Seven Key Strategies for Punching Success in Sheet Metal Fabrication

The punch press technology is a well-established process in sheet metal fabrication industry. Despite the versatility of the punch press technology, there are numerous processing variables that must be considered in order to maintain part quality and production efficiency. If not properly managed, these variables can lead to decreased performance and reduced output. By gaining an understanding of the key principles and fundamentals of the punching process, it is possible to effectively control these variables and ensure consistent, high-quality results. In this article, we will discuss 7 strategies for punching success in sheet metal fabrication.

1. Forming Variables:?The process of creating a formed sheet metal part from a CAD drawing involves taking into account various factors such as bend radius?and material thickness. It is important to consider the design intent and critical dimensions, as material thickness can vary from one source to another. Material thinning during forming can lead to a mismatch between the solid CAD model and actual part volume. Punch press forming operations differ from stamping presses in the application of force and clamping pressure, but recent advancements in tooling and technology have expanded the potential for punch press forming.
2. Handling?Slugs:?To prevent slugs from sticking to the face of a punch during piercing, you can cut slots in the punch face or use a punch with a spring-loaded steel or urethane pin in the center. A punch with a "rooftop" or high point can also help, as it tends to cause the slug to spring back. In the die, a "negative-positive" geometry or a welding tool to create a smaller die opening can also help retain the slug.
3. Avoiding?Galling:?To prevent galling, make sure the punch material is different from the workpiece material. To reduce friction and heat, consider modern tool coatings and back-taper on the punch. For die clearance, test different clearances and consider slower punch speed, shorter stroke length, and doubled/tripled up tooling to reduce overheating. Avoid negative taper on the die and allow room for debris to evacuate.
4. ?Removing?Pinch Points:?The utilization of rectangular punches during punching operations may lead to the formation of hard overlap marks and make pinch points to appear. To mitigate this, the application of obround punches is recommended. An alternative solution is the implementation of a pincher-roller wheel tool that forms a groove, reducing the risk of hard overlap marks. While this method may require a slightly longer cycle time on the punch press, it eliminates the need for secondary operations such as deburring, making it a cost-cutting solution.
5. Reducing?Sheet?Vibration:?The use of microtabs, or "shaker tabs," in punching operations is a common method for managing numerous parts cut from a single sheet. Once the sheet has been punched, workers remove the parts for sorting by shaking them from the nest. It can can cause "sheet shake" leading to inaccurate positioning. To prevent this, adjusting the punching sequence so the sheet remains solid most of the time, with microtabs added last, is effective.
6. Monitoring?Progress for Sheet Metal Punching:?Tracking progress is important in any manufacturing process, and sheet metal punching is no exception. By tracking progress, you can monitor the efficiency of the punching process and identify areas for improvement. To track progress, it is important to keep accurate records of th?production process, to monitor the condition of the equipment, and to perform regular quality checks on the final product.
7. Guarantee Constant Equipment Maintenance:?Proper maintenance of equipment is crucial to the success of the punching process. By regularly cleaning, lubricating, and maintaining the equipment, you can ensure that it operates smoothly and efficiently, leading to better quality products and reduced downtime. It is also important to regularly inspect the equipment for signs of wear and damage, and to replace or repair parts as needed.

In conclusion, the punch press technology is a crucial process in sheet metal fabrication, and to achieve?high-quality?results, it?requires an effective implementation of key strategies?and?the right equipment. Hennordic ?uses?machines such as Prima Power SGe 5, Prima Power e5x, and TruPunch 5000 to provide?high-quality punching?services?and?deliver top-notch?sheet metal?products to?the final?customers.