Metal Sheet Spinning process | Advantages and Disadvantages of Spinning
- Practiced by pressing a tool against a circular metal preform.
- Involves no significant thinning of work metal; essentially a shaping process.
- Used for prototype manufacture or in production runs less than 1000 pieces.
- Metal is deformed using high shear forces.
- Use of automated CNC machines.
- Significant thinning of metal preforms.
- Suitable for high production runs.
Thickness of cylindrical parts reduced by spinning them on cylindrical mandrel rollers.
Steps in Spinning Process
Step 1 :Metal Forming
This step involves the laying down of the material onto the mandrel.
It is accomplished with short inside to outside moves.Material gets easier to form as the part is closer to completion
Step 2 :Trimming
Parts having been spun are trimmed at the end to blunt sharp edges and also to bring the component to the desired length.
Step 3 : Finishing
Finishing is done at very high RPMs (1200+) so that a minimum of force need be applied and verysmooth strokes can be used. The flat side of Duckbill spinning tool is used for straight surfaces an rounded side for curves and radii.
- Machines for spinning are specified by the diameter and length of the largest component that can be spin
- They are also specified by the maximum load that can be applied to the work.
- The capacity of spinning machines ranges from 0.455m in diameter and 0.380m in length to 6m in diameter and 6m in length.
- Metal spinning machines can be both vertical or horizontal.
- Machines used for spinning large diameters, such as 1.8m or more are usually vertical.
- Mostly lathe based machine tools ( both conventional and CNC-based) are employed for spinning operation.
- Most modern machines used for spinning are at least semi-automated; that is, they are loaded and unloaded by the operator, but the entire spinning cycle is controlled automatically.
- Tooling costs less, and investment in capital equipment is relatively small
- Setup time is shorter
- Design changes in the workpiece can be made at minimum expense
- Changes in work metal composition or thickness require a minimum of tool changes
- Skilled operators are required, because uniformity of results depends greatly on operator skill
- Manual spinning is usually slower than press forming
- Available force is more likely to be inadequate in manual spinning than in press forming Equipment
- Vases, baskets, basins and bowls.
- Bottoms for tanks, hoppers and kettles.
- Housings for blowers, fans, filters and fly-wheels.
- Ladles, nozzles, orifices and tank outlets.
- Cones, covers and cups.
- Funnels, cylinders, domes and drums.
- Rings, hemispheres and shells.
- Vents, venturis and fan wheels.
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