sintered metal-Scientists Build a Low-Cost

OK， so maybe youpowder metal aren´t interested in making your own toys， cellphone cases， or glow-in-the-dark Christmas decorations。 How about a brake drum?
Until now， 3D printing has been a polymer affair， with most people in the maker community using the machines to make all manner of plastic consumer goods， from tent stakes to chess sets。 A new low-cost 3D printer developed by Michigan Technological University´s Joshua Pearce and his team could add hammers to that list。 The detailed plans， software and firmware are all freely available and open-source， meaning anyone can use them to make their own metal 3D printer。

Pearce is the first to admit that his new printer is a work in progress。 So far， the products he and his team have produced are no more intricate than a sprocket。sintered metal But that´s because the technology is so raw。 "Similar to the incredible churn in innovation witnessed with open-sourcing of the first RepRap plastic 3D printers， I anticipate rapid progress when the maker community gets their hands on it，" says Pearce， an associate professor of materials science and engineering/electrical and computer engineering。 "Within a month， somebody will make one that´s better than ours， I guarantee it。"

Using under $1，500 worth of materials， including a small commercial MIG welder and an open-source microcontroller， Pearce´s team built a 3D metal printer than can lay down thin layers of steel to form complex geometric objects。 Commercial metal printers are available， but they cost over half a million dollars。
His make-it-yourself metal printer is less expensive than off-the-shelf commercial plastic 3D printers and is affordable enough for home use， he said。 However， because of safety concerns， Pearce suggests that for now it would be better off in the hands of a shop， garage or skilled DIYer，powder metal since it requires more safety gear and fire protection equipment than the typical plastic 3D printer。

While metal 3D printing opens new vistas， it also raises anew the specter of homemade firearms。 Some people have already made guns with both commercial metal and plastic 3D printers， with mixed results。 While Pearce admits to some sleepless nights as they developed the metal printer， he also believes that the good to come from all types of distributed manufacturing with 3D printing will far outweigh the dangers。

In previous work， his group has already shown that making products at home with a 3D printer is cheaper for the average American and that printing goods at home is greener than buying commercial goods。

In particular， expanded 3D printing would benefit people in the developing world， who have limited access to manufactured goods， and researchers， who can radically cut costs of scientific equipment to further their science， Pearce said。 "Small and medium-sized enterprises would be able to build parts and equipment quickly and easily using downloadable， free and open-source designs， which could revolutionize the economy for the benefit of the many。"

"I really don´t know if we are mature enough to handle it，" he added cautiously， "but I think that with open-source approach， we are within reach of a Star Trek-like， post-scarcity society， in which ´replicators´ can create a vast array of objects on demand， resulting in wealth for everyone at very little cost。 Pretty soon， we´ll be able to make almost anything。"

Solid Concepts 3D prints world´s first metal gun
3D printing company Solid Concepts has announced that it has 3D printed the world´s first metal gun€"other guns printed using 3D printers have been made of plastic。 Representatives for Solid Concepts say they created the gun to demonstrate how strong and accurate products made using 3D printing technology can be。

Over the past year， reports of guns being printed using relatively inexpensive 3D printers have raised concerns regarding a new way for people to gain access to weapons。 Such concerns have died down， however， as newer reports have pointed out the weaknesses of plastic guns€"they don´t last more than one or two firings。 That´s not the case with the gun printed by Solid Concepts€"engineers there fired their weapon over 50 times， with no apparent problems。

Printing with metal instead of plastic requires a whole new level of printer€"one so expensive that most could not afford to buy or even rent one， thus， news of a printed metal gun isn´t like to spark much if any controversy。 It does however， as the company that printed the gun points out， highlight just how far 3D printing has come。 In this case， the printer uses what is known as a direct metal laser sintering (DMLS) process€"metal powder is heated to create a type of ink that can be used for printing。 In the past， the process has been used to create surgical implant and aerospace parts。 The newly printed gun， created using blueprints of a real handgun formerly used by the US military， was made by printing almost all of the parts€"it was finished by assembling by hand。 No machining was necessary， just some hand tooling。 The process even included rifling (grooves inside the barrel that cause the bullet to spin as it´s ejectedsintered metal) to ensure accuracy。

Reps for Solid Concepts also note that printing their gun was completely legal€"the company holds a Federal Firearms License。 They add that the metal in their gun has less porosity than poured metal and allows for more complexity than metal that is cut using lasers。 They hope to begin selling hard-to-find gun parts to manufacturers in the very near future。