ANDY TOMS
Laser hardening is today recognized as an efficient and cost-effective method of heat-treating ferrous metals, offering a precision alternative to traditional techniques. However, in almost every case, the process is achieved by taking the component to a dedicated workstation. While this is a perfectly acceptable solution for many applications, having to remove and transport large and heavy components such as automotive mold or press tools for processing can be both time-consuming and expensive in terms of lost production.
The AL-ROCK mobile laser hardening system offers a highly efficient alternative by taking the process to the part, enabling large and complex automotive tools to be processed in situ, generating significant savings in time, and keeping production on the move.
Time is money, as they say. This is especially true in automotive manufacturing plants, where volume is high and even short stoppages can run into many thousands of dollars in lost revenue.
The automotive press shop is at the heart of vehicle production and, subsequently, any stoppages here can have a significant impact on all downstream areas of production. While tool changes—either to accommodate different model variants or for maintenance purposes—are usually planned with military precision, there are always instances where tools require immediate attention to maintain dimensional or quality standards. It is these unplanned events that can often result in excessive downtime to remove and repair or replace large, heavy, and complex tools.
Driving press shop efficiencies with AL-ROCK
AL-ROCK is the world's first mobile robot targeted specifically for laser hardening applications on metal surfaces. Combining the efficiency of a diode laser system with the flexibility and dexterity of a six-axis robot, all mounted to a self-propelled crawling chassis, allows the technology to be taken directly to the press and the laser hardening process to be performed in situ (FIGURE 1). This can generate significant cost savings for automotive manufacturers by reducing the time that the press is out of action to a minimum.
Stoppages in a volume-production car plant can run into many tens of thousands of dollars per hour, so the ability to be able to work on press tools at short notice, with a minimum of downtime and using a hardening process that is also both fast and efficient, makes for a shrewd investment with a potentially short payback time.
The extensive horizontal reach of the robot makes it possible to cover the large areas and complex shapes normally associated with automotive press tools. The diode laser system and zoom optics allow precision selective hardening to be carried out without the risk of affecting surrounding areas from residual heat, with the added benefit of being highly energy-efficient when compared to traditional induction or flame-hardening alternatives. The system delivers 3000W of output power, making it possible to case-harden to a depth of approximately 2mm, depending upon the material. The process time for selective laser hardening is also extremely short, requiring just a few seconds to heat the area of the part to the required temperature.
The ability to easily transport the AL-ROCK system, not only from press to press but from one manufacturing plant to another, means that the benefits of the system can be realized across a number of sites, thus spreading the initial investment cost.
Further flexibility enhances financial justification
Although the system is designed to be mobile, with all the advantages brought within the automotive press shop environment, the system can also operate as an off-line laser hardening cell (FIGURE 2). The flexible laser safety-guarding package that comes with the system can be used to set up a static workstation. In this configuration, the AL-ROCK can work in conjunction with static work tables or additional servo-controlled turn and tilt axes to process components that are smaller and more easily transported. Also, the combination of the six axes of the robot with the additional turn-and-tilt axes allows the system to process to even the most difficult-to-access areas. This means that the system can remain productive when not required for in situ laser hardening, enhancing the financial justification of the system.
The AL-ROCK system is available in the UK from TLM Laser. To view video of the system in action, please visit https://www.youtube.com/watch?v=_wuG06HayCM.
ANDY TOMS([email protected]) is the director of TLM Laser, Bromsgrove, Worcestershire, England; www.tlm-laser.com.