Rolling process
Overview of the rolling process
Rolling is a processing method that uses pressure to plastically deform a material, forming screw threads, gear teeth, and other shapes. In roll forming, specialized tools (rolling dies and rolling rolls) are used to continuously apply pressure to the metal, extruding it into shape. This allows for highly precise shaping and increases strength and durability compared to cutting.
Types of thread rolling
- Flat die rolling is a method of machining on a flat surface using a rolling die. It is widely used for machining small parts such as screws and can roll at high speed and with high precision.
- Round die rolling: A machining method using a round die. Suitable for machining hollow bolts and similar parts. Productivity is lower than the other two methods.
- Rotary die rolling is a process that uses a cylindrical die to rotate the material while processing it. It can handle medium to large parts and can form high-precision threads and grooves by applying high torque.
Rolling process
Roll forming is primarily carried out through the following process:
- Preparation of materialsGenerally, the material to be processed is prepared in the form of a metal rod or wire and then shaped to the appropriate dimensions and form. At our company, however, we use 100% forged blanks.
- Rolling die settingsThe die (tool) is set according to the shape and size to be processed. The type and shape of the die will vary depending on the shape and dimensions to be formed.
- Material rollingThis process involves shaping the material by applying continuous pressure using dies and rolls. The pressure applied by the die causes the material to deform to conform to the shape of the die.
- Cooling and lubricationHigh pressure and friction occur during the process, so machining oil is often used. This prevents overheating of the die and material, and maintains the quality of the rolling process.
- Finishing and inspectionAfter the rolling process, the products undergo finishing and surface treatment as needed, and are inspected to ensure that their dimensions and shape conform to the specifications.
Advantages of thread rolling
- High-strength products: Because the material is formed under pressure, the crystalline structure inside the metal flows, increasing its strength and durability. Compared to screw manufacturing by cutting, the strength is improved by approximately 30-40%.
- High surface precision: Because the surface is not machined, the rolled surface is smooth and highly precise. Wear and friction are reduced, extending the product life.
- Less waste of materials: Unlike cutting processes, this method deforms the material rather than removing it, resulting in less material loss.
- Excellent for mass production: Because it allows for high-speed and efficient molding, it is suitable for mass production. It is particularly often applied to the manufacture of automotive and aircraft parts.
- environmentally friendly ：Since no chips are produced, there is less waste, making it an eco-friendly manufacturing method.
Points to note during thread rolling
While thread rolling offers many advantages, there are several points to consider in order to ensure accuracy and quality.
- Material SelectionSince the material undergoes plastic deformation under pressure, it is necessary to check whether the material's hardness and ductility are suitable for rolling. Materials that are too hard are difficult to roll, and tool wear will be severe.
- Tool wear managementDue to the high pressure applied, dies and rolls are prone to wear and tear, requiring regular maintenance. As wear progresses, accuracy decreases, affecting product quality, so proper maintenance is crucial.
- Adjustment of processing speedMachining at too high a speed can negatively affect material quality and tool durability, so machining at an appropriate speed is recommended.
- Use of processing oils It is important to use an appropriate lubricant to reduce friction during machining and maintain the surface quality of the product and tools.
Applications of rolling
Rolling is commonly used in the following fields:
- Automotive partsEngine parts, gears, shafts, screws, etc.
- aerospace industry: Components that require high strength and durability.
- Precision equipment: Parts for watches and cameras, small components for electronic devices.
- Construction bolts and screwsBolts and screws that require strength and durability.