Smartphones are booming. Their performance capabilities increase with each device generation. The centrepiece of the mobile power packs are circuit boards that are produced with the assistance of a laser exposure system. The highly precise manufacturing process is reliably performed by technically advanced positioning systems. Pre-harnessed energy supply systems ensure the necessary long-term operational reliability, smooth travel, lack of vibration, and low wear, which is mandatory for cleanroom production.
"Producing smart phone circuit boards as mass products was not yet possible a few years ago with the then available, low flexibility machinery and production technology", explains the Managing Director of Jenaer Antriebstechnik GmbH, Dipl.-Eng. (FH) Stephan Preuß. Whereas circuit boards were exposed with templates in the past, today's process uses special systems capable of high speeds and accuracy, while also being able to produce multilayer circuit boards efficiently. The laser technology-based exposure principle results in a significant throughput increase in the circuit board manufacturing process. At the same time, manufacturing costs drop dramatically: important aspects for mass-producing electronic equipment.
The exposure and laser structuring systems are moved by a complex positioning unit, which can be precisely integrated into the machinery of the overall machinery manufacturer based on the interfaces coordinated with him. "Our customer benefits from our many years of experience with a wide range of applications", Stephan Preuß underscores. Jenaer Antriebstechnik GmbH supplies these mechatronic systems for subsequent installation to an internationally active machinery builder, who exports the complete systems worldwide.
About 140 circuit boards per hour can be exposed today. An aggregate circuit board, also called a blank, is used to surface mount at least 30 smartphones with individual circuit boards with a wide range of circuit functions. The highly complex plants are in operation 24/7. "Plant downtime is expensive and must be prevented, Dipl.-Eng. Christian Koch notes. "While the actual production conditions are not problematic, the high service life nevertheless mandates rugged and reliable components, including in the sub-system.
In order to reliably guide the drive, measurement system, and compressed air lines and other media in the positioning unit, the Thüringen-based drive technology specialists are using completely pre-harnessed energy supply systems made by igus® GmbH, Cologne, including strain reliefs, connectors, guide troughs, and mounting brackets. The so-called "readychains" have been in production in Cologne for nearly 20 years, and are each extensively tested for their functionality before being delivered within one to ten business days. The advantages for the customers are obvious: the project planning and primarily the assembly effort drops dramatically.
Whereas two particularly quiet energy chains from the E6 product range prove their strength on the approx. 2 m long Y-axis, the approx. 400 mm long, highly flexible energy chain from the T3 product range demonstrates its capabilities on the Z-axis. Both systems are compatible with cleanroom production conditions. "The circuit boards must be exposed in a cleanroom", explains Stephan Preuß. "Accordingly, abrasion needs to be minimised “
Jenaer Antriebstechnik GmbH was founded in 1990 by former development engineers from Carl Zeiss Jena. Today, approx. 90 employees develop, produce, and distribute servo drives and mechatronic sub-systems. "Because of their versatility, our products and systems can be found in a wide range of applications, Stephan Preuß explains. "Thinking in terms of systems has become a tradition for us. We not only develop drive components, but also supply our customers with complete mechatronic sub-systems for installation into their machinery. “
The primary applications include machinery for electronics manufacturing, laser technology, assembly automation, and handling plants. These applications call for high dynamics at concurrently high accuracy. "Yet another field where our drives really shine is in automating continuously operating processes, such as in the printing industry", the Managing Director reveals.
In the medical technology field, the drives from Jena perform the positioning task for patient platforms in magnetic resonance tomographs, without impacting the imaging process. "And our drive and control technology even facilitates looking into space on large scale telescopes."
An important element of the positioning unit is the exposure table. It is sized at 27" x 27". After loading, the circuit boards are processed in the exposure step. The table is lowered, transported to the rear, and reloaded. A second table has been loaded in the meantime. The exposure process starts over. It is of paramount importance that the scanning process is performed in a completely uniform, jerk-free motion to prevent any malfunction while the circuit boards are being printed. For the energy chain, this means that it must operate entirely uniform while also being quiet. In addition to a uniform motion profile and smooth operation, low vibration and low abrasion are of essential significance for a malfunction and defect-free manufacturing process. "And since the plant runs an extreme number of cycles, our attention is of course also directed to the topic of reliability", Christian Koch adds.
The E6 energy chain system without the classic pin/bore connection is currently the lowest noise and vibration solution in the igus® energy chain product range, and is therefore a particularly good match for the low-vibration drive concept of the linear motors in this application. The so-called polygon effect, which can occur during the rolling action of an energy supply system, is reduced to a minimum. "Since no more than 2 µm must be attained between the target and actual positions, we need completely uniform operation", Christian Koch reinforces once again.
The extensive product range – including for interior separations – supports selecting a tailored chain size. At an inner height of 40 mm and a bending radius of 63 mm, all cables in this application are reliably guided by the Y-axis.
System T3 is used on the Z-axis. It also combines smooth operation with a low noise profile. This is complemented by the easy assembly of the e-chain® . The side plates clip into each other and replace the conventional pin/bore connection, therefore preventing relative motions between the joints. This achieves almost complete resistance to wear, therefore facilitating cleanroom applications. The geometry of the T band ensures that almost no polygon effect is generated during the rolling action of the e-chain®. The T band features harmonious and smooth operation, and therefore has extremely low vibration and noise. Due to the low dead weight, the solution is suited for applications with rather low fill weights and short strokes – even in combination with high accelerations and speeds, which are however not particularly high on the two axis of this positioning system.
"Due to our extensive experience, we originally relied on our own cable concept", Christian Koch recalls. Because of the demanding customer requirements, we decided to compare the original solution in the Cologne-based test lab with chainflex® cables from igus®. The endurance test clearly favoured the igus® product, primarily with respect to cleanroom compatibility. We therefore decided to also procure the pre-harnessed cables in addition to the energy chains from a single source. This also reduced the leadtimes in the our production process.
The special requirements on core cross-section combinations, bending resistance, and cleanroom compatibility favour chainflex® cables from the standard product range. However, these can also be adapted to customer needs when required. This is exacerbated in this application by their relatively large number, the tight bending radii, the low space availability, and the low abrasion. In addition, they also must not influence each other to prevent impairing the long-term functionality of the plant as a whole.
"This application places extreme demands on all partners", Stephan Preuß explains. "We need to respond quickly to a wide range of customer needs. The configuration of the energy supply systems changes all the time. We have had good experience with the collaborative effort. Our local contact is always available to assist us. "The pre-harnessed energy supply systems are provided to us as separately packaged units on the desired delivery date. Among other features, each package is accompanied by a cleaning certificate therefore providing peace of mind with respect to cleanroom compatibility from the start.
On other projects, the design engineers use the igus® online tools for electrical engineering tasks. They provide high process reliability and a straightforward and fast selection based on the desired motion and installation parameters, including cables if needed. "However, we are making an effort to limit energy chain variety", Stephan Preuß concludes. "We generally rely on the System E6, which has repeatedly demonstrated its technical superiority and also compels with its smooth operation. The rolling action of the chain is nearly devoid of noise, a feature that our customers also value greatly. “