31 March 2014
Earlier in March, Andy Taylor, Operations Manager at Oneflow, attended a Low Volume Manufacturing seminar at Warwick University. The event was presented by Benjamin Woods and Paul Milne of the Polymer Innovation Team at WMG. The event was focused around Additive Layer Manufacturing (ALM)
and the role it can play in low volume manufacturing. In particular the session looked at how ALM could bridge the gap between prototypes and mass production. See Andy's summary below of the days learning which included more than just making a plastic octopus!
ALM, or 3D printing as the mass media incorrectly refers to it, comprises of a range of different processes using a range of materials. All techniques, of which 3D printing is one and of which Selective Laser Sintering (SLS) or Fused Deposition Modelling (FDM) are other commonly used ones, produce 3-Dimensional parts in "space" from the input of a CAD model. They all work on the principle of building up and solidifying layers of polymer material. These layers can be imagined as slices of the product you are trying to create, each one being built upon the previous. The advantages are; no tooling costs, no assembly, complicated structures can become simple, every part can be individual. It is even possible to make live hinges and have different materials in one product.
This all sounds great and for the world of design and prototyping it is. The design you drew in the morning can be manufactured in the afternoon, reviewed the following day, modified and re-made to the next iteration. Multiple designs and prototypes can be produced in days if not hours and at a fraction of the cost of more traditional rapid prototyping methods. ALM has actually been around for a long time and to date has been limited to this world. It can only make one part at a time (or multiples with long cycle times), it can't achieve the same standard of parts as mass production methods (such as injection moulding) and there are no economies of scale. The challenge therefore has been in how to use ALM to make not one, but hundreds of parts without the cost of investing in hard tooling or capital equipment.
The Polymer Innovation Team at Warwick University has come up with an answer. Instead of making parts using ALM, make the tooling using ALM processes. So instead of having a metal injection moulding tool for example, the tool can be made of a suitable plastic using ALM techniques. The tool can then be put into a normal injection moulding machine and parts can made with the same materials and methods as they would be in full or mass production. The parts are then truly representative of production parts but the design can still be rapidly developed and modified by simply making a new ALM tool for every design change. The downsides are that tool life is short and moulding cycle times have to be reduced. However the team have worked on a number of commercial projects using these methods. As a comparison to having made a traditional metal tool to manufacture a polypropylene component, ALM tooling was able to make 2400 parts before a metal tool would have been more cost effective. The most powerful part is that this included making 16 iterations of the ALM tool. That's 16 design changes over those first 2400 parts.
The world of "3D-printing" is perhaps some way from the view portrayed in the press where we will all have a printer in our homes manufacturing the consumer products we want. What is apparent however is that ALM has and is moving on. Whilst the use of ALM techniques to make Rapid Tooling can't be the answer for every part, its advantages are clear. Its use to shorten design lead times and provide parts closer to real production seems the next logical step with real commercial benefits. This will allow further reduction in product development lead times with reduced development costs and allow early production volumes or even total life volumes to be produced without the need to invest in hard tooling.
John Baldwin, MD at Oneflow reflected on the outcomes of the day "Given that Oneflow works with a number of customers who produce in low volume with tight development budgets and time-scales, the use of ALM technology in this way seems entirely appropriate. The benefits demonstrated by the Polymer Team at Warwick are ones Oneflow will be looking to explore in the coming months as we kick off several new customer projects".
Thanks to all at Warwick University and to Benjamin Woods and Paul Milne for hosting such an informative day and thanks for the Octopus!
You can find out more about the Polymer Innovation Team, based at the International Institute for Product Service and Innovation, here.