Rodriguez t4c Medical Welding Systems
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Transcript of Rodriguez t4c Medical Welding Systems
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MEDICAL WELDING
SYSTEMSAssignment in Industrial ElectronicsRodriguez, Karen Joyce M.
T4C
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WELDING SYSTEMS
WELDING, the fusing of the surfaces of
two workpieces to form one, is a precise,reliable, cost-effective, and high-tech
method for joining materials.
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MEDICAL WELDING SYSTEMS
Three most commonly used welding systems for
medical applications:
1. Orbital Welding
2. Laser Welding
3. Ultrasonic Welding
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ORBITAL WELDING
SYSTEM
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ORBITAL WELDING SYSTEM
In environments that require extremely hygienic
and sterile conditions, orbital welding has been
proven to be an effective method for joining
stainless steel tubing for systems in which
products flowing through them must be free of
contamination.
It has the capability of making smooth, crevice-
free welds that maintain uniformity and
consistency for thousands of joints
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ORBITAL WELDING SYSTEM
Orbital welding, ideal for pipes or round objects
requiring a strong, secure weld, is performed by
contract manufacturers to join components in
medical device manufacturing.
In the continuous orbital welding process, a
welding arc is rotated 360 degrees around an
object, using non-consumable electrodes and
tungsten inert gas to produce clean, low particlecount welds.
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ORBITAL WELDING SYSTEM
Open welding heads use flexible hoses to
supply power, gas, coolant, and filler wire, which
is sometimes required when welding thicker tube
walls or difficult materials.
Closed chamber weld heads are often used on
larger diameters to position the torch precisely
and to securely hold the pipe.
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LASER WELDING
SYSTEM
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LASER WELDING SYSTEM
Two Categories:
1. Macro-scale seam sealing
2. Micro-spot
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LASER WELDING SYSTEM
Macro Welding: Implantable devices
End-effector attachements for surgical tools
Require excellent weld quality with minimal heatinput
Seam Welding of implantable devices requires 300-
600 micron core beam delivery fibers to provide
maximum process stability and weld speed
Key: integration of motion with laser control to create
the contour weld, such that the pulse repetition rate
is tied to the speed, and weld nugger spacing and
energy input are consistent
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LASER WELDING SYSTEM
End-effector attachment is usually a fillet
weld requiring smooth transition between the
two material thicknesses such that no dirt or
debris can accumulate
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LASER WELDING SYSTEM
Micro welding: Reducing spot size, and therefore rapidly increasing
peak power density, is great for drilling applications
but presents significant obstacles for welding
When creating micro-welds, methods of heat sinking
and means to avoid material balling around the joint
are critical.
Balling occurs when the joint material simply melts
and forms a ball under surface tension pulling awayfrom, rather than wetting, the other interface.
Laser needs to operate around 100-500mJ, and down
to as little as 20mJ.
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LASER WELDING SYSTEM
Laser welding of polymers in medical device
manufacturing has special requirements as
related to:
colors of the materials
process control
documentation of the process parameters
The usage of laser-based plastics joining brings
in some aspects which make this joining method
for particular applications advantageous
compared to classical plastics joining methods
like ultrasonic or heat-stamp.
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LASER WELDING SYSTEM
Advantages of laser welding of polymers:
its excellent welding quality
the protected welding zone (inside welding) the clean surfaces (no particles)
the high optical quality of the seam
the minimal thermal load to the work piece
easy designs (flat surfaces e.g.) the contact-free welding process (no deterioration of
the welding quality)
the online closed-loop process control and
documentation.
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LASER WELDING SYSTEM
The colors of the materials involved determine
the degree of the complexity of the process itself.
The laser is used to generate a melt pool in-
between the interfaces.
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LASER WELDING SYSTEM
Except for the welding of two transparent materials, all other
material combinations are joined using a sandwich of a laser-
transparent part on top of a laser absorbent part (Figure 1).
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LASER WELDING SYSTEM
Due to the absorption time and the generation of the melt pool, as wellas for the wetting process of the melt pool onto the transparent plastic,
such a process needs a certain time frame and cannot be done infinite
fast (Figure 2).
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LASER WELDING SYSTEM
The contour welding method is rather slow but allowsthe controlled dosing of the applied heat to the work piece.
The simultaneous welding method, however, is suitedfor fast and high-volume processes, but has thedisadvantages of inflexibility and inhomogeneous heating
along the contour. Mask welding is also inflexible since for each contour a
new mask is needed and it consumes much more laserpower than needed, making the process inefficient.
The quasi-simultaneous welding method combines the
contour welding with a fast galvo-scanning process. Incombination with a pyrometer the quasi-simultaneousmethod allows fast and precise welding with controlledheat and simultaneous storage of the relevant process datafor quality control and traceability.
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LASER WELDING SYSTEM
The various
methods (Figure
3) used in laser-
based plastics
welding.
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LASER WELDING SYSTEM
Laser welding systems used for manufacturing
medical devices are generally automated and
require custom:
Software
Motion
Vision
Tooling
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LASER WELDING SYSTEM
Software Development
Has 2 parts: the graphic user interface (GUI) and
the underlying code
GUI must provide a method for SPC and FDA
data collection
GUI and control code require the user to define
functionality and precisely how and what needsto be seen and controlled
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LASER WELDING SYSTEM
Motion System Encompasses the required positional accuracy
and repeatability and the orientation of tooling
and support structures to allow sufficientaccessibility for welding and loading
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LASER WELDING SYSTEM
Vision SystemAn essential component in medical laser welding
systems
It can offer correction in all three orthogonal axeswithin a predetermined field of view ofinterst
based on stack up tolerances
Lighting for vision, along with software
configuration of what is expected to be seen iscritical to the system reliability
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LASER WELDING SYSTEM
Tooling Use of remote diagnostics via PC and modem
connections permits monitoring and
implementation of modifications
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LASER WELDING SYSTEM
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LASER WELDING SYSTEM
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LASER WELDING SYSTEM
A Classic Product of LaserPlastic Welding:
Ostomy bags of this kindhave been mass produced usinglaser welding since 2003. The
joint line is hidden in the interiorand satisfies the highest hygieneand quality specifications.
Another plus point for lasertechnology in this application is
the minor, easily controllableenergy input. Welding machinesfrom the LQ-Integration seriesare equipped with a pyrometer foronline process monitoring.
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LASER WELDING SYSTEM
99 RNA Sensors in anExtremely Compact Unit:
This laser-weldedmicrofluidic cartridge is partof a complete, highlyspecialized mini-laboratory.
This opens up a whole newrange of opportunities forsurgeries and clinics lackingsophisticated laboratoryfacilities. LPKF was selectedto make this product because
of the specified two-meter-long joint line, particle-freeand additive-free contactsurfaces, complete tightness,and guaranteed channelcross-sections.
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LASER WELDING SYSTEM
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ULTRASONIC
WELDING SYSTEM
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ULTRASONIC WELDING SYSTEM
Ultrasonic welding is an industrial technique
whereby high frequency ultrasonic vibrations are
locally applied to work pieces being held together
under pressure to create a solid-state weld.
It is commonly used for plastics and especially
for joining dissimilar materials.
In ultrasonic welding, there are no connective
bolts, nails, soldering materials, or adhesives
necessary to bind the materials together.
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ULTRASONIC WELDING SYSTEM
It does not introduce contaminants or
degradation into the weld and the machines can
be specialized for use in clean rooms.
The process can also be highly automated,
provides strict control over dimensional
tolerances and does not interfere with the
biocompatibility of parts.
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ULTRASONIC WELDING SYSTEM
Items such as arterial filters, anesthesia filters, bloodfilters, IV catheters, dialysis tubes, pipettes,cardiometry reservoirs, blood/gas filters, face masksand IV spike/filters can all be made using ultrasonicwelding.
Another important application in the medicalindustry for ultrasonic welding is textiles. Items like
hospital gowns, sterile garments, masks, transdermalpatches and textiles for clean rooms can be sealed andsewn using ultrasonic welding. This preventscontamination and dust production and reduces therisk of infection.
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ULTRASONIC WELDING SYSTEM
For joining complex injection molded thermoplastic parts,ultrasonic welding equipment can be easily customized tofit the exact specifications of the parts being welded.
The parts are sandwiched between a fixed shaped nest
(anvil) and a sonotrode (horn) connected to a transducer,and a ~20 kHz low-amplitude acoustic vibration is emitted.
When welding plastics, the interface of the two parts isspecially designed to concentrate the melting process. One
of the materials usually has a spiked energy director whichcontacts the second plastic part. The ultrasonic energymelts the point contact between the parts, creating a joint.This process is a good automated alternative to glue,screws or snap-fit designs.
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ULTRASONIC WELDING SYSTEM
It is typically used with disposable medical tools but it can
also be used on parts as large as a small automotive
instrument cluster.
Ultrasonics can also be used to weld metals, but are
typically limited to small welds of thin, malleable metals,
e.g. aluminum, copper, nickel.
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ULTRASONIC WELDING SYSTEM
Ultrasonic welding of thermoplastics causes local melting
of the plastic due to absorption of vibration energy. The
vibrations are introduced across the joint to be welded.
In metals, Ultrasonic welding occurs due to high-pressuredispersion of surface oxides and local motion of the
materials. Although there is heating, it is not enough to
melt the base materials. Vibrations are introduced along
the joint being welded.
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ULTRASONIC WELDING SYSTEM
The benefits of ultrasonic welding are that it is much fasterthan conventional adhesives or solvents.
The drying time is very quick, and the pieces do not need toremain in a jig for long periods of time waiting for the jointto dry or cure.
The welding can easily be automated, making clean andprecise joints; the site of the weld is very clean and rarely
requires any touch-up work.
The low thermal impact on the materials involved enablesa greater number of materials to be welded together.
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ULTRASONIC WELDING SYSTEM
All ultrasonic welding systems basic elements: A press to put the two parts to be assembled under pressure
A nest or anvil where the parts are placed and allowing the highfrequency vibration to be directed to the interfaces
An ultrasonic stack composed of a converter, an optional booster anda sonotrode . All three elements of the stack are specifically tuned to
resonate at the same exact ultrasonic frequency (Typically 20, 30, 35or 40 kHz)
Converter: Converts the electrical signal into a mechanicalvibration
Booster: Modifies the amplitude of the vibration. It is also used instandard systems to clamp the stack in the press.
Sonotrode: Applies the mechanical vibration to the parts to be
welded. An electronic ultrasonic generator (US: Power supply) delivering a
high power AC signal with frequency matching theresonancefrequency of the stack.
A controller controlling the movement of the press and the delivery ofthe ultrasonic energy.