A cloud-operated multi-cell manufacturing concept offers a glimpse of the future of 3D printing
The various additive manufacturing techniques that have been developed over the past couple of decades or more are now not just well-established tools for their original application area of rapid prototyping, but also for actual production. But in that latter role the take-up of the technology has always been impeded by a number of persistent factors apart from the intrinsic slowness of the fabrication technique itself. These include the fact that the machines tend to be bulky standalone pieces of equipment and that they require manual unloading of finished parts.
But what if those inhibiting factors could be largely abolished? What if additive manufacturing could be carried out by a bank of appropriate machines stacked side by side or on top of each other to create a simultaneous multi-cell production capability for either identical or different parts? What if those cells could operate on an extended unattended basis because they had both a co-located stock of raw material to draw on and could unload finished parts automatically? Also, what if they possessed an integral self-scheduling capability so that manufacturing could be automatically routed to the first available cell? And what if that overall control could be affected by a web-based cloud computing system so that the machines could operate in almost any location, irrespective of where they were managed, to serve local markets and thus greatly reduce the costs of transporting finished goods?
What you would then have, observes Stratasys’ Roger Kelesoglu, would be a “no-tooling, zero inventory” and therefore economically viable means of manufacturing parts in volumes much larger than is normally associated with additive techniques. And intriguingly, according to Kelesoglu, who is director of sales enablement for the US-based additive specialist, this prospect is no way fanciful. Instead, it is precisely what is embodied in a technology demonstrator unit unveiled by the company within the past couple of months.
At first sight, the Stratasys Continuous Build 3D Demonstrator looks almost like a large vending machine composed, as it is, of multiple stacked rectangular units, each of which has a plastic basket in front of it to catch ejected parts. But each of the units is, in fact, an additive manufacturing device employing the fused deposition modelling (FDM) technique in which objects are built layer-by-layer using a liquid polymer extruded through a nozzle.
Surprisingly, perhaps, Kelesoglu said that actual development of the Demonstrator did not take too long because it is effectively a combination of existing state-of-the-art technologies upgraded to provide the machine with its ‘smart’, autonomous characteristics. Indeed, he pointed out that the Demonstrator’s software-based capabilities in areas such as “load balancing, scheduling and print optimisation” are every bit as crucial as the more visible enhancements within the cells themselves. “When you send a print order to the machine, you are not sending it to a particular cell but to a virtual print capacity,” he explained. Interestingly, he adds that those capabilities are derived from Stratasys’ operation of its bureau services in which it uses its own equipment to make parts for customers.
Perhaps the most obvious of the more physical enhancements to existing additive technology is the entirely novel self-unloading capability that obviates the need for a human operator to remove completed parts before work can start on making a new one. This innovation involves using a roll of plastic sheeting as a base upon which new parts are fabricated. When a part is finished, the sheet is cut and the section on which the part is standing ejected into the basket. A new section is then unrolled so that a subsequent build-process can commence immediately.
The print cells themselves, Kelesoglu added, use the current “highest-end” version of company’s FDM technology to manufacture parts in ABS material, although there is no reason why other materials could not just as easily be used. Kelesoglu indicated that one multi-cell machine could quite feasibly offer print options in a range of materials with different cells supported by their own dedicated reservoir of raw material. Similarly, though, the current configuration of the machine allows for the on-board storage of enough raw material to support “six days” of unattended operation that again could easily be altered according to requirements. But whatever the amount involved, an “inventory of materials” is, as Kelesoglu observed, always cheaper to maintain than an “inventory of finished parts”.
Stratasys doesn’t yet have a timetable to bring the Continuous Build capability to the market as a commercial product. But Kelesoglu confirmed that it is working “with some urgency” to develop the concept in cooperation with a small number of real users.
One of those operations already exploring the potential of the Demonstrator is FATHOM, an advanced manufacturing and consultancy outfit operating from Oakland, California, and Seattle on the US West Coast. Co-founder and principal Rich Stump said that the company has been operating a six-cell Demonstrator at Oakland since early this year, in addition to its existing battery of over 35 standalone additive machines of various types.
Stump explained that the fundamental objective is to help push additive techniques much further “into production, not just for our company but the industry as a whole”. As such, he confirmed Kelesoglu’s belief that a key attribute of the Demonstrator is its ability to increase the volume of parts that can be made economically and efficiently without the need to invest in hard tooling. On that count he is quite specific, stating that whereas previously anything over 500 parts made tooling necessary – a relatively low number that would necessarily increase unit cost quite significantly when the capital investment in the tooling was amortised over it – that figure has now increased to around 2,000.
But Stump also made it plain that more than just cost is involved and that the Demonstrator concept also provides a number of other advantages. Perhaps the most important of those is “agility”, which he defines as the ability to make design changes in a part once production has started – something likely to prove impractical with hard tooling without scrapping it completely and making a new investment. Moreover, such changes can be put into effect in just a few “days”, whereas creating new mould tooling would necessarily be a matter of “weeks”.
Stump also confirmed that the Demonstrator’s integral scheduling capability greatly simplifies the management of the manufacturing process. “You just input the design file, tell it how many parts you want to make and then the software allocates them to the different cells,” he said.
Stump added that the machine has already been used to help fulfil real commercial contracts, including in the fabrication of parts for a very unusual and arduous application – a monitoring device attached to great white sharks by a team from the Monterey Bay Aquarium Research Institute to track the animals’ behaviour at sea down to depths of 250m.
In the immediate term, further development work to increase the range of materials that can be used and the current build envelope of 5 x 5 x 5in will be necessary, said Stump. But his answer to the question of whether the basic concept underlying the Demonstrator has been validated is emphatic and unambiguous: “Yes, certainly.”