A couple millennia ago, tens of thousands of spectators watched gladiators fight to the bitter end in the world-famous Roman Colosseum. Crowds roared to the clash of metal-on-metal: steel swords against bronze armor, all crafted by the most advanced metallurgical techniques the world had ever seen.
We’ve come a long way as a civilization since the days when mortal combat was a national pastime, but the thrill of watching two (or more) warriors engaged in a no-holds-barred melee remains. In the modern world, blood and sweat have been replaced by oil and hydraulic fluid. The gladiators and the craftsmen who armed them have merged into a single unit, as teams of highly skilled engineers, technicians, and operators pit their robotic fighters against each other in brutal matches of machine versus machine.
From Gladiators to Battlebots
Although the ancient Romans would no doubt be mystified at much of the technology involved in a Battlebot battle, there’s also a lot that would be familiar: many of the weapons are essentially derivatives of the same things gladiators were swinging and hurling at each other all those centuries ago, such as spikes and spinners.
Some of the techniques that are used to build battlebots would also be recognizable, albeit in much more sophisticated forms: stamping, forging, welding—the technological gulf between a gladius and a spinning bar is not as far as one might think.
Of course, we shouldn’t discount the difference that hundreds of years of technological progress can make. The Ancient Romans might still have a thing or two to teach us about concrete, but when it comes to machining and metallurgy, there’s really no comparison to be made. The best way to see this is with a specific example, so let’s take a look at one modern competitor, aptly known as Bloodsport.
Meet Bloodsport
The technical specs won’t tell you the whole story of this stalwart heavyweight and its dedicated team of more than a dozen technical experts. Bloodsport’s designers, builders, and operators come from backgrounds ranging from mechanical engineering to video game design. The version of Bloodsport you see above is actually the team’s third iteration, and you can see how far the bot has come by looking back on the bot’s first and second generations, as well as the prototype in between.
“Bloodsport is our bread-and-butter combat robot,” said Justin Marple, Bloodsport’s driver and team captain. “We’ve also been developing other robots off to the side, but Bloodsport’s the one that most people know.”
What makes Bloodsport—or, more specifically, this version of Bloodsport—unique, is its incredible comeback after its 2023 Battlebot matchup against Caustic Creations heavyweight, Copperhead.
Battle of the Bots: Bloodsport vs Copperhead
Aaaaaaand in this corner: the clobbering Colorado crusher, weighing in at 250lbs and armed with an eggbeater drum spinner, iiiiiiit’s Copperhead!
The two teams faced off against each other in the first Fight Night of Battlebots World Championship VII in Las Vegas, which aired in January of this year. As Marple tells it, that first fight did not go in their favor:
“We were facing Copperhead—they’re a big drum spinner—and there was a big ‘One-Hit K’ in the first match. Basically, all of our weapon’s energy went into theirs, and all of their weapon’s energy went into ours, so we flew across the arena and, unfortunately, we landed upside down. Now, the top of our robot had a housing that’s 3D printed. The reason for that is that we were worried about raising the center of gravity and we thought, at least for certain robots, that we wouldn’t need the metal. Of course, when you have a 250-pound robot land upside down onto a 3D-printed piece of plastic, it shatters into a million pieces. Then the whole head went up in flames, so we lost the match.”
In the days of Ancient Rome, a gladiator’s head going up in flames would most likely be the end of his career but, fortunately, in the realm of Battlebots, it’s only a setback. Of course, for Team Bloodsport, this setback required some creative thinking and speedy manufacturing.
“We got out of that fight at 8pm that night,” Marple explained, “and we had 48 hours to produce something else that would work in our next fight against a robot called Gigabyte, which was also a very high-energy spinner, so we knew there was a high potential to flip over in that match as well.”
Enter Protolabs
Bloodsport’s team was faced with a classic engineering crunch: 48 hours to design and build a new component to fix a fatal design flaw. The original housing was 3D-printed from TPU for shock absorption, but plastic clearly wasn’t going to cut it in the next match. The team worked from 8pm that night until 4am the next day coming up with a solution.
“We took the original design that was made out of plastic and iterated on it, basically redesigning the whole head so it could be machined out of aluminum [AA7075],” Marple said. “One of the challenges was that the plastic part was much thicker, so we had to figure out how to shrink all of the dimensions, otherwise it would’ve weighed ten pounds!”
By 4 am, the team had their design for the new housing, but with only 36 hours to go, the next issue was how to get the replacement part in time for Bloodsport’s match with Gigabyte.
“We had experience with Protolabs with rapid prototyping when we were testing the robot before the event,” Marple said. “There was an issue with our weapon system because it has two bearings and a nut on top, and the nut was overtightening and causing the weapon to seize. Protolabs made us an aluminum spacer to put between those bearings, and we got that in three days, so we already had confidence in the process. We were pretty sure that if we sent them the design, they could send us the part in time for the next match.”
Marple and his team reached out to Protolabs in the morning and explained their situation: “We woke up at 8am, called up Protolabs and said, ‘We need this part. Can you get it to us by tomorrow evening?’ and I don’t understand how it’s even possible, but they managed to do it! We ran it for the rest of the matches, and we didn’t have a single issue.”
From machining the parts in Minnesota to shipping them to Las Vegas, the whole endeavour took Protolabs less than 36 hours.
Quick-Turn Manufacturing to the Rescue
As a former software engineer for a 3D printer company, Marple had seen the impact of quick-turn manufacturing in industrial environments firsthand. “In the past, it took five months to do a prototype for a single printer,” he explained. “Now it’s closer to two or three per week! The industry is just getting faster and faster and you need companies like Protolabs to stay competitive, where you can get parts right away instead of waiting three or four weeks to get them from China. The digital manufacturing world has exploded over the last few years, and to see it at this level is kind of mind-blowing as an engineer.”