Computer-aided design (CAD) is so amazing that it can assist people in better metal processing. But the truth is that precision metal stamping has some of the same problems. One way to remedy these problems is to work with a metal stamping engineer early in the design process.
As precise as the metal stamping process is, it has its limitations. The thickness, hardness, and grain orientation of the material can have a significant impact on the final product. Commonly processed materials include ferrous metals, non-ferrous metals, stainless steel, and other materials. When manufacturers choose the right material, engineers can help them ensure that the material meets their needs and doesn’t suffer from problems such as cracking.
If you understand how metal stamping works, you can avoid making mistakes. This can avoid spending a lot of money and ensure a smoother production process.
Table of Contents
Design Criteria for Metal Stamping
In metal stamping, coils or sheets of metal are pressed and cut into a specific shape. Stamping includes many different forming methods such as punching, blanking, embossing, and progressive die stamping. Depending on the complexity of the workpiece, these methods may be used individually or in combination. To achieve the best results, engineers should follow the standards for the manufacturing process.
Slots and Holes
In metal stamping, steel tools called punches are used to pierce the metal and form holes and slots. In the process, the punch presses the sheet or strip of metal into the hole of the die. When the material begins to yield to the force of the punch, it is cut and sheared off. Eventually, the material is completely severed and breaks at the point where the punch and die edges meet.
This creates a hole with a smooth top and a tapered bottom and leaves burrs at the material break. Due to the way this process works, the slots and holes are not perfectly straight. They can be made to have identical walls by means of an additional processing step. However, secondary processing increases costs.
Minimum Diameter
The design standard for the minimum diameter depends on the material selected. For ductile materials such as aluminum, the minimum diameter of the hole should be at least 1.2 times the material thickness. For materials with higher tensile strength such as stainless steel alloys, a minimum diameter of 2 times the material thickness is recommended.
In addition, the groove width should be at least 1.5 times the material thickness. Although smaller diameters can be used, they require expensive special processes or tools. This increases the cost of the part and increases the likelihood of tool damage.
Distance from Edge
Grooves and holes can be close to the edge, but they should be at least twice the material thickness away from the edge. If this is not done, the material between the hole and the edge may bulge outward. If the hole is too close to the edge, it may bulge or deform during stamping. These features will need to be reworked or go through other steps, which will make them more expensive.
Distance from Bends
Make holes or slots that are less than 0.100 inch wide or thick with a spacing of at least twice the material thickness (2x MT) plus the shape radius. For holes or slots larger than this, the minimum spacing should be 2.5 times the material thickness plus the shape radius. Distortion, swelling, or stretching may occur when holes and slots are positioned closer than the recommended standard.
Bending and Forming
Bends and other forming features are often found in the final stages of progressive die stamping. The direction of the material grain is a key factor when considering bending features. When the grain direction of the material is in line with the direction of the bend, the material is prone to cracking, especially in high-strength materials. Such as stainless steel alloys or tempered materials. When designing a bend, the direction of the material grain should be considered for best results, and the direction of the grain should be indicated on the drawing.
Bend Height
It is essential to ensure that there is enough material to form the bend correctly. One way to provide enough material to execute the bend correctly is to follow the minimum bend height standard. The recommended height for a bending feature is 2.5 times the material thickness plus the bend radius. Shorter bend heights are possible but require additional manipulation.
Bending Near the Edge
Bending features near the edge should either increase the material offset or have a release cut at the bend. Failure to do so may result in the tearing of the material on either side of the bent part. When increasing the material offset, the offset should be at least the same as the bend radius. Alternatively, the designer can create a groove near the bending area. The groove should be at least twice the material thickness wide and the length should be the bend radius plus the material thickness.
Preventing Deformation and Bulging
Relief grooves also help prevent deformation or bulging that can occur when bending thicker materials. The less the thicker material is bent, the more likely bulging is to occur. Designing relief grooves on both sides of the bend helps reduce bulging. It is recommended that markings be used on the drawing to draw attention to areas where bulging is not allowed.
Dimensions and Tolerances
For punched, perforated and stamped features, the dimensional feature should be measured from the cut edge. Internal dimensions are measured along the shortest part of the cut direction, and external dimensions are measured from the longest part. If critical features cannot tolerate edge breakage or taper applied. Then the manufacturer can achieve a straight edge through secondary operations. However, this will increase the cost of the project.
For formed features, designers should always give the dimensions inside the feature. For features placed on the outer end of a formed part, the angle tolerance of the bend (usually ±1 degree) and the distance at the bend should be considered. When the feature contains multiple bends, the superposition of tolerances should be considered and calculated.
Material Selection and Its Impact
In the field of precision metal stamping, the choice of material is very important. It is not enough to choose a metal, it is also necessary to understand its role in the stamping process and the requirements of the final product. Since the properties of the material can have a great impact on the result, it is important to understand the role of different metals and take expert advice.
The Role of Different Metals
Metal stamping can process a wide range of different metals. Whether ferrous or non-ferrous, stainless steel or aluminum. Each type of metal has its own unique properties. It is important to understand these nuances in order to obtain the desired results.
Metal properties and their effect on stamping results:
- The hardness of a metal affects how easily it can be molded during the stamping process.
- The orientation of the grains affects the strength of the final product.
- The thickness of the metal also affects how easy it is to mold.
There are many different materials that can be used for precision metal fabrication. The following are some of the most commonly used materials:
- Ferrous and non-ferrous metals: ferrous and non-ferrous metals. Different types of metals have their own advantages. For example, ferrous metals are more magnetic, while non-ferrous metals are less likely to rust or corrode.
- Stainless steel: known for being strong and resistant to rust.
- Aluminum: Very light and easy to shape, making it ideal for creating intricate patterns.
- Titanium and precious metals: these metals are known for being strong and resistant to oxidation or corrosion.
- Pre-plated metal and polyester films: give stamped parts extra protection or certain characteristics.
- Wires: Commonly used for specific tasks that require flexibility.
Expert Guidance on Material Selection
Simply choosing the right metalworking material is not enough. Expert advice can be very helpful in ensuring that the material meets the design and production needs.
The importance of consulting a metal stamping engineer:
- The expertise of an engineer helps to connect design goals with production challenges.
- They can provide you with information on how the material will react during the stamping process, thus ensuring that the final product meets your needs without sacrificing quality or utility.
Possible problems with certain materials and alternatives:
- There are many types of metals. Some of them may be more prone to cracking during stamping.
- Materials that are too fragile may not be suitable for designs that require great flexibility. In this case, a metal stamping engineer can provide alternatives that are better suited to the needs of the design.
- The expertise of an engineer can help a company avoid mistakes that cost money and delay production. This ultimately ensures a smoother process from design to processing of the product.
Debunking the Myths of Metal Stamping
Metal stamping is a versatile and efficient process. However, it is not always perceived correctly. There are some common misconceptions that can lead to poor decisions or fail to get the best results. If we address these misconceptions, we can ensure that metal stamping projects run more smoothly and accurately.
Replacing Other Materials and Processes
Many people think that metalworking can replace other materials and methods. This is because it looks so beautiful, but the truth is not so complicated.
When metal stamping is used instead of man-made or cast parts, a number of problems arise. Metal stamping, while accurate and fast, is not the best way to solve all problems. Molding and casting each have their own benefits, and replacing them directly with stamping can be difficult. For example, a complex part molded in plastic may not be easily turned into a metal stamping. This is because of the nature of the material and the different manufacturing methods.
Real-life examples can illustrate the complexity of the problem. For example, a manufacturer wants to make a metal version of a part molded in plastic. It is easy to make complex patterns in plastic molding, but expensive to make them in metal stamping. It requires more than one mold station, which increases production time and cost. Therefore, the metal process is not a substitute for all other processing methods.
Solving Key Problems
When stamping metal, great precision is required. However, problems can arise if there is a lack of clarity or if important aspects are changed at the last minute.
Important issues must be clarified from the start. When designing stamped metal parts, it is important to identify critical dimensions as early as possible. These dimensions are important to the work and fit of the part. By determining these dimensions ahead of time, metal stampers can ensure that the production methods and tooling meet the requirements. This results in the production of a part that meets the user’s requirements.
The cost of changing important dimensions after the tooling has been developed or even manufactured can be prohibitive. These changes require modifications to the tooling and can cause work delays. For example, if the design of a part has been finalized and the tooling has been made.
However, if the quality department adds more critical dimensions, then the tooling may need to be changed. Such changes may increase costs and extend production time. This shows how important it is to have clear communication and thorough planning from the beginning.
Accuracy and Tolerances in Design
Achieving accuracy in metal stamping requires a careful balance between the designer’s requirements and actual manufacturing. It is important to understand the details of tolerances and the tools used in the design process to ensure that the finished product works well and costs less.
The Role of Computer-aided Design
Computer-aided design (CAD) has changed the way we design and manufacture things. However, it is also important to understand its limitations and the problems it can cause.
CAD design can sometimes be overly restrictive, and the accuracy of CAD software can sometimes be misperceived by designers. It is possible to create parts with extremely tight tolerances on a computer. But it is difficult and costly to actually produce or machine metal stampings with the same precision. For example, CAD may set itself to a certain number of decimal places. This may work on a computer, but not in high-volume production.
It is important to reproduce realistic and cost-effective standards in metalworking processes. It is good to strive for perfection, but it is also important to find a balance between design goals and reality. If tolerances are too specific, they increase production costs. And the value of the final product will not increase.
Talking to a metal stamping expert during the design phase will help ensure that the CAD design is realistic. This will make the production process smoother and ensure that the product meets standards without costing too much.
Design Safe and Effective Edges
The sides and edges of metal stamped parts are very important to how they work and how safe they are. Care must be taken to craft these parts. Ultimately, it is important to ensure that the parts work as they should without jeopardizing personal safety.
Problems arise when trying to resolve sharp sides and edges. Sharp sides and edges can be dangerous. This is especially true during part assembly or when using the part for the first time. In addition, overly sharp shapes can cause problems during the stamping process. For example, molds wear out faster or have a higher chance of error.
Getting a safer, more effective design solution. Designers shouldn’t just say “remove all sharp edges.” Rather, they should state which parts of the part require specific edge conditions based on how the part works.
For example, if the sharpness of one corner might cut or wear another part. Then it would be best to set a rounded edge there. Talking to a metal stamping expert can help you find the best edge design that combines safety, practicality, and ease of production.
Support for Design for Manufacturing (DFM)
Design for Manufacturing (DFM) is a proactive approach to design. It ensures that products are not only useful and aesthetically pleasing but also simple and inexpensive to manufacture. By considering manufacturing issues and opportunities early in the design process, DFM can help build products better, get them to market faster, and reduce costs.
Comprehensive DFM Review
In order to identify possible manufacturing problems and opportunities as early as possible in the design process. A thorough DFM check must be performed. This check ensures that the plan is optimal for manufacturing the product quickly and cost-effectively.
A thorough DFM review process includes the following steps:
- Review of customer requirements: Find out what the part will be used for, how long it will last, and if there are any other requirements.
- Rules and laws that must be followed: Ensure that the design follows any rules or standards that apply to the organization.
- Evaluate materials and their function: Select the appropriate material for the part’s use and manufacturing method.
- Tools: Ensure that the plan can be completed quickly and easily using existing tools and machines.
- Final Assembly and Packaging Needs: Consider how the part will be assembled into the entire product and what limitations there are in terms of transportation or packaging.
The importance of collaboration between the manufacturer and the metal stamping company:
- When both parties collaborate, it ensures that both know what the goals and limitations of the design are.
- The metal stamping company can provide useful information on how to produce the design.
- The manufacturer, in turn, can clarify any functional or aesthetic needs.
- This collaborative approach can help people make better design choices. This leads to fewer changes on the design side and a smoother production process.
The Role of Prototyping
Making prototypes is an important part of the DFM process. This is because it allows a company to test and ensure that its design will work before going into mass production.
When and why to prototype:
- If there are questions about how a design will work in the real world, a prototype can help resolve them.
- For complex or innovative designs, a prototype can show you any problems or opportunities you didn’t anticipate.
- You can also use prototypes to see how the market will react to a new product before you put it into mass production.
Benefits of using simulation software to check if a plan is feasible:
- Simulation software can produce a model of how the design will work in different situations. This helps to find weak points or areas where improvements can be made.
- Designers can identify and solve problems in production early in the planning process by simulating the production process.
- Using simulation software reduces the need for real prototypes. This can save time and money. However, simulation and prototyping can work together when actual verification is needed. Ultimately, it can give a full picture of how the design is working.
To Summarize
Understanding the ins and outs of metal stamping during the design phase can help make the production process more efficient. This results in savings of time, money, and resources. Expert collaboration and advice are key to ensuring that ideas are both innovative and realized.
If you still have some questions about precision metal fabrication, Yonglihao Machinery can solve them. Yonglihao Machinery has many years of experience in metal fabrication production. We have partners all over Europe and the United States who can perfectly solve any of your needs.