[background] carbon forged
carbon forging involves heating and compressing carbon fibers to create an incredibly strong and durable material. this material is then used to create watch cases, dials, and other components. in this case it is used to make the watch case for v02.0x. the resulting carbon forged watch is not only incredibly resilient, but also boasts a distinctive and eye-catching appearance that catches the light differently as you move.
v02.0x is a carbon forged chronograph made by resin watch lab. it uses a st1901-2 movement which is based on the Venus 175 chronograph movement. this watch uses stainless steel hardware, luminous hands, and 2 sapphire crystals. it is the first resin watch lab made chronograph and is the first mechanical movement used by this lab.
[objective] understand forged carbon manufacturing
these white-papers are intended to give readers a basis of knowledge to understand the process of hand-making high performance materials. specifically forged carbon in molded form - for watch making.
[ideal reader] the curious - the contributor
the ideal reader is seeking a better understanding of the manufacturing process and is hopefully considering the feasibility of doing it themselves. resin watch lab believes in a technologists approach, meaning that the knowledge should be open source but the execution of it is what should define the maker. if you can make one better we want you to do it - that’s how we raise the bar for watch making as a whole.
[methodology] making v02.0x
a master part is clayed and draft angled in line with the watch case body. it’s then sealed to release easily from the mold material that will be poured to the part. after a few sealing layers are applied the female mold is poured to the part. once cured its removed from the mold housing and the clay is removed. the part stays in the female mold however. another layer of seal is applied to the underside of the master part and the male mold half is poured. once cured the molds are separated, the master part is removed and the molds are inspected and refinished to ensure there are no overhangs or defects in the molds. the molds are then taken and specially heat treated to ensure durability for carbon forging.
1” chopped carbon tow is hand laminated and packed in roughly ~30+ layers into a female mold that has had drafted side walls. each layer (packed by hand) is weighed before packing to ensure consistency (pioneering watch manufacturers had noted difficulties in packing consistencies).
carbon forging is recommended to follow a 60% carbon to 40% resin ratio - in this case this ratio is being applied to a part that is less than 10 grams when the process is done. therefore the application process is slightly more complicated considering the very small amounts of materials being used. thus more resin is used than kept. 2 reasons for this, 1 the mold will help to extrude excess resin and 2 adequately laminating all the fibers with only 4 grams of resin would require switching this to a machine process.
patience and a very very slow curing resin are crucial. this is likely a multi-hour process.
carbon forging demands ppe (gloves, goggles, respirators, skin coverage, etc). a carbon fiber splinter sucks - can’t imagine it in lungs.
assuming the mold is packed consistently - the male mold is lightly pressed into the female mold and slotted into a portable press. this press will be slowly tightened- roughly every 15-20 minutes. while this occurs the mold and press will be heated in a designated oven (assuming the resin is not heat curing. this is not a process to accidentally expedite). over tightening is entirely possible, there is an ideal pressure. the mold’s seams is the best gauge of the ideal pressure as seams will touch an separate depending on under/over-tightening.
once the curing of the part is complete the mold is split using specially made relief cuts. the part is removed thanks to specifically made draft angles. essentially there aren’t perfectly flat faces, they angle out slightly so that the piece can separate from mold easily without causing damage.
the carbon forged body is then placed into a silicone mold of the master part. a laminating layer of resin will be injected into the silicone mold and perfuse the part to fill in any voids that may have persisted the carbon forging process. this will ensure a consistent and fully formed part in an otherwise very error prone process. this step solves a lot of typically difficult problems associated with carbon forging.
now that the case body is fully formed, excess materials and sanded and polished before the body is covered in a protective removable tape, preventing damage during machining. light adhesive is crucial.
the case body is placed in a rotational vice in a hand mill machine and the case back lug holes are machined using a template case back to ensure consistent fitment.
the rotational vice is placed horizontal and the case body tube hole is machined, which is where the winding/setting stem will go.
the vice is rotated +27.5 degrees from case tube center and -27.5 degrees from case tube center and a pusher hole is machined each time. these holes will be threaded and the pushers screwed in. an a additional partial hole will be machined to allow the pusher to sit tangent to the movement as the case body does have drafted angle faces and would cause the pushers to be off angle from the pusher tabs in the st1901-2.
for the final step of machining the integrated draft lugs will be machined out in .5 mm layers. this is just the generally recommended thickness for a 1.5mm tungsten carbide milling bit. a broken bit can mean a broken case and a lot of wasted time.
once machining is complete, measurements are taken to triple check depths, diameters, locations, etc.
the protective taping is removing, pushers are carefully screwed in, sapphire crystal is pressed into place, and the movement is placed in the watch. the friction fit case tube is pressed into the machined hole and the winding stem is cut and fitted with the crown.
then the case-back bezel (also carbon forged-identical process to make as case body) has a sapphire crystal pressed in and a silcon greased Hytrel "I" watch gasket is places between the case-back bezel and the case body. the case-back bezel is rotated to alignment with the machines case-back screw holes and it it pressed into place. screws and carefully set and the watch is completed.
now imagine failing a few times each step before you finish the first prototype watch.
[key findings #1]
post-forging lamination is crucial to high quality case bodies that are forged to shape. it’s certainly possible to mill the case body out of forged carbon billets but that is an entirely different process.
[key findings #2]
higher precision milling machines are a necessity for this process. case bodies are made or destroyed by a tenth of a millimeter.
[key findings #3]
hand making anything difficult requires 2 things. confidence that problems will arise - and the arrogance that a solution can be found. having accurate and higher precision tooling can make a lot of that arrogance a reality. the rest is not taking it too seriously - there are no rules.
[key findings #4]
some people prefer the first prototype’s blockier case design, others prefer a more integrated lug angle into the strap.
[key findings #5]
there are requests for different dial designs - these may need to occur during a maintenance in the future as dial making is not the expertise in house and no dial manufacturer connections make the desire quality in the desired low volume.
[key findings #6]
in house made gaskets will likely become part of the next iteration of screw down display case backs
[conclusion] testing its grit
the carbon forged components never cease to be surprising how little give even the smallest features have.
the bottom of the pass through lugs feel as rigid as the thicker case body walls and the internal lamination when milling is wildly consistent.
pushers are rigid and consistent - no movement lateral or vertical since wear.
watch has resisted steam tests, worn under ski gear, but needs to take water resistance test.
expectation is rm 55 level of water resistance (~6 bar). but wouldn’t generally encourage prolonged submerged water wear - unsure how salt water interacts with glossy laminate.
wacks - door dings- car maintenance and daily wear have shown no signs on case body.
overall, this watch is not only proving to have been a mechanical and material science moonshot for resin watch lab, but a respectable, robust chronograph. competitive forged carbon watches certainly exist in the space and this watch shouldn’t claim to outcompete in every category - however as far as handmade, limited run, forged carbon chronographs go. .. this piece should mark a new level of watch making here at resin watch lab.
[observation] “watching” a wearer
integrated pass through lugs and the draft angled faces give v02.0x a completely distinct look that would be hard to confuse with any other case.
watching others with v02.0x - it looks like a tool. it looks like it has a purpose that’s both unknown to the onlooker but has an exciting reason for being there.
the black of the carbon fiber and stainless steel don’t demand attention but when as you get to about 5 feet away you start to notice the differing patterns fo fiber catching the light.