Imagine working on something so top secret, that even the person building it didn’t have the clearance to know what it was. That was the reality of Jim Colegrove’s military and aviation composites engineering before he was brought on as part of the team that developed the OCLV (optimum compaction low void) process in 1990. Colegrove is now the head Manufacturing Engineer and has been instrumental in the development and improvement of Trek’s carbon fiber production.
We were lucky enough to get a personal tour of Trek’s Waterloo carbon bicycle production from the man himself, from start to finish. See how an OCLV Carbon trek is made, in Wisconsin, step by step, after the break!
Before any carbon ever hits the assembly line, all of Trek’s carbon bike designs start here at the Advanced Composites lab. Think of it as a test facility, where new carbon designs and layups are tested in a scale replica of Trek’s carbon production lines. Over the years there have been two common misconceptions about Trek’s carbon bikes that I’ve come across: the idea that Trek has never made any carbon bikes in the US, and the thought that once Trek’s factories overseas were “OCLV certified” that meant the end of the US made bikes – neither of which are close to being true. While Trek did start with all of their carbon production in Wisconsin, they have slowly shipped more production overseas to stay competitive, though Trek’s investment in quality control, testing, and manufacturing practices has kept the bikes from overseas to Trek’s standards.
The highest end carbon bikes however, are still very much made in Wisconsin, and the factory is pumping out new bikes on the daily.
Inside the ACL are all of the same carbon cutting and pressing tools you will find on their production floor, only in smaller quantity. This is where all of the prototype carbon frames are made and likely their pro athletes’ frames as well as the processes are developed for use in the full line. The tag line we heard over and over again was quality, precision, and repeatability. The blue machines on the top rows are individual carbon molding machines (more on these later), with a computer aided carbon cutting table below.
Above, one of the workers works on the bottom bracket/chainstay lug of either a Madone or a Domane. There were some interesting bikes hung up on the wall – bikes that I wasn’t able to get close ups of… The ACL also has its own freezer for raw carbon next to the green curing oven for finished frames.
Once designs have been finalized, tested, and approved, they begin here at Trek’s in house composite lug production line. Jim jokingly tells us to respect the no photography sign – we were allowed photography access under Jim’s supervision.
Step onto the production floor and you are greeted with the huge carbon storage freezer, which keeps all of the carbon rolls of prepreg (pre-impregnated carbon with resin already added so it’s ready to form) shown to the right in cold storage until they are needed. The out time, or the life span of the carbon rolls before use in frames, of the carbon is about two weeks – the amount that Trek removes from cold storage is equivalent to what they will utilize in less than one week’s time. Take note: no food or beverage in the carbon freezer! If you’re curious as I was, the carbon is packaged in 70lb rolls, which at $35-40/lb works out to just over $22k worth of carbon sitting there on the floor.
The rolls of raw carbon are cut into more manageable pieces in a variety of ways. The machine with the yellow bar in the first picture is one of the cutting tools, or rolls of carbon are rolled out onto a cutting table to be divided by hand. Trek uses both unidirectional and woven fibers like any bike company though what we saw was mostly UD. Woven carbon is typically used as a top layer for appearances, though it can have functional uses in frames. UD carbon is stronger since all of the fibers are oriented in the direction they are applied which allows engineers to tailor the layup to the specific use or part of the frame. Trek currently sources their carbon fiber from Hexcel (US carbon) and Toray though they have used Mitsubishi carbon in the past. You may have heard that some of the carbon Trek uses is not able to be used in non-Nato countries – this is still true, and is one of the reasons Trek’s high end bikes are still made in the US. These high and ultra high modulus carbons are actually classified as strategic materials which are not allowed into non-Nato countries to prevent them from building weapons with it instead of bikes. This also means that there is still a difference in some of the carbon fiber used between the overseas made and US made Trek bikes.
Above, each roll is printed with serial numbers specifying the material, when it was made, etc. Jim mentioned that one of the reasons aerospace carbon parts are so expensive is the amount of verification needed to certify the materials as they are made into the final product. Basically, if a plane’s wing fails, they need to be able to track each material back to the factory. For bicycle manufacturing there isn’t quite the need for such measures, so the whole process is relatively cheap comparatively.
The red film on the woven carbon, or tow (under 12,000 fibers), is a release agent. It keeps the carbon from sticking to itself in the roll and is then removed before application to the mold.
Once the carbon is on the cutting table, a laser guidance system projects patterns onto the carbon below showing where and how to make cuts. The laser moves extremely fast, which your eye sees as a complete image, but when photographing it only part of the pattern is visible depending on shutter speed. An incredibly high tech system of Sharpies and permanent markers is used to identify the pieces of carbon sheet after they have been cut.
When it comes to intricate carbon pieces that are too complicated to cut out by hand, a computerized router cuts out hundreds of pieces with the quickness. The layout of the pieces in the programing is such that there is as little waste as possible, and any left over scraps that can’t be reused are sent for recycling. Trek sends their scrap carbon to Material Innovation Technologies’ South Carolina facility for repurposing in reinforced thermoplastic applications, including aerospace, automotive, medical and recreational applications. There are three types of carbon that Trek can recycle including raw prepreg trimmings shown above, non-comformant parts (things that weren’t made to spec, etc), and returned warranty frames.
Once the small pieces of carbon are cut out on the router table, they are organized in the various bins shown to the right. Each bin corresponds to a single piece of carbon, used for a single purpose on a single bike. When bikes are scheduled to be assembled the necessary parts picked out and placed on cookie sheets with build tags specifying the bike. Next up was 2013 Madone Wednesdays!
Complex designs with small parts are prepared by workers who take the trays and begin to assemble the preformed structures which are then sent off to the molds. These were likely chainstays or fork blades being mad here, enlarge the picture to see how many tiny pieces of carbon are needed to make the dropouts.
Larger structures like the seat tube lug being made here are laid into the molds piece by piece. There are multiple instructional aid for the employees to ensure perfect placement of every piece of carbon. The mold on the top is a top tube/head tube/ down tube lug.
Once the carbon is all in place, somehow the OCLV bladder is positioned and the mold is closed up. This is a very secretive part of the whole OCLV process that we were definitely not allowed to photograph. The molds are then plugged into a 480 volt power source and the mold is placed in a giant press so the carbon is under incredible pressure from the inside and outside all while at high temperatures – this mold was currently at 195°F. The pictures above only show a few of the molding stations Trek has. Behind me was another bay of stations 3-4 times bigger than the one shown here.
After an undisclosed amount of time, pressure, and temperature the part is removed from the mold and sent to this area where they are QC’d with the various gauges shown above and are then assembled into a group according to work orders. Note that this is not the final QC for the bikes, just making sure the parts are ok to move on to the next stage. There are stringent QC procedures at each stage ensuring that once the parts reach the final steps that there are no issues.
Carbon wheels? Yeah, those are done here too. Finished rims sit on the table and an employee opens a wheel mold.
Proof I was actually in Wisconsin. No factory in Wisconsin is complete without an inspirational Vince Lombardi quote.
If post-molding machining of frames, parts, or wheels is needed they end up here in yet another machine shop. Anyone still wondering where the machines are? Here a Speed Concept frame gets the internal cable routing drilled out by a CNC mill.
Most of the machines weren’t in use during our visit (Friday afternoon), but there were so many different stations it was dizzying. Trek utilizes cellular manufacturing groups meaning all of the machining for a certain frame is carried out in one location. The station directly above is the Madone cell, with various cells for different bikes found across the factory.
If the 3D printer was one of the most interesting design tools, this was definitely one of the most interesting manufacturing tools. This massive robot, nick named Buzz, has one task and one task only – drilling spoke holes in carbon rims. The angle, size, and depth of the holes is critical enough to warrant this yellow monster that has its own cage. Rims are clamped in place on the pedestals in the center, the cage is closed, and the robot goes to work while those massive hoses vacuum up any carbon dust or shards.
If you’re not familiar with Trek’s carbon lug process, lugs are used because they allow for each part of the frame to be easily tuned to specific characteristics. It is more realistic to do so than with a monocoque – which is a term that Jim hates since he says the industry uses it incorrectly as it refers to the outer structure bearing the load without any internal support structures. However, the joints will always be the weakest part since there aren’t continuous fibers running through them. To compensate for this, Trek developed their Step Joint technology where the joint is terraced to three different interlocking thicknesses. The joint is then longer and maintains a continuous wall thickness the whole length of the joint. Epoxy resin is dispensed from a fountain on the side of what could pass as an outdoor shed. To build a bike simply fill up a cup, and mix in the glass beads. The 4 thousandth of an inch beads ensure a perfect bond in the joints by filling the tiny gaps between the parts.
I then asked how they figure out how much epoxy to use for each joint, to which Jim replied “I’m glad you asked.” The amount of epoxy is calculated based on the size of the joint and the thickness needed. Voids that hold the exact amount of epoxy needed are machined in to this block of aluminum where an epoxy artist like Manuel here spreads out the epoxy from the cup into the divots making perfect servings for each joint. This is part of the whole repeatability thing – having a bunch of extra epoxy inside the frame will lead to increased variance in total frame weight, not to mention a waste of epoxy. Exactly enough is used so that it completely fills the joint, and is over filled just enough to squeeze out the ends to guarantee a strong bond.
From there the pieces are assembled into the full bike, and Manuel uses cloths soaked in denatured alcohol to remove the excess. We didn’t to see it during our visit, but at some point the exterior of the joints is smoothed out before painting which results in the sleek finish you see on the showroom floor.
Completed frames are then loaded up on specially made carbon curing jigs and loaded into the curing oven. The jigs are made out of the same carbon as the frames, meaning they have the same rate of thermal expansion. This is very important when trying to guarantee perfect alignment, especially with how precise today’s bikes can be. With older designs it wasn’t as critical, so metal jigs were used because these are so expensive, but now all frames here use the carbon jigs. Once they are done curing, they are removed from the oven, and each bike is released from the jig.
More quality control, although this time computerized. The frame above isn’t completely situated as it would be tested, but it gives you the idea. All of these measurement devices are connected to the computer to assure perfect tolerances.
The guys who sand each frame by hand deserve some major credit. While ventilation systems keep the sanding room very clean, it was one of the loudest, harshest work places I’ve seen. I suppose with proper hearing protection and masks you would get used to it, but I wanted to leave after 5 minutes. There are a lot of stations in here, with three different bays.
Forks anyone? Finished Madones, Speed Concepts, and Sessions wait for paint. Finished or partly finished parts were everywhere waiting for the next step. Manufacturing is alive and well in Wisconsin.
In the spirit of constant improvement, and an investment in Trek’s wildly popular Project One custom paint service, a new automated paint booth was just being installed as we visited. This futuristic paint booth includes a decontamination chamber straight out of science fiction with nozzles to blast you with air, and a mat that traps dirt from your feet so that you don’t contaminate the painting area. Once installed the bikes will travel through the booth on a conveyor and the robotic arm inside will do the painting.
Once painted, frames move to the decal room where wet transfer decals are applied before the frames are clear coated.
Project One frames are diverted here before being built up and shipped out to the bike shop. We were told that this sPartHacus Domane frame was getting shipped out to Germany – we’re wondering if sPartHacus is reading, or got their bike yet?
Bicycles travel throughout the factory on a conveyor belt that travels up over a lot of the factory.
Finally, once everything is stickered, painted, and tagged they get boxed up for assembly over in Trek’s Whitewater, WI facility.
Make sure to check out parts 1 and 2 if you haven’t already!
