Arburg has already shipped several production versions of its Freeformer additive manufacturing machine, with existing customers showing a lot of interest in its ability to produce 100 or so parts without having to make a mold.
“People need to make something very quickly and they only need a short run,” said Heinz Gaub, Arburg’s managing director of technology and engineering, in an interview this morning at the company’s booth at NPE2015 in Orlando, Florida. “Or a design engineering change was just made and they need a few parts quickly. “ Another great application is the quick manufacture of spare parts that are no longer inventoried.
The Freeformer, an innovative approach to additive manufacturing, was formally announced at K2013. Beta testing took place at customer sites in Europe in the second half of last year. Several materials were qualified, some adjustments were made to the technology based on customer feedback, and series production began earlier this month, with machines being made in the company’s Black Forest factory in Lossburg, Germany.
Arburg began research on an additive manufacturing machine using its injection molding expertise starting in 2005. Research was put on hold during the economic slump of 2008-2009. Research resumed, and Arburg surprised the industry with an actual demonstration of the technology on the eve of the K Fair. The technology was developed in cooperation with the University of Munich.
Arburg refuses to discuss the market price for the Freeformer, but a very rough guess would put the machine in the area of a quarter million dollars. Arburg also will not disclose any of its customers or initial applications, but several blue chip German companies have major additive manufacturing labs. They are also important customers of the injection molding industry and they would seem to be logical landing spots for the machines. They include Mercedes, Siemens and Braun.
Many of the customers interested in the Freeformer are using it to make very complex parts that are too expensive or are just plain impossible with any conventional manufacturing technique, even five-axis machining. Arburg supplies two “injection units” so that customers can either do two component parts or use a water-soluble support system to make very complex parts. The support system is easily washed away post production. The material is polyvinyl/pyrrolidone (PVP), a polymer supplied by BASF. It’s also used a binder in pharmaceutical tablets. BASF pioneered PVP 50 years ago.
The big advantage of the Freeformer over existing additive manufacturing systems is its ability to use standard plastic pellets. Some other additive manufacturing systems such as Fused Deposition Modeling can also use standard plastics, but they are supplied as cartridges that are significantly more expensive than standard pellets. They can be as much as 100 times more expensive. Other systems use proprietary plastics that are also very expensive and are often not useful as functional replacements for standard plastics.
The Freeformer uses a traditional molding plasticizing unit with a specialized screw that helps maintain a steady 500 bar pressure so there is enough force to push molten resin through a tiny nozzle that creates droplets via a pulsing force. Parts are made one drop at a time so the processing speed for the Freeformer is still slow, and in the same ball park as competitive additive manufacturing systems.
The amount of residence time in the barrel is greater than in standard injection molding and is on the edge of what plastics can tolerate. So far, though, so good, Gaub said in the interview. The other potential issue with the Freeformer is the processing of glass-filled compounds. Getting the fiber through the nozzle is problem one. Corrosive wear on the nozzle is problem two.
Another issue will be developing new technology that will allow use of high-heat plastics, such as Ultem polyetherimide. PEI is a good candidate for the Freeformer because it’s widely used to make complex parts for aircraft applications, where time and cost is less critical than in the automotive industry. There is also a huge push to find lightweight plastics applications to replace metal.
Plastics already qualified are ABS, polycarbonate, polyamide 12, thermoplastic elastomer and PVP. Development work is under way on polyamide 6 and PBT-type polyester. PEEK is also a down-the-road candidate.