For more than a decade, 3-D laser cutting technology has been recognized as the only process capable of handling hot stamped steel in automotive mass production environments. With its increasing capabilities and flexibilities, 3-D laser cutting has also gained popularity in secondary processing of metal formed parts due to its high quality, efficiency and process reliability.
Forming is a common manufacturing process in today’s metal fabrication world. The most well-known forming technologies include hot stamping, deep-draw stamping, hydro-forming, metal spinning and tube bending.
At its core, forming is a method for turning raw materials into 3-D shapes. Before final assembly, however, it’s usually required to cut out holes and trim flanges on the 3-D parts. Given the complexity of the metal forming process, sometimes it’s difficult, if not impossible, to incorporate these functions into the forming process. As a result, secondary processing of the metal formed parts is often required.
Traditional limitations
Traditional methods for incorporating secondary processes into the forming process typically involve custom dies and punches or a bandsaw. A typical process can be described in the following manner:
- Make a fixture to conform to and secure the part with repeatable positioning
- Choose the right tool: custom die, custom punch, drill, saw, hand tool or CNC machine tool
- Accurately locate holes and flanges on the 3-D surface in relation to the tool
- Process the part without deforming it
- Deburr and rework to meet edge quality requirements
- Modify fixture and tool if design changes
The process requires highly skilled workers and is labor intensive while process repeatability is hard to achieve. To add insult to injury, the design, build and inventory of custom fixtures and dies as well as high rates of scrap parts and multiple operational steps add up quickly in the form of time and cost. The limitations of traditional methods are wide ranging.
Historically, these secondary processes produce low-quality results. High positional accuracy and repeatability at ±0.01 in. or greater is hard to achieve, thin materials are easily deformed and post-processing such as deburring is often required. Flexibility can also be an issue. Small lot sizes and large varieties of parts require fast and accurate setups, and it is difficult to make adjustments and changeovers. The overall higher costs can include extensive labor, low throughput and high scrap rates. Small lot sizes typically do not justify the tooling investment. The design, building and inventory required for custom fixtures and dies ramp up manufacturing costs, as well.
3-D cutting solution
It’s easy to see where a traditional approach falls short, but what does an optimal 3-D cutting solution look like?
- The 3-D part is efficiently positioned and accurately located
- The part is cut with high edge quality; no deburring required
- There is no deforming of the cut part
- Ability to handle a variety of materials from 0.01 in. to 0.5 in. thick
- Simple and reliable fixturing or tooling
- Short turnaround times; quick setups and fast changeovers
- Flexible: Easy to make adjustments based on design changes
- Less parts handling and hazards for the operator
- Environmentally friendly
- Reasonable costs
The key, therefore, to low-volume, high-quality production is all about using the right technology to streamline the manufacturing process, eliminate manufacturing steps and manual labor, and minimize tooling costs. In many manufacturing technologies, 5-axis laser cutting technologies stand out as a solution to address these challenges.
With the latest development of modern features and smart functions, secondary processing of metal formed parts has been made easier for operators by utilizing 5-axis laser cutting. And in that regard, Trumpf offers a complete solution that includes 5-axis laser cutting machines, such as the company’s TruLaser Cell series, that utilize a fiber-delivered solid-state laser and offline programing software.
At Trumpf, the 3-D laser cutting solution starts with TruTops Cell, an offline programming system for 3-D machining and the interface between the CAD system and the multi-axis laser machine. The executable, process-reliable NC program is generated offline while the machine is in production. Compatibility is important so that offline programing software does not only know the correct tool path, but also the technology and machine’s unique features to access extensive process rules.
Fundamental features
What is also important for fabricators is the capability to make simple and low-cost fixtures. When generating the fixture, TruTops Cell uses the cutting path defined in the X and Y direction to generate the entire 3-D fixture and the 2-D unfolding for the supports. These fixture plates can be cut on the same 5-axis machine being used for the 3-D laser cutting or the fixture parts can be exported as DXF files to cut with a TruTops 2-D laser.
Automatic focus adjustment is also key because high laser cutting quality is the result of an optimal combination of cutting parameters, including laser power, focus, speed, gas pressure and piercing strategy. To that end, Trumpf experts have integrated optimized laser cutting parameters in the machine control system. Operators only need to select the material and thickness and then the machine chooses the correct parameters, which result in high quality cuts.
In that regard, the TruLaser Cell series machines are equipped with FocusLine technology, a function to adjust laser focus position automatically. With FocusLine, the machine can set the laser focus point as desired to achieve burr-free cutting for different materials of varied thickness without manual adjustment.
Another feature offered within the TruLaser Cell is X-Blast technology, which allows operators to double the working distance between the nozzle and workpiece and also double the bandwidth. This greatly reduces the chance of nozzle collisions and, therefore, reduces interruptions during the production process. At the same time, the machine can cut complicated shapes at very high quality, resulting in stable and reproducible parts quality.
Faster production
Prototype and low-volume manufacturers face the challenge of constant part changeover, so quick setup and adjustment are the keys to success. Knowing that, Trumpf successfully transferred many of the proven smart functions from the TruLaser Cell series into the newly designed TruLaser Cell 5030 to reduce setup time.
The magnetic clutch prevents damages to the cutting optics from a crash, and it can be restored within just a few minutes. To verify that the machine is in perfect condition before cutting, the operator can benefit from a new function, ObserveLine Professional, to verify optical alignment within a few seconds.
Should there be any misalignment detected, operators can use the Smart Optics Setup, a swivel device mounted on the machine body that allows automatic optics orientation and thus adjusts the optics alignment through the power NC control system.
Another feature is TruTops Cell Basic, an online tool that allows operators to make quick adjustments, such as move contours, change points, change diameters and insert micro joints with a few mouse clicks. Furthermore, every change can be visualized with the process path and cutting head shown on the machine control panel. Instead of going through lines of NC code, operators can make changes with confidence with just a few clicks, significantly reducing the adjustment time after the first cut.
Thanks to these important features, fabricators can see higher productivity and lower costs, enhancing their competitive advantages in 3-D laser cutting. And with Trumpf’s energy-efficient TruDisk laser and flying optics, the TruLaser Cell 5030’s productivity is tremendously boosted. Compared to traditional hybrid 3-D machines with a CO2 laser source, the machine productivity is increased by 200 percent while operating costs are reduced by nearly 50 percent. As a result, the cost per job is significantly reduced.
When it comes to 3-D laser cutting for prototype and low- to medium-volume production, the user of a TruLaser Cell 5030 can not only produce parts quicker with higher quality, but can also produce them at greatly lower costs. Considering all factors, including programming software, ease of setup, quick changeovers, cutting quality and reliability, 3-D laser cutting technologies represent the most effective and efficient manufacturing solution in secondary processing of 3-D metal formed parts.
