Flowforming or Metal Spinning (Spin Forming)
a Precision Metal Forming Process
PMF is a contract metals fabricator, specializing in flowforming seamless, complex, hollow metal parts. PMF's capability to combine flowforming, or metal spinning (spin forming), with an array of other in-house metal forming processes, such as deep drawing, rotoforming, hydroforming, electromagnetic forming, and other metal fabricating processes, means that PMF controls the manufacturing process of your part or assembly from concept to completion.
When you combine PMF's engineering and technical capabilities and in-house family of manufacturing processes, you get a unique offering capable of manufacturing precise complex designs at a cost savings that cannot be matched by any other company.
Flowforming is an excellent method for forming nickel-cobalt-based super alloys, stainless steels, aluminum, brass, tantalum, columbium, titanium, and other heat-resistant steels. Flowforming produces parts that are cylindrical, conical, or contoured with precise control of desired wall thicknesses.
Flowforming is sometimes referred to as a controlled metal spinning process. A key difference between flowforming and metal spinning is that spinning does not reduce wall thickness of the starting blank; therefore spinning does not hold precise control of contours. Flowforming is based on a calculated reduction of the thickness of a starting blank or preform. The reduction is closely controlled, which results in precise wall thicknesses and accurate profiles of the final part.
Another difference between flowforming and metal spinning is in the stability of the formed part. The typical spinning process heats the preform to provide the required ductility and often distorts the final part during cooling. Flowforming is a cold forming process, which ensures the final part's controlled characteristics are to design with no distortion.
The flowforming process starts with the design of a preform that is calculated to ensure the most efficient use of materials. The preform can be produced in several different methods. The most common industry methods use bar, forgings, or tubing. Although PMF does efficiently use these methods, our most cost-effective method uses plate or sheet metal.
The preform is then flowformed against a hardened mandrel utilizing CNC equipment to control wall thicknesses and profiles to within a few thousandths of an inch. PMF's state of the art CNC flowforming equipment ensures part and process repeatability.
PMF uses one of the three distinct processes to achieve the part's final profile or shape:
- Forward axial flowforming
- Reverse axial flowforming
- Shear forming
Each of these processes can use a one, two, three, or four roller configuration based on the part profile and starting wall thickness.
View an animated demo of flowforming.
The unique features of the flowforming process allow for innovative, cost-effective engineering or redesign of your product or part, resulting in the following features:
- Traditional multi-piece designs can be formed as a single, seamless piece
- Increase mechanical properties, such as tensile/yield strength and hardness
- Provide design versatility to produce a unique seamless profile with varying wall thicknesses
- Produce cylindrical, conical, or contoured shapes up to 47" diameter
- Typical interior finishes of 15Ra without additional manufacturing steps
- High material utilization from near-net shape forming process
What Makes a Component Ideal for Flow Forming?
- Symmetry around a centreline - cones and cylinders (or a combination).
- Final part wall thicknesses between .020 and .200in.
- Diameters between 1 and 24in.
- Length-to-diameter ratios greater than 2.5 to 1.
- Controlled variations in wall thickness, especially where there are heavy bottoms and thinner side walls.
- Difficult-to-form materials, including stainless steel, Hastelloy, Inconel, and other heat-resisting alloys.
- Requirements for various additional manufacturing processes, including machining, welding, or finishing.
- Parts that can benefit from the effects of coldworking on the material- increased strength and wear resistance, harder surfaces.
- Tolerances that exceed the capabilities of deep drawing or spinning requiring precision that approaches machined parts.
- Parts that can benefit from design changes to optimise the effectiveness of flowforming - without adversely affecting function.
- Parts capable of carrying a higher overhead than is incurred with simple stamping, sheet-metal bending, or other basic forming operations.
For more information on PMF's capabilities, contact us.