The Forming Process of Metal Spinning

Metal spinning is a near-net-shape metal forming process performed on a metal spinning machine. It transforms flat metal blanks into hollow, axisymmetric workpieces by using rotary motion and local rolling pressure, without removing excess material like cutting operations.

Working Principle

The metal blank is clamped tightly onto a rotating mandrel. As the spindle drives the blank and mandrel to rotate at high speed, the spinning rollers move along the preset path, applying continuous local pressure on the blank surface. Under the combined action of rotation and roller extrusion, the metal blank gradually flows and fits the contour of the mandrel, forming the target hollow part.

The picture shows a typical multi-roller CNC metal spinning machine. Two spinning rollers work synchronously on both sides of the tubular workpiece. The rollers press the rotating metal tube, forcing the material to produce plastic deformation to reduce the tube diameter or shape the outer profile.

Main Processing Steps

1. Workpiece Clamping: Fix the metal blank or tube blank on the mandrel, ensure concentricity and firm clamping to avoid vibration during high-speed rotation.

2. Parameter Setting: For CNC spinning machines, input the spinning track, spindle speed, roller feed rate and pressing force according to the part drawing.

3. Pre-spinning & Forming: The spindle starts to rotate. The spinning rollers approach the workpiece and perform multi-pass progressive extrusion. The metal deforms step by step to prevent cracking or wrinkling caused by one-time heavy pressing.

4. Finishing Spinning: Carry out light finishing passes to optimize surface smoothness and guarantee dimensional accuracy of the finished part.

5. Unloading & Inspection: Stop rotation, take down the finished spinning part, then check dimensions, wall thickness and surface quality.

Advantages of Metal Spinning Process

• Material saving: Plastic forming, no chip removal, material utilization rate far higher than turning.
• Good part mechanical performance: Metal grain structure remains continuous after spinning, improving tensile strength and hardness.
• Flexible production: One set of equipment can produce various axisymmetric parts by changing mandrels and programs, suitable for small-batch and medium-batch production.
• Wide material adaptability: It can process aluminum, copper, carbon steel, stainless steel, alloy steel and other ductile metals.

Typical Application Parts

Metal spinning technology is widely used to manufacture lamp housings, pressure vessel shells, nozzle parts, fan covers, automobile exhaust components, aerospace thin-walled parts and pipe reducing sections.

Key Notes During Machining

• Select reasonable spinning passes. Too large single pressing amount will cause workpiece cracking, wrinkling or roller damage.
• Control the spindle speed and feed matching. Stable rotation helps obtain uniform wall thickness.
• Use lubricant during processing to reduce friction between rollers and metal, improve surface finish and reduce tool wear.