The 3D printing world is rapidly moving towards serial part production, which includes also a number of new technologies emerging that are directly aimed at volume production. One of these companies is Evolve Addititive Solutions, which has developed a new additive manufacturing technology called Selective Thermoplastic Electrophotographic Process, or STEP.
Steve Chillscyzn, the CEO of Evolve, and who himself comes from an engineering background, says the company differs from other 3D vendors: “Our entire mission in life is to be creating for production. We could do prototyping but we choose not to, which means that we don’t have a legacy of having to worry about all the things that prototyping does.”
Evolve, which is a spin off from Stratasys, was founded in 2017 and has raised some $19m in equity funding from a number of investors that include Lego and Stanley Black and Decker, Stratasys and an as yet unnamed company. Chillscyzn claims that STEP is the first true polymer manufacturing technology, which of course nobody else has ever said to a room full of journalists before. He continued: “There’s over 100 patents that define STEP and another 100 others that we’ve licensed from other companies that help support it so millions of dollars have been spent on this.”
The STEP process is interesting, at least to those of us that have come from the commercial print world, because it builds on the standard electrophotographic process, which is the basis behind most office copiers as well as many commercial production printers. Thus a full-width LED bar is used to write each layer to a photoconductive drum, which attracts the toner to the image areas, and the toner is then pressed onto a base or the previous layer, followed by an IR fusing unit to fix it. Other companies have looked at this approach but Evolve says that it was the first to solve the problem of charge build-up that prevented others from building 3D parts of useful thickness, adding: “We believe it was a fusion of 2D and 3D printing thinking paradigms that helped us to come up with this breakthrough which is a true paradigm shift in the industry.”
The company has built its own printer, the Evolve SVP, which stands for Scaled Volume Production. The first of these has already been installed as an alpha version sent to a strategic partner in 2018. Chillscyzn says: “The Alpha stage is key to our progress and provides the necessary feedback to R&D to get to commercialization.” He adds: “That system has been performing above expectations and the results have been phenomenal.” The company is currently taking orders for beta versions, which it is planning to ship in 2020.
Evolve has designed the SVP but is buying in sub assemblies from some partners and then building the machines themselves at its plant in Minnetonka, USA. The SVP has in part been based on a Kodak Nexpress EP press. Chillscyzn says: “We chose it because it’s the most robust machine in the world. We need to be able to produce millions of parts and that’s the most reliable.” He adds that using a standard 2D printer like the Nexpress has allowed Evolve to keep costs down, making their parts cheaper than those produced from other 3D processes.
Kodak is supplying the 600dpi imaging unit from a Nexpress as a complete sub assembly. Evolve will also take advantage of Kodak’s operator replacement component model where spare parts are stored near the machine and operators trained to install them to help keep the machine running.
A standard electrophotographic press has four stations for the process print colours – cyan, magenta, yellow and black – though the Nexpress has room for a fifth colour or special effect. Each colour station is a complete print engine, with laser writing and photoconductive drum. Evolve is planning to use each of the colour stations to lay down a separate material. In theory that means that up to five materials could be put down to create each layer before they are fused together, so that it’s possible to build parts with multiple materials. In practice, Evolve is planning to ship the SVPs with four print stations, with the initial machines running just two of these, loaded with ABS part material and ABS support material. Evolve says that as other materials become available, customers will have the option to make multi material parts by using two different materials in the print stations.
Chillscyzn adds: “We print a layer in 4.5 seconds and can fuse all these materials at the same time. Today these materials have to match thermally but we can have different materials in the same layer.” He says that the company is planning to speed up the machine to one or two seconds per layer.
The SVP uses IR heating after each layer is printed to fuse the layers together, and although there is some shrinkage the system can cope with this. Chillscyzn says there’s less shrinkage than other approaches because they are managing the heat layer by layer. The parts come out finished and ready to use from the machine. The SVP has a build area of 600mm long x 300mm wide x 100mm high.
Evolve is partnering with other companies, both to create a finishing unit to work alongside the SVP and to develop simulation software. Evolve will work with a range of existing software, with Chillscyzn explaining: “Manufacturing Industries don’t really like proprietary software. It’s expensive to implement and more expensive to maintain. Customers want to be able to integrate with what they have.”
Evolve says that it will work with multiple partners to supply materials though so far most of the materials appear to come from Evonik and appear to be standard polymer-based materials converted into toner particles. Evolve has said that it is using a toner manufacturing process that’s been developed by Kodak to make the part toners for the Evolve system. Evonik, which was founded in 2007, has produced a range of specialty polymer powders such as PEBA and PEEK, as well as its Vestosint range of Polyamide 12 powders. For Evolve, it will mostly be supplying PA 12 and PEBA polymers. Chillscyzn said at the press conference that Evolve will look to license materials from other suppliers but the price will have to make sense at volume.
Chillscyzn says that the 3D printer industry does have to develop applications that will give good ROI to likely customers. Evolve has had some success with plating ABS parts so that they look like metal to add value, and he added: “We want to deliver more materials and embedded electronics.”
Certainly the possibility of embedding electronics directly into printed parts does sound interesting though this is some way off. For now, it’s possible to pause the build and move the part to a separate unit that could insert an electronic component and then be returned to the SVP to complete the build. Evolve says that another option is to print electronic circuits on the final part, which should be possible due to the high quality of the surface finish that the SVP can achieve. However, in a statement, the company added: “We see this as a future capability as we introduce a STEP system which is track based.”
It’s also worth noting that several other vendors, notably HP, have also talked about inserting electronics into parts but all appear to be at the same stage as Evolve.
Chillscyzn says that when developing the system, Evolve talked with 700 or so companies worldwide to find out what they wanted from an additive manufacturing system. He says that those requirements can be boiled down to five things: it has to meet the cost they expect; it has to be fast enough for real production; the materials have to be real thermoplastics; the quality of the printed parts has to match that of injection moulding; and it has to be scaleable. Naturally, for the purposes of a press conference Chillscyzn says that the STEP system can meet all of these criteria though they mostly seem to me to be quite subjective, especially since Evolve is not able to elaborate on the most important of these, the pricing.
Instead, Evolve says that it is still finalizing pricing for each of the components in the SVP system. The company added: “Internal benchmarking is demonstrating that the SVP is an extremely cost competitive system due to its capability to nest many parts very close together and very fast build speed, in addition to using base engineering plastics like ABS that already have commercial economies of scale.” Perhaps a more useful indicator at this stage is the involvement of the Danish toymaker Lego, which Chillscyzn says has invested for production flexibility to produce actual parts rather than injection moulding.
Another issue will be that of scaleability. Chillscyzn suggests that people can add another print engine to achieve more volume, which is a typical answer for people selling equipment but less popular for those buying that kit. In the commercial print world people did indeed buy multiple production printers and there are plenty of companies with several Nexpresses sitting side by side. But more recently they’ve been replacing those with inkjet machines, which simply offer higher production volumes than toner.
So in this context it’s perhaps worth noting that Evolve’s parent company, Stratasys, also owns a chunk of Xaar 3D, which is developing an alternative, inkjet-based system – High speed sintering – that’s also aimed directly at serial part production using polymer materials and which is also looking to install beta machines.
But regardless, there are still plenty of good reasons for continuing to use toner printing in the graphics world and the STEP technology remains interesting precisely because it offers high volumes of good quality parts at reasonable costs and, at the very least, appears to be a good alternative to injection moulding. We’re bound to hear more about this next year as Evolve starts installing its beta machines and if the company can make good on its promises to print multiple materials side by side, and to embed electronics, then it’s likely to go far beyond the beta stage.
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