1 Winding onto the purple Smart Mandrel begins.
2 The Smart MandrelTm is heated and softened for easy removal from the completed winding.
– Capable of producing highly versatile shapes.
– Reduced labor costs due to the ease with which the mandrel can be removed.
– Reusable and adaptable tooling.
– Simple to remove mandrel from component.
– All parts have the distinctive “look” of filament-wound products.
– Limited availability because it is a patented process.
Volumes of production
For now, small runs and prototyping only, but this recently developed process will be equally suitable for large-scale production, since the mandrels are durable and can be used to make many parts.
Unit price vs. capital investment
Smart MandrelsTM offer big savings for low production runs. This is because there is no need for expensive, multipiece tooling, with the price staying at the same level for large production runs.
Speed
Cycle times are several minutes for each part, but it is significantly quicker than conventional filament winding with rigid mandrels (see p.158) because there is no need to assemble and disassemble the mandrel for each part.
Surface
No post finishing necessary, but the parts do have the distinctive “look” of filament-wound products.
Types/complexity of shape
The main advantage with Smart MandrelsTM is that they allow for more complex forms to be produced using the filament-winding process. These can incorporate undercuts and returns that would normally be impossible to produce, because the mandrel could not be removed from the component.
Scale
Machines can be built to produce filament windings to a massive scale. The only limitations on scale will be the size at which the shape-memory alloys and polymers can be made and remain effective.
Tolerances
Not the kind of process that is suitable when high tolerances are required.
Relevant materials
Any thermoset plastic material, and glass or carbon fiber.
Typical products
Aeronautical components, tanks, rockets, and housings.
Similar methods
Pultrusion (p.99), and contact molding (hand or spray lay-up) (p.152).
Sustainability issues
Filament winding is largely automated so electrical energy is required to power the motors. The high speeds at which the machines can operate help to make efficient use of this energy through high-volume production. The high strength-to-weight ratio also offers significant weight savings.
Further information
www.crgrp.net
Incremental Sheet-Metal Forming
Product |
sample of incrementally formed sheet |
Materials |
stainless steel |
Manufacturer |
sample produced by Institute for Manufacturing, Department of Engineering, University of Cambridge |
Country |
UK |
Date |
2006 |
Researchers Julian Allwood and Kathryn Jackson of Cambridge University are two of the many researchers internationally who are looking at ways of developing the process for wider industrial use. The stepping seen in this sample illustrates the path of the tool as it traces across the metal sheet, slowly pushing it into shape.
This close-up image shows the single-point tool poised over the clamped sheet of metal, which is about to be formed into shape.
One of the major research areas in manufacturing at the moment is in the arena of “industrial craft,” a term that embraces a range of technologies that allow for a very flexible approach to mass-production by eliminating the need for specialized tooling. Incremental sheet-metal forming has the potential to revolutionize sheet-metal forming, making it available for low volumes of production for customized parts.
In essence, incremental sheet-metal forming is a type of rapid prototyping for sheet metal using a mobile indentor, so that almost any three-dimensional shell-shape can be made, without the need for specialized tooling. It is a term used to describe a number of methods of sheet forming that employ a generic, single-point tool that presses against a metal sheet in three axes (the work piece is held in a clamp), depressing it into a shape based on a path that is supplied by a CAD file.
The process has been in use for 15 years, but its potential is still not widely adopted in industry, chiefly as a result of the difficulty in assuring geometrical precision in the formed part. However, Toyota has explored the process for forming parts for prototyping cars, using a one-sided die in order to gain more control.
There are a number of researchers exploring different variations of the process, some of whom are using two indentor tools at the same time, on either side of the work piece. Negative and positive dies can also be employed to give greater control of geometrical accuracy and surface finish.
– The main advantage of this process lies in its ability to produce complex forms using a generic tool, which ultimately means that there are no tooling or setup costs for one-off or small-production volumes.
– Limited availability.
– Still in its infancy.