Inside Giant's Taiwan frame factory - part two

How the world's largest bike manufacturer builds carbon fibre frames

In part one of this four-part series, we showed you how Giant takes rolls of raw carbon fibre and turns it into usable unidirectional pre-preg fabric. Now we'll show you how Giant takes that material and turns into a frame. The process is much more involved than you might expect.

While carbon fibre is more correctly described as 'carbon fibre reinforced polymer', it's the fibre that gives the part its incredible structural properties; the epoxy resin is just there to hold everything together. Every carbon fibre frame is made of a collection of individual pieces – some as small as a SIM card – and all of them have to be placed and orientated precisely in order for the end product to work as intended.

See also

Giant bicycles' taiwan factory

Video: Inside Giant Bicycles' Taiwan factory

It's not a matter of pulling a lever and spitting out a complete frame as if one were moulding plastic toys. According to Giant, just one frame can take up to nine hours to build from start to finish.

Pieces of the puzzle

It's difficult to envision just how many different pieces of carbon fibre are used in a factory of this scale.

According to Giant, a full composite frame such as the flagship TCR Advanced SL comprises more than 500 individual swatches with additional variations for each size. Each frame model then also has its own specific set of pieces, and Giant makes dozens of different carbon fibre frame models. Even when two models share the same exterior shape – and thus, use the same mould – their fibre contents are usually different, requiring yet another specific collection of pieces.

Do the math and it's a staggering number of little chunks of carbon fibre material to keep straight.

Each carbon fiber frame is composed of hundreds of individual pieces of material. larger sheets are cut into those puzzle pieces here: each carbon fiber frame is composed of hundreds of individual pieces of material. larger sheets are cut into those puzzle pieces here
Each carbon fiber frame is composed of hundreds of individual pieces of material. larger sheets are cut into those puzzle pieces here: each carbon fiber frame is composed of hundreds of individual pieces of material. larger sheets are cut into those puzzle pieces here

Each carbon fibre frame is made up of hundreds of individual pieces of material

Each of those pieces of carbon fibre starts out the same way, however. Up to six rolls of pre-preg fabric (which are made in-house) are loaded on a big carousel that can be rotated to access the specific type of fabric required for a production run.

Sheets are first rough-cut into more manageable pieces, and then the individual swatches are stamped out on hydraulic presses like high-tech cookie dough. Afterward, each 'cookie' is individually marked, collected, and (very carefully) sorted into labeled bins.

Different types of carbon fiber pre-preg sheet are queued up on this rotating rack: different types of carbon fiber pre-preg sheet are queued up on this rotating rack
Different types of carbon fiber pre-preg sheet are queued up on this rotating rack: different types of carbon fiber pre-preg sheet are queued up on this rotating rack

Different types of carbon fibre pre-preg sheet are queued up on this rotating rack

All of this is also done in a climate controlled room so as to prevent premature resin curing – a critical requirement given Taiwan's tropical setting.

Every room that handles uncured carbon fiber is controlled for temperature and humidity: every room that handles uncured carbon fiber is controlled for temperature and humidity
Every room that handles uncured carbon fiber is controlled for temperature and humidity: every room that handles uncured carbon fiber is controlled for temperature and humidity

Every room that handles uncured carbon fibre is controlled for temperature and humidity

It's one thing to keep all of those little bits sorted and separated but it's another entirely to make sure they're all placed where they need to go in a mould. Giant's solution for minimising errors and maximising the efficiency of the process seems particularly clever.

Needless to say, workers had better read carefully before depositing carbon fiber pieces in here: needless to say, workers had better read carefully before depositing carbon fiber pieces in here
Needless to say, workers had better read carefully before depositing carbon fiber pieces in here: needless to say, workers had better read carefully before depositing carbon fiber pieces in here

Workers had better read carefully before depositing carbon fibre pieces in here!

Every frame sub-assembly is visually depicted on one or more corrugated plastic boards with individual spots for each piece of carbon fibre. Every spot is clearly labeled, in text and images, and outlined with rigid borders that correspond to the actual shape of the piece.

In other words, if it doesn't fit in the box, it isn't supposed to be there.

This is one of the secrets of giant's world renowned carbon frame production. most frame assemblies are depicted on these build boards, which organize all of those little pieces of carbon fiber into a visually intelligible layout. each board contains pieces required for a specific frame section along with brief guidelines for where each piece is supposed to go: this is one of the secrets of giant's world renowned carbon frame production. most frame assemblies are depicted on these build boards, which organize all of those little pieces of carbon fiber into a visually intelligible layout. each board contains pieces required for a specific frame section along with brief guidelines for where each piece is supposed to go
This is one of the secrets of giant's world renowned carbon frame production. most frame assemblies are depicted on these build boards, which organize all of those little pieces of carbon fiber into a visually intelligible layout. each board contains pieces required for a specific frame section along with brief guidelines for where each piece is supposed to go: this is one of the secrets of giant's world renowned carbon frame production. most frame assemblies are depicted on these build boards, which organize all of those little pieces of carbon fiber into a visually intelligible layout. each board contains pieces required for a specific frame section along with brief guidelines for where each piece is supposed to go

Most frame assemblies are depicted on these build boards, which organise all of those little pieces of carbon fibre into a visually intelligible layout

Gathering up pieces for a frame, therefore, is sort of like filling out an order form: workers simply match up the description in the tray compartment with the storage bin and if it all goes well, that piece of carbon fibre should fit perfectly.

We've already pointed out the enormous number of individual pieces of carbon fiber that need to be organized in the giant factory on a daily basis. however, look at the shelves overhead, too. they're absolutely loaded with additional build boards that weren't in use on that particular day: we've already pointed out the enormous number of individual pieces of carbon fiber that need to be organized in the giant factory on a daily basis. however, look at the shelves overhead, too. they're absolutely loaded with additional build boards that weren't in use on that particular day
We've already pointed out the enormous number of individual pieces of carbon fiber that need to be organized in the giant factory on a daily basis. however, look at the shelves overhead, too. they're absolutely loaded with additional build boards that weren't in use on that particular day: we've already pointed out the enormous number of individual pieces of carbon fiber that need to be organized in the giant factory on a daily basis. however, look at the shelves overhead, too. they're absolutely loaded with additional build boards that weren't in use on that particular day

We've already pointed out the enormous number of individual pieces of carbon fibre that need to be organised in the Giant factory on a daily basis. However, look at the shelves overhead, too. They're absolutely loaded with additional build boards that weren't in use on that particular day

Once those trays are filled, they're then loaded into covered carts and transported to another climate-controlled room where the pieces are laid up into frame pieces.

Complete build boards are loaded into rack for transport to the next station. the carts are sealed up before leaving this climate controlled room to help keep the carbon from curing prematurely: complete build boards are loaded into rack for transport to the next station. the carts are sealed up before leaving this climate controlled room to help keep the carbon from curing prematurely
Complete build boards are loaded into rack for transport to the next station. the carts are sealed up before leaving this climate controlled room to help keep the carbon from curing prematurely: complete build boards are loaded into rack for transport to the next station. the carts are sealed up before leaving this climate controlled room to help keep the carbon from curing prematurely

Complete build boards awaiting transportation to the next station

While Giant takes great efforts to remove potential errors from the process, actually assembling all those little pieces of carbon fibre is still highly labour intensive. There's a massive amount of tooling involved, too.

Some frame sections are built straight from bins: some frame sections are built straight from bins
Some frame sections are built straight from bins: some frame sections are built straight from bins

Some frame sections are built straight from bins

Frame sections are built up on a mix of rigid plastic mandrels, internal silicone rubber moulds, and steel inserts. The mandrels provide workers with a solid surface on which to lay the carbon pieces and since they closely approximate the desired negative space of the frame, those carbon pieces are more likely to stay where intended after the frame is cooked.

Internal silicone rubber moulds – which stay in place during the curing process – further help to produce crisp interior dimensions, particularly in areas with complex geometry like bottom bracket shells, head tubes, and seatstay yokes.

The start of a carbon fiber bottom bracket shell: the start of a carbon fiber bottom bracket shell
The start of a carbon fiber bottom bracket shell: the start of a carbon fiber bottom bracket shell

The start of a carbon fibre bottom bracket shell

Areas with especially tight tolerances like head tube and bottom bracket openings get additional steel inserts so that bearings and bearing cups fit correctly after the frame is fully assembled.

These bottom bracket shells are all laid up and ready to place into a mold. note how areas subject to chain suck damage are additionally reinforced: these bottom bracket shells are all laid up and ready to place into a mold. note how areas subject to chain suck damage are additionally reinforced
These bottom bracket shells are all laid up and ready to place into a mold. note how areas subject to chain suck damage are additionally reinforced: these bottom bracket shells are all laid up and ready to place into a mold. note how areas subject to chain suck damage are additionally reinforced

These bottom bracket shells are all laid up and ready to place into a mould

After each assembly is laid up, an inflatable plastic bladder is fed through and then it's all sandwiched inside a massive steel clamshell mould for baking.

Long-nosed pliers help feed the bladders through the front triangle: long-nosed pliers help feed the bladders through the front triangle
Long-nosed pliers help feed the bladders through the front triangle: long-nosed pliers help feed the bladders through the front triangle

Long-nosed pliers help feed the bladders through the front triangle

As you might expect, given the magnitude of this operation, the actual curing process is highly automated. Once the clamshell moulds are loaded, robotic conveyors and carriers move each mould into and out of a bank of ovens.

This not only guarantees that frames will cook for the prescribed amount of time and at the correct temperature but also helps decrease the risk of injury since workers won't have to directly handle piping-hot steel moulds themselves.

Empty molds are first sprayed with a release agent so that the pieces can be more easily removed after curing: empty molds are first sprayed with a release agent so that the pieces can be more easily removed after curing
Empty molds are first sprayed with a release agent so that the pieces can be more easily removed after curing: empty molds are first sprayed with a release agent so that the pieces can be more easily removed after curing

Empty moulds are first sprayed with a release agent so that the pieces can be more easily removed after curing

Afterward, the moulds are cracked open, the cured frame sections are removed, and then begins a series of finishing operations. Excess moulding flash is knocked off with files, rough edges are smoothed with a variety of sanding tools, holes are drilled for water bottle bosses, computer sensor mounts, and front derailleur tabs, and seat tubes cut square and slotted.

This cart transports frame molds into and out of the banks of ovens: this cart transports frame molds into and out of the banks of ovens
This cart transports frame molds into and out of the banks of ovens: this cart transports frame molds into and out of the banks of ovens

This cart transports frame moulds into and out of the banks of ovens

Once that's all done, the frame sections are sent to yet another room where they're glued together, overwrapped with additional layers of carbon fibre, fixture in alignment jigs, and sent for another round of curing.

One final strip of carbon fiber is applied to finish off each joint: one final strip of carbon fiber is applied to finish off each joint
One final strip of carbon fiber is applied to finish off each joint: one final strip of carbon fiber is applied to finish off each joint

One final strip of carbon fibre is applied to finish off each joint

After the glue is fully cured, the frames are sent off for yet another round of finish work. Surfaces are buffed with finer-grit sanders, small imperfections are masked with filler compounds (a common practice in large-scale carbon frame manufacturing), and metal pieces such as riveted in place.

Few companies are so open about it but yes, fillers are occasionally used to fill in minor surface imperfections. it's for this reason that you rarely see bare clearcoat finishes on mass produced carbon frames: few companies are so open about it but yes, fillers are occasionally used to fill in minor surface imperfections. it's for this reason that you rarely see bare clearcoat finishes on mass produced carbon frames
Few companies are so open about it but yes, fillers are occasionally used to fill in minor surface imperfections. it's for this reason that you rarely see bare clearcoat finishes on mass produced carbon frames: few companies are so open about it but yes, fillers are occasionally used to fill in minor surface imperfections. it's for this reason that you rarely see bare clearcoat finishes on mass produced carbon frames

Few companies are so open about it but yes, fillers are occasionally used to fill in minor surface imperfections

It's only after all that (and countless quality control checks) do the frames finally head off to paint, final assembly, and packing.

First coats of paint: first coats of paint
First coats of paint: first coats of paint

First coats of paint

We'll first take a look at how Giant builds its higher-end aluminum frames in part three of this exclusive series later this week.

James Huang

Former Technical Editor, US
James was BikeRadar's US tech editor from 2007-2015.
  • Discipline: Mountain, road, cyclocross
  • Preferred Terrain: Up in the Colorado high-country where the singletrack is still single, the dirt is still brown, and the aspens are in full bloom. Also, those perfect stretches of pavement where the road snakes across the mountainside like an artist's paintbrush.
  • Beer of Choice: Mexican Coke
  • Location: Boulder, CO, USA
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