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Tech: Inside Giant's Taiwan bike factory, part three

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Clean frames ready for finish work

Clean frames ready for finish work (Image credit: Jonny Irick)
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Giant receives raw aluminum tubing into its Taichung, Taiwan factory from another Giant facility that smelts its own alloys. All of the butting, shaping, and drawing is done here in house

Giant receives raw aluminum tubing into its Taichung, Taiwan factory from another Giant facility that smelts its own alloys. All of the butting, shaping, and drawing is done here in house (Image credit: Jonny Irick)
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Giant has a veritable army of welders on hand in its Taiwan factory

Giant has a veritable army of welders on hand in its Taiwan factory (Image credit: Jonny Irick)
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For the most part, welders are supplied with individual cubicles so they can get their work done relatively undisturbed

For the most part, welders are supplied with individual cubicles so they can get their work done relatively undisturbed (Image credit: Jonny Irick)
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Various jigs are used for the initial tack welding

Various jigs are used for the initial tack welding (Image credit: Jonny Irick)
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Front triangles sit on this rotating rack as they transition from the tacking station

Front triangles sit on this rotating rack as they transition from the tacking station (Image credit: Jonny Irick)
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Head tubes are apparently a very handy way to store frames in transition

Head tubes are apparently a very handy way to store frames in transition (Image credit: Jonny Irick)
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Sure, the frame itself is fairly interesting on its own - but take a good look at the industrial jig to which it's connected. Wow

Sure, the frame itself is fairly interesting on its own - but take a good look at the industrial jig to which it's connected. Wow (Image credit: Jonny Irick)
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Checking dropout alignment

Checking dropout alignment (Image credit: Jonny Irick)
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Frames must match the dimensions as specified in the drawing

Frames must match the dimensions as specified in the drawing (Image credit: Jonny Irick)
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These tack welds just hold the frame pieces in alignment until they can fully welded

These tack welds just hold the frame pieces in alignment until they can fully welded (Image credit: Jonny Irick)
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Racks of frames on their way into the solution baths post-welding

Racks of frames on their way into the solution baths post-welding (Image credit: Jonny Irick)
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Racks of frames travel overhead into sequential solution tanks. If the surfaces aren't perfectly clean, the paint won't stick

Racks of frames travel overhead into sequential solution tanks. If the surfaces aren't perfectly clean, the paint won't stick (Image credit: Jonny Irick)
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Some welds are left raw while others are sanded down, depending on the specifications outlined in the drawing

Some welds are left raw while others are sanded down, depending on the specifications outlined in the drawing (Image credit: Jonny Irick)
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Something about this process doesn't seem particularly safe

Something about this process doesn't seem particularly safe (Image credit: Jonny Irick)
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Primed frames travel through the rafters on their way to the paint department

Primed frames travel through the rafters on their way to the paint department (Image credit: Jonny Irick)
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Frame welders are apparently among the highest-paid workers in the Giant factory. It's a process that isn't easily automated in this situation and the results hold not only structural but visual consequences

Frame welders are apparently among the highest-paid workers in the Giant factory. It's a process that isn't easily automated in this situation and the results hold not only structural but visual consequences (Image credit: Jonny Irick)
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As with the carbon frames, individual frame sections have all of their requisite holes formed before the sections are joined together

As with the carbon frames, individual frame sections have all of their requisite holes formed before the sections are joined together (Image credit: Jonny Irick)
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Giant manufactures a heck of a lot of aluminum frames so it's no surprise to see massive amounts of raw materials on site

Giant manufactures a heck of a lot of aluminum frames so it's no surprise to see massive amounts of raw materials on site (Image credit: Jonny Irick)
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Raw aluminum tubing racked up and waiting for its turn through the machine

Raw aluminum tubing racked up and waiting for its turn through the machine (Image credit: Jonny Irick)
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Giant uses a wide range of tube dimension, each of which requires its own die

Giant uses a wide range of tube dimension, each of which requires its own die (Image credit: Jonny Irick)
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Giant uses both air-assisted forming and hydroforming to shape its aluminum tubes. Air-assisted forming is less expensive and is reserved for mid-priced frames while the more expensive hydroforming process can create more complex shapes

Giant uses both air-assisted forming and hydroforming to shape its aluminum tubes. Air-assisted forming is less expensive and is reserved for mid-priced frames while the more expensive hydroforming process can create more complex shapes (Image credit: Jonny Irick)
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Giant has several of these massive hydroforming presses on site

Giant has several of these massive hydroforming presses on site (Image credit: Jonny Irick)
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Freshly hydroformed seat tubes and top tubes

Freshly hydroformed seat tubes and top tubes (Image credit: Jonny Irick)
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Giant's hydroforming process can create surprisingly intricate shapes out of essentially round blanks

Giant's hydroforming process can create surprisingly intricate shapes out of essentially round blanks (Image credit: Jonny Irick)
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The air-forming process isn't as involved as hydroforming, says Giant. The two ends are sealed off and then the interior is pressurized under heat to push the walls out against the mold walls

The air-forming process isn't as involved as hydroforming, says Giant. The two ends are sealed off and then the interior is pressurized under heat to push the walls out against the mold walls (Image credit: Jonny Irick)
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The machinery involved in hydroforming is absolutely enormous as compared to the relatively small parts that are being formed

The machinery involved in hydroforming is absolutely enormous as compared to the relatively small parts that are being formed (Image credit: Jonny Irick)
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After forming, the tubes are subjected to various chemical and heat treatments to prepare them for welding

After forming, the tubes are subjected to various chemical and heat treatments to prepare them for welding (Image credit: Jonny Irick)
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All cleaned up and ready to miter

All cleaned up and ready to miter (Image credit: Jonny Irick)
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Frames and frame parts are soaked in automated solution baths

Frames and frame parts are soaked in automated solution baths (Image credit: Jonny Irick)
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The aluminum half of Giant's Taichung factory is certainly more cacophonous than in the carbon side, which is comparatively quiet and peaceful

The aluminum half of Giant's Taichung factory is certainly more cacophonous than in the carbon side, which is comparatively quiet and peaceful (Image credit: Jonny Irick)
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The welded joints on Giant's hydroformed aluminum frames require complex miters

The welded joints on Giant's hydroformed aluminum frames require complex miters (Image credit: Jonny Irick)
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There are endless shelves of fixtures and clamps for various frame models and processes

There are endless shelves of fixtures and clamps for various frame models and processes (Image credit: Jonny Irick)
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Look up! Frames travel at eye level but also overhead as they make their way to various areas

Look up! Frames travel at eye level but also overhead as they make their way to various areas (Image credit: Jonny Irick)

This article first appeared on BikeRadar.

Many already know about how Giant is one of very few companies that manufactures carbon frames from raw fiber instead of ready-made pre-preg materials. What isn't as well known, though, is that Giant also uses a similar in-house approach for its aluminum bikes, too. Take a walk with us as we give you an exclusive look at how it's done.

That Giant builds such a staggering number of carbon fiber frames in-house from raw fiber – not ready-built pre-preg shipped from suppliers – is impressive on its own. What's even more incredible, though, is that the company adopts a similar approach with its aluminum frames, too.

Giant's alloy frames start life about 800km (500mi) north in Kunshan on mainland chain at a facility called Giant Light Metal. Here, Giant actually smelts its own alloys, casts its own billets, and extrudes its own tubing. In other words, when the company slaps its house-brand 'ALUXX' label on a frame, it really is a Giant product and not simply a rebadged item from someone else.

Raw tubing is shipped from Giant Light Metal over to the frame factory in Taichung where it undergoes more rigorous forming operations. As it arrives, the tubing is all round, relatively thick and straight-walled, and far too heavy for use in higher-end bicycles.

Once in Taichung, that tubing is cut to manageable lengths and then forced through a number of dies that reduce the wall thicknesses and refine the grain structure to make it both lighter and more durable than before. As this point, the tubing can already be used to build high-quality frames.

Giant goes further yet, however, with additional shaping that gives the tubing more direction-specific properties. Hydroforming (which uses pressurized oil to push the tubing outward against a steel mold) is the preferred method for higher-end frames while air forming (which uses hot, pressurized air instead of oil) is used for mid-range models.

In either case, the result is complex tube shapes with very good tube wall thickness control. In many cases, the tubes can emerge from the press with hard points such as suspension pivot mounts built right into the structure of the tube, thus cutting down on subsequent forming and welding steps.

Afterward, tube ends are mitered and deburred, and holes are drilled for water bottle bosses, internal housing ports, and suspension hardware. Each process is done on a dedicated jig to help ensure repeatability and accuracy.

Once the shapes are formed, all of the tubing is prepped for welding. All of the tubing is given a rough polish and is chemically treated to remove any surface contaminants that might otherwise preclude a reliable joint.

Now that all of the preparatory steps are completed, it's time to set everything up in jigs and do some welding. Contrary to popular misconception, these frames aren't built by robots. Instead, Giant employs banks of actual people to lay down the welding rod.

As one would expect in an operation of this size, though, there are some processes in place to boost efficiency. While each frame isn't completely welded from start to finish by one worker, they're not done in full-on assembly line style, either.

Rather, frames progress in a handful of steps through several workers. For example, jigging and tacking is done in one area, one worker might weld an entire front triangle, and then another might do the rear end.

Alignment is checked at several points during the process, too, using a mix of manual gauges and laser sights.

Once welding is completed, frames are sent off for the first round of heat treatment (to T4 spec, for those that are interested), checked again for alignment, then sent for the final round of heat treatment (T6 spec).

After all that, the frames are off for final polishing, cleaning, and prep for painting.

From the time the raw tubing arrives in Taichung to finished product, Giant says an aluminum frame can theoretically be manufactured in about two hours.

In the final installment, we'll see how Giant's workers paint, decal, and install and adjust components on their framesets in record time.

See also: Part one, part two, and part four of the series.