High-speed, high-volume manufacturers are engaged in a constant race against the clock, yet they cannot compromise on the quality of what they produce. These constraints mean that for the marking of parts or assemblies in such environments, on-the-fly laser marking systems are the only option.
The marking of products or assemblies with indelible serial, part, or batch numbers is an essential task in almost all manufacturing and production environments. Static laser marking is an established, cost-effective, and reliable method for the creation of these marks, but it is not suitable for all applications. For high-speed, high-volume manufacturing in particular, creating marks on components or batch materials using such systems can be challenging.
Some conventional static marking techniques such as scribing or dot matrix, for instance, cannot be used readily in-line in continuous automated manufacturing processes. Other techniques might need the manufacturing process to be paused momentarily. Even though each of these pauses might only last for fractions of a second, in high-speed, high-volume processes they can quickly add up, costing a business significant money in lost production time.
Reach for the lasersThe obvious solution to this problem is to adopt a laser-based system that is able to track the component or assembly as it moves along the production line, creating a precise and indelible mark as it does so, without interfering with the production flow.
By laser marking in this manner, it is possible to eliminate delays in production without sacrificing the quality of the marks being made. These detailed marks exhibit no distortion, even on components that are moving at break-neck speeds. Furthermore, laser marking can be performed at all common production line speeds, reducing cycle time while improving the quality of marks being made. Able to lay down unique, serialized Data Matrix codes in as little as half a second, on-the-fly marking lasers are set to become a vital component of high-volume manufacturing.
On-the-fly laser marking processes begin the moment the component enters the marking cell and, as it passes through an extremely narrow window, the marking process continues. By the time the component exits the marking cell, all of the relevant data will have been recorded on it.
The implementation of such systems, however, can require a number of significant technical challenges to be overcome.
Making a mark
First and foremost, the marks, which can be highly complex, must be applied in the correct place and to the required quality on the part. Marks must be permanent and indelible, clearly legible, and may have to appear several times on a single component. There may also be predefined locations for the marks; a marking window of around 0.16 in. square (100 mm2) is a common specification.There is also a wide variation in the types of marks that might need to be made. Some applications may require only the marking of a serial number, a production day number or batch number. In other applications, unique marks may be required as part of sophisticated data capture systems that track individual units as they pass through the production cycle.
The properties of the material to be marked, such as its hardness, must also be factored in, as must the required depth of the mark. Further thought must be given to the volume of data that needs to be recorded during each marking process.
Setting the pace
As such, in order to ensure that the mark possesses all the right qualities, it is vital that the speed of the production line is recorded accurately at all times. This speed can be measured using an encoder wheel, which sits on the conveyor or on the component itself and feeds the data it gathers back to the marking machine, which can then tailor its operation to even minor fluctuations in line speed.
A high-power laser, which can produce marks of sufficient depth and clarity in short periods of time, can match the speed of even the fastest line. Alternatively, a larger marking window may be employed, effectively giving more time for the process to be carried out. Even so, it can take as little as half a second to create a complete, unique machine-readable Data Matrix code for each component or section of material as it passes through the cell.
Data capture software can be used by manufacturers to monitor the quality of the components they produce. This data may be layered, adding new information as each component passes through the production process, and can be read at different stages before additional information is tagged onto that component. By recording the time and day that the part was processed at each different station and at each subsequent inspection process, it is possible to determine the productivity of specific lines, for instance.
As we have seen, there is much to consider when implementing an on-the-fly laser marking system. Inevitably, each installation will be tailored to the specific application for which it will be used and will need to be customized quite heavily. In some cases, the marking system and its related equipment can be designed with the production process from the ground up, but for the bulk of applications, the marking process must be integrated into an existing line. Here, the available space is typically limited by equipment already in place.
For high-speed and/or high-volume manufacturers, however, the benefits that can be reaped further down the line make the work associated with the installation of on-the-fly marking systems more than worthwhile. Such systems eliminate any production delays associated with critical marking processes - saving manufacturers time and, ultimately, money.