Hybrid additive manufacturing machines combine some degree of construction layer by layer using an additive process with conventional subtractive machining. For example, the idea behind Matsuura’s Lumex Avance 25, which features laser sintering of metal via Yb fiber laser and high-speed milling, is to speed up production of mainly mold and die components. Laser sintering adds layers of material, and the machine’s milling spindle then machines the material to ensure a quality surface finish. The production of mold cores and cavities in this manner takes advantage of the additives’ abilities to produce molds with conforming cooling channels and to alter the sinter density in molding applications that require the placement of porous structures to facilitate gas evacuation. Additionally, laser sintering helps produce deep features by building them one layer at a time, eliminating the need to etch them via EDM.
The company has since introduced a larger model, the Lumex Avance 60, which opens up the technology to larger applications in new industries, such as aerospace and automotive. This model accepts a maximum XYZ part size of 600 Ã 600 Ã 500 mm (compared to 260 Ã 260 Ã 100 mm for the Lumex Avance 25 model) and a maximum weight of 1300 kg. It also has a 1 kW Yb fiber laser source against 400 W for the Lumex Avance 25 model, increasing the sintering speed. Its milling spindle goes up to 45,000 rpm and the automatic tool changer carousel has the capacity to hold 20 tools (the maximum tool diameter is 10mm).
The eight-cylinder engine block on display at the Japan International Machine Tool Fair (JIMTOF) (see above) shows a possible application of this technology, although it is only a partial construction, in part, to show the areas where the additive process was able to reduce weight. A full 9.6 kg version of this engine block made of AlSi10Mg material (including supports) was completed in 95 hours (90 hours for sintering and 5 hours for milling). Total production time including bracket design, programming, fixture design / manufacture, setup, etc. was 15 days. Although it may seem like a long time, the company’s tests on a five-axis machining center showed that it would take around 22 days to machine the engine block from a solid blank, including the time for the design / manufacture of assembly, programming, machine configuration, etc. .
The Lumex Avance 60 on display at the show also included the company’s Automatic Powder Recovery (APR) system which filters unused powder through a sieve and collects it in a tank. This powder is automatically returned to the machine for reuse. A range of powdered materials are available from the company, including maraging steel, titanium TI6A4V, stainless steels 630 and 316L, cobalt-chromium superalloy, nickel 718 and AlSi10Mg.