5.19.2020 – Words by Ben Farver

For those that read last week’s Tech Tuesday titled Back to Tubes , I bet you thought we were going back to Tube to Tube style construction. Ha! Really?? No way, no how. The technology we’ve developed to make the frame junctions is unlike anything currently being done in the bicycle industry. To be honest, the composite technology most widely used to make bicycles is fairly antiquated. It is our goal here at Argonaut to utilize the most advanced technologies from the broader composite industry to create the best carbon fiber bicycle frame possible. In the case of the frame junctions, we’ve even created our own patent pending process.

The goal in making any composite part is high compression, the elimination of air bubbles or voids, and fiber orientation control. To accomplish this with our frame parts we’ve invented a unique twist on an existing technology called trapped rubber molding. Trapped rubber molding consists of laying plies of carbon on a silicone mandrel, then placing the carbon wrapped mandrel in an aluminum or steel cavity. When heated the silicone expands creating an immense amount of pressure while the resin in the carbon cures. Sealing the mold keeps the resin from being squeezed out of the part and pressurizes the entire system, creating a 100% void free finished part. Because the plies are laid on a mandrel mirroring the final internal shape, there is zero fiber distortion. High compression + void free + no fiber distortion = perfect carbon fiber frame part.

The use of trapped rubber molding technology also allows us to be much more vertically integrated, controlling every process save for actually making prepreg carbon. The key technological advancement that happened between the time I started making carbon frames and now that makes trapped rubber molding on a small, custom scale possible?… 3D printing. Before 3D printers became so accessible and accurate the mold to make a silicone mandrel could only be CNC machined. Using a 3D printer, creating silicone mandrel molds is viable on a low volume, custom scale.

The new Argonaut road frame will be offered in either pre-designed or custom geometries. Every Argonaut has a custom layup pattern based on the size, power output, and riding style of the individual rider. For those whose touch points on the bike line up with one of our pre-designed geometries, their build starts with selecting their layup pattern and molding their frame parts with tooling, or frame molds, that has already been machined. Their frame junctions are laid up on the correlating silicone mandrel.

For custom geometries, we actually cut new, custom frame tooling. This is unprecedented in the bicycle industry. No other company machines a set of molds with the actual customer’s name on them. The corresponding silicone bladder molds are printed in our 3D printer, and the silicone bladder is created by injecting liquid silicone into the cavity.

Trapped rubber molding using 3D printed mandrel molds is the only process I’m aware of that can create a perfect, custom frame part. Every other process involves some sort of compromise, whether it be quality of construction or design / geometry limitations. Our new molding technology has no limitations and makes no compromises. Perfect, custom carbon bicycles.

Thanks for reading.

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