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Enterprise and innovation alive and well in London.
If
you’ve not already heard of microfluidics, then rest assured
you will, and sooner rather than later too, thanks to enterprising
and innovative companies such as London-based RoBio Systems. So
what is microfluidics exactly? It is probably best described as
the generic technology of manipulating sub-microlitre-scale volumes
of fluids on a chip. Microfluidics exploits precision fabrication
techniques to form fluidic channels and networks, often with integrated
chemical reaction and detection features, to create previously unobtainable
functionality in devices with dimensions of just a few millimetres.
Thanks to its investment in a design-to-manufacturing system that
includes EdgeCAM intelligent solids-based manufacturing software,
RoBio Systems is delivering the rapid design iterations and fast
turn-round times that its customers require.
 RoBio
Systems Limited.
RoBio Systems was formed in 2004 as a microtechnology
company that provides engineering consultancy, product design, prototyping
and manufacturing for the biology and biotechnology industries.
The RoBio Systems team already had a proven track record in microfluidics
since the founders of the company - chemists, biologists and engineers
- all carried out pioneering work in the field as members of the
Bio and Chemical Instrumentation group at CRL, formerly the Thorn
EMI Corporate Research Laboratories.
Flexibility is of the essence.
Bryan Miller is Fabrication Technologies
Engineer at RoBio Systems. He says, “We are primarily concerned
with developing microfluidics devices that handle biological samples,
developing them into products not available elsewhere in the market.”
Bryan explains, “Many of our designs are based on moulded
PDMS (silicone rubber) bonded to glass. We create master moulds
with multiple machined microscopic cavities into which we inject
silicone to make the actual devices. The mouldings generally comprise
a network of channels tens of microns deep, connecting multiple
ports and wells formed by upstands. These often have complex geometries
and have precise dimensions to give accurate mould closure. The
mouldings are then plasma-bonded to glass such as a microscope slide.
A non-contaminating joining technique like this is vital in biological
applications.” He continues, “For our major client,
flexibility is of the essence. That is why we do everything in house:
concept design and testing, prototyping and manufacturing. Our strength
is the ease with which we iterate designs, being able to make, test
and review a new design idea on as short as a two day cycle. This
leads to faster and lower-risk design development.”
Knowing exactly what to look for.
Bryan Miller again, “I guess you
could call us educated users. Because of our previous experience we
knew exactly what to look for when setting up RoBio Systems and we
budgeted for this from the outset.” Bryan points out, “The
complex central zone of our devices contains all our ingenuity and
the only effective way to design it is in 3D. For that we chose SolidWorks.”
He continues, “We then looked for a CNC solution that was intuitive
and easy-to-use and would be up and running quickly on company start
up. In order to meet our turn-round times, the CNC software would
also have to work seamlessly with SolidWorks models without translation
or intervention. It would have to drive our Kern high precision micro
milling machine, too.”
Demonstrating the importance of 2D/3D integration.
According to Bryan, “We researched
the possibilities through the Internet and various message boards
and forums. Rejecting expensive software that was rated as complicated
to use, eliminating low cost software with limited functionality and
poor support, we reduced our list of ten potential suppliers to just
two: EdgeCAM and one other. We downloaded and tried time-limited evaluation
versions of both and invited the suppliers to demonstrate to us.”
He continues, “At the formal EdgeCAM demonstration, we saw the
integration of 2D and 3D, important to me because much of what I need
to do to complete the mould, adding alignment pins, silicone inlet
ports and so on, is best done in 2D.” Bryan adds, “Simulation
was vital, too. Because of the extremely fine machining involved,
we needed to be absolutely certain that the programmes would run correctly.
Previous CAM software I’d used let me down in this respect and
I did not want a recurrence.
 Free-standing
EdgeCAM works seamlessly with SolidWorks.
There were other factors to consider,
as Bryan points out, “Working on very fast turn-round, we needed
separate seats of design software and machining software so that the
designer and the manufacturing engineer could work on the same part
simultaneously. EdgeCAM was completely free-standing but the alternative
we looked at required its own dedicated copy of SolidWorks to get
the same functionality. Had we gone that way, it would have added
significantly to the cost of the solution.” In Bryan’s
experience, “Another important point: EdgeCAM, a SolidWorks
Certified CAM product, was more windows-compliant and easier to use
than the alternative we looked at.”
EdgeCAM Code Wizard saves the day.
The decision was made: EdgeCAM Solid
Machinist. Bryan explains, “It all came down to the quality
of the EdgeCAM solution. The difference in cost between the different
packages didn’t make a huge difference.” He comments,
“EdgeCAM has proven to be very easy to use. I can use simple
pre-set blocks operations or I can define for myself every element
of the toolpath.” Bryan continues, “The software was installed
over a year ago. I familiarised myself with it, then took the training,
which, by the way, was spot on. Since then we’ve produced up
to 20 programs and changes a day.” He adds, “We’d
chosen a KERN Micro high precision five axis micro-milling machine
because of its better than ± 1 micron precision, though in
the interim, we hired a Datron mill. That meant I had to face the
problem of buying two post processors, but EdgeCAM’s no-cost
Code Wizard post-processor generator saved the day.” Bryan says,
“I had expected that the process would be complicated, but it
wasn’t, far from it. No other CNC software we looked at had
anything like it.”
EdgeCAM/SolidWorks associativity reduces time to manufacture.
RoBio Systems produces hundreds of designs
a year with many and frequent design iterations. “With this
solution,” says Bryan, “Malcolm Austen, our Head of Design,
can be using SolidWorks to design the ‘business end’ of
our designs whilst I can be working on the same part using EdgeCAM.
Thanks to the associativity between the two, I am immediately alerted
to changes that Malcolm has made to the model and offered the option
to regenerate the toolpath or not. Doubling up in this way significantly
reduces our time to manufacture.”
No more tool gouges.
By using EdgeCAM, Bryan has been able
to eliminate the tool gouges that plagued him at CRL. He says, “There,
we’d find we could machine the part correctly, but because of
the extremely small size of the features, we’d get to the end
of the machining cycle only to find the features may have been machined
over on tool entry or exit. When this happened, we’d have to
use all our ingenuity to adjust the programme. We’d also get
frequent programme crashes if we were making a single mould with repeated
and identical cavities.” He adds, “It was a time problem
rather than a material cost problem. We could lose valuable hours
getting programmes right. Now, we have no such problem. Not only does
EdgeCAM work properly in this respect, we can properly simulate the
toolpath, manipulating the part and zooming in so that we can get
a really good view of what was going on.” Bryan is certain,
“The time we’ve saved through eliminating tool gouges
has enabled us to do much more machining than we used to. The effect
of errors? I don’t actually get any.”
EdgeCAM is a massive leap forward.
Summing up, Bryan says, “We’d
never actually heard of Pathtrace until we started looking. We found
they were very professional and knew their stuff. Thanks to the
combination of SolidWorks, EdgeCAM and Kern we are now able to make
anything we design. EdgeCAM alone has driven out many hours from
the process compared with the previous software I’d used.
Another important factor is the ease with which we will be able
to upgrade to simultaneous 4 and 5 axis, something we will need
to do as our designs evolve.” Bryan concludes, “Pushing
the accuracy envelope, we have complete confidence that a 20-micron
deep channel in an SW model will also be a 20-micron channel in
the finished part. Our customers are very impressed with what we
have delivered, a testimony to our whole approach. “EdgeCAM
is a massive leap forward. I can’t fault it in any way.”
www.kern-microtechnic.com
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