Dogan Basic, product marketing manager, GF Machining Solutions
Just like medical device manufacturers, electronics manufacturers are under enormous pressure to miniaturise components in parallel with an exponential need for increased performance
This constant pressure has repercussions on the entire production chain and, in particular, on the manufacture of the tools necessary for producing electronic microcomponents. Factory managers are therefore looking for solutions that allow them to simplify increasingly complex processes, to reduce ever rising costs and to support an increasingly scarce skilled workforce.
It is during very challenging periods such as this that so-called conservative industries are more compelled to adopt innovative technologies and advanced manufacturing processes long since adopted by more progressive industries. This is the case with laser technology, which can be used either together with or in place of traditional machining technologies, such as for the machining of microcavities used in the manufacture of connectors for electronic devices and for the machining of pin cores for optical lenses in cameras, respectively.
Traditional technologies and their shortcomings The growing complexity of electronic microcomponents is pushing some traditional machining technologies such as die-sinking electrical discharge machining (EDM) or milling to their limits. EDM and milling clearly offer advantages recognised by all industries and particularly by mould makers. However, for the most complex applications, a new approach is needed, namely laser technology either needs to be used alongside or instead of traditional machining technologies.
This is even more true when one enters the field of micromachining and particularly the machining of microcavities used in the manufacture of electronic microcomponents, which play an essential role in electronic devices. In the highly competitive world of mould making, the traditional process of manufacturing mould inserts for electronic microcomponents combines milling and wire-cutting EDM or die-sinking EDM. This multiple step process requires the production of many electrodes and can involve long setup times, machining times and the skills of an experienced operator.
Copper electrodes.
The most pressing questions from manufacturers contemplating laser technology are:
- How is the increase of manufacturing complexity addressed?
- How is the lack of labour skills addressed?
- How flexible is it possible to be in terms of current manufacturing capabilities?
- Do electrode manufacturing and the die-sinking EDM process represent an obstacle to being ahead of the competition?
- How is the machining of small shapes on non-conductive materials addressed?
Customer issues
Process complexity
Making mould inserts is becoming more and more complex with the involvement of multiple technologies. Manufacturers often need to manage multiple steps involving cutting tools, electrodes and handling equipment among different technologies. With each individual step and handling process, customers risk making mistakes and alignment errors.
In addition, the creation of microcavities or high-precision microcomponents requires high-end machines that are often expensive and deliver slower speeds for conventional moulds or lower precision components. This makes it necessary to acquire additional equipment and signifies a greater investment to meet throughput needs.
Labour skills shortage
The use of die-sinking machines or high-precision 5-axis milling machines requires strong expertise and a highly skilled workforce. In today's market, and with the digitisation-focused younger generation, manufacturers struggle to attract employees with the necessary skills and experience to use traditional technologies.
Hard metals
Traditional processes such as EDM tend to be long and costly due to the machining of electrodes as well as hard metals. An example of the latter is the machining of punches in carbide.
Flexibility
Traditional processes focus on one type of machining, making it difficult to jump quickly to new applications, materials and processes. This is critical when OEM customers are demanding new types of parts, faster.
Non-conductive materials
Ceramics, such as silicon carbide (Si), are used more and more in the electronics industry. It is difficult to keep them smooth without deviation or even impossible for companies to machine them with traditional technologies.
Taking into consideration the challenges mentioned above, laser technology can support complex processes without completely replacing traditional technologies.
Laser technology solutions
Laser technology has begun to enhance tooling applications with the potential to create complex, high-quality moulds for parts such as the connectors used in electronics but also any microcavities or microcomponents.
A laser technology demonstrator.
Two laser regimes, relying on nanosecond and femtosecond pulse durations, dominate in the realm of laser machining. Pulsed lasers in the nanosecond regime (nanolasers) entered the manufacturing industry first and remain a viable option in many applications, but pulsed lasers in the femtosecond regime (femtolasers) bring about the highest precision with burr-free ablation. Although the cost of nanolasers is lower than that of femtosecond lasers, nanolasers cannot equal the precision of EDM or femtosecond laser machining.
In general, the advantages of laser versus traditional technologies are as follows:
Laser vs. EDM
Advantages of Laser
+ No consumables are needed+ Non-conductive materials can be machined
+ Uniformity on large area+ More adjustable and more flexible+ Functional textures are possible
+ Micron-scale texture structure made can be made with femtosecond laser
Laser vs. milling
Advantages of Laser
+ No consumables are needed, contactless+ Super hard and brittle materials canbe machined
+ Burrs-free with femtosecond laser+ Small spot, small processing features
+ Small features ensure removal rate and high processing efficiency
There are constraints and limitations for each machining technology. Therefore, sometimes an intelligent combination of two or more technologies is required.
Laser ablation capabilities
Best surface fs on steel: Ra 0.15 μm
Max depth fs: 5 mm
Minimum inside corner radius fs: 11 μm
Best surface ns on steel: Ra 0.4 μm
Max depth ns: 3 mm
Minimum inside corner radius ns: 20 μm
Best tapper ns and fs (Infrared): 8
°Cutting capabilities: Yes, max 0.5 mm depth (fs)
Best position accuracy: ±2 μm (depending on which machine)
Laser technology provides a clean, reproducible process that requires neither electrodes nor electrode production, results in no scrap, uses no die-sinking EDM oil and dramatically reduces the need for consumables. The combination of laser roughing and machining with die-sinking EDM enables manufacturers to curtail production time and cost while reaching the desired surface quality of these parts. This combination of technologies does the best job of engraving deep cavities, which traditional subtractive processes cannot reach.
The AgieCharmilles LASER P 400 U system from GF Machining Solutions. The system is capable of single-setup operations that can include laser blasting, engraving, marking and/or texturing.
EDM alone is less economical than the combination of laser and EDM. Die-sinking EDM requires electrodes, which require milling, and the micromoulding process uses up many electrodes, each with a short production life. The cost of the electrode material, be it copper or graphite, plus the cost of electric production is high, and material costs for electrodes continue to climb.
A combination of femtosecond laser and die-sinking EDM enables manufacturers to achieve much faster, more economical processes that eliminate the need for milling operations, cutting tools and many of the electrodes that an EDM process requires. Lasers achieve highly repeatable quality in engraving mould cavities, with none of the risks of tool breakage associated with traditional subtractive processes.
A manufacturer active in the automotive industry revamped its production process using the AgieCharmilles LASER P 400 U 5-axis system from GF Machining Solutions and EDM surface finishing, thus shortening its lead times on moulds for electronic connectors from roughing to pre-finish by a factor of five.
A laser machined silicon carbide (Si) insert.
The manufacturer’s previous EDM process to create electrodes for die-sinking EDM required a total of 15 hours. Its new process requires only 12 minutes to rough and pre-finish the moulds with laser ablation, followed by 4.5 hours of EDM finishing, and the same accuracy as with the previous process is achieved.
The AgieCharmilles LASER P 400 U is capable of single-setup operations that can include laser blasting, engraving, marking and/or texturing, and is designed for easy transfer of workpieces through GF Machining Solutions’ System 3R automation and work holding technologies.
Shops that purchase femtosecond laser equipment for one application—for example, to produce electronic connectors—can use the same equipment to tackle other challenges that previously exceeded their capabilities. Femtosecond laser technology can machine a long list of materials, including copper, gold, silver, nickel, hardened metals, glass,sapphire, ruby and polymers, all with repeatable precision. Furthermore, typical femtosecond laser equipment occupies a small footprint that saves space on the factory floor, enabling shops to upgrade their procedures and still make room for other operations or processes.
Femtosecond lasers can be used to engrave shapes and forms with no limit on material hardness. However, their use without finishing with a traditional technology is rare and limited to a certain number of applications for which the constraints of laser technology are not an obstacle.
Conclusion
Laser processes can be combined with or replace traditional subtractive processes in electronic component factories. A combination of technologies can improve the results for OEMs’ internal mould making or micromachining operations.
Lasers offer manufacturers a faster, more precise and more versatile way to create mould inserts and much more, thus affording greater productivity and profitability.
Laser machined stamping devices.
GF Machining Solutions