Exclusive Tesla Cybertruck Factory Tour Shows How The Engineers Made It Buildable

The Tesla Cybertruck has received tons of criticism for the build quality of its edgy, stainless-steel body, with loads of car websites ripping on prototypes and Elon Musk himself  reportedly voicing his displeasure and mandating strict LEGO-like build quality standards. So it’d make sense if you’re curious how the truck is built, and how those mandates are followed; the good news is that manufacturing experts at Munro & Associates have gotten an exclusive tour of the Cybertruck’s body stamping factory. Here’s what they saw.

The stainless steel exterior panels of the Cybertruck are one of its prime standout features, though construction presents some engineering challenges. With no coatings or paint on the panels, the stainless steel must be as corrosion resistant as possible. This requires careful selection of material, as not all stainless steels are as stainless as you might hope. Beyond that, the fabrication process must not mark the panels in the slightest, as there are no layers of primer and paint to hide these sins. To show and explain how Tesla conquered these problems, Munro gets a tour from Lars Moravy, the VP of Vehicle Engineering at Tesla. Along with Moravy’s commentary, we’re treated to insights from a number of Tesla plant crewmembers who stayed back after-hours to share their knowledge. Access like this isn’t something you get every day, either. Some automakers strictly limit even their own employees from sharing video or photography from inside a plant to protect their accumulated manufacturing knowledge.

It’s Called ‘Hard Freaking Stainless.’ And It Arrives In Rolls

Tesla uses a custom stainless steel alloy for the Cybertruck. It’s referred to as Hard Freaking Stainless, or HFS (yes, really). It was formulated to be hard and highly corrosion resistant while still maintaining enough ductility to be readily formable during manufacturing. As we’re shown in the video, Tesla receives HFS not as flat sheets, but on giant rolls. These must first be unrolled and flattened out before following manufacturing operations can begin.

This is all achieved on a laser blanking line which Tesla developed with Schuler. After the large rolls of stainless steel are uncoiled, they pass through rollers that act as straighteners. This works out any residual internal stresses in the material that would want to keep the material in its curved, coiled state. The process requires finesse, as overdoing things at this stage can “work harden” the material, which would cause it to fail in the bending processes later (a metal’s ability to bend is important when you’re forming it).

Once flattened, the sheets of stainless steel are cut into blanks using a pair of lasers. Moravy notes that they are currently achieving roughly 80% utilization of the panels. That’s a pretty solid figure, with the rest sent to the line’s dedicated stainless steel scrap collection. A lot of that is down to the shape of the Cybertruck’s panels, which are fairly square, making them easy to nest, Moravy notes. It’s also supported by the fact that the rolls of stainless steel are sized to the specific parts being produced, which also helps reduce wastage.

No Paint To Hide Defects, So Stacking Is Tricky

Once cut, the blanks are carefully stacked by machine, with Moravy explaining that it’s a delicate process. The stainless parts are naturally hard enough to scar each other, so they have to be placed down gently without scuffing or rubbing against each other, causing defects. As Munro notes, it’s typical to cut such parts with a plastic coating on to avoid minor scratches and damage during handling, but Tesla doesn’t do that here. With no coatings, there is naturally less waste and no need to add the step of peeling it off at some point during the production process.

We’re also filled in on the thickness of the stainless steel used in the Cybertruck’s panels. The doors are 1.8 mm thick, or roughly 0.07 inches thick. The other panels are thinner, at 1.4 mm (0.055 inches). Engineering efforts during the development of the Cybertruck were key to slimming the required thickness down. “We worked hard to get that strength up on the stainless,” explains Moravy. “The original, we were about 2.5, 3 [millimeters thick]… we actually increased the strength of HFS over time.”

Quality Control

Periodic quality checks are carried out on the blanks using a 2D scanner. The camera or machine vision component appears to be mounted quite high above the scanning bed, such that we don’t see it in the video. The outline of the flat blank is compared to a digital template and the system shows markers at various points indicating compliance. It’s a key tool for the team to ensure that panels are being produced to the exact right dimensions, because if the blanks are off, the final parts will be as well.

Why Tesla Needs Stamping Dies That Wear Out Quickly

Next up, we’re treated to a look at one of the dies used to stamp the inner panels for the front doors. Each door is made up of the flat stainless steel outer, which forms the outside body of the car, and an inner panel that adds structure and serves to mount the interior trim and hardware. “Forming stainless as an A surface is kind of hard because you get drag marks and what not, so we had to work really hard on this process as well” explains Moravy. For those outside the automotive business, a Class A surface basically refers to interior touch points and exterior panels that must have absolutely top-tier surface finish and aesthetic quality.  On a normal car, paint and finishing would hide many flaws, but the all-stainless construction of the Cybertruck doesn’t allow that.

As you might expect, the stamping die looks pristine, with visibly smooth and shiny surfaces. That’s no surprise, because whether you’re stamping or casting something, the part’s surface finish can only be as good as the die’s surface finish. Thus, to produce high-quality stamped parts that look nice and flat and shiny, you need a die with excellent surface finish just the same.

The die inserts are made with an aluminum bronze alloy on its as this allows the production of stainless steel parts with minimum to no drag marks. The inserts are hardened and have a coating on top to give them the best possible longevity. Aluminum and its alloys aren’t really the most hard-wearing materials for constructing press tooling, but it’s a necessary compromise here to produce mark-free parts. It’s also explained that Tesla is still experimenting with different lubricants for the press process for the best possible results.

Munro is amazed the aluminum bronze is being used for stamping , but Moravy explains that it’s working well given the constraints. “When you use steel we get drag marks, [but] you know aluminum can’t last, right?” says Moravy. “So we obviously have to replace these inserts a reasonable amount of time but they’re lasting quite a longer than we thought they would.” At this stage, the plant has only run around 1,000 to 1,200 stamps for each part. “I think we’re gonna get about, based on our prototype trials, anywhere from 50 to 100 before we start doing rework” says Moravy. An engineering interpretation would suggest he means 50,000 to 100,000 stamps, not merely 50 to 100. If it were just 50 to 100, there’d be no way to build the Cybertruck in real numbers as the press tools would be getting serviced every few hours.

All in all, it’s clear Tesla has done some novel engineering on the manufacturing side. “I’ve never really stamped stainless steel without a coating” says Munro. “I don’t think anyone has,” replies Moravy. “Certainly not for an A-surface quality part.” Without checking every plant in the world, we can’t verify this, but stainless stamping for automotive isn’t exactly common, regardless.

We next get to see the hot stamp process, which produces the door rings (or “body side inners”) for the Cybertruck chassis. The line has three furnaces each with seven chambers, which can heat 21 blanks at a time ready to be pressed. The blanks are heated up to 900°C (1652°F) before they are plucked out by a robot and put in the press. The press brings the upper and lower dies together, and holds them in place for around 6 to 8 seconds, with water running through the dies to help quench the part. The parts are then ideally unloaded into racks automatically by a robotic racking system, but it’s not quite implemented yet. The video of this process is only compromised by one thing—industrial safety. If you ever find yourself filming in a modern automotive plant, you’ll quickly tire of trying to shoot through metal grids and plastic shields as I did in my former career.

‘Airbending’

Perhaps most interesting, though, is the bending process used to produce the Cybertruck’s door panels. Moravy refers to the process as “airbending.” Typically, in the sheet steel bending world, that refers to a bending process where the sheet metal doesn’t fully bottom out in the tool, versus bottom bending, where it does. But the airbending process used on the Cybertruck panels actually involves a cushion of high speed air blown through the bottom press tool to float the metal panel. When bending a door panel, the bottom surface is left unmarred by the tool because it sits on this cushion of air. This surface then becomes the outer surface when assembled on the car. The upper press tool does contact the inner side of the outer door panel, but as this isn’t seen, the small amount of marring that does occur is not a problem.

We get to see one of the door production cells in action. A robotic arm with what appears to be a suction gripper picks up a stainless steel blank. It then places it in the air bending tool, with a Trumpf TruBend 5320 press performing the first bend in the part. The robot then rotates the work piece so the second bend can be performed. The part is measured by the bending machine during the process to ensure the bends are to the correct angle. The parts have a 5mm (~0.2 inch) internal bend radius according to Moravy. Once complete, the robot delivers the part to an output conveyor where it can be retrieved from the cell.

Notably, even though only the outer side of the door panel gets an air cushion, even the inside door panel surface looks great. Minimal marring is visible in the video, though it would be likely more apparent in real life. The door panels may be just millimeters thick, but that doesn’t mean they’re not tough. “It takes about 75% of the side crash loads, just through the panel itself,” Moravy explains. He notes the extra thickness versus the other Cybertruck panels provides desirable stiffness in this area.

Trying To Keep These Unpainted Panels Looking Good Is Like Walking On Eggshells

The door panels themselves must be assembled, with the simple bent outer paired with the pressed inner. Naturally, this poses a challenge—how do you join the two without marking particularly the outside panel?

It’s actually a fairly straightforward process. The inner door panel first gets welded to a hinge reinforcement panel for added strength. The combined part is then laid atop an exterior door panel. A laser welding process runs around the perimeter of the inner panel, welding it to the back side of the exterior panel. It took a great deal of tweaking over many months to achieve this process without heat marks, distortions, or burn through being apparent on the outer surface of the Cybertruck’s doors.

There are some minor burn marks that are visible on the welds between the inner and outer door panels on the back side; where these are visible in the final product, a laser ablation step burns these off. The outer door panel also has two sound-deadening pads stuck inside to dampen noises and vibration. Final finishing of the door is achieved by a pair of robots with buffing pads that run over the complete door.

“As you can see, with all the equipment, we’re ready to roll at like, high volume,” says Moravy, while noting that the plant is currently not operating at full speed. He explains that quality is the first priority, with production running slowly until that task is mastered. One thing that’s also apparent in the video are the swathes of unused space on parts of the factory floor. For now, some of it is taken up with parked construction vehicles, but in time, it could prove useful space to add more manufacturing capacity.

We also get some side manufacturing lessons, too. Munro pays great credit to the supplier choices for tooling at the plant. It’s very much personal taste, of course, but engineers like Munro place great stock in the lessons learned from industrial experience. He quotes an old adage he lived by in his manufacturing days—”Don’t save me any money, I can’t afford it,” says Munro. It’s a sage piece of advice. While some brands of machinery may be more expensive, if they produce better parts, fewer defective parts, or cause fewer problems for engineers to solve, they probably save far more money in the long run. The initial cost of a machine is often quite small compared to the potential losses from downtime when a broken machine can’t make parts and holds up a whole plant.

Overall, it’s rare that an automaker welcomes in a video crew to show you exactly how they’re doing something. It’s even less common when it’s something brand new and interesting. Obviously, the Cybertruck and its stainless steel construction are fairly unique and novel, and it’s probably unlikely any other automakers will be rushing to replicate its work. In any case, though, it’s always interesting to learn about how cars are made, especially when they’re a bit weird like this one. It’ll be interesting to see how Tesla is able to crank up volume, and whether the company can keep the quality up.

Image credits: Munro Live via YouTube screenshots, Lewin Day (diagram)