workshop.
Chapter 4: Stamping Workshop Information
4.1, Stamping Workshop Information Classification
According to the basis of internal and external information flow in an automotive stamping workshop, all quality information on the automotive stamping company workshop such as the internal checks, external quality problems, the quality of the stamping plant alarm upgrade process and other relevant quality information can be classified below:
4.2, Quality Inspection in the Stamping Workshop
The automotive production line workers check the first and last pieces of the materials. All materials are checked within one minute to form a one-minute inspection record. When one-minute check information passes, the inspectors of the material section check each part of the packaging material is observed, the plate surface is observed for defects. After that, they measure the length, width, and thickness of each batch of a sequential stack of materials above the first thing to fill in the results sheet quality record of the card. When the plate quality information passes the production line process, the quality inspector checks the stamping plant equipment per shift, and fill in the TPM checklist. The last framed staff of the production line put the failed pieces into a box and then fills out a substandard product identification card to pass the non-conforming product.
4.3, The Information Generated by the External Quality Problems
The stamping plant SIP station checks the quality problems related to the stamping plant, that is, the Global Customer Audit (GCA) is reviewed as well as the stamping problem found in other workshops. The workshop engineer will give feedback to the corresponding section of the stamping plant in the card of quality information or the form of Product Category Rules (PCR) which clearly states the information of quality problem.
4.4, Other Relevant Quality Information
The manufacturing engineers analyze the operation of the plant quality objectives from the daily, weekly and monthly reports. They then make the quality cost for each report. The unqualified materials pass to the change point to check their properties and then make the lists of the tracking change point. Process management is carried out through the technical measure notice.
Chapter 5: Conclusion
In any automobile metal stamping company, the manufacturing process quality information management is an important link of the quality control in the process. It is an important role for the detect defects and deviations early in process of manufacturing, this ensures the process quality control is carried out effectively. The quality of manufacturing engineering refers to the manufacturing process quality, it points to the design requirements, through the production process manufacturing and actually reaching physical quality, is the realization of the design quality. The operation of the quality as a whole process requires the close cooperation of various departments in an automobile plant. Secure sharing of information can make the relevant departments obtain the required information in the shortest time, under the premise of doing the work of the department. The information provided by the initial production phase will greatly improve the quality of corporate governance in all aspects and product quality, accelerate the development of the automobile company and enhance the competitiveness of the automobile company.