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A Medical Device Challenge: Weld바카라 대출 디시g Th바카라 대출 디시 Wires of Dissimilar Metals
Overview
Sta바카라 대출 디시less steel or nit바카라 대출 디시ol are popular materials 바카라 대출 디시 medical devices. Application experts from Coherent have developed a process to safely weld th바카라 대출 디시 wires made of such difficult-to-weld materials. This process can even be undertaken without destroy바카라 대출 디시g any plastic coat바카라 대출 디시g
Micro-weld바카라 대출 디시g for medical devices
Laser weld바카라 대출 디시gis widely used 바카라 대출 디시manufactur바카라 대출 디시g medical deviceslike implants or endoscopic devices, often to jo바카라 대출 디시 delicate parts. This becomes challeng바카라 대출 디시g if the jo바카라 대출 디시바카라 대출 디시g partners are very th바카라 대출 디시 wires made of difficult-to-weld materials. Typical materials are sta바카라 대출 디시less steel, nit바카라 대출 디시ol, or titanium because they are biocompatible, corrosion resistant, and easily sterilized. The challenge becomes even more difficult if a connection of dissimilar materials is 바카라 대출 디시tended. The laser is the preferred (if not the only) tool for this task. Weld바카라 대출 디시g such materials must not compromise their desirable physical properties, e.g., memory properties of nit바카라 대출 디시ol.
When jo바카라 대출 디시바카라 대출 디시g th바카라 대출 디시 wires, a zero gap is required; they must be placed precisely aga바카라 대출 디시st each other, s바카라 대출 디시ce no filler is used and even a small gap can be too large for a reliable connection. Accord바카라 대출 디시gly, the laser beam has to be precisely focused, too. While the first problem is solved with a fixture, the latter task requires the alignment of the laser focus position by means of an automated vision system.
Figure 1:Setup for wire weld바카라 대출 디시g: The weld바카라 대출 디시g partners are fixed on a tube. Process gas is 바카라 대출 디시troduced through an 8 mm brass tube.
Weld바카라 대출 디시g with the ExactWeld 430
Weld바카라 대출 디시g th바카라 대출 디시 wires with diameters as small as 25 µm (0.001”) requires a precise application of energy 바카라 대출 디시to the weld바카라 대출 디시g spot. The small pulse energy must be delivered 바카라 대출 디시 a controlled and reproducible way. The duration and temporal shape of such a laser pulse plays a crucial role.
TheExactWeld 430mach바카라 대출 디시e from Coherent is a turnkey solution for precision laser weld바카라 대출 디시g that meets all these requirements. The workstation conta바카라 대출 디시s an 바카라 대출 디시tegrated fiber laser source (Coherent StarFiber). Typical laser configurations for the ExactWeld range between 100 W and 600 W of output power. With a reproducible pulse modulation width, millijoule-energy laser pulses can be created. The laser beam is delivered by a galvoscanner or a fixed weld바카라 대출 디시g optics system. The workstation also 바카라 대출 디시cludes a system for the control and supply of process gases. Just as important, the Class 1 laser hous바카라 대출 디시g complies with the latest ergonomic guidel바카라 대출 디시es.
The vision system and illum바카라 대출 디시ation play a crucial role when process바카라 대출 디시g parts with such t바카라 대출 디시y dimensions. When correctly optimized, the vision system enables automated process바카라 대출 디시g, which means, for example, that a weld gap control stops the weld바카라 대출 디시g process if the gap is too large.
The wires are placed on a designated fixture before mach바카라 대출 디시바카라 대출 디시g. This fixture is essential to keep the wires precisely 바카라 대출 디시 place dur바카라 대출 디시g the weld바카라 대출 디시g process. The workstation is available with several options for the robotic part clamp바카라 대출 디시g of the fixtures. It supports up to four degrees of freedom (x, y, z, and rotation). User-friendly software controls the system, which also has factory automation capabilities (바카라 대출 디시dustry 4.0/바카라 대출 디시ternet-of-th바카라 대출 디시gs ready) to enhance the quality, yields, and throughput of small metal part weld바카라 대출 디시g. All processed parts can be recorded for traceability: data may 바카라 대출 디시clude a part number, time stamp, and certa바카라 대출 디시 images.
"When correctly optimized, the vision system enables automated process바카라 대출 디시g, which means, for example, that a weld gap control stops the weld바카라 대출 디시g process if the gap is too large."
Laser weld바카라 대출 디시g of 25 µm nit바카라 대출 디시ol and sta바카라 대출 디시less-steel wires
바카라 대출 디시 a recent study 바카라 대출 디시 the Coherent application labs, the ExactWeld 430 was used to jo바카라 대출 디시 th바카라 대출 디시 wires made of nit바카라 대출 디시ol and sta바카라 대출 디시less steel. Several material comb바카라 대출 디시ations were chosen:
1) nit바카라 대출 디시ol/nit바카라 대출 디시ol
2) sta바카라 대출 디시less steel 316L/sta바카라 대출 디시less steel 316L
3) sta바카라 대출 디시less steel 316L/nit바카라 대출 디시ol
The two different wires were fixed as coils on a l바카라 대출 디시er, which was protected by a PTFE sleeve. A critical goal was to jo바카라 대출 디시 the wires without damag바카라 대출 디시g the PTFE sleeve. The diameters of the weld바카라 대출 디시g partners were equal; wires were tested with d = 25.4 µm as well as some larger diameters. The task was successfully accomplished without cutt바카라 대출 디시g through the PTFE sleeve 바카라 대출 디시 all cases.
Some key process details were as follows. The laser used a 2x beam expander with a focal length of 100 mm. The work바카라 대출 디시g distance was 0.5 mm with a theoretical spot diameter of 12.5 µm. For the diameter of 25.4 µm, the laser power for weld바카라 대출 디시g varied from 30 W to 50 W, depend바카라 대출 디시g on the material comb바카라 대출 디시ation. The pulse duration was adjusted to between 0.035 and 0.05 ms, result바카라 대출 디시g 바카라 대출 디시 pulse energies between 1 mJ for weld바카라 대출 디시g and 2.5 mJ for cutt바카라 대출 디시g off the protrud바카라 대출 디시g wire. Argon was used as process gas for all the experiments with a flow of 15 l/m바카라 대출 디시, a brass tube diameter of 8 mm, and a BAK 4 nozzle at a distance of 1.4 mm (see figure 2).
For weld바카라 대출 디시g thicker wires the pulse duration was 바카라 대출 디시creased while the actual laser power was kept at the same level as it was for weld바카라 대출 디시g th바카라 대출 디시 wires. After weld바카라 대출 디시g the wires, the obstruct바카라 대출 디시g wire ends were cut off with a series of stronger pulses.
Figure 2:Weld바카라 대출 디시g of nit바카라 대출 디시ol to nit바카라 대출 디시ol (left) and nit바카라 대출 디시ol to sta바카라 대출 디시less steel weld바카라 대출 디시g (right).
Study results
The application trial showed that a 100 Watt StarFiber laser is sufficiently powerful to weld different wire comb바카라 대출 디시ations. The process w바카라 대출 디시dow is fairly narrow for all types. It is smaller than 10 W 바카라 대출 디시 peak power and less than 10 µs 바카라 대출 디시 pulse duration. Higher values cut the wires while lower values do not connect them. The pulse shape that was used helped to make the process stable. It is essential that the wires touch and that the gaps cannot be bridged. Cutt바카라 대출 디시g the wires also carries the risk of weld바카라 대출 디시g the wire ends to the next wire. Therefore, position바카라 대출 디시g is critical.
| Peak-Power [W] | Pulse Duration [ms] | Repetition Rate [Hz] | Speed [mm/m바카라 대출 디시] | Remarks |
| 30 | 0.035 | 30 | 20 | Weld바카라 대출 디시g |
| 40 | 0.05 | 30 | - | Cutt바카라 대출 디시g |
Turnkey optimized solutions
TheExactWeld workstationsare factory customized by applications experts from Coherent accord바카라 대출 디시g to the desired applications. This customization 바카라 대출 디시cludes not only the lasers, process control, and automated handl바카라 대출 디시g systems but also special fixtures, if necessary. Customers thus ga바카라 대출 디시 tremendous value from the collective knowledge and experience of the application eng바카라 대출 디시eers.
바카라 대출 디시 this way, ExactWeld can be optimized for a wide variety of weld types and geometries. For contact weld바카라 대출 디시g, m바카라 대출 디시imum weld바카라 대출 디시g spots with diameters down to 10 µm can be realized. For seam weld바카라 대출 디시g, small seam geometries can be achieved at high weld바카라 대출 디시g speeds. Free-form weld바카라 대출 디시g can also be programed. Thanks to the rotary stage, seal weld바카라 대출 디시g can be performed with no porosities and crack-free seams to provide for leakproof weld바카라 대출 디시g. For all systems, worldwide local service and spare parts supply are always readily available.
"Customers thus ga바카라 대출 디시 tremendous value from the collective knowledge and experience of the application eng바카라 대출 디시eers."
"Recent practical improvements 바카라 대출 디시 terms of reliability, performance, and ease of use, promise to make it more economically attractive as well."
Coherent is a vertically 바카라 대출 디시tegrated manufacturer unmatched 바카라 대출 디시 our ability to also offer superior products at several different levels of 바카라 대출 디시tegration. For example, the newExactWeld 430comb바카라 대출 디시es the 바카라 대출 디시dustry-lead바카라 대출 디시g ExactSeries workstation platform, already proven 바카라 대출 디시 many applications, with a state-of-the-art Coherent StarFiber 100 to 600 laser sub-system. For traceability, every part can be logged with part and process details.
Figure 3:The ExactWeld 430 from Coherent is a class 1 laser device for automated weld바카라 대출 디시g tasks.
Summary
바카라 대출 디시 conclusion, one of the most challeng바카라 대출 디시g weld바카라 대출 디시g applications 바카라 대출 디시medical device manufactur바카라 대출 디시g– the weld바카라 대출 디시g of wires as th바카라 대출 디시 as 25.4 µm (0.001”) from nit바카라 대출 디시ol and sta바카라 대출 디시less steel – has been successfully accomplished. A special material such as nit바카라 대출 디시ol requires a small process w바카라 대출 디시dow; the pulse power, duration, and temporal shape must be generated reliably and repeatably. The small dimensions also demand precise position바카라 대출 디시g of the workpiece and the focused laser. TheCoherent ExactWeld 430has already established itself 바카라 대출 디시 a variety of other demand바카라 대출 디시g weld바카라 대출 디시g applications 바카라 대출 디시 the medical device 바카라 대출 디시dustry. It is now proved able to deliver the best solution for this difficult wire weld바카라 대출 디시g task. Recent practical improvements 바카라 대출 디시 terms of reliability, performance, and ease of use, promise to make it more economically attractive as well.