A perfect fit with no wobbles

© Photo | Shenzhen Lv

The EVA Group always has a solid-state laser in operation to make sure that its copier frames are both precise and strong.

At the press of a button, photocopiers can produce multiple copies of any document in fractions of a second. All around the world, millions of people take this process absolutely for granted. But a copier that stops working is a headache that eats up time and money. In fact, keeping a copier system working reliably is far from straightforward.

The company:

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EVA Precision Industrial Group, established in 1993 in Hong Kong is a leader in the field of precision mould and component manufacturing for office automation equipment, which is also its principal business. More about the company

As simple as it might look, under the skin of these seemingly mundane office machines lies a multifunctional  high-tech product that depends on the highest levels of precision. This is especially true of the copier’s base frame, a component that has dozens of openings worked into it to hold moving parts such as the high-speed gearbox, rollers and the toner cartridge mounts.

As the machine copies up to 100 pages per minute, these parts have to move quickly and will vibrate. But this must not be allowed to affect the shape of either the frame or the openings in which the moving parts sit. Otherwise these will fall out of sync — resulting in loud noises, paper jams or distorted colors.

Highest precision

This is the reason EVA Group, a large Chinese manufacturer of base frames for all-in-one copiers, makes sure that its products stay in shape over the long term — and at competitive prices. For a long time, the Shenzhen-based company and its 8,000 employees relied on screws and bolts in their assembly work. Each month, 100,000 copier frames would leave the production facilities after being bolted together.

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Zhang Wenbing, manager of Welding & Automation Applications Technology Center at the EVA Group, who first replaced screws with laser processing and then swapped the initial lasers for advanced ones

But assembly using screws involved some disadvantages. “Screws are easy to handle and cheap to procure, but they often don’t join individual parts together precisely enough and over longer periods of time they lose their mechanical stability — especially when they have to cope with vibrations and jolts,” explains Zhang Wenbing, manager of the Welding & Automation Applications Technology Center at EVA Group.

Advantage: laser welding

Using lasers instead of screws:  That’s why the company decided to change its production process and weld the base frames using a laser. At first, EVA Group used a CO₂ laser, which not only joined the frames considerably more ruggedly and precisely, but also doubled productivity compared to assembly using screws. “At the same time, production costs continued to be very attractive, especially considering the time savings and the fact that we could then optimize the design for laser assembly,” explains Zhang Wenbing.

The company found the efficiency it wanted in the form of a disk laser that feeds two welding robots in turn via fiber optic cables.

But EVA Group was not completely satisfied with these re sults and sensed that there was even more potential to be had. “For bigger frames in particular, the CO₂ laser’s limited ability to work along the Z axis was a problem. In addition, it can feed only one station at a time. All this meant that we were losing lots of productivity each time we had to reposition the workpiece.”

Increased productivity through disk laser

The company found the efficiency it wanted in the form of a disk laser that feeds two welding robots in turn via fiber optic cables. This process increases the station’s productivity by 40 percent, since the laser hardly ever goes offline and instead is always kept busy processing a workpiece.

“Our products really benefit from the time-sharing model,” reports Zhang Wenbing. “On average we weld around 100 short seams on each frame.Since the laser can now continue welding at another point while we reposition one of the robots, it’s almost never out of action.”

Great benefits and new product geometries

TRUMPF LaserNetwork:

The energy from a single laser assembly can be used at multiple processing stations – thanks to the . TRUMPF LaserNetwork.

There is another advantage, too: the disk laser’s shorter wavelength means that metal work pieces absorb more laser energy, and that makes welding faster than with a CO₂ laser of similar power. Meanwhile, the greater mobility of the welding robots fed by the disk laser makes it easier to assemble larger copier frames and permits new product geometries.

Customers, too, appreciate these benefits.A list of EVA Group’s customers reads like a “who’s who” among manufacturers of all-in-one copiers. All of them have cost pressures to deal with — and they pass this challenge on to EVA Group.

Double success: the disk laser convincing through it’s shorter wavelength and time-sharing.

That’s why the company’s engineers work with their customers to optimize the design of the base frame, making full use of the disk laser’s capabilities. “One of the ways we achieve outstanding results is by reducing material thicknesses and altering the structure of the frames,” explains Zhang Wenbing.

“Because this laser delivers such high-quality welds, design changes such as these have no impact on product quality.” By optimizing the design in this way for one recent major order, EVA Group managed to cut base frame production costs by almost 30 percent.

Contact:

EVA Precision Industrial Group
Wenbing Zhang
Phone: + 86 755 27629999 ext 8200
E-Mail: zhangwenbing@eva-group.com

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