Stamping die is a special process equipment for processing materials (metal or non-metal) into parts (or semi-finished products) in cold stamping processing, called cold stamping die (commonly known as cold stamping die). Stamping is a pressure processing method that uses a mold installed on a press to apply pressure to the material at room temperature to cause separation or plastic deformation to obtain the required parts.
PTJ specialist in design various types of progressive die, compound die, deep drawn die, spinning die, die for high speed precision stamping, which are used in automotive, household appliance, electronics, motorcycle, architecture, lighting, E-Bike, furniture, etc, always exceed customers’ requirement both on surface and functionality. Our engineers will involved in parts design from the stage of development if invited by customers, they offer their valued suggestions and concerns how to realize the part more economically but in stability.
The Classification Of Stamping Dies
According to the nature of the process
- – Punching die A die that separates the material along a closed or released outline. Such as blanking die, punching die, cutting die, slitting die, trimming die, cutting die, etc.
- – Bending mold A mold for bending and deforming a blank or other blank along a straight line (bending line) to obtain a workpiece with a certain angle and shape.
- – Deep drawing die is a die for making a blank sheet into an open hollow part, or to make the hollow part further change its shape and size.
- – Forming mold is a mold that directly replicates the blank or semi-finished workpiece according to the shape of the convex and concave molds, and the material itself only generates local plastic deformation. Such as bulging molds, necking molds, flaring molds, undulating forming molds, flanging molds, shaping molds, etc.
Classification according to the degree of process combination
- – Compound mold There is only one station. In one stroke of the press, two or more stamping processes can be completed on the same station at the same time.
- – Progressive die (also called continuous die) In the feeding direction of the blank, there are two or more stations. In one stroke of the press, two or two passes are completed successively on different stations. Die for the above stamping process.
- – The transfer mold combines the characteristics of single-process mold and progressive mold. The robot transfer system is used to realize the rapid transfer of products in the mold, which can greatly improve the production efficiency of the product, reduce the production cost of the product, save the cost of the material, and at the same time, the quality is stable. reliable.
Classified according to the processing method of the product
According to different product processing methods, molds can be divided into five categories: punching and shearing molds, bending molds, drawing molds, forming molds and compression molds.
- – Punching and shearing die: The work is done by shearing. Commonly used forms are shearing die, blanking die, punching die, trimming die, edge punching die, punching die and punching die.
- – Drawing mold: Drawing mold is to make flat blank into seamless container with bottom.
- – Forming die: refers to the use of various local deformation methods to change the shape of the blank. Its forms include convex forming die, curling edge forming die, necking forming die, hole flange forming die, and round edge forming die.
- – Compression mold: It uses strong pressure to make the metal blank flow and deform and become the required shape. Its types include extrusion die, embossing die, imprinting die, and end pressure die.
the first sort
Process parts, which directly participate in the completion of the process and have direct contact with the blank, including working parts, positioning parts, unloading and pressing parts, etc.;
The progress of advanced mold manufacturing technology is mainly reflected in:
General milling processing adopts low feed rate and large cutting parameters, while high-speed milling processing adopts high feed rate and small cutting parameters. High-speed milling processing has the following characteristics regarding general milling processing:
High precision. The machining precision of high-speed milling is the same as 10μm, and some precision is even higher.
In view of the above advantages of high-speed machining, high-speed machining is being widely used in mold manufacturing, and is gradually replacing part of grinding and electrical machining.
- – EDM machining
- – Slow wire cutting technology
- – Grinding and polishing processing technology
- – CNC measurement
The complexity of the product structure will inevitably lead to the complexity of the shape of the mold parts. Traditional geometric inspection methods can no longer adapt to the production of molds. Modern mold manufacturing has widely used three-coordinate numerical control measuring machines to measure the geometric quantities of mold parts, and the detection methods of mold processing have also made great progress. In addition to the high-precision measurement of complex surface data, the three-coordinate numerical control measuring machine has a good temperature compensation device, reliable anti-vibration and protection ability, strict dust removal measures and simple operation steps, which make on-site automatic detection possible.
The application of advanced mold manufacturing technology has changed the traditional mold-making technology where the quality of molds depends on human factors and is not easy to manipulate, making the quality of molds dependent on physical and chemical factors, the overall level is easy to manipulate, and the ability to reproduce the mold is strong.
In-mold tapping, also known as in-mold tapping, is a new technology that replaces traditional manual tapping. At present, traditional tapping equipment can hardly meet the needs of stamping products, its efficiency is too low, and the processing time is long. It is far from satisfying the market. Needs. The guidance of in-mold tapping technology has made the stamping die truly automated and efficient. The tapping range can reach the minimum M0.6 and the maximum M45. The accuracy can reach 0.01mm, and the in-mold tapping technology enables The punched out products do not require a second manual tapping. The quality of the extruded products is guaranteed, the surface finish is good, the efficiency is high, and the cost is low. It is widely used in the stamping die industry.
Stamping Die Materials
With the improvement of product quality, the requirements for mold quality and life expectancy are getting higher and higher. The most effective way to improve the quality and life of molds is indeed to develop and apply new mold materials and new heat and surface treatment processes to continue to improve performance.
- – Carbon tool steel
- – Low alloy tool steel
- – High carbon and high chromium tool steel
- – High carbon medium chromium tool steelThe high-carbon medium-chromium tool steels used for molds include Cr4W2MoV, Cr6WV, Cr5MoV, etc. They have low chromium content, less eutectic carbides, uniform carbide distribution, small heat treatment deformation, good hardenability and dimensional stability. sex. Compared with high carbon and high chromium steel with relatively severe carbide segregation, the performance is improved.
- – High-speed steel
- – Base steel
- – Cemented carbide and steel bonded cemented carbide;The hardness and wear resistance of cemented carbide are higher than any other type of die steel, but the bending strength and toughness are poor. The cemented carbide used as the mold is tungsten-cobalt. For molds with low impact resistance and high wear resistance, cemented carbide with lower cobalt content can be selected. For high-impact molds, cemented carbide with higher cobalt content can be selected.
– New materials;New technology of heat treatment and surface treatment;Materials for making molds require high hardness, high strength, high wear resistance, appropriate toughness, high hardenability, no deformation (or less deformation) after heat treatment, and resistance to cracking during quenching.
When the production batch of stamping parts is particularly large, the material of the punch and the die of the working parts of the mold should be high quality, good wear resistance mold steel. The parts and materials of other process structure parts and auxiliary structure parts of the mold should be improved accordingly. When the batch is not large, the requirements for material properties should be appropriately relaxed to reduce costs.
The performance of the material being stamped, the use conditions of the mold parts
- – Material performance:The hot and cold processing performance of the material and the existing conditions of the factory should be considered.
- – Reduce manufacturing cost:Pay attention to the use of micro-deformed die steel to reduce machining costs.
- – Development of special tool steel:For molds with special requirements, mold steels with special properties should be developed and applied.
- – Consider the production and use of molds in my country:The choice of mold material should be determined according to the conditions of use of the mold parts, so that under the premise of meeting the important conditions, low-cost materials are selected to reduce costs.
The development trend of stamping die manufacturing technology in the future
The development of mold technology should serve the requirements of “short delivery time”, “high precision”, “good quality” and “low price” for mold products.The following items are urgently needed to meet this requirement:
(1) Comprehensively promote CAD/CAM/CAE technology
Mold CAD/CAM/CAE technology is the development direction of mold design and manufacturing. With the progress and progress of microcomputer software, the conditions for popularizing CAD/CAM/CAE technology are almost mature. Enterprises will increase CAD/CAM technical training and technical services; further expand the application scope of CAE technology. The progress of computer and network is making it possible to spread CAD/CAM/CAE technology across regions, enterprises, and institutions across the entire industry, realizing the reintegration of technical resources and making virtual manufacturing possible.
(2) High-speed milling
The high-speed milling process developed in foreign countries in recent years has greatly improved the processing efficiency and can obtain a very high surface finish. In addition, high-hardness modules can also be processed, and it also has the advantages of low temperature rise and small thermal deformation. The progress of high-speed milling processing technology has injected new vitality into the manufacture of large-scale cavity molds in the automotive and home appliance industries. At present, it has progressed in the direction of higher sensitivity, intelligence and integration.
(3) Mold scanning and digitization system
High-speed scanner and mold scanning system provide many functions from model or physical scanning to processing the desired model, which greatly shortens the mold development and manufacturing cycle. Some fast scanning systems can be quickly installed on existing CNC milling machines and machining centers to achieve fast data collection, automatically generate various CNC system processing programs, and different formats of CAD data, which are used in the “reverse engineering of mold manufacturing industry” “. The mold scanning system has been successfully applied in industries such as automobiles, motorcycles, and home appliances, and it is believed that it will play a greater role during the “Tenth Five-Year Plan” period.
(4) EDM machining
EDM machining technology is also known as EDM generative machining technology. This is a new technology that replaces the traditional forming electrode machining cavity. It is a simple tubular electrode with high-speed rotation for three-dimensional or two-dimensional contour machining ( Like CNC milling), there is no longer a need to manufacture complex forming electrodes, which is obviously a major development in the field of EDM machining. Machine tools using this technology have been used in mold processing abroad. It is estimated that this technology will make progress.
(5) Improve mold standardization
(6) High-quality materials and advanced surface treatment technology
(7) Mold grinding and polishing will be automated and intelligent
The quality of the mold surface has great obstacles to the service life of the mold and the appearance quality of the parts. It is an important development trend to study automated and intelligent grinding and polishing methods to replace the existing manual operations to improve the surface quality of the mold.
(8) Development of automatic mold processing system
This is the goal of our country’s long-term progress. The mold automatic processing system should have a reasonable combination of multiple machine tools; equipped with accompanying positioning fixture or positioning plate; have a complete machine tool and tool numerical control library; have a complete numerical control flexible synchronization system; have a quality monitoring and control system.
Stamping dies are important process equipment for stamping processing. Stamping parts are indeed completed by the relative movement of the upper and lower dies. Due to the continuous opening and closing of the upper and lower molds during processing, if the operator’s fingers continue to enter or stay in the mold closed area, it will bring severe threats to their personal safety.
Important parts, functions and safety requirements of the mold
The convex and concave mold is a straightforward working part that makes the blank shape. Therefore, it is the key part of the mold. The convex and concave mold is not only detailed and complicated, it should meet the following requirements:
- – It should have sufficient strength and cannot be broken or damaged during the stamping process;
- – Appropriate requirements should be placed on its materials and heat treatment to prevent brittleness due to high hardness.
Positioning parts are parts that determine the installation position of the blank. There are positioning pins (plates), stop pins (plates), guide pins, guide plates, side knives, side presses, etc. When designing positioning parts, it should be considered convenient to operate, there should be no positioning, the position should be easy to watch, it is best to adopt forward positioning, outer profile positioning and guiding pin positioning.
Pressing, unloading and discharging parts
Binder parts include binder ring, binder plate and so on. The blank holder can exert pressure on the drawn blank, thereby preventing the blank from arching and forming wrinkles under the action of tangential pressure. The function of the holding plate is to prevent the blank from moving and bouncing. The function of ejector and discharge plate is to facilitate the ejection of parts and the cleaning of waste materials. They are supported by springs, rubber and air cushion push rods on the equipment, and can move up and down. The ejector parts should be designed with sufficient ejection force and movement should be limited. The unloading board should minimize the closed area or mill out empty hand slots in the operating position. The exposed unloading plate shall be surrounded by protective plates to prevent people from reaching out with fingers or foreign objects from entering, and the edges and corners of the exposed surface shall be blunt.
Guide post and guide sleeve are the most widely used guide parts. Its function is to ensure that the convex and concave dies have a precise fit clearance during the stamping work. Therefore, the gap between the guide post and the guide sleeve should be smaller than the blanking gap. The guide post is set on the lower mold base, and the upper end surface of the guide post is at least 5 to 10 mm above the top surface of the upper template when the bottom dead center of the stroke is reached. The guide post should be arranged far away from the module and the pressing plate, so that the operator’s arm does not need to cross the guide post to feed and retrieve the material.
Support and clamping parts
It includes upper and lower templates, mold handles, fixed plates for convex and concave molds, backing plates, stoppers, etc.; upper and lower templates are the basic parts of the die; various other parts are not installed and fixed on it. The plane size of the template, especially the front and back direction, should be adapted to the workpiece, too large or too small is not conducive to operation.
Some molds (blanking, punching molds) need to set up a backing plate under the mold base for the convenience of parting. At this time, it is better to connect the backing plate and the template with screws, and the thickness of the two backing plates should be absolutely equal. The spacing of the backing plates is subject to the parts that can be delivered, and should not be too large to prevent the template from breaking.
It includes screws, nuts, springs, pins, washers, etc. All adopt standard parts. There are a lot of standard parts of stamping dies, and the design and selection should ensure the needs of tightening and elastic ejection, so as to avoid the fasteners from being exposed on the surface operation position to prevent hand injury and hinder operation.
Safety points of mold design
Various parts on the mold should have sufficient strength and rigidity to prevent damage and deformation during use. The fastening parts should have anti-loose measures to avoid accidental damage to the operator.
does not promise that waste or workpiece missiles will occur during the processing, which will hinder the operator’s attention or even injure the operator. In addition, the burrs of the blanking parts should be spared to cut the hands. It is not promised that the operator will have an excessive movement range during the punching operation, so as to avoid showing that the body loses a stable posture; it is not promised that there will be too many and over-accurate movements during the operation. Should try to avoid strong noise and vibration during stamping processing. The mold design should indicate the mold weight on the general drawing to facilitate installation and ensure safety. Lifting and handling measures should be adopted for the processing of parts over 20 kg to reduce labor intensity. When assembling and disassembling the mold parts, it should be convenient and safe to avoid the possibility of pinching or cutting hands; the mold should be easy to disassemble and store. In short, even the subtle consultation questions in the mold will hinder safety. Only by analyzing the specific consultation questions in each job can the safety precautions in the mold be put forward.